Unit 9 Mini Case Studies

Question 1

Global distribution of earthquakes

Answer 1

Significant tectonic activity in the Pacific Ring of Fire encircling the Pacific Ocean
Destructive in the Andes Mountains or Japan trench
Constructive in the Mid-Atlantic ridge
Transform in the San Andreas Fault in California and the Alpine Fault in New Zealand
Intraplate in the New Madrid seismic zone in the USA
Subduction sonce in the Tonga or Mariana trench

Question 2

Global distribution of volcanoes

Answer 2

Especially in the Pacific Ring of Fire with 75% of all active volcanoes
Destructive in the Andes Mountains and the island arcs of Japan and the Philippines
Constructive in the Mid-Atlantic Ridge and Iceland
Hotspots in the Hawaiian Islands and Yellowstone
Shield volcanoes in Iceland and Mauna Loa in Hawaii

Question 3

Global distribution of tsunamis

Answer 3

Mainly in areas like the Pacific Ring of Fire. Coastal regions like Japan, Indonesia and Chile are especially at risk

Question 4

Examples of island arcs

Answer 4

Aleutian Islands off the coast of Alaska USA
Japanese Archipelago
Lesser Antilles in the Caribbean
The Philippines
The Mariana Islands

Question 5

Examples of hotspots

Answer 5

Hawaii Islands with the Pacific plate moving over a hotspot
Yellowstone has a continental hotspot below it
Iceland is a hotspot that contributes to volcanic and geothermal activity
Galapagos islands formed from volcanic activity due to a hotspot

Question 6

Examples of mid ocean ridges

Answer 6

Mid-Atlantic ridge runs down the centre of the Atlantic ocean separating the Eurasian and North American plate on one side and the African and South American on the other. The East Pacific Rise is a section of mid ocean ridge in the Pacific
Indian Ocean Ridge

Question 7

Disposal of liquid waste causing earthquakes

Answer 7

In the Rocky Mountains in Colorado wastewater was injected into underlying rocks during the 1960s. Water was contaminated by chemical agents and transport of toxic waste for offsite disposal was too expensive. It was therefore disposed of down a 3500m deep well. Disposal began in March 1962 and a series of minor earthquakes followed where there was no activity before. Between 1962 and 1965 700 minor earthquakes were recorded. The injection of waste into bedrock lubricates and reactivates faults that were inactive. The more wastewater injected, the larger the number of minor earthquakes. In 1966 the well was filled in and the number of recorded earthquakes fell

Question 8

Underground nuclear testing causing earthquakes

Answer 8

In 1968 testing of 1200 tonne bombs in Nevada set off 30 minor earthquakes in 3 days. Since 1966 the island of Moruroa has been the site of 80 underground nuclear explosion tests. Over 120000 live on the island. In 1966 a 120000 tonne nuclear device was detonated producing radioactive fallout 300km downwind

Question 9

Fracking causing earthquakes

Answer 9

The use of high powered water to break shale rocks triggered 2 earthquakes in Lancashire in 2011. This is a reason why Chinese engineers have not tried to develop the Sichuan province for shale gas which is a tectonically active area after a major earthquake in 2008

Question 10

Increased crustal loading causing earthquakes

Answer 10

In 1935 the Colorado River was dammed by the Hoover Dam to form Lake Mead. As the lake filled over 10 years the underlying rocks adjusted to the increased load of over 40 km^3 of water, long dormant faults were reactivated causing 6000 minor earthquakes. Over 10000 events were recorded up to 1973, 10% of which were strong enough to be felt

Question 11

Major earthquakes and focus depth

Answer 11

Haiti 2010 - 13km deep
Sichuan 2008 - 10km deep
Christchurch 2011 - 5km deep

Question 12

Hindu Kush Afghanistan earthquake 25th March 2002

Answer 12

A series of earthquakes lasting 10 hours killed 900, inured 4000 and left 20000 homeless in a remote mountain region. Towns were flattened. The region is remote and poor and recent droughts left it without the resources to cope with an earthquake. The houses were inappropriate to withstand ground shaking

Question 13

Taiwan earthquake 30th March 2002

Answer 13

Occurred in a tectonically active region known as the Taiwan Collision Zone where the Philippine plate is subducting beneath the Eurasian plate. The focus was 10km below the surface

