Tectonics Flashcards
what are intra plate earthquakes
occur in middle or interior of tectonic plates and are much rarer than boundary earthquakes
what is a volcano
a landform that develops around a weakness in the earths crust from which molten magma, volcanic rock and gases are ejected and extruded.
what are seismic hazards
generated when rock within 700km of the earths surface come under such stress that they break and become displaced.
where do most earthquakes occur
on plate boundaries
what % of earthquakes occur on pacific ring of fire
70%
name 3 places that earthquakes can occur
- ocean fracture zones eg mid Atlantic ridge
- continental fracture zones (across) activity found in mountain ranges eg Himalayas
- scattered earthquakes in continental interiors eg along old faults such as church stretten shropshire
where do volcanoes usually form
hot spots
how many volcanos are there in the world and how many erupt each year
500
-50 yearly
what is the size of a volcanic eruption determined by
amount of dissolved gases released
name some characteristics of continental crust
30-50km thick
-layer of granite, sedimentary and metamorphic rocks floating on mantle
name some characteristics of oceanic crust
6-8km thick
- thinner and composed of several layers
- top layer composed of basalt
what are intra plate earthquakes and how do they occur
- in the middle of the plate
- occur as over time stress builds and releases pressure in ancient faults causes to become active again
- however they dont occur in well defined patterns along plate margins and are harder to predict
what is a volcanic hotspot
- area in mantle where heat rises as hot thermal plume deep in the earth often called a magma plume.
- caused by heat and pressure melt rock of lithosphere
what is james huttons theory of the earth
- 1785
- realised erosion, deposition and uplift were connected and these processes operate continuously
- driven by earths internal heat
what other findings were concluded by james hutton
- after studing strata and rock deposits in various locations, he also concluded that the earth was much older than people believed at the time which was around 6000 years old
- came up with rock cycle (rocks transported to sea, buried, solidified and later lifted back to earth surface through tectonic processes.
what was Alfred Wegeners theory
continental drift
-suggested 200 million years ago supercontinent called pangea broke into pieces and parts moved away from one another and fragments we see today are pieces of that
how did wegener support his theory
by finding matching rock formations and similar fossils across continents
-concluded these were onced together
why was wegener ridiculed
because of religion
what theory did harry hess come up with
1962
- hypothesis of sea floor spreading
- theory of oceans basins which outlined a theory which later was known as seafloor spreading
- he discovered oceans were shallower in the middle
how did Hess conclude his theory
identified presence of mid-ocean ridges which were as high as 1.5km above flat sea floor and envisaged that oceans great from their centres with molten material/basalt oozing up from the earths mantle creating sea floor spreading each side
what did john tuzo wilson come up with the theory of
1963
- was sceptical of tectonic theory but then became a great supporter
- wondered why volcanoes occur 1000s of miles from plate boundaries and proposed hotspots which occur in middle of plate form volcanic island chains
what did tuzo wilson discover
-the idea of a 3rd plate boundary called transform faults or Conservative plate boundaries
what is the plate tectonic theory
lithosphere broken up into several major and minor plates
-these plates moved relative to each other over asthenosphere and a number of processes drive their movement
what is the asthenopshere
mantle below lithosphere made of semi-molten rock
what is Palaeomagnetism and how did it help confirm a theory?
study in 1950s confirmed sea floor spreading
- every 400,000 years the earths magnetic fields change direction and N and S swap
- when lava cools and becomes rock, minerals inside the rock line up w/ earths magnetic direction/ polarity at the time
what is mantle convection
- heat produced by radioactive decay in core heats lower mantle creating convection currents
- hot magma currents move within asthenosphere in circles causing plates to move
(this theory now less responsible for plate movement)
what is slab pull
newly formed oceanic crust at mid-ocean ridges becomes denser and thicker as it cools.
-causes it to sink into mantle under its own weight pulling the rest of the plate down with it
which is a more relevant theory of plate movement between mantle convection and slab pull
slab pull
what is subduction
-process of plate being destroyed when either two oceanic crusts or oceanic and continental plates move towards each other and the less dense slides under the other into the mantle where it melts into an area called the subduction zone
what is seafloor spreading
- process of a new crust pushing tectonic plates apart
- mid ocean ridges or underwater mountain ranges are formed when hot magma is forced up from the asthenosphere and hardens to form a new oceanic crust
how much do plates move a year
5-15 cm
name 3 types of plate boundary
convergent-destructive margins
divergent- constructive margins
conservative- transform margins
what is a divergent margin
two plates moving apart leading to formation of a new crust hense constructive.
