hazerdous_earth_2_0_2025_05_22_071653 Flashcards

Question

Features of lava at *divergent* boundaries

Answer 1

bcdefType: *Basalt* (runny)Acidic/basic: *Basic*Silica content: Low (thin, milk-like)Temperature: HighViscosity: Low (runny)Frequency: HighDuration: Often

Answer 2

bcdefBasic lava is runny (has low viscosity)

Answer 3

Runny basaltic rock creates *pillow lava* formations (round igneous rocks) - eruption of magma occurs mostly underwater. Magma erupting directly onto sea bed is rapidly cooled which forms pillow lava.*Lava plateaux*, e.g. Giant's causeway.*Mid-ocean ridge* formed by new crust (long chain of underwater mountains).Low, flat *shield volcanoes* formed by runny lava.*Rift valley*

Answer 4

Very long chains of mountains on the sea floor.Altogether have a combined length of 60,000km.At intervals, ridges are broken by *transform faults*.Vary in shape depending on rate of spreading (determined by amount and rate of magma rising).

Answer 5

What is a mid-ocean ridge?

Answer 6

*Transform faults*Small, shallow-focus *earthquakes* occur along their lengths as they slip.

Answer 7

Large-scale faults in the crust at right angles to a mid-ocean ridge, which can displace the ridge laterally by tens to hundreds of km. Volcanic activity is absent along transform faults as it is on a conservative margins, but as they slip energy is released in the form of earthquakes

Answer 8

bcdefLave flows far which forms low, gently sloping volcanoes.Runny basic lava erupts gently.Less viscous lava flows far (flows easily).Creates wide, gently sloping volcanoes.

Answer 9

(Rift valleys are found on land and at the bottom of the ocean) Divergent plate boundaryRising magma creates dome/bulge.Plates continue to spread.Brittle rocks fracture and fault.Dome subsides (sinks) forming a steep-sided valley.E.g. African rift valley (African plate splitting apart).

Answer 10

bcdefContinental crust must be thin for rifting to occur.E.g. Red Sea northwards to Turkey:Crust has been stretched, causing faulting and forming a sunken valley known as a *graben*.As rift widened, magma erupted to surface.Eventually rift valley sank below sea level, forming the present-day Red Sea.

Answer 11

bcdefOceanic-continentalOceanic-oceanicContinental-continental (collision)Plates have different densities.Continental: 2.6-2.7kg m^3Oceanic: 3.0kg m^3

Answer 12

bcdefNazca plate -> South American plate

Answer 13

bcdefConvection currents cause plates to converge.The denser oceanic plate subsides beneath the less dense continental.*Slab pull* accelerates movement of oceanic plate.

Answer 14

bcdef1. Plates push together by convection currents.2. The more dense oceanic crust subducts beneath the less dense continental crust.3. Friction from plates rubbing together heats plates. Water from the ocean helps crust melt forming viscous acidic magma. Pressure builds up causing deep and shallow *earthquakes*.4. Magma forces through continental crust (viscous lava has explosive eruptions).5. *Slab pull* pulls subducting plate faster.*Volcanoes* and *fold mountains* are formed near the edge of continental crust.

Answer 15

bcdefSubduction brings *volatiles* (water + CO2) which cause melting of rock.

Answer 16

convergentacidic lava, so high silica content, high viscosity, lower temperature at eruption violent eruption, vent and top of cone often shatteredmaterials erupted: gas, dust, ash, lava bombs and tephralow frequency of eruptionshape (already know from other flashcard)

Answer 17

Acidic lava has a high silica content which makes it viscous (thick). Therefore it does not flow easily so builds up steep *composite volcanoes* (layers of rock and *tephra*).

Answer 18

Pressure builds up over long periods of time due to high viscosity and slow flowing magma.

Answer 19

Description:Cone-likeSteep-sidedHave a crater at the topComposite (made up of layers)Have secondary ventsLayers of ash and acid lava built up over successive eruptions.Lava intrudes into layers, forming *sills* (horizontal intrusion of magma) and *dykes* (vertical intrusions of magma). Vents of volcano can be sealed by solidified magma/lava (*plug*).This causes pressure to build up, resulting in explosive eruptions.Magma erupts violently as air bubbles finally burst.Throws droplets of lava as *tephra* and *lava bombs*.E.g. *Mount Etna, Italy*

Answer 20

bcdefDescription:BasinExplosive eruptions empty the magma chamber beneath the volcano.The lack of support beneath causes the volcano to collapse on itself, forming a caldera crater.Collapsing of volcano's sides can cause *tsunamis*.E.g. *Krakatoa, India*

Answer 21

bcdefTwo plates being pushed into one another which builds up immense amount of pressure.Faulting and fracturing takes place in the *benioff zone*.Causes pressure and energy to be released which creates earthquakes.

Answer 22

The boundary between the subjecting ocean plate and over-riding continental plate.Seismic energy is released here as rocks fault and fracture.

Answer 23

Slightly denser plate will be subducted.

Answer 24

bcdef*Ocean trench* where the denser plate subducts.E.g. *Mariana trench* nearly up to 11,000m deep.*Island arcs*. As descending plates melt, magma is produce and rises to surface. Eruptions form chains of strato volcanoes.E.g. *Mariana islands* up to 820m above sea level.

Answer 25

bcdef1. Convection currents push crust together.2. Denser oceanic crust subducts under less dense oceanic crust. This movement is speedened up by slab pull 3. Forming an *ocean trench* at the area of subduction.4. *Volatiles* help descending crust to melt and forms magma which rises and erupts forming *island arcs*.5. Composite volcanoes are formed from viscous acidic lava.

Answer 26

bcdefCreates deep *ocean trenches* and tall mountain ranges (*island arcs*).

Answer 27

Explosive eruptions form:*Strato (composite) volcanoes* made up of layers of tephra and acidic lava which contain complex internal systems which create *dykes* and *sills* underground.*Caldera craters* which appear as a large crater, group of small islands or as a large lake.

Answer 28

bcdefFault lines and cracks can occur in crust as energy from earthquakes

Answer 29

*Himalayas* (Indian plate <-> Eurasian plate)

Answer 30

Because they collide.They move together but aren't dense enough to subduct.

Answer 31

2 continental plates converge.Little, if any subduction occurs due to similar densities.Accumulated sediments are compressed into rock which buckle and fold forming *mountain ranges*.

Answer 32

Convection currents push plates together. However they move slower because there is no slab pull or ridge push to accelerate movement.

Answer 33

bcdefFriction builds up at the collision zone. Rocks crack and fault and when pressure reaches the threshold energy is released as an earthquake.Earthquakes are usually have a shallow focus and are of moderate strength. E.g. Nepal, 2015 (7.0MW)

Answer 34

Fold mountain chains are formed - the Himalayas formed due to the collision of the Indian and Eurasian tectonic plates began 50 million years ago and continues today, apporx 2,500 km in lengthLoss of ocean floor due to tectonic uplift.Cracks and faulting in rocks.Synclines and anti-synclines (bending of rock).

Answer 35

bcdef*San Andreas Fault* California

Answer 36

Crust is neither created or destroyed, just conserved (slide past each other).

Answer 37

bcdefPlates move past each other.Pacific plate (LA) moves north west by 5-9cm /year.North American plate (San Fran) moves north west by 2-3cm /year.*Slab pull* as crust subduct at different boundaries.Difference in rate means North American plate moves south-east in relative terms.

Answer 38

bcdefNo subduction or spreading occurs.Rock doesn't melt.Therefore no formation and pressure build up of magma.

Answer 39

- Plates do not move steadily (they move intermittently).- Plates rub against each other creating frictional resistance and they sometimes get stuck.- Pressure gradually builds up until it reaches the threshold.- Rocks fracture and energy is released as shallow-focus earthquakes. Plates move in a 'jolt'.Rocks move suddenly and energy is released as shallow-focus, high magnitude earthquakes, causing a large amounts of surface damage

Answer 40

bcdefShallow-focusHigh magnitudeLateral movements (plates move past one another) (P and love waves)

Answer 41

- Do not create large landforms. - in some places it is possible to discern active plate boundaries extending through the landscape like a giant tear. - Landforms across the faults can also be displaced.e.g. River channels deflected by movement of faults, effecting drainage- Can create major faults across landscapes (San Andreas Fault): The fault zone is marked by distinctive landforms that include long straight escarpments, narrow ridges, and small undrained ponds formed by the settling of small blocks within the zone. Many stream channels characteristically jog sharply to the right where they cross the fault.

Answer 42

Hawaiian islandsMiddle of pacific plate

Answer 43

A particularly hot section of mantle. This can melt through the crust causing volcanic activity. Hot spots usually occur away from plate boundaries. Some are found at plate boundaries, e.g.Iceland.

Answer 44

bcdef1. Plume of particularly hot mantle.2. Melts through crust forming volcano and island.3. Movement of plate transports volcano away from hot spot. 4. Volcano becomes extinct. New volcano formed at hot spot. Oldest (smaller) island: Kauai (formed 3.8 million years ago)Newest (bigger) island: Hawaii (big island) Some 30km from the big island the next volcano in the chain, Loihi is rising up from the ocean floorCrust moves away from hot spot so it cools and becomes denser making it subside (sink), and becomibg underwater mountains or seamountsIslands have been *eroded* by waves, weathering and mass movement making the older islands much smaller.

Answer 45

*Shield*, gently sloping, wide volcanoes.Because basaltic lava is less viscous meaning it flows easily and flows further.*Effusive eruptions* build huge volcanoes.