Question 14

Volcanic gases example

Answer 14

Lake Nyos in Cameroon in 1986 killed 1700 from CO2 poisoning

Question 15

Volcanic tsunamis example

Answer 15

Krakatoa in 1883 tsunami killed 36000

Question 16

Sichuan 2008

Answer 16

In May and earthquake M7.9 occurred on the eastern rim of Tibet overriding the Sichuan basin. The crust rose 9m up a shear face due to compressional forces. Epicentre area was 300x10km and 15000 secondary landslides, rockfalls and debris flows killed 20000. It concentrated energy at the top of slopes maximising landslide impacts. There was flooding as 33 lakes were created by landslide dams causing some flash flooding. There were 10000 potential rockfalls in deforested areas but the lag time makes it hard to link them to the original earthquake preventing reconstruction funds being claimed

Question 17

Nevado del Ruiz impacts

Answer 17

Is a stratovolcano where the Nazca plate is subducting under the South American plate capable of explosive eruptions. In 1985 20% of snow cover was melted by pyroclastic flows and channels 100x4m were eroded into the icecaps. Lahars 50m thick crushed and eroded everything in their path. Later, part of the ice cap melted causing rivers to flow and dams to burst causing mudflows over Armero. A flood then went over Rio Lagunillas from an upstream lake that was displaced by lahars. This caused 23800 deaths in Armers and 2000 elsewhere

Question 18

Nevado del Ruiz government issues

Answer 18

The government was sued for not having warning or preparation systems by 1000 people for $45 million. The government was eventually cleared of responsibility but was a catalyst for improvement in disaster protection in Colombia and systems at provincial levels

Question 19

Boxing Day 2004 tsunami

Answer 19

Followed one of 4 largest earthquakes with the Indian plate subducted under the Burma plate causing a 1600km fault rupture with most slip in the southern 400km. The primary hazard was the tsunami which caused 280000 deaths in 5 hours. Sumatra and Sri Lanka were hit hardest. Banda Aceh had 31000 deaths. Bangladesh was in an area of slow procession so reduce water displacement. In Simeulue people know from the 1907 tsunami to evacuate to inland hills after the initial earthquake so only 7 out of 78000 died

Question 20

Lake Nyos Cameroon impacts

Answer 20

Is 2k wide and 200m deep. In 1986 lots of gas escaped from the lake and travelled to a village up to 25km away. The clouds of gas were 50m thick travelling 70km/h. 1700 were suffocated and 3000 cattle died as well as all animal life but not plants. The gas was CO2 and deprived people of oxygen

Question 21

Lake Nyos Cameroon source and responses

Answer 21

The source was a basaltic chamber of magma which leaked and accumulated in Lake Nyos. The water was warmer near the surface and colder and denser at the bottom which absorbed the CO2. There was a disturbance at the bottom of the lake causing overlying pressure to be reduced allowing the CO2 to escape. Only 66% of the CO2 escaped and it is building up again so there is a potential for disaster but authorities are trying to drain the CO2 with pumps

Question 22

Sichuan 2008 earthquake impacts

Answer 22

850000 deaths
5300 children died in collapsed schools that were not built to building standards
375000 injured
4.8 million homeless
$146 billion to rebuild and develop region
15000 landslides
10000 potential rockfalls
33 lakes with debris over 10m deep

Question 23

Syrian earthquake background

Answer 23

On february 6th 2023 a M7.8 earthquake struck Southern Turkey and north west Syria followed by a M7.5 aftershock
The region has consistently experienced tectonic activity but this one was the most severe since the Aleppo earthquake of 1822

Question 24

Causes of the Syrian earthquake

Answer 24

Turkey is located along 2 major fault lines along with the movement of 3 major plates where the African, Arabia and Eurasian plates converge. This results in westward compression of the Anatolian block along the East and North Anatolian faults. The east Anatolian fault (EAF) is a 700 km long transform fault with slip rates decreasing east to west. The Dead Sea fault (DSF) is a transform fault between the Arabian and African plates with faster movement in the south compared to the north . The EAF consists of vertical or nearly vertical fractures which involve horizontal movement of cracks. In 2023 multiple segments of the fault failed simultaneously causing a large earthquake. The 2023 earthquake originated from the DSF due to movement between the Arabia and African plates causing the rupture of the southern EAF and the northern DSF. from the Hatay Junction it extent to the northeast and southwest. Tremors were detected in Cyprus, Lebanon, Iraq and Jordan
The initial earthquake caused a 300 km surface rupture and along with the transform movement there was vertical displacement reaching 11.4 m. the second earthquake causing another 125 km of rupture. Overall the causes were the result of highly complex plate movements that proved exceptionally challenging to predict