-in oceans this divergence forms mid ocean ridges and on continents forms rift valleys
example of a divergent plate boundary w/ oceanic crust
- mid atlantic ridge
2. 3km long
describe the tectonic hazards at mid ocean ridges
-earthquakes- shallow focus as less than 70km into crust and occur frequently but pose little threat to humans as they occur underwater
-volcanoes- submarine volacnoes can occur which grow above sea level to create a new island eg) iceland which is on mid atlantic ridge
however these eruptions are less explosive and more effusive especially underwater
what does effusive mean
-eruption where lava flows steadily from volcano
what is a rift valley and how is it formed
- when continental plates move apart at divergent plate margins
- the crust breaks and stretches into sets of parallel cracks called faults
- the land between the fault collapses forming steep sided rift valleys
example of rift valley
east african rift valley, divergent plate boundary with continental crust
describe the tectonic hazards at rift valleys
earthquakes-similar to midocean ridges, shallow but low magnitude
no volcanoes
what is a locked fault
CONVERGENT
in a subduction zone as plates move together they can get stuck due to frictional forces
-these faults may store strain for long periods and pressure will build and is eventually released in a large magnitude earthquake
what is the benioff zone
area of seismicity corresponding with slab being thrust downwards in subduction zone
why do earthquakes occur at destructive plate boundaries
-in sybduction zone where two plates join together and the moe dense plate slides under the thicker less dense plate forming a locked fault where there is a build up of frictional resistance and stress which can be released as an earthquake in the benioff zone
how do deep ocean trenches form
when oceanic crust subducts underneath continental cust it forms deep ocean trenches, continental plate is pushed up to form fold mountains chain
describe the tectonic hazards at convergent plate boundaries on oceanic meets continental
-explosive volcanoes are generated here as magma created from melting oceanic plate pushes up through the faults in the continental plate
why is nepal prone to earthquakes and how big was the 2015 Earthquake
sits on continental meets contental plate boundary between eurasian and india plates and is a conservative boundary where two continental plates collide
-2015 7.8 mag earthquake
what is the pacific ring of fire
oceanic pacific plate meets many plate boundaries causing hundreds of earthquakes
where can deep ocean trenches form
convergent
what is the difference between oceanic meets continental and oceanic meets convergent plate boundary
- when oceanic meets continental plate boundary the oceanic plate subducts as it is thinner and forms deep ocean trenches and the continental plate is pushed up into fold mountains
- when oceanic meets oceanic they converge and the faster more dense plate would subduct and mountains that are formed, are formed by continuous eruptions of magma from asthensosphere
when two continental plates meet what is the margin called
collision margin because neither plate is subducted or destroyed but is push upwards into fold mountains
-because both plates are similar density and less dense than asthenosphere beneath
may be some subduction inevitably caused by compressed denser sediments
example of fold mountains
himalayas
describe what a conservative plate margin is
aka transform fault-
two plates are sliding past each other resulting in a major break in the crust between them as they move
-the break is called a fault and on large scale is transform fault
give example of transform fault and how big was the last earthquake here
san andreas
1906- 8.3
movement to the left at a conservative plate boundary is called
sinstral
movement to the right at a conservative plate boundary is called
dextral
describe tectonic activity at conservative plate boundaries
- no volanoes as neither plate subducts so no magma is formed similarly to continental meets continental
- shallower powerful earthquakes as large build up of stress due to frictional resistance plates stick as they move past one another causing stress and pressure to build
is there a benioff zone at conservative plate boundary
no
why could next earthquake at san andreas be big
100 years since last one so a lot of stress will have built up and because it is shallow focus it will have large impact
why are volcanoes more likely along some plate margins than others
common where one plate subducts such as oceanic and continental where the oceanic plate subducts and melts to form magma which can rise to the surface forming volcanoes.
-less likely at C meets C as neither subducts to form magma and also same at conservative
how do plates behave at conservative plate margins
slide past one another
what % of earthquakes are along plate boundaries
95%
what is an earthquake
energy is released as seismic waves which cause the ground to shake and is released from inside earths crust along a fault
what is the hypocentre
point inside the crust where pressure is released
aka focus
what is the epicentre
directly above hypocentre on top of earths crust
what are P waves
+characteristics
- aka Primary or body waves which travel through earths body
- fastest and first to reach surface (8km/sec)
- travel through solids and liquids
- move in backwards and forwards motion (longitudinal)
- only damaging in most powerful earthquakes
what are L waves
aka Love waves
- they only travel on earths surface
- slowest and last to arrive
- move in side to side motion and are larger and cause MOST DAMAGE
what are S waves
- secondary waves which are also body waves as they go through earths body
- slower than P (4km/sec)
- only through solids
- transverse waves in up and down motion 90 degrees to direction of travel
- more damage than P
how is severity of earthquake determined in terms of seismic waves
- amplitude and frequency
- ground may be displaced horizontally/ vertically or slanted obliquely during earthquake depending on strength of individual waves
how do we predict earthquakes
currently no method to accurately predict when or where earthquake will hit but we can forecast where it is likely to happen with current understanding of how plate boundaries work
-research focuses on foreshocks which can suggest major earthquake is going to happen
what human factors can determine effects of earthquake
- population density
- level of development
- effectiveness of emergency response teams
- impact of secondary hazards
- how prepared they are education
what are primary effects of an earthquake
happen as direct result of earthquake
what are secondary effects of an earthquake
secondary effect of earthquakes happen as result of primary effects and often cause more damage
examples of primary effects
- ground shaking causes buildings roads infrastructure to collapse
- crustal fracturing- when earths crust cracks due to energy released
examples of secondary effects
- landslides or avalanches
- tsunamis
- liquefaction
how do landslides or avalanches occur due to earthquakes
-slopes fail as shaking places stress on them resulting in landslides, rock slides mudslides and avalanches
how does liquefaction occur
- when surface rock lose strength and become more liquid than solid.
