Hazards Flashcards

Question

How does silica content affect the lava?

Answer 1

> amount of silica, more sticky + explosive it will be

Answer 2

Not erupted for 10,000 years and is not expected to again

Answer 3

Volcano which has had an eruption in the past 10,000 years + is expected to again

Answer 4

Not currently active but is expected to erupt again

Answer 5

British Overseas Territory In Caribbean Surrounded by Caribbean sea

Answer 6

Part of island arc Formed from subduction of the South American plate under the Caribbean plate Therefore = volcanic island formed from multiple eruptions

Answer 7

Pyroclastic flows reached 600 degrees celsius + 120km/h Violent eruptions- rhyolitic lava + pyroclastic flows Main explosion was 2 years after the 1st eruption

Answer 8

-Islands airport was destroyed by being in the path of the pyroclastic flow -2/3 of all houses were buried by ash/flattened by rocks -South of the island was covered by pyroclastic flows, including ash, lahars + rocks- ended up being an exclusion zone -People had to abandon homes + businesses -19 killed -100s left homeless -Pyroclastic flows caused associated fires + also caused burns + inhalation injuries -Many chose to evacuate- became ghost island

Answer 9

-Setting up Montserrat volcano observatory in 1995- predicted the 1997 eruption -NGOs provided aid -Rebuilt the tourism industry- used volcano as an attraction -People on Montserrat granted full residency rights in the UK- could choose to migrate -Making the south, including the former capital Plymouth, an exclusion zone

Answer 10

-Plates can’t move past each other easily -Two plates become locked -> friction -> pressure builds up -Pressure released -> seismic waves

Answer 11

Point directly above the focus on the Earths surface

Answer 12

Point at which rock moves- seismic waves start here Deep focus = greater magnitude- but do less damage because energy is further dissipated

Answer 13

Body waves: -Primary waves = move backwards + forwards -Secondary waves = move vertically/horizontally Surface waves: -Love waves -Rayleigh waves

Answer 14

Shallower + less powerful Occur on mid-ocean ridges - away from land

Answer 15

Shallow focus Compressional forces high- continental plates drag past each other Very powerful- severe damage in dense populated areas

Answer 16

-tend to be at depth -compressional forces at greater- subduction one crust in narrow area -very powerful -can take place under sea- tsunami threat

Answer 17

Logarithmic 1-10 Each increase, 30x more energy Accuracy decreases for larger earthquakes

Answer 18

Total distance fault has moved + force needed to generate it Now used worldwide

Answer 19

12 point scale Effect on people + infrastructure Severity on humans rather than objective measurement Qualitative

Answer 20

-Mining = highest number of human-induced earthquakes worldwide - removal of material -> instability -> collapse -Dam building -Fracking. - disposing of wastewater used in the process -> high pressure -> cracks rocks

Answer 21

Human: -population density -level of development -prediction -earthquake proofing -education + politics -wealth Physical: -location of epicentre -time of day -geology -depth of focus -plate boundary

Answer 22

1. Soil liquefaction 2. Tsunamis 3. Landslides + avalanches

Answer 23

-Japan located at junction between 4 major plates -Magnitude of 9 = biggest ever recorded -Depth of 30km -Preceded by large foreshocks over previous 2 days -shaking lasted over 3 minutes

Answer 24

Primary: -16000 killed, 6000 injured -shifted Earth on axis by 10cm -limited damage in Sendai + Tokyo- earthquake proofing -127000 buildings destroyed + 1 million damaged in northeast Japan -4.4 million households left without electricity + 1.5 million without water -only 4 trains derailed Secondary: -1800 houses destroyed when Fujinuma dam failed -tsunami waves after 20 minutes - travelled 10km inland in Sendai -nuclear meltdown in 3 reactors -ice calved from Sulzberger ice shelf -cost > $300 billion - most expensive natural disaster in history

Answer 25

-116 countries + 28 international organisations -military had to bury in mass graves -declared state of emergency -55 nuclear reactors taken offline -> rolling power blackouts common for weeks -food exports restricted (radiation fears)

Answer 26

Huge low pressure storm which develops within the tropics Powerful Cause devastation to small islands + coastal regions

Answer 27

-ocean temp > 27 degrees (therefore mostly occur in summer/autumn) -ocean depths > 70m -high heat -> violent updrafts of air -high levels of humidity -trade winds (major winds all blowing in same direction) -between 5-15 degrees N+S of Equator- needs spin from Coriolis effect

Answer 28

-Measures tropical storm -Wind speed + give estimate on how much damage a storm will cause -Category 5 = strongest, catastrophic damage -Category 1 = weakest, limited magnitude of damage

Answer 29

-Heavy rainfall -High winds -Storm surges

Answer 30

Physical -low lying land = 51% New Orleans at/below sea level -storm surges = warm waters nearby intensify Human -high population density - 485k in New Orleans -failure of levees -loss of wetlands- used to provide natural barrier -delayed implementation of rescue plans