Question 25

Geological effects of the Syrian earthquake

Answer 25

Liquefaction occurred in former lake beds, river valleys and coastal areas at the southern end of the EAF This led to ground failure and lateral spreading Coastal areas and ports experienced widespread damage due to liquefaction Large residential areas, Hatay airport and canacls were affected, causing flooding In Iskenderun a sea-water incursion 200 m island was caused by rupture subsidence and a minor tsunami

Question 26

Impacts of the Syrian earthquake

Answer 26

Affected 18 million people in Turkey and SYria causing 55,000 deaths and 130,000 injuries 2.6 million were accommodated in tent cities and 1.6 million on the streets 300,000 buildings were destroyed or rendered unusable It accounted for 9% of Turkey's GDP in 2023 Disruption to roads leading to rural areas devastated livelihoods from agricultural production resulted in short term food shortages and long term disruption to farming incomes Water pipes and sewers were disrupted increasing the risk of diseases especially with the living conditions and shelters. 1 in 7 health facilities were partially functions Thousands were traumatized and long term investment in mental health services will be needed 5.4 million children are at risk of anxiety, depression and PTSD on top of the impacts of COVID-19

Question 27

Factors affecting the scale of disaster of the Syrian earthquake

Answer 27

Winter weather Time of day Large child population Syrian civil war since 2011 Transboundary issues International response

Question 28

Challenges to recovery for Syria

Answer 28

Long term displacement Reconstruction of homes and infrastructure Over 90% of Syrian refugees depend on humanitarian assistance for survival Economic decline and global inflation. Syria has seen a price increased of over 800% in the last 2 years resulting in 12.1 million people facing food insecurity The economic downturn has increased the risk of child labour, gender violence, early marriage and other exploitation COVID-19 was a threat due to overcrowded conditions making it hard to improvement public safety measures The war in Ukraine impact food supplies

Question 29

Future threat to Syria

Answer 29

Turkey has 579 dams which leads to Syria and Iraq being highly vulnerable in the event of a dam burst but they lack the financial and political leverage to hold Turkey accountable Turkey is constructing a nuclear power station in an earthquake prone area where a potential meltdown could endanger the whole southeast Mediterranean Istanbul's large population and geographical location means no level of preparedness can fully mitigate the impacts of a large earthquake

Question 30

LEDC building design

Answer 30

Pakistan straw houses Haiti has concrete roofs and not properly reinforced walls Peru houses are reinforced with plastic mesh Indonesia brick walls are framed and connected to the roof

Question 31

San Francisco land use planning

Answer 31

Roads and houses YES on: - flat to gentle slopes subject to local shallow sliding, soil creep and settlement - gentle to moderately steep slopes in solder stablised landslide debris, subject to settlement, soil creep and shallow and deep landsliding - steep to very steep slopes, subject to mass wasting by soil creep, slumping and rock fall NO on: - gentle to very steep slopes in unstable material subject to sliding, slumping and soil creep - moving shallow landslide - moving, deep landslide subject to rapid failure

Question 32

Predicting volcanoes examples

Answer 32

Since 1980 19 of Mt St Helens 22 eruptions have been recorded as well as Alaska Redoubt volcano in 1989. In 1976, 72000 Guadeloupe residents were forced to leave homes and Mammoth Lake in California in 1980 saw a fall in tourist numbers due to volcanic activity concern. Ultrasound used in Pinatubo, El Chichon and Mt St Helen. Observations in Gunung Agung, Java, Indonesia. In 1991 the Pinatubo eruption was successfully predicted and evacuated but did not predict the Mammoth Mountain Ski Area eruption causing reduced visitors and economic activity. St Vincent and St Kitts are high risk, St Lucia and Grenada are low risk

Question 33

Monserrat volcano

Answer 33

Soufriere Hills volcano first erupted in 1995 with the worst on July 25th 1997 killing 9 and destroying Plymouth (capital) and burying most of the south under ash and pyroclastic flow. 7000/11000 residents evacuated to the UK under the resettlement program while others migrated north. Caused 1bn in damages destroying Bramble Airport and the min port. Over 1/2 the land was uninhabitable with ash deposits up to 12m thick. The UK allocated 200m for recovery and rebuilding including housing projects and a new airport and exclusion zone. Has redeveloped northern regions like Little Bay as an economic hub and the observatory