Answer 46

bcdefThey are caused by a build-up of pressure and movement of ground due to volcanic activity.Small earthquakes, generally shallow focus FrequentCaused by movement of magmaMost where hot spot it (Hawaii).

Answer 47

*Hot spot volcano chain*- Magma activity at hot spot- Basic lava- Effusive- Shield volcano- Formed in a sequence- Big age difference*Island arcs*- Magma activity (subduction and volatiles)- Acidic lava- Explosive- Strato volcano (composite)- Closer together in age, less variation as they are formed together.

Answer 48

*Yellowstone, Wyoming*North American plate

Answer 49

A volcano that erupts more than 1000km^3 of material in a single eruption.Are usually found as giant *calderas*.They occur when rising magma cannot break through crust.Pressure increases as more magma rises until magma violently forces its way through as a huge eruption.

Answer 50

bcdef*Basic* (Basaltic) Lava is free-flowing and can run for considerable distances.*Acidic*Thick, pasty lava doesn't flow easily. Everything in the path of lava is burned/buried destroying infrastructure/properties/crops.Rarely cases injuries/fatalities because people can escape the flow.

Answer 51

Combination of hot gases (500degC+), ash and rock fragments travelling at high speeds (100km/hr). Follow contours of ground and destroy everything in path.Inhalation of hot, poisonous gas can result in almost instant death.

Answer 52

tephra: Any material ejected from volcano into air.includes Fine ash/volcanic bombs.Buries farmland, destroying crops, disrupts transport on ground and in air.Iceland's volcanic eruption (2010) led to cancellation of 100,000 flights due to ashBuilds can collapse due to weight of accumulated ash.People with respiratory diseases have difficulty breathing. A significant hazard due to the long term damage it causes to infrastructure.

Answer 53

Effects of Gas Emissions: Deadly Threat to Humans: High concentrations of CO₂ can displace oxygen, causing suffocation (e.g., Mammoth Mountain, USA—CO₂ emissions from volcanic activity have caused tree die-offs and pose a risk to humans).CO is highly toxic and can cause poisoning. Acid Rain Formation: SO₂ combines with atmospheric water to form sulfuric acid (H₂SO₄), leading to acid rain.Example: Mount Pinatubo (1991)—released SO₂ that caused acid rain, damaging crops and water sources. Environmental Damage: Acid rain increases rock weathering, affecting buildings and historical monuments Soil and water pollution harm ecosystems and agriculture (e.g., Laki eruption, Iceland (1783)—caused crop failures and famine across Europe). very most significant hazard, as it often does undetected, l

Answer 54

bcdefType of mud flow (consistency of wet concrete).Travel up to 50km/hr.Destroy/bury everything in it's path.Eruption in Columbia (1984) killed 23,000 due to lahars.

Answer 55

bcdefVolcanic eruptions beneath ice field/glacier results in rapid melting. Iceland's volcano lies beneath ice and snow.Eruptions cause vast quantities of water to accumulate until it finds an exit.Results in torrents of water, can cause devastating floods.

Answer 56

bcdefEruptions of island volcanoes cause displacement of ocean water creating tsunami waves that travel up to 600km/hr. Tsunamis created by eruption of Krakatoa in 1883 believed to have drowned 36,000 people. Although these kill significant amounts of people, they are an infrequent hazard of volcanic eruptions, so is less significant than the hazards that occur with every eruption.

Answer 57

bcdefA measurement used to rank and compare different volcanic eruptions using:- volume of erupted material.- height the ejected material reaches.- duration in hours.- qualitative measures ('gentle', 'mega-colossal').

Answer 58

The release of stress that has built up within the Earth's crust caused by tension, compression or the shearing of rocks.Release of energy causes *seismic waves* to be released from the *focus*.

Answer 59

bcdef*Focus* point at which waves originate from (point where stress is released).*Epicentre* directly above the focus (where most severe impacts will be).*Seismic waves* energy released travels as waves.*Fault line* where movement in plates occur.

Answer 60

bcdef*Mid-ocean ridge* (divergent boundary)/*rift valleys* (constructive boundary)*Ocean trenches* (convergent boundary)/*island areas* (destructive)*Collision zones* (convergent)*Conservative margins* (conservative)*Away from plate margins*

Answer 61

0-70km deepOccur in cold, brittle rock resulting from fracturing of rocks due to stress within the crustVery commonReleasing low levels of energyHigh-energy, shallow quakes are capable of causing severe damage Shallow earthquakes cause the most damage.

Answer 62

70-700km deepIncreasing depth = extreme temps/pressures Rarely cracks rock - strong but does less damage

Answer 63

bcdef*Primary (P) waves*Fast-travellingLow-frequencyCompressional wavesVibrate in the direction they're travellingTravel through Earth's interior (through solids and liquids)*Secondary (S) waves*Half the speed of P wavesHigh-frequencyVibrate at right angles to the direction they're travellingCannot pass through liquids (so cannot travel through outer core)*Surface (L) waves*Slowest wavesLow-frequencyRolling movements that move the surface verticallyTravel through outer crust only

Answer 64

*Richter scale*Measure of *energy released* on a logarithmic scale (each whole number represents a 10-fold increase in amplitude).Largest record quakes are magnitude of around 9.Doesn't measure damage (partly determined by magnitude but also by population density and level of preparedness). *Modified Mercalli Scale (MMS)*Qualitative measure of *damage experienced* related to ground movement (impacts felt and seen by people). Attempts to measure both intensity and impact.Based on observation and description. *Moment magnitude scale (Mw)*Measures energy released more accurately than Richter. Measures amount of movement of the ground - a direct function of energy. Accurate for large earthquakes but not useful for smaller ones.

Answer 65

Positive correlationStronger earthquakes = more energy = more damage

Answer 66

bcdefMeasures direct energy that causes ground movement so can be used to predict damage.

Answer 67

Associated with formation of *mountain ranges* (e.g. Himilayas) at *collision boundaries*. Collision of India and Eurasian plates led to complex pattern of folding and faulting of rocks creating the world's highest fold mountains: 96/109 of world's peaks >7000m located here. * Rift valleys* *along mid-ocean ridges* (e.g. East Africa - evidence of earthquakes on morphology of Earth's surface)*Fault scarps* and *escarpments* of rift valleys mark locations of faults caused by tension and compression within crust. Rift valleys are weathered and eroded so over time fault scarps are worn away and blend into landscape, can even disappear under accumulated sediments.

Answer 68

bcdefEvery year, around 100 earthquakes with potential to impact significantly.2000-2015: estimated 800,000-900,000 killed by earthquakes.

Answer 69

Vertical and horizontal movement of ground. Severity depends on: - Earthquake magnitude - Distance from epicentre - Local geology Close to epicentre of high-mag quakes with unconsolidated surface layers with high water content will experience extreme shaking. Swaying of buildings impacts their stability Displacement of rocks along fault lines can: - Rip apart pipelines and sewers - Sever rigid structures (railway tracks and roads) - Cause building collapse - Disrupt drainage systems (diverting streams and rivers, affecting movement of aquifers) - can have serious implications for public water supply and irrigation for agriculture.

Answer 70

Vibrations of quake cause surface materials with high water contents (fine-grained sands, alluvium, landfill) to behave like liquids.Materials loose strength; slopes (river banks) collapse and structures tilt and sink as foundations give way. One of the smallest hazards, as it doesn't pose a huge risk to human life, only infrastructure. Japan 2011 earthquake - soil liquefaction occurred over a large area. Some 27,000 structures sank or tilted, causing massive damage

Answer 71

bcdefShaking loosens lopes on mountains causing slope failure. E.g. Himilayas - unstable/vulnerable (increased by deforestation and monsoon rains) even small tremors can cause landslides.Nepalese quake (2015) triggered multiple landslides and avalanches caused by ground shaking.- Block transport routes where accessibility is already difficult.- Block rivers - natural dams create temporary lakes which lead to flooding when dam fails.

Answer 72

Underwater earthquakes Cause *sea bed uplift* - displaces water above, producing powerful waves at surface which spread outwards from epicentre. Wave height increases as they approach shoreline and shallower water. Local height of wave affected by shape of sea bed and coastline. *Underwater landslides* When large volume of rock displaced underwater it slumps down, displacing water, creating a wave which radiates outwards. One of most significant hazard presented by earthquakes due to the scale of the impact, particularly for low-income areas with poorly structured buildings and ineffective warning systems.

Answer 73

USA, HAWAII, 2018 (AC) INDONESIA, 2010 (EDC) DRC, 2021 (LIDC)

Answer 74

Active*: erupted within the last 10,000 years.E.g. Kilauea (Hawaii) erupting continuously since 1983. *Dormant*: has not erupted in last 10,000 years, expected to erupt some time in future.E.g. Yellowstone erupted 70,000 years ago. There are ongoing earthquakes, geothermal features such as geysers and ground inflation). *Extinct*: not expected to erupt ever again.E.g. Kohala (Hawaii) erupted 120,000 years ago.

Answer 75

JAPAN, 2011 (AC) MEXICO, 2017 (EDC) NEPAL, 2015 (LIDC)

Answer 76

Location: - East Asia, Japan - Tohoku - northern region of main Island of Japan - - Honshu Island. - 70km offshore - North part of main island Tectonic context: - Convergent (destructive) oceanic - continental plate boundary - Pacific (oceanic) subducts beneath Eurasian (continental) - 9.0Mw (BIG)- Shallow focus earthquake (30km deep) - 11th March, 2011- Numerous aftershocks (7.0-8.0Mw)

Answer 77

Perception of risk - Investment in education/engineering builds feeling of security. - Experiences 400 earthquakes each day (most can't be felt) - minor earthquakes help Japanese feel accustomed to these hazards. - Earthquakes and their effects are part of Japanese culture and folklore. - Small geo-thermal power plants since the 1960's. - There has been an attempt to increase the scale of operations especially in the wake of the Fukushima nuclear meltdown. - Intensive agricultural industry made possible by extremely fertile volcanic soils. - Volcanic activity has become a major tourist attraction in Japan.