- the subsoil loses its ability to support buildings and infrastructure foundations so they sinks or tilts
how do aftershocks occur
occur in area of original earthquake and are a result of the earth settling down or readjusting along part of the fault that slipped originally
- can occur weeks/months/years after quake
- larger earthquakes have larger more frequent aftershocks
- capable of causing additional damage and stopping recovery efforts
example of large aftershock
2011 6.3 in christchurch after 2010 quake and actually caused more damage than orginal and loss of life
when was the loma prieta earthquake
1989
what was the main reason for damage in lloma prieta
rock type- softer rock amplifies the effects of the earthquake
- the marina district was built on soft sandy soil which amplified ground shaking and liquified causing buildings to collapse
- the area of the freeway built on bedrock did not collapse
what kind of plate boundary did the loma prieta earthquake occur on
conservative
what is a volcano
most next to plate margins, some on hotspots
area in earths crust where lava gas and ash erupt
-get bigger as more eruptions occur
over last 300 years how many have died due to volcanic hazards
260,000
primary hazards of volcanos
- lava flows
- pyroclastic flows
- tephra and ash falls
- gas eruptions
what are lava flows
how hot??
- streams of lava erupt onto earths surface, destroy everything in path but not generally life threatening as its slow moving
- 1170 degrees and take years to cool
what are pyroclastic flows
how fast flow?
how hot?
- mixture of hot dense rock, lava, ash and gases ejected
- destroys everything in paths
- much faster than lava flows as they are 100km/h
- 700 degrees
what are tephra and ash falls
- tephra is pieces of volcanic ash and rock that blast into the air during eruptions
- large pieces tend to land near volcano when they can injure/kill and damage structures
- smaller pieces can travel 1000km’s
- ash can be very disruptive and covers everything causing poor visability and slippery roads. roof may collapse under weight and engines can be clogged and stop working
what are gas eruption
- magma contains dissolved gases that are released into atmosphere during eruptions
- water vapour 80%, C02 and sulphur dioxide GHGs
- can travel 1000km’s
- some gases can be potentially hazardous to humans and livestock
what are secondary hazards of volcanic eruptions
- Lahars
- Jokulhlaup
what are lahars
- masses of rock that travel quickly down the sides of the volcano
- very in size and speed can we 100m’s wide and travel 10m/s so too fast to outrun
- A lahar is a mudflow composed mainly of volcanic debris and water. They are formed when rainwater washes away the volcanic ash on a volcano slope. Sometimes caused lahars when crater lakes leak. Lahars are among the biggest risks of a volcanic eruption
what are jokulhlaup
- aka glacial outburst floods
- heat of volcano melts snow and ice in glacier causing heavy sudden floods
- suddenly release large amounts of water, rock and gravel and ice that can be extremely dangerous and flood land and structures
how do scientists predict eruptions
- more accuracy than earthquakes
- use equipment such as GPS and satalite based radar placed on and around a volcano to monitor the signs:
- small earthquakes which caused by magma rising+breaking rock which can be detected by seismograms
- changes to surface volcano swelling due to magma
- changes in tilt of volcanoes moving magma inside can change slope or tilt
when was the eyjafjallajokull eruption
march to april 2010
how high did the plume of very fine volcanic ash of icelands volcano go
33,000 ft
which spread over west europe
what were the secondary impacts of the iceland eruption
jokulhlaups
-warm 17 degree water
what were the social impacts of the eyjafjallajokull eruption
- ash contaminated local water supplies
- evacuating due to lava melting glacier causing flooding
- people had to were face masks and goggles due to thick ash
- many roads shut
- stranded people who couldnt board flights
how many evacuated in iceland eruption
700
how many passengers unable to board flights
10 million
economic impacts of iceland eruption
- commercial flights cancelled
- airlines lost lot of money
- european economy lost money
- many different european transport companies such as trains able to benefit
how many more passengers did eurostar see
50,000
how many commercial flights cancelled
100,000
how much did airlines lose in iceland eruption
$1.7 billion
how much did europe economy lose in iceland eruption
$5 billion
what is a tsunami
series of larger than normal waves usually caused by underwater earthquakes but some caused by underwater landslides or asteroid strikes
-energy released during quake causes sea floor to uplift, displacing water collumn
what is a water collumn
an area of seawater from surface to sea floor
are ships able to detect tsunami waves
its harder as the wave is smaller out to sea as there is small wave height (1m high out to sea but 30m inland) and long wavelength of around 150-250m
how can some energy of the tsunami be lost when nearing coast
sea floor irregularities
what does the nature of tsunami waves depend on
- cause of wave eg eruption of earthquake
- distance travelled from source as energy is lost as they travel
- water depth over route affects energy loss through friction
- offshore topography and coastline orientation
why is wave higher closer to shore
-wave energy is concentrated into a smaller volume of water
name some characteristics of a tsunami
- fast up to 50mph
- when wave crest reaches shore it first produces vacuum effect by sucking water out to sea exposing a large amount of sea floor which is a warning sign
- linked to plate boundaries eg ring of fire
how can you predict tsunamis
- cant predict before occur as underwater earthquakes dont effect us