Question 34

Examples of living with volacnoes

Answer 34

History in Iceland and the Philippines Important for tourism in St Lucia and Iceland Culturally symbolic in Mt. Fuji, Japan

Question 35

Adaptations of living with volcanoes examples

Answer 35

Japan's Sakurajima volcano is closely monitored with an alert system for evacuation warning. Roofs have steep angles in Indonesia to prevent ash accumulation and reinforced structures to withstand tremors. In Iceland residents are trained in evacuation procedures and emergency kits and routes are maintained.

Question 36

Rotational slump example

Answer 36

Scarborough in 1993 where the Holbeck Hall Hotel slumped into the sea

Question 37

Landslides in Puerto Rico location

Answer 37

70-80% is hilly or mountainous. Average annual precipitation is <1000mm along the south cost to >4000mm in the Sierra de Luquillo rainforest in the north east. There is more rain in May to October during tropical storm season. The Upland province has 3 mountain ranges and dense vegetation. 45 degree slopes are common. Northern Karst province includes the north areas. The Coastal Plains province is gently sloping with the major cities. 60% of the 3.35m people live in the 4 largest cities on flat or gentle coastal areas. Urban growth is pushing developing onto surrounding steep slopes

Question 38

Puerto Rico landslides causes and effects

Answer 38

Upland and Northern Karst have high relief, steep slopes and abundant rain. In October 1985 a tropical storm triggered thousands of debris flows and a rockslide that destroyed Mameyes killing 129. It is the worst ever Puerto Rico landslide. 100 homes were destroyed and many were later removed due to further risk

Question 39

Puerto Rico landslides responses and costs

Answer 39

Road maintenance is the greatest cost. Frequency of storms suggests an average of 5 deaths, tends of houses destroyed and hundreds damaged per year

Question 40

Chinas 2010 landslide effects

Answer 40

700 died in NW Gans when an avalanche of mud and rock engulfed the town of Zhouqu in a valley. Heavy rain triggered valley mudslides. Landslides levelled an area 5km long and 500m wide, destroying 300 houses

Question 41

Chinas 2010 landslide causes and responses

Answer 41

Heavy tree felling and rapid hydro development made the area vulnerable. The landslide create a loose earth dam. Water levels behind fell after a controlled explosion to make a funnel channel. The landslide was the worst in 60 years and killed nearly 1500

Question 42

Italian mudslide 1998 overview

Answer 42

In May 1998 mudslides in Campania killed 300. In the 2 weeks prior, 1 year of rain fell. It is geologically unstable with active volcanoes, mountains and fast flowing rivers. 18 m pounds were allocated to repair damage. Since 1892, 1173 serious landslides were recorded and have caused 7 deaths per month since 1945

Question 43

Italian mudslide 1998 causes

Answer 43

River Sarno bed was dried and cemented. The mountain clay soils were loose due to fires and deforestation. Houses had been built in landslide zones due to the uncontrolled building in the 1960s. Over 20% of Sarno houses were built without permission, move over a 2m layer of lava. Heavy rain makes the lava liquid washing away 900 m tonnes of material

Question 44

Italian mudslide 1998 risks

Answer 44

Similar will occur in Spain, Portugal, Greece and Turkey since natural absorbers of rainfall are destroyed with development. In Sicily up to 20000 holiday homes have been built without planning permission, drainage or foundations. The Villaggio Coppia di Castelvolturna town with 15000 people was built entirely without permission near a dry river that becomes torrent during storms

Question 45

Venezuela mudslide 1999 government rebuilding plans

Answer 45

Restore the northern coast by rebuilding homes, expanding the airport and constructing diversion canals. Plan includes 40000 new homes in Vargas. Macuto and Camuri Chico were restored for tourism and $100m expanded the airport. Seaport in Vargas was modernised. Devastated towns were not rebuilt but turned into parks, bathing resorts and outdoor facilities. In 2008, mudslides caused 14 deaths. 18000 were affected, 2840 houses were damaged and 363 destroyed. Those affected in 1999 were affected in 2005