Answer 78

Largest ever recorded earthquake to hit Japan (9.0Mw). Shaking lasted 3-7 minutes. Many aftershocks.7.0-8.0Mw Tsunami waves created.Reaching up to 40.5m tall (far higher than sea defences).Travelled 10km inland (reaching the city of Sendai).Waves reached Antarctica and USA. Earthquake nocked out power supply to Fukushima Nuclear Power Plant.Tsunami flooded back-up generators and triggered nuclear meltdown in three reactors. 400km stretch of coastline dropped 0.6m vertically.Honshu island moves 2.4m east.

Answer 79

Cost of the event estimated at nearly $181 billion. Just less than 50,00 buildings destroyed; around 140,000 damaged. 15 ports damaged, 4 destroyed. 4.4. mullion households and thousands of businesses in northeast Japan were left without electricity. Japanese stock market fell - major companies affected (Sony, Toyota, Panasonic) as power cuts halted production and port damage prevented export of goods. Fishing industry affected as radioactive wast contaminates Pacific Ocean Farmland flooded by tsunami contained by salt - land made infertile. Fukushima nuclear power plant had to be decommissioned after meltdown.

Answer 80

16,000 people were killed and 6,000 injured. Bodies disposed of in mass graves to reduce the chance of disease. Extent of damage meant reconstruction of house, schools and health centres took 5 years. 5,800 people evacuated and permanently relocated from fallout zone following fukishima

Answer 81

Government increased national debt to help recovery efforts; spent billions of yen to stabilise economy. A large movement against nuclear power has developed and spread globally. The government is yet to decide on the future of nuclear power. International travel advice against visiting Japan (USA, France, Australia).Foreign residents (e.g. international students) left the country.

Answer 82

Risk (R) = (HxV)/CH - *Frequency* or *magnitude* of hazardV - Level of vulnerabilityC - Capacity of population to cope and adapt *(H)*Frequent hazards would increase risk because...- People do not have time to recover from previous hazard (they're still vulnerable).- Regular disruption would limit economic/social development.- Reduce investment in an area.Stronger hazards would increase risk because...- More energy causing more damage (more likely to be devastating).- Less likely to mitigate successfully against unusually high magnitude hazards.* (V)*Vulnerability = whether people have to ability to *withstand* hazards.More vulnerable people are at greater risk from hazards because small changes can have significant socio-economic impacts.E.g. Subsistence farmers losing an area of crops are severely affected. Large landowner with same proportion of land affected would be less severely affected. # *(C)*More resilient populations are at less risk because...- Reduces damage done my hazard.- Able to afford better mitigation strategies.

Answer 83

: Sea-floor spreading occurs at divergent plate boundaries, where new oceanic crust forms as tectonic plates move apart. This process leads to the creation of mid-ocean ridges, volcanic activity, and can trigger seismic events along the ridges.

Answer 84

: Slab pull occurs when a denser oceanic plate subducts beneath a less dense continental plate. As the oceanic plate sinks into the mantle, it pulls the rest of the plate along, driving tectonic plate movement and contributing to volcanic and seismic hazards.

Answer 85

: Hotspots are areas of intense volcanic activity caused by plumes of hot material rising from deep within the Earth’s mantle. These plumes remain stationary while tectonic plates move over them, forming chains of volcanic islands (e.g., Hawaii, Iceland).

Answer 86

: Social factors like population density, education, and preparedness influence how vulnerable a community is to tectonic hazards. For example, densely populated areas or those with limited resources may face higher risks due to poor evacuation systems or lack of infrastructure.

Answer 87

: Wealthier communities are generally better equipped with infrastructure, technology, and emergency response systems, making them more resilient. Poorer areas may lack these resources, leading to slower recovery and greater loss of life.

Answer 88

: Political factors like governance, disaster response preparedness, and international aid can significantly influence how well a community can prepare for and recover from tectonic hazards. Strong governance systems ensure effective mitigation, response, and recovery efforts.

Answer 89

: The Park’s Model illustrates the stages of disaster response. It shows the initial relief phase after a hazard, followed by recovery and reconstruction. It also compares the pre-disaster situation with post-disaster recovery, with an emphasis on vulnerability reduction over time.

Answer 90

: The Hazard Management Cycle is a continuous process involving:Mitigation: Reducing the likelihood and impact of disasters (e.g., building codes).Preparedness: Planning for disasters and educating the public.Response: Immediate actions after a hazard (e.g., rescue operations).Recovery: Long-term rebuilding and recovery efforts.

Answer 91

.... suggests that a disaster occurs when a hazard intersects with a vulnerable population. The severity of the disaster is a function of the hazard's magnitude and the population's vulnerability (e.g., lack of preparedness or resources). Whose model is this?

Answer 92

What is Degg’s Model of disaster?

Answer 93

....... explain how people perceive and respond to risks. Factors like personal experience, media influence, and cultural beliefs shape how individuals and communities understand and prepare for hazards. For example, people living near active volcanoes may perceive the risk differently than those far away.

Answer 94

What are the hazard perception theories?

Answer 95

: The 2010 Haiti earthquake killed over 230,000 people. Haiti's vulnerability was due to factors such as extreme poverty, poor infrastructure, lack of effective governance, and a dense population in Port-au-Prince. These factors resulted in a catastrophic loss of life and delayed recovery.

Answer 96

: Japan’s 2011 earthquake had significant impacts, but Japan’s advanced warning systems, strict building codes, and government response allowed for quicker recovery compared to countries with less preparation. Japan’s resilience was also aided by its high levels of wealth, technology, and infrastructure.

Answer 97

: Secondary hazards include:Tsunamis: Triggered by underwater earthquakes or volcanic eruptions (e.g., Japan 2011 tsunami).Landslides: Often caused by ground shaking during an earthquake or volcanic eruption.Fires: Can occur after an earthquake, especially in densely populated areas with gas lines.

Answer 98

Ridge push occurs at divergent plate boundaries, where new oceanic crust forms at mid-ocean ridges. As the crust cools and becomes denser, it slides down the slope of the ridge, pushing the older, neighbouring plate away from the ridge. This process drives the movement of tectonic plates.

Answer 99

Basic (or basaltic) lava, which is low in silica, is produced at divergent boundaries due to the upwelling of mantle material that is less viscous, allowing it to flow easily. In contrast, acidic (or andesitic) lava, which is high in silica, forms at convergent boundaries where subducted oceanic plates melt and the resulting magma is more viscous, leading to explosive volcanic eruptions.

Answer 100

Upper mantle is made up of: lithosphere (uppermost part) and aesthenosphere

Answer 101

Several years before the disaster warnings had been made about the poor defences that existed at nuclear power plants in the event of a tsunami. A number of executives at the Fukushima power plant resigned in the aftermath of the disaster. A movement against nuclear power, which Japan heavily relies on, developed following the tsunami. The disaster at Fukushima added political weight in European countries were anti-nuclear bodies used the event to reinforce their arguments against nuclear power.

Answer 102

Increased rainfall: Heavy rainfall can trigger landslides in earthquake-prone regions, especially after tremors. For example, after the 2015 Nepal earthquake, intense monsoon rains caused numerous landslides and avalanches, exacerbating the devastation.Melting glaciers: Glacial lake outburst floods (GLOFs) pose an increased risk in seismically active regions. For example, the 2010 GLOF in Nepal (caused by glacier melt) worsened the impact of the earthquake damage.Rising sea levels: Rising sea levels increase the potential impact of tsunamis. Tsunami Japan 2011 had devastating impacts and rising sea levels today make such events more destructive.

Answer 103

Warmer temperatures: Increased storm frequency can enhance lahar flow. After the Mount Pinatubo eruption in 1991, heavy rains in the Philippines triggered devastating lahars that affected over 200,000 people.Increased rainfall: In 1998, the eruption of Mount Rabaul (Papua New Guinea) combined with heavy rains, causing massive lahars that destroyed crops and infrastructure.Melting glaciers: The 1991 eruption of Mount Nevado del Ruiz (Colombia) released volcanic ash and melted glaciers, creating lahars that buried the town of Armero, killing around 23,000 people.

Answer 104

A rift zone is a region where the Earth's crust is being pulled apart due to tectonic plate movement, leading to the formation of faults, fissures, and volcanic activity.

Answer 105

A graben is a down-dropped block of crust between two parallel normal faults. It forms when the central section of the rift valley sinks further due to continuous stretching. Does a Graben Always Form?Not always. A graben forms if faulting is intense enough to cause a large, distinct down-dropped block.Some rift valleys may form through a series of step faults instead of a single graben.

Answer 106

ankipro Mexico City’s proximity to fault lines: Despite being located near the Cocos and North American plates, Mexico City remains one of the world's largest urban areas, with a population of over 21 million people.Earthquake preparedness and building regulations: After the 1985 earthquake, Mexico City invested in seismic-resistant infrastructure, improving safety.Cultural and economic significance: Mexico City is a cultural and economic hub, contributing around hundreds of billions to Mexico's GDP. The city's historical and cultural sites attract millions of visitors annually, making it an appealing place to live.Agricultural benefits: The fertile volcanic soil, especially near active volcanoes like Popocatépetl, supports agriculture and is vital for food production in the region.