Answer 31

-1800 died -value of property damage = $161 billion -4 years later - 1000s displaced residents still living in trailers -Head of FEMA resigned -led to looting in New Orleans -2015 = population of Lower Ninth Ward <40% pre-storm level -residents in Lower Ninth Ward = held pessimistic views about recovery of the community

Answer 32

-May 2008 -in monsoon region of Asia -next to Bay of Bengal - warm and moist air -had limited mitigation + organisation after the event -> more deaths -nearly 2 million people along coastline living on land < 5m above sea level

Answer 33

Distinguished from other forms of fire event by being beyond control for an initial period of time in a natural environment. Known as ‘quasi-natural’ wildfires = created by human + natural factors

Answer 34

1. fuel 2. oxygen 3. a heat source -all 3 must be present for fire to continue

Answer 35

-Large forested areas -warm climates e.g. California -rural hazard -can occur in most environments -areas with distinct dry seasons e.g. Mediterranean

Answer 36

Ground fires = burns beneath ground in layers of dry organic peat, 540 degrees, smoulder, burn for longer periods Surface fires = across surface vegetation, dry conditions, 900 degrees, easiest to control Crown fires = spreads across tree canopies + forested areas, 1100 degrees, quick + intense, little control, worse on steep slopes

Answer 37

Winds blow ‘fire brands’ away from crown fires onto new areas, like fireballs- fly from burning treetops to other new places -> spreads new fires

Answer 38

Large, destructive fires

Answer 39

Occur in large forested areas, mostly in warm climates such as California Can occur in most environments Expansion of towns/cities mean they’re now closer to human occupation Dry vegetation is most susceptible to natural wildfires from lightning strikes Distinct dry seasons, such as in Mediterranean makes them high risk

Answer 40

Humidity = > 15%- wildfire risk = low, < 7% risk is much > Temperature = higher temps mean absorb moisture from fuels -> can catch fire as more dry

Answer 41

Wind = change direction of fire, provide fresh supply of oxygen Topography = fires move faster uphill, steeper slope = faster burning (as more fuels in close proximity)

Answer 42

USA = summer has > fires, heat makes fuels drier + provides richer oxygen West Africa = Harmattan Winds (Nov - March), blow from Sahara desert + make fires burn more

Answer 43

> 9,000 wildfires in last months of 2017 -> 1.2 million acres of land, killed 46, destroying around 11,000 structures 2 major outbreaks -> October event know as Northern California firestorm where 21 of these fires became major fires

Answer 44

at least 12 of Northern fires caused by electric power + distribution lines Exacerbated by strong Santa Ana winds

Answer 45

-Little precipitation from May 2017 onward- autumn precipitation was substantially delayed- Sep-Dec precipitation = exceptionally low -Population growth placed more people in the way of fires (building on the wildland-urban interface- 3.6 million properties situated here) -2017 = longest duration of Santa Ana winds for > 70 years- brings warm + dry air (low humidity) -Policy = fewer control burns as policy is to just suppress all fires -> poses > risk when fires occur (constrained in ability to prevent fires) -Winds drove fires west + south across slopes- made it more destructive

Answer 46

Social = shutdown of US 101 (traffic disruptions), school closures, > 230,000 forced to evacuate Economic = wine industry experienced damage ($58bn to state in 2016), damage estimated to be $180bn Environmental = burned over 307,900 acres, floods + mud/debris slides (damage to topsoil) Political = fires had a larger impact as funding goes into suppression + not prevention

Answer 47

-Satellite imagery -Air quality updates -Social media to send messages -“Major disaster declaration” approved by Trump -deployment of California’s National Guard -FEMA sent aid (40,000 meals, 40,000 blankets) -$18.9 million spent on emergency relief

Answer 48

-Legislators = increase fuel treatments by timber thinning + prescribed burns -Gov. Brown = issued to establish training + certification programs for prescribed burns -> doubled number of actively managed acres

Answer 49

-Located on a plate boundary -Located in Gulf of Mexico- prone to tropical storms -Earthquakes, tropical storms, flooding, mudslides

Answer 50

-Social = 800,000 had to live in 450 camps (only 3 had potable water), collapsed buildings caused most deaths, 4,758 schools damaged/destroyed -Economic = capital city destroyed, capital’s main port was destroyed -Environmental = cholera from infected UN troops (10,000 deaths), bodies buried in mass graves -Political = gov + parliament buildings destroyed, political unrest + gang violence, US felt responsibility to help, injured survivors went to hospital in Dominican Republic + overwhelmed them

Answer 51

-Physical = Enriquillo fault line runs through Haiti, shallow earthquake + epicentre 25km away from capital -Human = living in flimsy huts, buildings made with weak cement without steel rods, poverty (poorest country in Western hemisphere), low level of resilience

Answer 52

Aid workers used GPS to show current coordinates of camps + potential dangers- allowed to keep track of logistics of delivering aid People hand-moved rubble First 2 weeks- tents could only be provided for 25% homeless

Answer 53

40% rubble removed after 2 years by UN partners + locals Little available space to move people out of emergency tents due to lack of rubble clearance 2 years later- $5.5bn pledged by countries + agencies but only 53% released to projects