Question 46

Venezuela mudslides 1999 causes and effects

Answer 46

The first 2 weeks of December saw 40-50% higher than average rainfall. On the 15th and 16th the 2000m slopes of Mt Avila saw avalanches of rock and mud burying a 300m coastal stretch. The mudslides, landslides and flash floods killed 10000-50000 between the mountains and the Caribbean Sea. 150000 were left homeless in Vargas and Miranda

Question 47

Venezuela mudslides 1999 secondary effects and responses

Answer 47

People in Vargas were bured 8-10m deep while roads, bridges, factores, crops and telecommunications were also destroyed, ruining the tourist industry. The Caracas airport closed as did the coastal highway. Flash floods damaged seaport containers in Maiquetia and they leaked hazardous materials. The seaport efforts to bring emergency supplies were hampered by floods and the economic damage was estimated at $3bn

Question 48

Venezuela mudslides 1999 other effects and responses

Answer 48

May also have been due to corrupt politicians who allowed the building of shanty towns in steep valleys. The immediate response was search and rescue and emergency relief but this was hindered by the poor infrastructure. Up to 70% of the population lives in the overcrowded coast interior which the government was planning to redistribute away from

Question 49

European avalanches of 1999

Answer 49

Killed 75 people in the Alps in February 1999. Occurred in an area that was thought to be safe. Measures (avalanche wall) were taken to defend Taconnaz village Montronc and Le Tour villages has no defences. Swept through the Chamonix Valley killing 11 and destroying 18 houses. Rescue efforts were hampered by cold temperatures and compact snow. Avalanche was 150m wide and 6m high travelling 90 km/h. Region experienced 2m of snow in the previous 3 days. There was minimal avalanche experience in the region since they were a ‘safe zone’. The disruption of weather due to global warming has increased snowfall so the ‘safe zone’ statement would need to be reevaluated

Question 50

Snow slides 2009-2010

Answer 50

Heavy snowfall combined with rain and an easing of the extreme cold prompted Meteo France (meteorological service) to raise the avalanche warning to high risk In 2009 London scientists said rising temperatures and melting permafrost could increase avalanche frequency

Question 51

Hong Kong's Comprehensive Landslip Prevention and Mitigation Programme

Answer 51

Hong Kong experiences frequency landslides due to steep terrain and intense rainfall. The governments mitigation program includes slope safety inspections, public education campaigns and advanced engineering solutions such as retaining walls and slope drainage systems

Question 52

Italy Vaiont Dam Disaster

Answer 52

The 1963 landslide caused a massive wave in the Vaiont Reservoir leading to over 2000 deaths. Lessons from this disaster emphasized the importance of monitoring slope stability and understanding geological conditions during large scale infrastructure projects

Question 53

Japan Kobe Landslides

Answer 53

Following the 1995 earthquake, numerous landslides occurred in Kobe. Japan's response involved extensive hazard mapping, the construction of debris flow dams and the integration of advanced seismic data into slope stability assessments

Question 54

USA Oso Landslide

Answer 54

The 2014 landslide in Washington State resulted in 43 fatalities. Subsequent investigations highlighted the need for improving hazard mapping and stricter land use policies. The area now serves as a case study for integrating historical records with modern predictive tools

Question 55

Describe the key differences in the impacts of Cyclone Idai and Cyclone Kenneth on Mozambique in 2019.

Answer 55

Cyclone Idai caused 603 deaths while Kenneth despite being a category 4 storm produced only 45. Idai also injured significantly more people at 1641 compared to Kenneth at 45. Due to the intense rainfall from Idai inland areas were subject to severe flooding reaching over 6 metres in some places and submerging entire communities. All 17 hospitals were damaged where Idai struck as well as roads in and out of the city along with communication networks. Idai destroyed 168,000 ha of crops which were ready for harvest, increasing the risk of famine in the country. Kenneth caused widespread power outages across urban areas due to house and tree damages. 4 ships were sunk off the coast of Pemba due to the 140 mph winds and 90% of houses were destroyed.

Question 56

Evaluate how physical factors, such as storm magnitude and rainfall, contributed to the severity of Cyclone Idai compared to Cyclone Kenneth.