Answer 107

- As Nepal is a LIDC, many residents will not have the resources to move away or are incapable of doing so due to poor infrastructure - Lack of education, large earthquakes are not frequent (around every 40 - 80 years) so people may not realise there is a threat - Subsistence farming is very prominent in Nepal's economy, farmers may have large plots of land and do not wish to leave -Family tradition/historical/cultural reasons for remaining in the area

Answer 108

ankipro Magnitude 8.1 earthquake on September 8, 2017: The earthquake killed 98 people, injured over 1,000, and caused widespread damage in Oaxaca, Chiapas, and Tabasco.Tsunami waves: The earthquake generated 1-meter tsunami waves along the Pacific coast, causing flooding and damage in coastal towns.Infrastructure damage: Over 12,000 buildings were damaged, and approximately 2,000 homes were completely destroyed.Economic losses: The total economic loss was estimated at $1.5 billion, including damage to homes, infrastructure, and businesses.Evacuations: About 5,000 people were evacuated from high-risk zones, primarily in Oaxaca and Chiapas.

Answer 109

9,000 people died and left 22,309 others injured.- Many people had to move to temporary shelters, likely to enhance the spread of disease- nearly half a million homes were destroyed,- Several culturally important locations were lost such as the Dharahara tower- Single women were disadvantaged for aid as most aid was controlled by men, inequalities - An avalanche killed at least 17 people at the Mount Everest Base Camp. - Many landslides occurred along steep valleys. For example, 250 people were killed when the village of Ghodatabela was covered in material. -

Answer 110

ankipro Damage to infrastructure: The earthquake caused extensive damage to roads, bridges, and utilities in affected areas, with repairs costing an estimated $1.5 billion.Agricultural loss: Around 30,000 hectares of crops, including coffee and corn, were destroyed, severely impacting local farming communities.Tourism impact: Tourism in coastal regions like Acapulco and Puerto Escondido dropped significantly, with a 25% decline in visitors following the earthquake.Cost of reconstruction: The total cost of rebuilding was estimated at $1.5 billion, with significant government spending directed to affected regions.

Answer 111

- economic loss of 10 billion US dollarsthe disaster - The United States Geological Survey (USGS) estimated economic losses to be between nine per cent and fifty per cent of GDP. - Tourism is a significant source of revenue in Nepal, and the earthquake led to a sharp drop in visitors. - 50% of shops were destroyed, affecting food supplies and people’s livelihoods.

Answer 112

ankipro Soil liquefaction: The earthquake caused soil liquefaction in coastal and low-lying areas, leading to significant damage to infrastructure and farmland.Landslides: More than 100 landslides were triggered by the earthquake, especially in the mountainous regions of Oaxaca and Chiapas. These blocked roads and isolated communities.Tsunami damage: The 1-meter tsunami along the Pacific coast caused damage to coral reefs and coastal ecosystems, affecting local marine life.Air and water quality concerns: The collapse of buildings, combined with volcanic ash, worsened air quality in urban centers, particularly Mexico City.

Answer 113

loss of forest and farm land due to landslides and avalanches changes to water sources increased sediment in rivers and risk of downstream flooding impacts on protected area and community forest management; and death of wild animals. A huge amount of debris was generated from damaged buildings, some of which was dumped in rivers, wetlands and forests. Hazardous waste included medical and electrical wastes (e.g. mercury), laboratory and industrial chemicals, and petroleum products. Some toxic chemicals will have ended up in ground water or rivers; some are persistent pollutants. Dead bodies and livestock carcasses contaminated the environment after the earthquakeMuch plastic waste generated in the relief phase was not properly disposed of.

Answer 114

ankipro Government response: The Mexican government, under President Enrique Peña Nieto, launched a large-scale, military-led rescue operation, deploying 10,000 troops to affected areas.Public trust: Despite some criticism for slow responses in rural areas, the government’s overall response was seen as effective, aided by previous experience from the 1985 earthquake.International support: The government received aid from several countries, including the U.S. and Japan, and the Mexican Red Cross received widespread support.Political pressure: Reconstruction costs, estimated at $1.5 billion, led to significant political discussions and calls for improved disaster preparedness and resource allocation.

Answer 115

The Nepali government was heavily criticized for its slow and ineffective response to the disaster. Many survivors lacked food, water, and shelter for days. Corruption concerns arose over the mismanagement of aid and delays in relief distribution. Nepal's political instability worsened due to the EQ, which was already poor due to recent problems with the democracy of the region, including coups Nepal had been struggling to draft a new constitution for years.The earthquake pressured political leaders to finalize it quickly, leading to the adoption of the new constitution on September 20, 2015—just five months after the disaster.However, the constitution triggered tensions with Madhesi and Tharu ethnic groups, leading to border blockades and political unrest.

Answer 116

ankipro Land-Use Zoning in Mexico City: After the devastating 1985 earthquake, Mexico City implemented land-use zoning to reduce risks, particularly in areas prone to liquefaction and near active volcanic zones.Restricting construction in high-risk zones: Authorities limit construction in high-risk areas, such as old lakebeds and near fault lines, reducing the risk of damage from earthquakes.Urban planning regulations: In areas like Xochimilco and Pedregal de San Ángel, development is regulated to prevent high-density buildings in dangerous zones.Land-use zoning outcomes: These zoning laws have helped reduce the development of the most dangerous areas, but informal settlements still exist in some high-risk zones.

Answer 117

- Land-Use Zoning in Kathmandu Valley Nepal lacks extensive land-use zoning laws, but after the 2015 earthquake, the government proposed better land-use planning for Kathmandu Valley and its surrounding areas. - Challenges with enforcement: Due to rapid urbanization, enforcement of zoning laws has been difficult. Many informal settlements in Kathmandu are built in high-risk areas prone to earthquakes, landslides, and flooding. - Growth in high-risk zones: Many informal settlements, especially in the Kathmandu Valley, are built in areas vulnerable to seismic hazards. - Future improvements: Post-2015, there is a push for stronger enforcement of land-use zoning laws, aiming to reduce vulnerability to future earthquakes.

Answer 118

ankipro Seismic-resistant buildings: Following the 1985 Mexico City earthquake, building codes were updated to incorporate earthquake-resistant design in all new constructions. Strengthening existing buildings: Older buildings, especially in the downtown area, were retrofitted with steel frames and base isolators to prevent collapse during earthquakes. Urban centers' preparedness: By 2017, over 60% of buildings in Mexico City had been constructed with seismic safety features, significantly reducing earthquake vulnerability. Building code enforcement: The enforcement of modern building codes has helped reduce earthquake risk, although some older, unreinforced buildings remain at risk.

Answer 119

- Building regulations after 2015: After the 2015 earthquake, Nepal implemented stricter building codes that require reinforced concrete and steel frames to improve earthquake resistance. - Challenges with enforcement: Enforcing building codes is difficult, especially in rural areas and informal settlements, where construction often lacks seismic resistance. - Reconstruction after the 2015 earthquake: The government, along with international organizations, focused on earthquake-resistant rebuilding efforts through the Build Back Better initiative. - Community-based efforts: Local communities, supported by NGOs, have been involved in constructing safer homes using modern techniques to improve resilience in rural areas.

Answer 120

ankipro Earthquake insurance in Mexico: Mexico has a developed earthquake insurance system, with both private and public options available. The FONDEN (National Disaster Fund) helps cover losses after earthquakes, supporting recovery efforts.Government-backed insurance: The FONDEN provides public funding to cover damages caused by disasters, complementing private insurance and ensuring quicker recovery.Insurance penetration: Only about 20% of households in Mexico are covered by earthquake insurance, leaving a large portion of the population vulnerable to economic loss after a major earthquake.Impact of insurance: In areas like Oaxaca and Chiapas, insurance coverage has helped with faster recovery and rebuilding, but coverage remains limited in rural areas.

Answer 121

- Lack of widespread earthquake insurance: Nepal lacks a formal, national earthquake insurance system. Most of the population is uninsured against natural disasters, making it difficult to recover financially after an earthquake. - Challenges with insurance accessibility: Low income and limited financial infrastructure prevent most Nepali people from accessing insurance products. - Post-2015 efforts: After the 2015 earthquake, there were efforts to introduce micro-insurance schemes, especially in rural areas, but these programs are still in their early stages. - Government initiatives: The government of Nepal is exploring the creation of a national disaster insurance system, but it is still in the planning phase due to political and financial challenges.

Answer 122

Mexico’s Educational Campaigns:Mexico’s public education efforts include nationwide campaigns on earthquake preparedness, targeting schools, businesses, and public spaces. These campaigns have significantly improved public awareness of safety procedures. Nepal’s Public Education Programs:Following the 2015 earthquake, Nepal launched campaigns that reached over 10 million people, educating the population on how to act during an earthquake. These include promoting safe practices like "Drop, Cover, and Hold On" during tremors. Japan’s Comprehensive Public Education:Japan has a strong earthquake preparedness culture, with ongoing education and safety drills reaching millions. The 2011 earthquake showed the success of these efforts, with nearly 90% of the population being familiar with evacuation and safety measures.Comparison:Japan’s public education efforts are the most extensive, supported by a well-established earthquake preparedness culture. Mexico has developed strong public education campaigns, while Nepal has made progress post-2015 but is still in the process of scaling up these efforts.

