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