- can notice early warning signs before it reaches the coast and threatens lives
how can you monitor tsunamis
seismic sensors to detect sub-marine earthquakes
DART Deep ocean Assessment and Reporting of Tsunamis
Computer modelling
what is DART
seabed sensors and surface buoys to monitor changes in sea level and pressure
- when wave detected system sends information via satellite to tsunami warning stations
- stations analyse data to estimate size and direction
pros of monitoring tsunamis w/ computer modelling
- can save lives
- info reviewed regularly due to multiple sensors and sea surface buoys
cons of computer modelling
- if equipment faulty will cause inaccurate data
- if shallow earthquake equipment damaged
where did the 2004 indian ocean tsunami badly hit first and how large was the earthquake that caused it and how much did it displace the ocean floor
Sumatra after 15 minutes
-estimated 9.0 magnitude earthquake heaved ocean floor up 15m sending out shock waves
how many people died in indian ocean tsunami
300,000
where did the 2004 indian ocean tsunami hit
- sumatra
- malaysia
- thailand
- sri lanka
- india
- maldives
- seychelles
- madagacar
- somalia
- kenya
- south africa
how many structures in somalia were damaged by 2004 tsunami
2000
how many left homeless in sumatra in 2004
700,000
describe nature of the indian ocean tsunami 2004
- especially large earthquake with epicentre close to densely populated coastal communities
- low lying coastlines meant waves could travel far inland
- no early warning systems in place
what % of villagers killed in coastal villages in tsunami 2004
70%
how many villages destroyed in sumatra 2004
1500
why was it hard to access coastal communities in 2004 IOTsunami
jetties had been washed away and much of the infrastructure lost
what % of sri lankas industrial infrastructure and fishing fleet destroyed
60%
how much did tourist industry lose in 2004 in thailand and how many lost their jobs
$25 million a month
120,000 lost jobs
what was the environmental impact of 2004 indian ocean tsunami
- ecosystems such as mangroves destroyed
- vegetation and top soil moved 800m inland
- freshwater supplies contaminated by salt water
what was the overall cost of the 2004 indian ocean tsunami
$10 billion
define hazard
percieved natural/ geophysical event that has the potential to threaten both life and property
define disaster
the realisation of a hazard when it causes a significant impact on vulnerable population
when does a hazard become a disaster
The CRED (centre for research on the epidemology of disasters) states that a hazard becomes a disaster when 10 or more people die or 100 people effected
what does deggs model show
hazardous geophysical events such as floods earthquakes ect when together with vulnerable or susceptable population to economic loss due to where they live means its a disaster
what is the hazard risk formula
(hazard x vulnerability) / capacity to cope = Risk
what does the level of risk depend on
- linked to hazard itself eg magnitude and duration
- human factors eg capacity to cope
how can you reduce vulnerability
- putting protective measures in place eg defences
- providing aid to people in poor countries
- specialised infrastructure
what is resilience
the ability to protect lives/ livlihoods and infrastructure from destruction and restore areas after a natural hazard has occured
name some political factors which determine how vulnerable a country is
- the existance of building codes and regulations
- quality of communication systems
- level of gov corruption
- existance of disaster preparation plans
- quality of infrastructure
name some economic factors which determine how vulnerable a country is
- level of wealth
- lack of income oppertunities
name some social factors which determine how vulnerable a country is
- people without access to education
- poor quality housing
- age of population
- communities with poor health care
name some environmental factors which determine how vulnerable a country is
- rapid urbanisation creates a need for more housing
- accessibility of area
- population density corresponds to poor quality housing
describe myanmars hazard and exposure score
significantly high natural hazard component due to potential for tsunami and earthquakes, floods and storms
describe myanmars vulnerability
moderate risk but relative low score
-been few natural shocks in recent years
describe myanmars coping capacity
poor coping capacity low level of internet/mobile phone signal access for older people and education is poor
describe the overal risk of myanmar to hazards
ranked 7th of 190 nations so disaster risk to elderly is very high
describe japns hazard and exposure score
subject to range of natural hazards
describe japans vulnerability
vulnerability is high compared to other wealthy nations due to aging population but is still low risk
describe japans coping capacity
coping capacity is good
the elderly tend to be educated
high internet connectivity
effective gov and low gender equality
describe the overal risk of japan to hazards
although exposed to hazards it is ranked 133rd of 190 nations thanks to strong coping capacity and lower levels of vulnerability
what % of people over 60 live in less developed regions
66%
why is age a sig factor in peoples resilience to hazards
elderly will be more vulnerable to hazards
what is the PAR model
pressure and release model
- to protect people from hazard govs and organisations must first understand how vulnerable a country is +why
- tool used to work out underlying causes of disaster
-based on idea that when disaster occurs it happens when two opposing forces interact (1 side is hazard other is factors making people vulnerable)
what factors does PAR model include