Answer 123

Mexico’s Rescue Teams:Mexico’s Rescue Brigades mobilize within two hours after an earthquake. For instance, during the 2017 Puebla earthquake, these teams rescued 50+ people from collapsed buildings, minimizing casualties. Nepal’s Disaster Relief Programs:After the 2015 earthquake, Nepal’s government, supported by international organizations, delivered relief to over 8 million people. This included food, medical supplies, and temporary shelter. Japan’s Rapid Response Teams:Japan’s Disaster Relief Teams are among the fastest in the world. Following the 2011 Tōhoku earthquake, rescue operations mobilized within hours, saving thousands. Japan’s response was supported by 120,000 soldiers and relief teams, reaching over 500,000 survivors.Comparison:Japan’s relief efforts are among the most advanced globally, with rapid deployment and significant resources. Mexico and Nepal have strong response systems, but Japan’s scale and speed are unparalleled.

Answer 124

Mexico’s Reconstruction Plans:After the 1985 earthquake, Mexico allocated $6 billion through FONDEN (National Disaster Fund) for recovery and rebuilding. By 1995, most affected areas had been rebuilt, improving resilience for future quakes. Nepal’s Post-2015 Reconstruction Efforts:Following the 2015 earthquake, Nepal allocated $4.1 billion for recovery. However, reconstruction has been slower due to bureaucratic delays and limited resources, and as of 2020, many areas still need rebuilding. Japan’s Post-2011 Recovery and Reconstruction:Japan allocated $300 billion for the recovery from the 2011 Tōhoku earthquake and tsunami, rebuilding devastated areas and reinforcing infrastructure. By 2017, 90% of homes had been rebuilt, and the country had restored its economy to pre-disaster levels.Comparison:Japan’s recovery from the 2011 earthquake was fast and well-funded, aided by both government resources and private sector participation. Mexico has a history of effective post-earthquake recovery, while Nepal still faces challenges due to limited resources and bureaucratic hurdles.

Answer 125

- Pre-Disaster (Normal Level of Development): Before a disaster occurs, society is at a stable development level with normal infrastructure and economy. - Relief Phase (Immediate Impact): Right after a disaster strikes, the immediate focus is on emergency relief, saving lives, and providing basic needs. The disaster causes a sharp dip in society's development. - Rehabilitation Phase (Recovery): In the weeks and months following the disaster, efforts are made to restore critical infrastructure and services. This period sees the beginning of recovery. - Reconstruction Phase (Development): Long-term recovery and rebuilding occur, with improvements in infrastructure and preparedness for future disasters. Society begins to improve and may even reach a higher development level than before.

Answer 126

- Geothermal Energy and Fertile Soil:Hawaii's volcanic soil supports over $600 million in annual agricultural production, including crops like coffee, macadamia nuts, and tropical fruits. - The volcanic environment also offers geothermal energy, contributing 38 megawatts to the state’s power supply. This is growing with the firm PGV having acquired permits to expand - Tourism and Scenic Beauty:Hawaii's tourism industry generated $17.8 billion in 2018 (1/4 of Hawaii economy) , with volcanic landscapes such as Hawai’i Volcanoes National Park, which attracted over 2 million visitors annually before the eruption. - Cultural and Historical Significance:Kīlauea and Mauna Loa are deeply embedded in native Hawaiian culture and history, with Pele, the goddess of volcanoes, being a central figure in mythology.

Answer 127

ankipro Fertile Soil for Agriculture:Indonesia is a major producer of rice, coffee, and vegetables, with over nearly 30% of the population employed in agriculture. Volcanic soil can boost crop yields by up to 20% compared to non-volcanic areas.Fishing and Marine Resources:Indonesia has a one of the largest fishing industry, with volcanic islands supporting rich marine biodiversity, wth about 12 million employedTourism and Cultural Significance:Mount Merapi attracts thousands of visitors yearly, and 2023 tourism contributes to the $14.4 billion (4.1% of GDP) Indonesian tourism industry.

Answer 128

- Mining Opportunities:The DRC contains around 50% of the world’s cobalt reserves, and many deposits are in tectonically active areas. Mining contributes over 1$0 billion to the national economy. - Fertile Land for Agriculture:Volcanic soil allows over 60% of the population to engage in subsistence farming, producing key crops like cassava, maize, and beans. - Cultural and Historical Factors:Goma, a city near Mount Nyiragongo, has grown to a population of 333,000, despite the risk of eruptions.

Answer 129

- 1,500+ cases of respiratory illnesses due to sulfur dioxide emissions. - "Vog" (volcanic smog) from sulfur dioxide caused asthma flare-ups and skin irritations. - Loss of Cultural and Recreational Spaces:Parts of Hawai’i Volcanoes National Park were closed for months, affecting 2 million annual visitors and the 30% of island employed in tourism - approx 700 homes destroyed - 0 deaths2,000 people evacuated - Estimated nearly $240 million in damages to public infrastructure, including 14.5 miles of waterlines destroyed.

Answer 130

ankipro Ash clouds caused major disruption to aviation across the region.Roads were blocked with cars and motorcycles as residents tried to flee the hazard zone.Vegetable prices increased because of the damage to crops.Heavy rain on 4 November 2010 caused lahars, washing ash and rock down into towns and destroying bridges.Schools were closed.353 people were killed and 577 people were injured.Overcrowded evacuation centres led to poor sanitation, no privacy and a serious risk of disease.evacuation led to displacement of almost 400,000 people living within 20 km from the summit for one and a half months.

Answer 131

- At least 25,000 people were displaced in Sake, 25 km northwest of Goma, and 7,000 travelled towards neighbouring Rwanda to seek refuge (UNICEF 23/05/2021). - 31 people died, and 24 were injured by the lava flows; over 200 missing. - Three villages and one neighbourhood in the city of Goma were destroyed by the lava, including more than 3,500 houses and five schools (OCHA 25/05/2021). - Over 20,000 people (4,500 households) lost their home and are currently living in host communities, public spaces, and schools.overcrowed refugee commitees with lack of proper sanitation = outbreak of diseases such as malaria and diarrhoea. - Over 1,400 metres of roads were potentially affected by the lava, effecting transport

Answer 132

- 2960 lost jobs - $800 million cost - geothermal power stations closed (which provided 25% of islands power) - lodging and tour bookings for May through July down 50%

Answer 133

ankipro Government officials reported economic losses from the eruption will surpass $600 million (5.5 trillion Rupiah), due to the death of livestock and damage to the tourism, manufacturing and agricultural sectors. The rice harvest on the mountain and surrounding area was lost due to the ashfall.number of tourism in followng year dropped by 30%

Answer 134

- thousands of buildings damaged - Farmers lost thousands of livestock and fertile land due to lava flows. - 15% of city covered in lava, 14 villages destroyed, Goma airport damaged

Answer 135

- sulfur dioxide emmisions - Lava entering the ocean produced toxic hydrochloric acid plumes ("laze") - 500 acres of forest reserve destroyed, including critical bird habitats - addition of 875 acres of new land beyond the old coastline - .Gas emissions were at the highest levels ever recorded at Kīlauea and impacted much of the State of Hawaii and areas as far away as Guam. - Hawaiis largest freshwater lake destroyed, Green lake

Answer 136

ankipro Pyroclastic flows travelled three kilometres down the heavily populated mountain sides.Volcanic ash fell up to 30 kilometres away and travelled six kilometres into the sky.sulfur dioxide was blown across Indonesia, the Indian Ocean and as far south as Australia.long term-improves fertility of the soil

Answer 137

- The 2021 eruption released tons of sulphur dioxide and carbon dioxide, both of which are acidic gases. - The emissions of sulphur dioxide have not ceased since. - contributing to acid rain, damaging ecosystems, and impacting human health - lava reached speeds of 64km/hr destroying forests and farmland - Pollution of Water Sources: Over 500,000 people faced water shortages due to groundwater contamination.* - Air Quality Issues: o Toxic gases increased respiratory illnesses in thousands of residents.

Answer 138

• Government Emergency Response: o Hawaii received a significant proportion of $788 million in disaster relief funds from FEMA, • Debate Over Land Use: o Some areas were permanently declared off-limits for rebuilding due to future risks.

Answer 139

ankipro * Government Response and Evacuations: oThe government has set up a special task force to support people that have been affected by the volcano either by family issues, or because they have lost their jobs.o The military played a key role in evacuations and rebuilding.* Strengthened Disaster Preparedness:The government improved early warning systems and evacuation plans after criticism.Needs for hazard education and for multiple eruption scenarios contingency planning

Answer 140

- Government and International Response: o EU allocates €2 million in emergency humanitarian funding - The Congolese government faced criticism for its slow response.* - Weak infrastructure and corruption hindered relief efforts.

Answer 141

Lava Diversion Efforts: - During the 2018 eruption, lava diversion was not actively attempted due to the scale and unpredictability of the flows. - Previous efforts, such as in 1960, had limited success, and the 2018 eruption produced 1 cubic kilometer of lava erupted through August, overwhelming potential diversion strategies.

