Hazardous environments

global distribution of earthquakes and volcanoes

earthquakes: occur in linear chains across plate boundaries which vary in size
broad belts of earthquakes associated with subduction zones whereas narrow belts are constructive
volcanoes: most found along plate boundaries which have molten rock along pacific ring of fire caused by subduction which produce more viscous lava then mid-Atlantic ridges

types of body waves in earthquakes

P waves which travel by compression and expansion able to ass through rocks, gases and liquids
S waves which travel in side to side motion only able to pass through solids
when these waves reach the surface some become surface waves in love or Raleigh waves that do damage

resultant hazards from earthquakes

may involve surface displacement along fault lines
landslides, liquification (conversion of unconsolidated sediment into liquids) and tsunamis

ways of measuring earthquakes

Richter scaler
Moment Magnitude scale which measures amplitude and seismic movement

factors affecting earthquake damage

strength and depth of earthquake, population density, type of buildings, time of day, distance from epicentre, types of rocks (solid rock over loose material), secondary hazards, economic development

Japan 2011 Earthquake causes

high seismically active with Eurasian, Pacific and Philippines plates where pacific plate was submerged under Eurasian plate
epicentre located on ocean floor creating 40m high tsunami
7.2 Richter scale which was 5th largest since 1900
4.9 trillion GDP

primary and secondary impacts for Japan

primary: 20,000 deaths, 300,000 buildings destroyed and 4,000 roads, 300billion damage to infrastructure
secondary impacts: 11 elderly people died in residential home due to temperatures below -4, outbreak of disease such as diaherrea bronchitis and hypothermia, Fukushima Daiichi nuclear power plant release of radiation with 4/6 nuclear reactors in trouble, 17,000 jobs lost

response Japan

short term: 330,000 housed in temporary accommodation and 500 evacuation shelters
accommodation in schools and public buildings but with no accommodation, closed all 54 power stations
Japanese Red Cross appealed for aid
long term: reconstruction agency 2012 provided 5 billion, plans for indoor arena to protect fishing vessels

ineffective

inadequate heating in evacuation facilities caused deaths by hypothermia
needed a rebuilding cost of 300 billion over 10 years

prediction earthquake

use seismology to give warning of potentially damaging earthquake to allow a response to the disaster to minimize loss of life and property
no accurate way to predict an earthquake
Haiti US geologists presented paper in 2008 that Port-au-Prince would face a 7.2 magnitude earthquake when did not know when

preperation earthquake

building designs and earthquake resistant structures (shock absorbers, shutters on windows, frames which shake with earth tremor)
land use planning (don't build services in high risk areas)
earthquake drills
emergency planning
Haiti- poor building codes due to unstable government with history of poverty and conflict (70% of population live on less then £2 a day)

monitoring earthquake

tiltmeters- measure ground shakes
changes in radon gas emissions
changes in animal behavior
remote sending of ground movement by satellites to help land use planning
Haiti- since earthquake there are now 7 seismic stations and seismology technical unit in Port-au-Prince helped by the US as during the event there was only 1 working seismology station and no seismic network

Haiti earthquake causes

occurred on Enriquillo fault with the meeting of Caribbean and North American plates with epicenter 15km away from Port-au-Prince and produced 3 after shocks
GDP 20.9 billion

impacts Haiti

primary: 222,500 deaths, 75,000 buried in mass graves, 1.5 million left homeless, main port destroyed, Leogane had 80-90% of buildings destroyed, 300,000 injured
secondary: cholera outbreak by UN workers killing 600 from improvised shelters, gang violence, 2 million left without water and food, crime levels increased from looting and sexual violence

responses Haiti

short term: USA sent rescue teams and 10,000 troops, 225,000 moved from Port-au-Prince to less damaged cities, UK donated 20 mil, assembled 24,600 shelter kits
long term: EU and world bank gave 330 million, repaired 683 homes in Port au-Prince and trained 6,000 in construction skills
however 1M still lived in shelters 1 year after, only 48% of money went directly to the people
low preparation due to high poverty levels

earthquake formation at destructive plate boundaries

denser plate subducts (oceanic) leaving a deep ocean trench and causing a build up of pressure from the melting plate that causes explosive volcanoes to burst through the continental plate
as plates lock with one another which when pressure builds produces seismic waves

earthquake formation at constructive plate boundaries

magma rises in-between the gap left by the two separating plates forming new land as it cools as plate move at different speeds pressure builds until late cracks causing fault lines and realising energy to produce earthquakes

why volcanic eruptions vary in magnitude from plate boundaries

plate boundary- destructive lead to subduction causing stratovolcanoes with highly viscous lava with high silicates where gas build up and lead to explosive eruptions
constructive have fluid basaltic lava and low silicates which flows easily so lower magnitude