Answer 56

Cyclone Idai brought very heavy rainfall causing significant flooding which killed 66 people alone. 5756 houses were damaged by floodwaters as well as 168,000 ha of crops. The main risk of this cyclone was the wind due to the poorly constructed houses. Roofs became a hazard in the high winds with 1500 people being treated for injuries due to flying debris. The storm surges that reached up to 4.4m in height, in addition to the earlier flooding, further devastated the city. Inland areas were also largely affected due to the flooding from intense rainfall. Cyclone Kenneth produced 140 mph winds causing widespread damage also but made landfall further north in a less densely populated area leading to a large reduction in the number of deaths.

Question 57

Discuss how socio-economic factors, such as poverty and corruption, have increased Mozambique’s vulnerability to tropical storms.

Answer 57

The reliance on agriculture increased Mozambique’s vulnerability to famine due to the floodwaters that destroyed many crops that were ready to harvest. The response to these cyclones is also likely to be slow due to the lack of reliable infrastructure and a lack of technology and communication in rural areas leaving them unable to receive warnings in sufficient time to evacuate or take the necessary precautions.

Question 58

Explain why Cyclone Kenneth, despite being of higher magnitude, caused less damage than Cyclone Idai.

Answer 58

The main reason is the level of predication and preparation. After the damage caused by Idai, the international community and Mozambique officials focussed on monitoring potential tropical cyclones. Accurate predictions were made about when Kenneth would make landfall leading to pre-disaster evacuations. 30000 people were evacuated before Kenneth. Kenneth also made landfall in a less densely populated area so less people were in danger and less people needed to be evacuated. Cyclone Idai also made landfall twice, the second time exacerbating the damages of the first time. In the case of Kenneth, the storm dissipated much faster over land, leaving a lesser impact on the area.

Question 59

Assess the effectiveness of local and international responses to Cyclone Idai. Include specific examples in your answer.

Answer 59

Due to the size of the cyclone, local efforts were not enough to mitigate the devastation that occurred. The National Disasters Management Institute coordinated the response by deploying boats and helicopters to rescue people from the most affected areas. However, a week after the initial impact, 15000 people still needed rescuing. Those that were rescued were placed in evacuation centres but these were in a poor condition with limited food and clean water leading to a cholera outbreak. This outbreak was mainly a result of the major flooding and the number of bodies that had not yet been buried.

Question 60

Analyse the role of NGOs, such as Medicines Sans Frontières, in mitigating the impacts of Cyclone Idai and preventing further health crises.

Answer 60

The UN World Food Programme declared the cyclone a level three emergency, rendering it the highest level of priority for them. The Medicines sans frontiers also provided relief by mobilising 140 international staff, establishing a 40 bed hospital and distributing chlorine and soap to over 10000 households in order to stop the spread of further disease. This response was relatively slow initially due to excess problems as a result of damaged infrastructure and an underestimation of the severity of the impacts and poor standards of communications in many rural areas

Question 61

Examine how Mozambique’s limited infrastructure and resources hinder long-term recovery efforts after major tropical storms.

Answer 61

There are limited government funds to prepare for disasters including investing in reliable infrastructure. Education programmes are limited so people are less prepared for what to do in the event of a tropical cyclone. This leads to less management and less warning time given when these events do occur. Due to poverty, evacuation can be difficult since not all of the population has access to phones or internet networks to receive evacuation warnings. There is also high population densities in informal settlements which are less stable in the event of tropical cyclones. Corruption in the Mozambique government has led to less capital being allocated to tropical cyclone management.

Question 62

To what extent do you think climate change will exacerbate Mozambique’s vulnerability to tropical storms in the future? Provide evidence to support your argument.

Answer 62

The impacts of rising sea temperatures on storms will cause higher sea levels and the impacts of storm surges will become more significant. This is especially destructive in Mozambique since funding poverty is a higher priority than constructing coastal defences to protect against these storm surges.

Question 63

Compare the evacuation strategies used for Cyclone Idai and Cyclone Kenneth, and discuss how they influenced the overall impacts of these events.

Answer 63

The response from international communities and NGOs to Cyclone Kenneth was much faster since they were already in Mozambique responding to Idai. The World Food Programme created stocks of food and water before the storm so they could be more easily distributed after the cyclone made landfall. 3000 people were moved to evacuation centres after the cyclone hit and a more extensive cholera vaccination scheme occurred to prevent a similar outbreak to the one after Idai.

Question 64

Using the Swiss Cheese Model, evaluate how the combination of multiple vulnerabilities and risk factors led to the catastrophic impacts of Cyclone Idai.