Answer 142

ankipro Hazard Mapping and Exclusion ZonesIndonesian authorities implemented hazard mapping to establish exclusion zones. A 2010 decision to extend evacuation zone from 15 to 20 km, leading to the evacuation of thousands of residents duLahar Dams and BarriersSince the introduction of sabo-dam structures on the river channels from the late 1970s, it has been possible to slow lahars (Lavigne and Thouret, 2002). Lahars were therefore constrained on the upper part of the rivers, and seldom exceeded a length of 10 km from the crater. As a result, lahar-related damages and casualties at Merapi have been limited since the 1980s (Lavigne et al., 2000a), and mainly occurred at the bottom of the valleys in quarries mining volcaniclastic deposits

Answer 143

- constructive, continental-continental plate boundary with the African plate being pulled apart into 2 parts of the East African Rift Valley - Nyiragongo volcano - 20km from goma

Answer 144

lack of funding for Goma observatory - World bank pulled funding for Goma observatory as people break in and vandalize equipmentbut also people were more prepared for eruption than in 2002 (greater lived experience) increases vulnurability of population as less advanced warning systems

Answer 145

- UNICEF installed 15 emergency station chlorination points close to the lake to avoid another cholera outbreak - UNICEF supported installation of 1500m pipe to replace melted pipes - temporary shelters built by Congolese authorities - rapid response teams provided first aid services to ~4600

Answer 146

hot spot on pacific plate

Answer 147

ankipro subduction zone of the Indo-Australian and Eurasian plates.

Answer 148

ankipro The Center for Volcanology and Geological Hazard Mitigation (CVGHM) monitored seismic activity and gas emissions, detecting increased activity in September 2010. This facilitated timely evacuations and hazard assessments.indonesia gov raised the alert for Mount Merapi to its highest level (4) and warned villagers in threatened areas to move to safer groundThe timely warnings and evacuations during the 2010 eruptions saved between 10,000 and 20,000 lives.

Answer 149

ankipro 210 evacuation centres were set up either as tents, in schools, churches, stadiums or government offices.The timely warnings and evacuations during the 2010 eruptions saved between 10,000 and 20,000 lives.2,682 people were moved to new, safer houses permanently.The government made money available to farmers to help replace their livestock.The government set up a special task force to support people who were affected by the volcano, either by family issues, or because they lost their jobs

Answer 150

ankipro 3 times in 2010

Answer 151

Advanced Monitoring Systems: - The Hawaiian Volcano Observatory (HVO) utilized a comprehensive network of seismic instruments, GPS stations, and gas sensors to monitor volcanic activity. - This allowed for the detection of magma movement and gas emissions, facilitating early warnings. Public Alerts and Evacuations: - The Hawaii County Civil Defense Agency issued timely alerts through various channels, including text messages, sirens, and media broadcasts. - This led to the evacuation of approximately 2,000 residents prior to significant lava inundation, effectively minimizing casualties. because of the unpredictability of disasters such as volcanic activity, as well as Hawaii’s isolation, island residents and visitors are vulnerable in case of a major natural disaster. For this reason, people who live in Hawaii are encouraged to have a 14-day emergency supply kit that includes water, food, medication, etc., that will last at least two weeks. also recommendation on having evacuation plans and staying indoor during ash falleducation in schools

Answer 152

- The Hawaii National Guard (HARNG) and Hawaii Air National Guard (HANG) members were called to report to assist in the response. They helped evacuate residents on the north shores of Oahu and Kauai to safe locations. They also assisted with fighting brush fires set off by lava on the Big Island - Individuals with damaged property were recommended to contact FEMA for financial support

Answer 153

ankipro pyroclastic flows at speeds of up to 100 km (62 mi) per hour

Answer 154

at least 32 died

Answer 155

353 people were killed during the eruptions, many as a result of pyroclastic flows.

Answer 156

No, the 2021 eruption of Mount Nyiragongo in the DRC was primarily characterized by lava flows, not pyroclastic flows

Answer 157

- UNOPS weekly radio program to raise awareness about the dangers of volcanoes - 2002 eruption made people more aware of risks (250 deaths), making them more likely to follow evacuation. orders. lived experience - 2 reasons Nyiragongo erupted without warning did not give off warning signs as erupted close to ceiling, volcano observatory had a lack of funding and equipment stolen

Answer 158

- Congolese authorities ordered the mass evacuation of 400,000 residents in fears of a limnic eruption - DRC Red Cross mobilised volunteers and built 500 temporary shelters - Unifcef installed 15 emergency water purification stations to prevent cholera spread heavy relience on aid

Answer 159

no credible attempt to mitigate against the eventand no attempt to relocate the nearby city goma

Answer 160

3 characteristics of the City of Goma itself which increases its vulnerability to eruptions - surrounded by vegetation, increasing wildfire risk - densely populated, with a lack of road networks for evacuations - Lake Kivu limits possible escape routes

Answer 161

- erupts effusively (gently) - releases low viscosity (very runny) lava that travels at fast speeds

Answer 162

earthquakes and volcanoes

Answer 163

- around 2414 km thick. - primarily of iron and nickel. - solid - 5,200° Celsius

Answer 164

- Primarily iron and nickelaround - 2,200 kilometers - 4,500 to 5,500 degrees Celsius - Liquid

Answer 165

ankipro 1,300°C more fluid than lithosphere

Answer 166

ankipro 300-500°C.

Answer 167

uppermost part of mantle and crust

Answer 168

ankipro Some 15,894 people died, and 26,152 people were injured. 131,000 people were displaced300 hospitals destroyed, 11 destroyed

Answer 169

- Nepal is situated in the middle of the collision zone where the Indo-Australian plate meets the Eurasian place in a convergent collision boundary - As the plates collide, pressures build up and energy is released as earthquakes - A 7.8Mw EQ occurred on 25th April 2015 due to a slip along the main frontal thrust fault in the collision zone - The epicentre was 90km northeast of Kathmandu, the capital of Nepal - shallow focus: The focus was only eight kilometres deep

Answer 170

Fukushima disaster suggested that Japan’s fifty-four nuclear reactors--most along the coastline--could suffer the same fate.This caused a political uproar as Japan was slandered for using nuclear energysparked global political discussion of the use of nucleur energy

Answer 171

- Nepal's economic impacts were felt more globally, as the call for international aid was required - As Nepal is more heavily reliant on agriculture, the environmental impacts hit the country harder - Poorer infrastructure and connectivity meant people were not prepared and aid was harder to get to certain areas - As the population density is nearly half of that of Japan, the concentration of people impacted was less

Answer 172

- The economic impacts for Japan were more severe, due to the higher level of built-up areas impacted and the concentration of expensive infrastructure and buildings - The newer technologies of Fukushima brought a widespread disaster on a larger, global scale - The political backlash was exaggerated as the Fukushima disaster was international news - However, Japan was able to source money for itself instead of requiring international aid due to its AC status, reducing the global impact - The impact on people was widespread, however this was mainly due to the tsunami and not the initial EQ - Despite good education and preparation schemes, not much could have been done to reduce lives lost from the tsunami, as even the 10m wall in Miyako subsided and let water through

Answer 173

ankipro Cocos plate and North American plate, cocos (oceanic plate)

Answer 174

ankipro 370 people died6011 people injured many multi-story buildings collapsed, while more than 20,000 homes, schools, and hospitals were damaged. Damage to cultural sites could reach $440 million

Answer 175

ankipro Mexico lost an estimated $160 million in economic production due to the September 2017 earthquaketotal losses from the 2017 earthquake were valued at $2.476 billion (0.15 percent of GDP).

Answer 176

ankipro 7.1 Mw and strong shaking for about 20 seconds.epicenter about 55 km (34 mi) south of the city of Puebla, Mexicoshallow focus: only 50km down

Answer 177

ankipro A 8.2 magnitude earthquake struck the Chiapas-Oaxaca region, causing significant environmental effects such as surface faulting, landslides, and potential impacts on ecosystems.

Answer 178

ankipro a significant drop in political trustGovernment Response Criticized: Many criticized the government's slow and ineffective response, with accusations of deploying professional rescue workers too late, relying on volunteers for shelters, failing to distribute donations, and preventing citizens from reaching those in need"Critical Juncture" and Democratization: The earthquake triggered a "critical juncture" that contributed to the end of a presidentially appointed regent for Mexico City and led to a popularly elected mayor, democratizing the municipal government.

Answer 179

continental fit glacial deposits geological sequences fossil evidence paleomagnetism

Answer 180

sea floor spreading explains Wegener's idea of the break up of Pangea and the subsequent drift of continentsplates were moved by sea-floor spreading from the mid-ocean ridges to subduction at ocean trenches

Answer 181

- Wegener examines the location of tiny rocks and the direction of grooves formed by large glaciers scraping across southern areas of Africa, South America, Australia, Antarctica, and India. - He concludes that if all these places were fitted together, they would form a continuous ice sheet expanding outward in all directions.

Answer 182

usually asymmetrical, long, narrow depressions with depths of 6000 to 11000m

Answer 183

(ONLY oceanic-oceanic plate convergent boundary) - e.g. Mariana trench - slightly older and therefore denser plate will subduct forming an ocean trench - movement accelerated by slab pull - as plate descends volatiles causes partial melting in the overriding mantle. - The magma rises to the surface, and island form by explosive eruptions

Answer 184

the downgoing plate is called the Pacific Plate, and the overriding plate is the Philippine Sea Plate

Answer 185

Any object, situation, or behaviour, that has the potential to cause injury, ill health, or damage to life, property or the environment.

Answer 186

Measure of energy released on a logarithmic scale (each whole number represents a 10-fold increase in amplitude).Largest record quakes are magnitude of around 9. Damage is determined by magnitude but also by population density and level of preparedness Advantages: - Logarithmic - Objective - Based on ground movement, so is more accurate and scientific Disadvantages: - Only accurate for magnitudes between 3 and 7 - Can only calculate it with a seismogram and a known distance from the epicentre

Answer 187

Measures energy released more accurately than Richter.Measures amount of movement of the ground - a direct function of energy.Accurate for large earthquakes but not useful for smaller ones.