why volcanic eruptions vary in magnitude

amount of dissolved gas as low-viscosity magma allows gases to move through the magma and to the surface whereas viscous magma traps gas bubbles that cannot escape
strata volcanoes are the most powerful as the gases within the magma are placed under intense heat and pressure and are released during eruption

volcanic hazards

eruption column blasting tephra to produce cloud and can result in ash fall that can collapse buildings
Volcanic gases- released even when not erupting that can produce acid rain or fluorine and lower surface temperature of earth
lava flows- molten rock that pours on earth where the less silica the easier it flows
Pyroclastic flows (nuee ardente)- avalanches of hot ash down a volcano
volcanic landslides common in steep volcanoes
laharas are mudflows or debris flows
can cause flooding with eruptions from melting of snow or tsunamis from violent submarine explosions

rock types

Rhyolite- high silica, high viscous, most explosive
Andesite
Basalt- low silica, low viscosity, low explosivity

volcanoes direct and indirect resultant hazards

direct: pyroclastic flows, volcanic bombs, lava flows, ash fallout, volcanic gases, nuees ardentes, earthquakes
indirect: ash fall out, landslides, tsunamis, acid rainfall and lahars

volcano prediction

seismometers , chemical sensors detect sulphur levels, lasers detect physical swelling, ultrasound monitors low-frequency waves, history of volcanic activity
however these factors often don't allow time to prepare
1987 Monserrat eruption precursors were ignored
very few records of old eruptions or have reliant recurrence interval

Monitoring volcano

seismology detects movement of magma in the ground through shaking , geodetic techniques look at ground deformation, gas monitored, thermal imagery

preparedness volcanoes

roof strengthening against tephra, building structures against Lahars, diverting lava through explosives, degass volcano and surrounding area, emergency responses, create exclusion zone
- Monserrat 1997 eruption 19 deaths due to failure to provide alternative safe lands fo farmers

E-14 volcanic eruption impacts

primary: 0 deaths, airlines lost £130M from no flying, contaminated local water supplies, 107,000 flights cancelled
secondary: sporting events cancelled, imports stopped causing 50,000 Kenyan farmers to be unemployed

E-14 volcanic PPM

56 seismic stations and 78 GPS stations
Icelandic metrological office worked with British to track the event
in 2006 government created a full scale test of evacuation plan
800 residents evacuated, declared no fly zone
European Red Cross provided food and evacuated 700

factors causing increased shear stress

removal of lateral support through undercutting (erosion by rivers), removal of underlying support (undercutting by rivers), loading of slope (weight of water), lateral pressure (water in cracks), transient stress (earthquakes)

factors causing reduced shear strength

weathering effects (disintegration of rock), changes in pore water pressure (saturation), changes of structure (fissures in clay), organic effects (burrowing of animals)

mass movement

movement of surface material due to gravity from natural or human activity

impacts on lives and property

financial loss in building damage
dependant on human activity such as increasing the slope angle by cutting through high ground or placing extra weight on a slope, removing vegetation or exposing rocks

conditions needed for tropical storm

sea temperatures above 27 degrees for a depth of 60m as provides energy as heat to drive the storms,
low pressure system away from the equator to stimulate Coriolis force (5-20 degrees N or S) for air to rotate
atmospheric instability so winds rise with high humidity for latent heat
weak winds in upper troposphere to transport excess heat away (low vertical wind shear) and allow eye to form,
presence of tropical disturbance in large areas of unsettled weather

tornado formation

- need moisture, instability, lift and wind shear
warm moist tropical air from equator meets cold air from the poles and rotate cyclonically due to Coriolis force causing warm air to rise and form intense low pressure system

tropical storms related hazards

rainfall and inland flooding in producing widespread rains
storm surge with heavy winds pushing the ocean causing sea level to rise
high wind speeds

tropical storm prediction

satellite imagery, ocean buoy data, hurricane hunter aircraft, ,weather balloons
well monitored at sea fed into computers to generate storm trackers
equipment is expensive
typhon Haiyan predicted two days before with storm surge warnings given to PAGASA but still 6,300 deaths
movement erratic so not possible to give more then 12 hours of notic
2006-2026 there were 20 tropical cyclones in the Philippines

tropical storm monitoring

satellite observations providing visuals, low lying probes, doppler radar, weather radar to monitor storm's characteristics, national updates in studying oceanic and atmospheric conditions and provide warning
allows for initial detection of hurricane to predict behaviour
monitoring data before hurricane forms is poor
Typhoon Hyhan generated 96 hour storm surge forecast by japan metrological agency and 6 hour weather bulletins to update the population

tropical storm preparation

install storm shutters, reinforce concreate columns to lift houses above ground, backup power sources, classify flood zones, vegetation to mitigate damage, education and evacuation plans, protective river embankments, risk assessments by analysing climatographic records or history of wind speeds, land use zoning
Haiyan extensive hazard maps published in 2013 in READY community project, Education campaigns set up to understand hazard maps, disaster risk reduction and management act 2010

tornado

small and short lived but highly destructive storms with no effective way of management