1= root causes eg limited access to resources or ideolgies 2= dynamic pressures such as lack of training and skills or macro forces such as deforestation or population growth 3= unsafe conditions such as fragile economy, environment, particular groups at risk
these show the progression of vulnerability from root cause to unsafe conditions so by tackling root causes you can improve vulnerability
what was the magnitude of the 2010 haiti earthquake
7.0
what was the number of people dead and missing of the 2010 haiti earthquake
316,000
what was the number of injuries of the 2010 haiti earthquake
300,000
what was the number of newly homeless people in the 2010 haiti earthquake
1.3 million
what was the economic cost of the 2010 haiti earthquake
$14 billion
what is the GDP per capita in Haiti
$1300
what is the type of economy in Haiti
developing
what was the magnitude of the 2008 china earthquake
7.9
what was the number of people dead and missing of the 2008 china earthquake
87,150
what was the number of injuries of the 2008 china earthquake
375,000
what was the number of newly homeless people in the 2008 china earthquake
5 million
what was the economic cost of china earthquake
$125.6 billion
what is the GDP per capita in china
$6600
what is the type of economy in china
emerging
what was the magnitude of the 2011 japan earthquake and tsunami
9.0
number of dead and missing in 2011 japan earthquake and tsunami
19,848
how many injured in 2011 japan
6,065
how many made homeless in japan earthquake and tsunami
130,927
what was the economic cost of japans 2011 E + T
$240 billion
what is the GDP per capita in japan
$39, 473
describe why haiti had the highest death toll of the 3 countries
-as developing country w/ corrupt gov they don’t prioritise people like they do the economy
what date was the 2011 japan tsunami
11th march
how large was the earthquake in japan in 2011
9.1
how much did the japan earthquake in 2011 cause the north island to move
15 cm north east tokyo
how long did the japan earthquake last
6 mins
why is japan effected by earthquakes
plate boundary where 4 plates meet: the eurasian, pacific, Phillipean and north american
what % of earthquakes in world effect japan
30%
what was the magnitude of the earthquake that hit japan 2 days before the main in 2011
7.2
how did soil type effect people in japan
upper 10m of soil of zone hit was soft soil
this amplified earthquake and caused liquifaction
how was fukishima power plant effect by the japan earthquake and tsunami
- nuclear plant- hydrogen explosion at unit 3 which destroyed upper reactor building due to water getting in. led to 20km exclusion zone
what % of victims of tsunami in japan were over 60
66%
how many children were separated from familes in japan earthquake
due to timing- 100,000
how many buildings destroyed in japan earthquake
300,000
how many tonnes of debris left over from earthquake and tsunami in japan
25 million tonnes
how many households lost electricity in japan
4.4 million
how many seismographs do they have in japan
how many seismic intensity meters do they have
200
600
how big is the sea wall in japan and how much of the coast does it cover
40%
10 meter high
how many troupes released in 2011 japan earthquake
110,000
how did japan alert people on what to do
- as soon as earthquake hit they switched the radios to earthquake coverage alerting people what to do
- video message from emperor to unify people
how many children were killed in 2008 china earthquake
5335
how was the china earthquake caused
collision of eurasion and indian plate
when and how big was the aftershock of the china earthquake
5.0
2 years later
how were china prepared for earthquake
- strong central government
- wealthy
how did chinas gov fail to prepare for earthquake
ignored poorly built structures
how many relief workers died during china earthquake
200
what % of chinas gdp do the 2 regions worst hit acount for
45%
how many relief workers and soldiers sent to effected areas
130,000
how much did chinese gov pledge to rebuild
$10 billion
within 2 weeks they had started rebuilding infrastructure
2 years after china earthquake what % of planned reconstruction finished
and what % of farm houses in rural areas badly effect rebuilt
-97%
99% of destroyed farmhouses rebuilt
where was most effected by the haiti 2010 earthquake
hispaniola
where is haiti located that makes it vulnerable
on fault between north america and carribean plates
how deep was the hypercentre of the haiti earthquake
13km shallow focus
why were haiti not prepared for earthquake
- pollitical corruption
- lack of building regulations
- little eductation
- little access to healthcare in rural areas
what % in haiti live in poverty
75%
how many people lost homes in haiti earthquake
in 2015 how many still homeless
1.5 million
in 2015 80,000 still displaced
how many effected by cholera outbreak after haiti earthquake
720,000
environmental impacts of haiti earthquake
- fires from cables
- deforestation from both earthquake and to make temp. camps
- landslides
how much in aid was donated to Haiti
how much of this stayed with US and how much to Haiti Gov
$13 billion
of this 70% stayed with US companies and only 2% to Haitians
positive outcome of Haiti earthquake
- new homes and infrastructure such as roads built to better standard than before
- health statistics improved
how did hurricane sandy effect recovery efforts in haiti
2013
slowed recovery
what is the richter scale
what does it measure
0-9 scale used to measure the amplitude of waves created by earthquake
what is the mercalli scale
what is bad about it
- measures experienced impacts on a roman numeral scale of I-XII measures peoples experience from chairs moving or awakening
- relative and doesnt give statistical data so hard to directly compare
what is the moment magnitude scale
- modern measure showing earthquakes in terms of energy released.