Answer 188

- Qualitative measure of damage experienced related to ground movement (impacts felt and seen by people). - Attempts to measure both intensity and impact. - Based on observation and description. Advantages: - No specialist equipment or training required - Quick and easy - Used to quickly identify areas for assistance Disadvantages - Subjective - Score would be much greater in a city compared to the countryside for the same earthquake - Inaccurate

Answer 189

-Convection currents cause the crust to dome and pull apart. -Partial melting causes magma to rise. -Shield volcanoes form in the Rift Valley. The crust stretches and thins, forming step-down faults, which may rotate, forming peaks or escarpments. Basaltic (runny) lava flows through the rift and forms new ocean crust through effusive eruptions, and pillow lava forms.As more lava is added, the sea floor spreads causing continents to move further apart. - Hydrothermal vents create black smokers.

Answer 190

Step-down faultsSmall, shallow-focus earthquakes occur along their lengths as they slip.

Answer 191

escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations.

Answer 192

A measurement used to rank and compare different volcanic eruptions using:- volume of erupted material.- height the ejected material reaches.- duration in hours.- qualitative descriptions ('gentle', 'mega-colossal').

Answer 193

approx 50 by 70 kilometers

Answer 194

Lava flows far which forms low, gently sloping volcanoes.Runny basic lava erupts gently.Less viscous lava flows far (flows easily).Creates wide, gently sloping volcanoes.This type of volcano is built entirely of fluid lava flows - the highly fluid lava causes the accumulation of broad sheets of lava

Answer 195

broad, gently sloping profiles, resembling a flattened dome

Answer 196

1. Plates converge due to convection currents.2. The more dense oceanic crust subducts beneath the less dense continental crust.3. Friction from plates rubbing together heats plates. Water from the ocean helps crust melt forming viscous acidic magma. Pressure builds up in the Benioff zone of earthquakes, causing high magnitude earthquakes at a variety of depths.4. Magma rises through the gaps in the continental crust (viscous lava has explosive eruptions).5. Slab pull pulls subducting plate faster, and ridge pull increases as you get closer to the subduction zone.Volcanoes and fold mountains are formed near the edge of continental crust.

Answer 197

deep ocean trench, e.g. Peru-Chile Trench, oceanic Nazca Plate subducts beneath the continental South American Plate, 8,065 meter below sea level Strato volcanofold mountains The Andes Mountains are a prime example of fold mountains, formed by the collision of the Nazca (oceanic plate) and South American tectonic plate (continental)

Answer 198

Lateral movement of new oceanic crust away from a mid-ocean ridge (constructive plate boundary).

Answer 199

Focus point at which seismic waves originate from (point where stress is released).Epicentre directly above the focus on the surface (where most severe impacts will be).Seismic waves energy released travels as waves, in the form of S waves or P waves.Fault line where movement in plates occur.

Answer 200

- ground shaking and ground displacement - liquefaction - landslides and avalanches - tsunamis associated with sea-bed uplift and underwater landslides - flooding

Answer 201

ankipro Nepal 2015 - precipitated a large rock–ice avalanche in the Langtang Valley. The resultant air blasts obliterated the Langtang village, a nearby forest, and led to the tragic loss of over 350 lives

Answer 202

2015 triggered over 21,000 landslides over an area of more than 25,000 km2. These landslides contributed to mass wasting, partially compensating the tectonic uplift by the earthquake. increased by monsoon season rainfall

Answer 203

Tsunamis: Underwater earthquakes, particularly those occurring along tectonic plate boundaries, can displace large volumes of water, generating tsunamis. When these waves reach coastal areas, they can inundate land and cause significant flooding. Dam Failure: Earthquakes can damage or destroy dams, leading to the sudden release of water. The resulting flood can be catastrophic, especially if the dam failure occurs upstream of populated areas. Ground Shaking: The shaking from an earthquake can cause landslides, particularly in hilly or mountainous regions. These landslides can block rivers, creating temporary dams. If these natural dams fail, they can release large amounts of water downstream, causing flooding.

Answer 204

New Zealand 2016: A landslide blocked the Clarence River, causing flooding. Ten farms were evacuated

Answer 205

Japan 2011

Answer 206

nepal 2015 - Over 500,000 houses were destroyed and another 269,000 damaged

Answer 207

primarly composed of Basic (Basaltic)Lava is free-flowing and can run for considerable distances. Hawaii 2018, lava flows destroyed over 700 homes and devastating residential areas in the Puna District.Everything in the path of lava is burned/buried destroying infrastructure/properties/crops.Rarely causes injuries/fatalities because people can escape the flow, it is more the secondary impacts due to infrastructure damage. It is therefore one of the least significant hazards. In EDCs, the lava flows can also be diverted in order to protect infrastructure.

Answer 208

lava flows, pyroclastic flows, gas emissions, tephra and ash lahars and flooding associated with the melting of ice tsunamis associated with explosive eruption.

Answer 209

Iceland 1996Volcano north of Grímsvötn lake belonging to the Vatnajökull glacier erupted. The resulting jökulhlaup reached a flow rate of 50,000 cubic metres per second, and destroyed parts of the Ring Road.

Answer 210

type of glacial outburst flood.

Answer 211

jökulhlaup

Answer 212

The Elgeyo Escarpment, part of Kenyas Great Rift Valley, was formed by faulting millions of years ago

Answer 213

Tectonic processes remain constant, meaning earthquakes and volcanic activity occur at roughly the same rates over time.

Answer 214

Over history the impact of tectonic hazards has overall increased:More people live in hazard-prone areas (e.g., along fault lines, near volcanoes, and coastal regions).Climate change has increased the likelihood of certain hazards caused by tectonic hazards, e.g. laharsTectonic hazards result global supply chain disruptions, which have worldwide consequences due to the increased interdependence of countries for goods, including necessities, e.g. food, as a result of globalisationsincreased variation in severity of mainly long-term impacts depending on development and financial resources of countries to respond to hazard. Short-term also effected, e.g. building codes and building collapse

Answer 215

Describe the changes in the impact of tectonic hazards over time (NOT modern history)

Answer 216

over the past 50 years there has been an increase in the number of disasters due to volcanic eruptions and earthquakes, which currently averages at around 30 a year. argues for decrease: Methods to mitigate against the vulnerability have improved significantly in terms of warning systems, building design, community preparedness, evacuation plans etc.- Globalisation has aided the delivery of aid and the spread of seismic-related technologies, minimising the losses.- In the past 20 years, there have been no volcanic eruptions resulting in a death toll >500.arguments for increase: Population growth means more people are living in vulnerable areas (e.g. the population density in Port-au-Prince was >80,000 people/km^2).

Answer 217

Describe the changes in the impact of tectonic hazards over recent history

Answer 218

Stage 1: Occurs prior to the event and shows that quality of life is at its normal equilibrium level.Stage 2: Where the hazard occurs and, again, at this point quality of life is at normal level.Stage 3: Where the event has happened and search and rescue is underway. Quality of life drops at this stage and stays low for several hours up to several days depending on the severity of the hazard and the level of development of the region/country.Stage 4: Where relief strategies are underway and there is an organised programme of help. It can take a variable amount of time, from hours and days to weeks and months to reach this stage, but quality of life improves at this time.Stage 5: Refers to long term human response; rebuilding and restoring normality. Quality of life returns to normal and in some cases can be higher than it was originally; especially if the repairs improve on the old infrastructure etc

Answer 219

Risk = frequency of magnitude of hazard x level vulnerability / capacity to cope and adapt

Answer 220

What is the disaster risk equation?

Answer 221

physical factors of hazard and external factors (earthquake/volcano characteristic, characteristics of weather (lahars) terrain,)human factors: built terrain (building codes, no building allowed in certain areas), degree of preperation of gov and individuals (hawaii disaster packs), quality and quantity of relief, etc.

Answer 222

A natural event (for example earthquake, volcanic eruption, tropical storm, flood) that threatens people or has the potential to cause damage, destruction and death

Answer 223

Hazards that create serious disruptions and damage

Answer 224

there is a large difference between the top ten most serious earthquakes vs volcanic eruption in terms of deaths by country.

Answer 225

Describe the contrast in risk between earthquakes and volcanoes

Answer 226

haiti 2010 : 300,000 indonesia 2004: 230,000

Answer 227

What was the death tolls for the two largest earthquakes by deaths in a country since 2000

Answer 228

Indonesia 2010: 322 DRC 2002: 200

Answer 229

What was the death tolls for the two largest volcanic eruptions by deaths in a country since 2000

Answer 230

The JMA helps in the creation of mitigation strategies for natural disasters, as it is responsible for providing information and warnings of impending earthquakes and tsunamisBuildings with aseismic designs created - e.g steel frames and braces capable of moving without collapsing, rubber shock absorbers in foundations, very deep foundations into solid rock,a soft storey at the bottom of tall buildings (allowing upper floors to sink down onto it instead of collapsing), counterweights on roofs to stop swaying, suspension bridges capable of movement rather than rigid cantilever design, flexible joints in utility pipesTsunami warning systems across the coast, The Japan Meteorological Agency issued tsunami warnings three minutes after the earthquake.fire-proofing older wooden buildings, which are common in historic districts of Japanese citiesCommunity preparedness - ongoing education and training for all ages - annual training in schools and businesses"

Answer 231

Mapping of high risk zonesBuilding code introduced in 2003Encouraging households to have a 'go bag' containing items useful in an earthquake emergency, e.g dried foods, bottles of water, water purification tablets, whistleo enhance earthquake preparedness in Nepal, particularly among children and communities, educational programs like "Seismology at School in Nepal" and National Earthquake Safety Day (NESD)

Answer 232

330 humanitarian organisations involved in the aftermath of the 2015 Ghorka EQ such as NGO's like Red Crosscountries such as Indonesia, Japan or the UK, and supranational organisations such as the Asian Development Bank, or UN - helped with search and rescue and economic recoveryIndia and China provided over $1 billion of international aid. The UK provided over 100 search and rescue responders, medics, and disaster and rescue experts, as well as three Chinook helicopters for the Nepali government.

