seismic hazards Flashcards
wht are the 5 ways you can predict seisimic hazards
-animal behaviour
-radon gas
-water level
-foreshocks
-seisometers
animal behaviour
animals have certain sensory perception that is denied to humans, the stanford research institute have a project called project earthquake watch in which 70 species of animals are studied to look for changes in behaviour.
advantages of using animal behaviour
-cheap
-animals can show signs up to several days before the earthquake
-high responses near epicentral regions
disadvantages of using animal behaviour
-time consuming
usually only show signs in very high category earthquakes
water level
changes in water level can indicate an earthquake, the rise and lowering of water is measured in deep wells 410-670 metres. around 3-10 days beforehand the water level will begin to change
advantages of using water level
-easy to measure
-large amount of time to allow people to evacuate
disadvantages of using water level
-only happens in certain regions
radon gas
radon gas is a radioactive has released prior to an earthquake, stations can measure radon levels up to hundreds of kilometres from the epicentre
advantages of using radon gas
-can be measured very far away from the epicentre
-can be measured days before the event
disadvantages of using radon gas
–equipment used to measure gas is very expensive
-can cause radiation sickness in some cases
what is the epicentre
the first point affected on land
what is the focus
the point inside the crust where pressure is released
how do seisometers work
Seismometers allow us to detect and measure earthquakes by converting vibrations due to seismic waves into electrical signals,
what is a wave
a vibration that transfers energy from one place to another
what is a p-wave
the first wave to arrive from an earthquake,they are the fastest and travel in longitudinal direction
what is an s-wave
a transverse wave that arrives second after a p-wave.
what is a love wave
a seismic wave that occurs at the surface
what is the first wave to arrive from an earthquake
a p-wave
what is the second wave to arrive froman earthquake
an s-wave
what wave occurs on the surface
a love wave
what is the point inside the crust where pressure is released
the focus
what scales measures the size of an earthquake
the richter scale, the mercalli scale and moment magnitude scale
what is the richter scale
a numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations.
what does the richter scale go up to
9
how do the numbers on a richter scale work
each number increases magnitude by 10x
what is the mercalli scale
a scale that measures how much damage is caused by the earthquake based on observations
what is the measurements on the mercalli scale
i to xii
what is the moment magnitude scale
a scale that measures the total moment release of the earthquake
what factors affect how much a place is impacted by an earthquake
-population density
-distance from epicenter
-time of day
-magnitude of earthquake
-ability to response
-income
how does the time of day have different impacts on a place
during the day people are more aware and will have more time to react,so the impacts will be lessened during the day.
how does the distance from epicentre have different impacts on a place
the shaking is greatest near the epicentre, so areas in closest proximity will experience the greatest damage
what is soil liquefaction
where saturated soil is shaken, creating damaging mudflows
where saturated soil is shaken, creating damaging mudflows
soil liquefaction
what are the primary impacts of an earthquake
-ground shaking (shockwaves travel from epicentre)
-ground rupture
-collapsing buildings
-death
what are secondary impacts of an earthquake
-landslides
-soil liquefaction
-tsunamis
-contaminated water
-unemployment
how does a tsunami form due to an earthquake
The sudden vertical displacements over such large areas, disturb the ocean’s surface, displace water, and generate destructive tsunami waves
what can ground shaking lead to
-damaged roads which will restrict access
-landslides
-collapsing of buildings
example of an LIC earthquake
Haiti earthquake
what year did the haiti earthquake take place
2010
where is haiti
Haiti is located in the Caribbean about 700 miles away from Miami, Florida
how many people were effected by the haiti earthquake
3.5 million
how many people were estimated to have died in the haiti earthquake
230,000
how many schools were destroyed in the haiti earthquake
400
how much was the cost of recovery in haiti
11.5 billion
what was the total cost of the earthquake in haiti
8 billion, 120% of haitis economy
what were the secondary impacts of the haiti earthquake
-diseases spread around camps due to deterioration of sanitation
-port was damaged so aid could not be transported there
-50,000 people ended up in camps, crime in these camps was severe
what are the primary impacts of the haiti earthquake
230,000 deaths
Over 1 million left homeless