- the magnitude is based on seismic movement calculated from: the amount of slip on fault, area affected and the earth rigidity factor
- used for larger earthquakes
what is the VEI
volcanic explosivity index
-relative measure of explosiveness of volcanic eruption
-which is calculated from volume of products (ejecta), height of eruption cloud and qualitative observations
(both quantitative and qualitative)
-an increase in one index indicates earthquake is 10x more powerful.
what does the n stand for in spearmans rank
number of items
what does the d^2 in spearmans ranks stand for
rank difference squared
when talking about factors influencing vulnerability and resilience of a community which 3 factors should you include
Development-
education, housing, healthcare, income oppertunities
Governance-
local, national
Geographical location factors-
pop. density, isolation/accesibility, degree of urbanisation
what does a tectonic hazard profile show
shows the characteristics of hazard (single or multiple) allowing comparisons to be made to help governments make disaster preparedness plans
factors such as the magnitude, speed of onset, duration, areal extent, spatial predictability and frequency of a tectonic event
advantages of displaying a tectonic event on a tectonic hazard profile
easy to follow, and compare between countries
helps with disaster plans for government
disadvantages of displaying a tectonic event on a tectonic hazard profile
comparing hazards may not be reliable as they have different impacts on people and communities
subjective and qualitative w/ no figures
why does an increase in population mean a more hazardous world
increased occupied living space means more concrete and impermeable building materials so flood risk increases
more people affected especially those on coasts
compare the death toll in Japan earthquake to economic cost
lower death toll in comparison 15,893
higher cost $240 billion
compare the death toll in Haiti earthquake to economic cost
compare the death toll in Haiti earthquake to economic cost
what is the overall trend with death tolls in natural disasters
where are numbers still high and by how much more
fewer deaths/ global number falling due to better protection systems, improved building codes, disaster preparedness plans
-3x higher in lower income countries
what is the overall trend with economic cost in natural disasters
increasing cost
in 1990 $20 billion
this increased by $100 billion a year between 2000 and 2010
explain why some disasters are more economically costly, while others are more costly in terms of human life
-level of economic development
japan-infrastructure costs more when damaged
-lack of resources-
haiti- majority live in poverty, many struggled with after effects of 2010 earthquakes cholera outbreak
killed 7000 affected 720,000
what characterises a tectonic mega disaster
- large scale spatially/ economically
- pose serious threats
- scale of impact may mean communities and gov need international support in immediate and long term
what is a multiple hazard zone/ disaster hotspot
places where a number of physical hazards combine to create an increased level of risk for the country + population
examples of multiple hazard zones
iceland, nepal, japan, usa, Philippines
what are the two types of natural hazard group
tectonic
hydrometeorological caused by climatic processes such as drought hurricanes floods and storms
how is the phillipines a multiple hazard zone
- along philippine plate and eurasion plate
- pacific ring of fire
- near the equator tropical monsoon climate so heavy rain (can also cause landslides)
- sits on major plate boundary so faces volcanoes and earthqaukes
- northern coast on pacific ocean very tsunami prone
- south east asia typhoon belt 15 typhoons a year
how many deaths do typhoon caused between 1960-2015
45,246
what is the landscape of the phillipines like
mostly mountainous, coastal lowlands and many people living and working on steep slope land
how many flights were effected by the 2010 iceland eruption
what and how did this effect trade
how did this effect perishable goods
100,000
airfreight holds great value to world trade
0.5% UK trade by weight but 25% by value
countries such as Kenya and Zambia who provide fruit to Europe had delays in transportation so fast-perishing fruit rotted and cost them over $65 million
what made the 2011 Japan tsunami/earthquake high profile
the effects of the fukishima power plant on Honshu.
the earthquake disabled the power supply leading to cooling of 3 reactors causing high radioactive releases and contaminated water going to fishing grounds.
how has the view of nuclear power changed since 2011 tsunami
loss of acceptability
germany and italy shut down plants and abandoned plans to build new ones.
how did japans energy mix change after the earthquake
before 27% was from nuclear
after- 44 reactors shut down and only 1% of energy was from a nuclear source
how did japans changing energy mix effect fossil fuel consumption
more fossil fuels imported
- price of electricity went up by 20%
- government debt rose as they were importing fossil fuels
- greenhouse gas emissions increased
by 2014 how was japans energy mix changing
high electricity prices from FFuels led to the reintroduction of nuclear power which now makes up 20-22%
how is rapid urbanisation effecting the Philippines
as it is only a lower middle income country, a fast growing population has led to rapid urbanisation and high population density which means that:
»>more poorl built, cheap and fast houses built that can’t withstand impacts of monsoon
where are most of the Philippine population situated
in coastal areas where effects of tsunamis and monsoons are hit worst
what % live in poverty in philippines
25%
what factors have increased the Philippines vulnerability to events
- fast growing population and rapid urbanisation
- poverty
- high population density
what were the effects of the 2006 earthquake in the Philippines
deaths
injured
damaged or destroyed buildings
15 deaths
inhured 100
destroyed 800
what were the secondary impacts of the 2006 earthquake in Philippines
- generated a tsunami which was 3m high
- triggered a landslide which breached a crator wall of a volcano and fell into a lake creating a flood which washed away houses.