Answer 64

Cyclone Idai is an example of the Swiss Cheese model which demonstrates how even relatively small magnitude events can have severe impacts when certain factors come together. Poorly constructed homes and defences provided insufficient protection against the storm while deforestation, climate change and poor urban planning exacerbated the flooding and damage. The warnings were insufficient to evoke timely evacuation and due to a lack of resources by local people and limited healthcare, the overall impacts were weighed as people could not respond effectively themselves.

Question 65

Where tornadoes occur

Answer 65

Tornado Alley USA. The central us (Texas, Oklahoma, Kansas, Nebraska) have the highest frequency due to ideal conditions for severe thunderstorms. Parts of Canada, northern Mexico, Argentina, Brazil and Bangladesh. Happen on every continent except Antarctica but less and weaker outside of north America. April - July have the most

Question 66

USA conditions that are favourable for tornadoes

Answer 66

Has the flat plains of Midwest (Tornado Alley) allowing unimpeded interaction between cold, dry air from Canada and Rockies and warm moist air from the Gulf of Mexico. The collision of air masses and strong upper level jet streams create the wind shear for tornado formation especially in spring and summer months. The USA has frequency supercell thunderstorms which are the main weather that produces tornadoes due to powerful rotating updrafts (mesocyclones)

Question 67

Indiana tornadoes overview

Answer 67

Indiana is in Tornado Alley with high intensity tornadoes. March to June is tornado season there. The most destructive are in March and April with June having the most in one day (37) and month (44) in 1990. From 1950-2001, 1024 tornadoes caused $1.7bn in damages and killed 223

Question 68

March 1925 Indiana tornado

Answer 68

The Tri State Tornado travelled 352 km from Missouri, Illinois and Indiana, Half of Princeton was destroyed with losses of $2m. 700 people died (74 in Indiana and 234 in Illinois)

Question 69

April 1965 Indiana tornado

Answer 69

11 tornadoes struck 20 counties in northern Indiana killing 137. 1700 were injured and property damage was $30m. It was part of a 50 tornado outbreak that hit the Great Lakes region causing 271 deaths and 3400 injuries

Question 70

April 1974 Indiana tornado

Answer 70

The most destructive tornado (super outbreak) occurred. 148 tornadoes hit 13 states with a 4000 km path of destruction. 300 died and 5000 were injured. In Indiana, 21 tornadoes hit 39 counties killing 47 with 5 of them reaching F5 and 23 reaching F4

Question 71

Recent volcanic eruptions

Answer 71

Mt Lewotobi, Laki Laki, Indonesia: November 2024, 10 deaths Mt. Semeru, Indonesia: December 2021, 57 deaths, 10000 displaced White Island, New Zealand: December 2019, 22 tourist deaths Fuego Volcano, Guatemala: June 2018, 332 deaths, communities buried

Question 72

Understanding, communicating and managing vulnerability and risk

Answer 72

Mt. Merapi, Indonesia: The community relies on traditional knowledge and early warning systems to manage risks. Local spiritual guardians work with scientists to enhance understanding and communication Eyjafjallajokull, Iceland: Communication in the 2010 eruption involved collaboration between scientists, emergency responders and media to minimise impacts and ash dispersal risks

Question 73

Maximising benefits during inactive periods

Answer 73

Mt Etna, Italy: Fertile volcanic soils support agriculture (vineyards and orchards). Tourism for hiking volcanoes contributes to the economy without increasing vulnerability Mt. Fuji, Japan: Attracts tourists for culture and recreation generating income for communities while preserving the spiritual significance

Question 74

Managing crises

Answer 74

Mt. Pinatubo, Philippines (1991): Timely evacuation of over 60,000 people saved lives through monitoring by the Philippine Institute of Volcanology and Seismology, collaboration with the US Geological Survey and extensive public education campaigns Nyiragongo, Democratic Republic of Congo (2021): The evacuation of 400,000 residents from Goma was a critical response but there were challenges due to limited resources and communication gaps

Question 75

Managing reconstruction and resettlement after a crisis

Answer 75

Mt. Tambora, Indonesia (1815): Communities rebuilt agricultural systems around the newly fertile soils which were a long term livelihood strategy Soufriere Hills Volcano, Monserrat (1995): Ongoing resettlement has focused on rebuilding infrastructure and developing livelihoods in the north after must of the south was uninhabitable