Typhoon Haiyan 2013 primary and secondary impacts

primary: 6,300 deaths, 2.02 billion in damages, storm surge 5-6 metres on coast of Leyte
secondary: economic losses of 1 billion, 1.9 million homeless, looting in Tacloban city
category 5 typhoon

Typhoon Haiyan reponses

curfews and security checkpoints to reduce looting, donations of 500 million from NGO's and governments, for field hospitals, shelter boxes and evacuation shelters, office of US foreign disaster gives 20 M
long term: UN set up habitat programmes and cash for crops for rebuilding

Explain why volcanoes are not found at all types of tectonic plate boundary. [6]

Volcanoes are formed by rising magma
• This may be due to the rising limbs of convection currents (divergent
boundaries)
• Or the melting of subducted plate edge material (convergent
boundaries)
• Neither of these situations arise at collision boundaries
• Or conservative (transform) boundarie

explain why the location of tornadoes varies

For tornadoes to form there needs to be a combination of moisture,
instability, lift and wind shear. These conditions vary spatially, thus tornado
locations vary. Tornadoes are formed when warm moist air meets cold dry
air. Thunderstorms often result from these conditions but many
thunderstorms do not develop into tornadoes. This is one of the reasons
why the location of tornadoes varies. There needs to be the correct
combination of factors. These factors vary in the location. Thus, the answer
needs to be based on a thorough understanding of these factors.

tornado damage

strong wind speeds, rotational movements and powerful uplift from low atmospheric pressure at vortex create falling debris
kill 60 people a year

tropical storm formation

-warm, moist air rapidly rises forming an area of low pressure-air from high pressure rushes in to take place of the rising air

-this air then rises forming a continuous flow of rising air

-as the air rises it cools + condenses. this releases heat energy which helps to power the tropical cyclone

-air at the top of the storm goes outwards way from the centre of the storm-the Coriolis force causes the rising air to spiral around the centre

-some of the air sinks in the middle of the storm forming the cloudless, calm eye

-the tropical cyclone moves westwards from its source

-when a tropical cyclone makes landfall or moves over an area of cold water it no longer has a supply of warm, moist air + loses speed + temperature. rainfall and winds decrease

tropical storm vs tornado damage

tropical storms cause more damage because of larger size, longer duration and variety of ways to cause damage as have larger diameter and can cause storm surge and flooding but tornadoes are smaller in diameter last for less time and only cause faster wind speeds

tropical storm vs tornado physical differences

Tornadoes- smaller diameters produced from single convectional storm with high vertical wind sheer, mainly over-land which develop through convection, last from minutes
Tropical storm- larger diameter comprised of several convective storms with low vertical wind sheer which develop over sea and die over land from loss of moisture, last for days

Moore tornado 2013

PI: 24 deaths 300 homes destroyed, 61,500 power outages, 7 children killed elementary school
SI: 2 billion damage
Moore tornado 2013 had warning and emergency centre 36 sirens and automated mass calls so only 24 deaths and 300 homes destroyed
Moore killed 1/3 less people then last evet with underground shelters

human activities increase risk of landslides

increasing slope angle
placing extra weight on the slope
removing vegetation
exposing joints and bedding planes

human activities decrease risk of landslides

building restraining structures
exacting and filling steep slopes
draining slopes
watershed management e.g. afforestation increasing interception reducing overland flow

avalanches

mass movements of snow and ice occuring on steep slopes especially where lack sun inhits stabilsation of new snow
loose avalanches form after snowfall wheras slab are later when snow has cohesion which are more destructive started by sudden rise in temperature

volcano primary and secondary impacts

primary: pyrocastic flows, lava flows and volcanic gases, ash fall damage property and people
secondary: lahars, tsunamis, climate chnange, ash clouds disrupt air travel

Explain the factors which influence the hazard of soil liquefaction.

population densities, vulnerable infrastructure etc

areas of loose, unconsolidated materials. These are typically found in coastal areas of marine deposits and river valleys with fluvial deposits. They may also occur in areas of glacial/fluvio-glacial and aeolian deposits such as former lake beds. Liquefaction occurs when the sediments are shaken such as by an earthquake. Thus, the location of the epicentre and the magnitude of a particular event

process by which water-saturated sediment temporarily loses strength and acts like a fluid.