how many natural disasters was the Philippines hit by in 2013
three within three months
- earthquake in october killed 223
- typhoon haiyan in November killed 6201
- floods from tropical depression kiled 64 people in jan 14
left gov in near constant state of emergency
what are the challenges of living in a multiple hazard zone
-lack of advances in other areas eg) education
-depletion of resources due to consecutive strain
»»3 natural disasters in 3 months
-contribution of one hazard leads to consecutive successive hazards such as earthquake triggered landslide in 2006
how do the effects of multiple hazard zones differ in MEDC and LEDC eg California USA and Philippines
California
>last time more than 100 died in disaster was 1933 Long beach earthquake
>frequent landslides, drought 2012-15, earthquakes and rarely volcanoes and floods
Philippines
>common earthquakes, volcanic eruptions, landslides, cyclones and floods but few droughts caused by El Nino
why is forecasting important?
it can encourage governments to enforce better building regulations in areas of high stress, or create improved evacuation porcedures in areas of high risk.
what is prediction? and forecasting
stating when an earthquake is going to take place and forecasting is giving a timeframe of when an earthquake could happen
is planning always reliable, why might it not always work
- event is bigger than expected
- unexpected secondary impacts
- regualtions are ignored (eg corruption china)
- other hazards interfere eg multiple haz zones philippines
how are earthquakes predicted and forecasted
- global seismic monitoring networks and historical records
- warning signs/precursors which can identify a pattern of seismic activity such as animal behaviours or radon emissions
are predictions always useful
(to enable evacuationof affected areas)
must be highly accurate, however many geoscientists believe that this wont happen in foreseeable future
which are more relaible/accurate to predict eruptions or earthquakes
volcanic eruptions
how is an eruption predicted
placing equipment and remote equipment on volcano such as GPS and satallite based radar scientists can monitor
>small earthquakes-caused by magma breaking rock
>changing shape of surface due to swelling of magma
>change in tilt of volcano caused by magma movement inside which can change slope angle or tilt
What caused the 2015 nepal earthquake
sudden release of pressure from the indian and eurasian plate boundary
how many died in nepal earthquake
8633
how many left homeless in 2015 nepal earthquake
3 million
what can catagorise a “disaster”
when a natural hazard strikes a vulnerable population that can’t cope using it’s own resources. The greater the scale the more vulnerable
assess nepals level of vulnerability
- low population density although earthquake hit kathmandu
- one of poorest countries 197 out of 229
- weak infrastruture
- nepal in himalayas and landslides caused by earthquake cutting off rural areas
- very earthquake prone
how much did 2015 nepal earthqauke cost
$5 billion 25% of their gdp
what is the hazard management cycle
process where governments and other organsiation work together to protect people, avoid poverty and loss of life and help those effected
- divided into 4 stages
- involves key players at all levels: governments, international organisations, businesses and community groups
what are the 4 stages of the hazard management cycle
mitigation, preparedness, response, recovery
describe mitigation strategies in HMCycle
preventing hazard events/ minimising impacts
»»identify potential hazard that causes poverty/loss of life to make communities less vulnerable
-zoning/land-use planning
-developing and enforcing building codes
-building protective structures such as tsunami sea defence walls
BEFORE and AFTER
describe preparedness strategies in HMCycle
minimising loss of life/poverty and facillitating the response and recovery phases >>>emergency plans implemented -preparedness plans -early warning systems -creating evacuation routes -stockpiling aid equipment and supplies
describe response strategies in HMcycle
coping with disaster and responding to event
»>save lives, protect property, make affected areas safe and reduce economic loss
-search and rescue efforts
-evacuation where needed
-restoring infrastruct.