Answer 233

Rescue workers and around 100,000 members of the Japan Self-Defence Force were dispatched to help with search and rescue operations within hours of the tsunami hitting the coast.The government declared a 20 km evacuation zone around the Fukushima nuclear power plant to reduce the threat of radiation exposure to local residents.international aid e.g. international help from US armyHundreds of thousands of people who had lost their homes were evacuated to temporary shelters in schools and other public buildings or relocated to other areas.Many evacuees came from the exclusion zone surrounding the Fukushima nuclear power plant. After the Fukushima Daiichi nuclear meltdown, those in the area had their radiation levels checked, and their health monitored to ensure they did not receive dangerous exposure to radiation. Many evacuated from the area around the nuclear power plant were given iodine tablets to reduce the risk of radiation poisoning.

Answer 234

Mexican military, police, and emergency services deployed for search operations. Los Topos (volunteer rescue teams) played a key role in rescuing survivors. International teams from the U.S., Japan, Israel, and other countries assisted.Emergency medical teams set up field hospitals. Thousands of injured received medical care in hospitals.Volunteers and organizations provided food, water, and shelter.Direct Relief arrived in Juchitán de Zaragoza, Oaxaca, with shipments of medication, gauze, surgical gloves, and other needed supplies.

Answer 235

Mexico City Building Code (after 1985 earthquake):Introduced stricter construction regulations for earthquake-resistant structures.Required reinforced concrete and flexible designs to absorb seismic shocks.Regular inspections for public buildings and critical infrastructure.Retrofitting Older Structures: Some efforts were made to strengthen older buildings, but enforcement was inconsistent. Earthquake Early Warning System (SASMEX) Implemented in 1991 after the devastating 1985 earthquake.Used seismic sensors along the Pacific coast to detect earthquakes and send alerts before strong shaking reached cities.Warnings were broadcast via radio, TV, and loudspeakers in Mexico City.Limitations: The system had gaps, and some areas did not receive adequate warnings before the 2017 quake.

Answer 236

cannot mitigate shaking

Answer 237

cannot mitigate against energy released. However a tsunami entering land can be mitigated, so can mitigate flooding.tsunami event: Dikes, dams, and other structures are regarded as core measures in disaster risk manage- ment in Japan.Seawalls were primarily designed to protect against tsunamis based on the 1960 Chilean earthquake tsunami, which had waves reaching 3-6 meters. The seawalls were designed to divert tsunamis to the side around the town using channels and river dykes.land use zoning that provided open spaces where people could assemble after disaster

Answer 238

not possible to mitigate against the energy released

Answer 239

rocks, dust, gas and pyroclastic material up to 20 km into the atmosphere at a rate of up to 100,000 tonnes per second, traveling at several hundred meters per second. This cloud will then collapse, creating a pyroclastic flow of hot volcanic matter

Answer 240

What are the features of an explosive eruption

Answer 241

A volcanic eruption is effusive when low-viscosity magma, usually basaltic in composition, is released from the Earth's crust. In an effusive eruption, gas escapes the magma as it erupts and forms lava that flows downhill continuously. This type of lava flow can build shield volcanoes, which are numerous in Hawaii.

Answer 242

How does an effusive eruption occur?

Answer 243

formation: due to continental rifting, where the African plate is splitting into two, causing the crust to stretch and thin, leading to magma rising to the surface and forming volcanic activityfeatures: shield volcanoes like Erta Ale with a lava lake, as well as stratovolcanoes and volcanic fields

Answer 244

East african rift valley

Answer 245

shield and stratoe.g. El Teide on Tenerife in the Canary islands, most recently erupted in 1990, is a strato volcano

Answer 246

highest: tsunamimedium: earthquakelowest: eruption

Answer 247

fastest: earthquakemedium: tsunamislowest: eruption

Answer 248

most dispersed: tsunami/earthquakemost clustered: eruption

Answer 249

longest: eruptionmedium: tsunamishortest: earthquake

Answer 250

highest: tsunamimedium: earthquakelowest: eruption

Answer 251

more precise: eruptionrandom: tsunami/earthquake

Answer 252

- Fewer people live around volcanoes- Volcanoes have a slower speed of onset and show pre-cursory warning signs, giving people time to react and respond.- Volcanic eruptions have minimal spatial variability with typically much more localised impacts.- International trade/aid ensures people have sufficient food/medicine to save lives that were previously lost to famine and disease.

Answer 253

440mn people live near 1 of 120 dangerous volcanoes, and yet 2.7bn people live in seismic areas

Answer 254

- The 1783 eruption of Laki killed >20% of Iceland's population by famine/disease with 8 months of lava and noxious gas emissions killed 60% of livestock.- The upcoming election in Martinique meant the government did not prepare/warn the population prior to the 1902 eruption of Mt Pelee, resulting in 32,000 being suffocated.- Armero, Colombia, was build in the path of an old lager, which paired with a slow reaction to the 1985 eruption of Nevado del Ruiz resulted in 23,000 people being killed by a lahar.

Answer 255

this will delay the response and make coordination poorer

Answer 256

- This delays the response since relief workers cannot go into hazardous/dangerous areas.- It also prolongs evacuations and the associated issues (e.g. lack of sanitation).

Answer 257

this means there is less money to invest in response and rebuilding, increase the recovery time and the reliance on external aid

Answer 258

this requires more coordination in lots of places, making the response more complex (and likely to go wrong) since areas will need to be prioritised

Answer 259

the more severe the hazards, the more overwhelmed the response and therefore the longer the recovery time

Answer 260

this means there is less time to mitigate against the event and prepare, meaning there is a more rapid decline in quality of life

Answer 261

the extent to which a community, structure, service or geographic area is likely to be damaged/disrupted by the impact of a particular hazard

Answer 262

the probability of a hazard causing harmful consequences

Answer 263

the physical, economic, social and institutional ways in which a society has strength and resources to reduce the risk/vulnerability of a disaster

Answer 264

the state of having no social, economic, political or physical protection from something harmful

Answer 265

the ability of a community to maintain certain functions, processes and populations after experiencing a disturbance

Answer 266

about reducing/preventing the effects of something from happening (i.e. reducing the risk)

Answer 267

- The risk of a threat becoming a reality is mitigated by different types of defence that are "layered" behind each other.- Therefore a lapse/weakness should in theory not materialise unless the 'holes' align.

Answer 268

- Infrastructure design- Robots- Randoseru bags

Answer 269

- The University of Nevada is developing earthquake-resistant bridge connections which they are design with 22-metre long bridge models and magnitude 8.0 earthquake simulations.- They are also looking at bridge columns made from metal alloys that dissipate energy without making the bridge permanently bend.

Answer 270

- DARPA have developed robots that can run at 30mph, jump over obstacles and lift heavy objects.- This makes them ideal for quickly sending supplies across unstable terrain (e.g. Nepal)

Answer 271

- These are sturdy leather backpacks used by Japanese primary school children since these bags can protect them from falling debris during an earthquake.- These bags have also become fashion staples/souvenirs for people of all ages with the new Otana Randoseru Large 003 having longer straps for adults and able to hold 15" laptops for commuters.

Answer 272

- Smartphone technology- Drones- Protecting aviation

Answer 273

- Scientists have found ways to use smartphone cameras to measure the release of volcanic gases since as gas emissions increase, they absorb UV light, making camera images appear darker.- This technology (e.g. Raspberry Pi) is >95% cheaper than previous monitoring methods and is used in countries such as Italy and Chile.

Answer 274

specially-adapted drones developed by Cambridge University allow close-range measurements of previously inaccessible, hazardous volcanoes; transforming how we forecast eruptions

Answer 275

- Newly defined 'safe limits' of ash in the air better estimate what levels of ash aircrafts can fly in, minimising flight disruptions.- Communication centres have been established to advise/inform the public during future air space closures to avoid confusion/delay.- Ash dispersion models (e.g. using AshCam which is small, cheap and light) help forecast ash concentrations during an eruption to predict which airspaces will close.

Answer 276

divergentbasic lava, so low silica content, low viscosity, higher temperature at eruptionlimited explosive forcegas, lava flowsmore frequency of eruption that explosivegently sloping sides, shield volcano, lava plateaux when eruption from multiple fissures

Answer 277

features of effusive explosions

Answer 278

a large, flat, elevated area formed by extensive lava flows, that cover a pre-existing landscape over time, resulting in a high, level area

Answer 279

what is a lava plateaux?

Answer 280

A significant hazard due to the long term damage it causes to infrastructure.

Answer 281

Hawaii (July 2015) lava flow extended for 20km without stopping.

Answer 282

modified magnitude scale

Answer 283

400km stretch of coastline dropped 0.6m vertically. Honshu island moves 2.4m east.

Answer 284

Japan 2011 earthquake - soil liquefaction occurred over a large area. Some 27,000 structures sank or tilted, causing massive damage

hazerdous_earth_2_0_2025_05_22_071653 Flashcards

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