formation of a tornado

cold air meets warm air to create instability
convention causes conombolous clouds to form
high vertical wind shear leads to horizontally rotating air column with updraft and downdraft separating forming supercell thunderstorm with rotating updraft as a mesocyclone
if warm humid air flows to mesocyclone it will stretch and descend with air pressure falling rapidly and touched ground as a tornado

tornado hazards

heavy rainfall from conombilous clouds form from instability and convection and ice droplets become large and accnot be supported, pressure imbalance rapidly reduces extrenal pressure so walls and roof explode outwards , strong winds, hail where water droplets are taken up by updratfs which freeze at top of the cloud and get larger coated with ice which fall and are too large too melt ,
US 400M damage kill 70 people

physical and human factors cause of landslides

physical: amount of rainfall, steepness of slope, vegetation cover, characterises of slope (weakness or bedding planes)
human: deforestation, climate change, urbanisation

mass movement prediction

look at locations occurred in the past and landslide inducing factors such as slope, geology and land use
warning messages sent by National weather service Montecito
LHASA model identifies areas with heavy recent precipitation used to generate maps in Guatemala and Honduras

mass movement monitoring

deformation monitoring through InSAR, satellites, rainmeter an pressuremeter to assess occurrence intensity and impact
US geologists created landslide monitoring programme 2023 recording 1,200 landslides above Montecito

mass movement preparation

Terracing. Afforestation. Drainage Controls. ...Relocation. ...Slope Leveling
low dam built by Army corps engineers 1964 with 16 basins
16 foot high dam
mandatory evacuation zones evacuated 21,100 Montecito 2018
government officials ignored warnings to build bigger basin or empty existing basins 17 of 23 deaths outside mandatory evacuation zone
national scale hazard assessment along St Lucia and Dominica for drainage interventions

Montecito primary and secondary impacts 2018

8,000 population, steep topography experienced drought then heavy rainfall and wildfires
PI: 23 killed 100 homes destroyed, 20,000 lost power, 30 mile sector of route 101 shut,
SI: £177M in property damage, Thomas fires burnt 280,000 acres of vegetation

Montecito short term and long term responses

short term: 300 residents in Romero canyon rescued, 1,250 firefighters dispatched for search and rescue. US army corps of engineers awarded contracts to remove debris
long term: 500,000 grants to local community, victim's fund provided 1.1M in direct financial assistance

hazards in Japan

111 active volcanoes with 15 events a year as located on the ring of fire
tsunamis, floods, typhoons, earthquakes

PPM in Japan

JMA earthquake observation network of 200 seismographs and 600 seismic intensity metres for 50 volcanoes
mobile observation teams and publish volcano information in bulletins
volcano observation and warning centres

Japan preparation

volcano warning and forecasts for each active volcano
tsunami evacuation drills 2017 for 800,000 people
47 societies for disaster reduction 2016
Earthquake 2011 where all municipalities had hazard maps but only 20% knew how to use them
695 designated hospitals for injured

Japan response

build back better scheme after 1995 earthquake collapsing 100,000 buildings to reconstruct and relocate to elevate land, increase height of sea wall

Hurricane Harvey PI and SI

280 miles wide, 130mph, 103 million litres of rain category 4
PI: 13 million affected, 204,000 homes destroyed, 125 billion in damage, 88 deaths
SI: 39,000 in shelters, 72/275 schools closed, 6.1M cubic metres of rubbish

Hurricane Harvey PR and LR:

PR: 6 billion by government, disaster response team, free school meals for 18 months
LR: used GIS to improve assessment of risk, medicines supplied by NGO's
Hurricane Harvey 27 projects removed 11,000 homes from floodplains, 2018 new building codes, 60 million spent to elevate homes

lahars

when tephra mixes with water (often from melting snow and ice) to create very fast deadly mud flows that cand have

what type of volcano is formed at a constructive (divergent) plate boundaries?

shield/cinder cone

what happens at a collision boundary?

-2 plates of similar density move towards each other-neither is dense enough to sub duct so the land is pushed upwards

what is the difference between oceanic and continental crust?

-oceanic crust is thin while continetal crust is thick-oceanic crust is dense while continetal crust is less dense-oceanic crust is young while continetal crust is old-oceanic crust is made of sima while continetal crust is made of silica and AK

Factors which influence the global distribution of areas most at risk from large-scale disturbances include:

Latitude: within tropical low pressure belt but away from the equator Oceanic origin: to supply moisture Westward movement with a poleward deflection Ocean temperature: min. 27°C ocean temperature needed for heat energy to a significant depth Coriolis force: drives direction of movement westwards

how storm surge form

The main cause of a storm surge is high winds pushing the seawater towards the coast, causing it to pile up there

lightening secondary tornado hazards

small ice crystals carried upwards in cloud and denser pellets fall and collisions occur which charge the thunderstorm ice crystals become positively charged an pellets negative so top is positive and lower is negative this is different to the charge of the ground where once it becomes large a conductive channel of air develops between the cloud and the ground and charge moves towards the ground and upward leader of opposite charge connects and when connected a powerful discharge is made