-ensure critical services like medical care still continue
describe recovery strategies in HMcycle in short term
focusses on poeples immediate needs and overlaps with response phase, can last a few weeks
- providing essential health and safety services
- restoring permanent power and water supplies
- re-establishing transportation routes
- providing shelter and food
describe recovery strategies in HMcycle in long term
same actions but may continue for months or years
»>taking steps to reduce further vulnerability which overlaps with mitigation phase and cycle continues
-rebuilding homes
-repairing infrastructure
-reopen businesses and school
compare management techniques of Japan/China/Haiti/Nepal
JAPAN- strict building regulations, offices equiped w/ emergency kits, early warning systems, earthquake drills practised at schools+work, help accepted fast
CHINA-quick reponse,medical services deployed quickly, fast rebuilding, 2 weeks temporary homes/bridges built
HAITI+NEPAL none from gov, high reliance on international aid
Issues ignored that increased level of impact in Japan/China/Haiti/Nepal
JAPAN-lack of prep at Fukishima powerplant, severe damage
CHINA-ignored building regulations, several days of delay meant international rescue teams couldnt get in
HAITI-lack of investment in infrastructure and disaster planning
NEPAL-lack of investment in hazard prep, weak infrastructure, lack of coping strategies
whats is the Parks model
a curve showing how a country responds after a hazard event and can be used to directly compare how areas at different levels of development might recover
shows deterioration and improvement >pre-disaster >relief (hours/days) >rehabilitation (days/weeks) >Reconstruction (weeks/years)
what are the key things to think about when looking at the Parks Model
- impacts of hazard change over time, dependig on size of hazard, level of development and amount of aid recieved
- all hazards have different impacts so all curves different
- recovery depends of wealth (faster)
- in hazard events involvig many countries there is a curve for each
what are the 3 theoretical frameworks in understanding the prediction, impact and management of tectonic hazards
- hazard prediction and forecasting
- hazard management cycle
- parks model
what are hazard mitigation strategies described as
strategies meant to avoid, delay or prevent hazard events
what are hazard adaption strategies described as
reduce impacts of event
what mitigation strategies has nepal used
volunteers w/ GPS trackers went to remote villages to collect data about the location of roads and tracks and quality of buildings
»» this data is used to help build an idea of how vulnerable communities are and helps build basis for projects to improve preparedness
name some hazard adaptation strategies in high tech monitoring
high tech monitoring -tech plays a role in monitoring volcanoes to predict in advance and tsunamis
>GIS tocreate hazard maps
>Early warning systems - detect signs of tsunami and volcano
One was used in Thailand in 2004 indian ocean tsunami which alerted tourists+residents
>satallite communication tech - transmit data from early warning equipment so early warnings can be given.
hazard adaption strategies2)what is crisis mapping
used days after the 2010 Haiti earthquake
live map made with info given by locals such as where people are trapped in rubble which help rescue workers to see where to direct resources.
accurately maps areas struck
this links to GPS trackers by cyclists in Nepal who went to remote villiages and got info on quality of buildings.
hazard adaption strategies 3) modelling hazard impact
> computer models allow scientists to predict the impacts of hazard events on communities .
Info fed to computer and allows scientists to compare effects of different scenarios such as if a community will benefit from the building of a sea wall.
this can help to aid in reducing impact of hazard.
hazard adaption strategies 4) public education?
> helps reduce vulnerability and prevent hazards from becoming disasters.
japan regularly practice earthquake emergency procedures and have a disaster prevention day every year.
also encourage production of emergency kits
hazard mitigation strategies
1) land use zoning
2) diverting lava flows
3) GIS mapping
4) hazard resistant design and engineering defences
what is land use zoning
regulate how land used in areas at risk from eg volcanic eruptions
used at Mount Taranaki in New Zealand
»»any settlements tend to be limitted/none
»»certain structures/facillities prohibited
»»some communities resettled such as those move upland from tsunami region
»»development in some areas that provide protection limitted such as mangrove forests which reduce impact of tsunami
what is GIS mapping
can be used in all stages of hazard management cycle
can identify evacuation routes and combine information on areas affected, locations of airports/strips and locations+populations of towns
what does diverting lava flows entale
buildings barriers, digging channels to try divert
successful in 1983 Mount etna
path taken by lava difficult to predict
terrain has to be suitable to divert
stopping lava from flowing towards one community may send towards another
what are hazard resistant designs and engineering defences
as collapsing buildings are the main cause of death and damage from tectonic events
- designing new buildings that can resist earthquake eg)latticework foundations deep in bedrock and rubber shock absorbers
- elevated buildings from tsunami
- sloped roofs near volcanoes reduces amount of ash build up so they don’t collapse
- protective structures such as sea walls
what have they done in pakistan to protect buildings from earthquakes
-houses built from bales of straw held with plastic netting sandwiched between layers of plaster which is cheaper and doesnt collapse just cracks.
who are the key players in managing loss after a disaster
- aid donors
- non- governmental organisations eg christian aid providing shelters/water and first aid
- insurance companies
- communities
what role do aid donors play in managing loss
- provide emergency aid- food water and shelter
- short term aid- restoring water supplies and temp shelters
- long- term aid- reconstructing buildings and infrastructure
it can be given straight to government or aid agencies eg Haiti
what role do NGOs play in managing loss
-play crucial role in disaster management and are especially important in disasters where local government is struggling to repspond or dont have resources to do so
»>can provide funds, coordinate search and rescue efforts and help with reconstruction plans
many are involved in hazard management cycle
how did ngos help in the 2005 Pakistan earthquake
- 3.5 million left homeless
- provided over 500,000 tents and blankets and safe water for 700,000 and helped w/ emergency medical care eg Red Cross
however aid agencies helped too
what is the role of insurance in managing loss
- in developed countries insurance companies and governments work together to provide insurance for economic loss from disaster
- these services are either not available in devloping or are too expensive
- there is little insurance for tectonic disasters as more focussed on other priorities
what is the role of communities in managing loss
- locals first to respond
- crucial in immediate search and rescue
- in 2015 afghanistan quake locals joined to look for those in need of rescue
- build resillience and also buildings :)
