Earthquakes

What is an earthquake?

shaking due to abrupt motion between two rock bodies

Where do most earthquakes occur?

along plate boundaries

Are earthquakes along transforms shallow or deep?

shallow

Are earthquakes along convergent boundaries shallow or deep?

both

where do the largest earthquakes occur

at subduction zones

What is induced seismicity?

seismicity caused by human activity

What is the cause of most induced seismicity?

subsurface disposal of water in oil and gas fields

What are the two measures of earthquakes?

magnitude and intensity

What controls intensity?

magnitude, distance from the epicenter, earthquake depth, and geology

What are earthquake impacts?

Damage to buildings and infrastructures, fires, slope failures, liquefaction, and tsunamis

What is the cause of tsunami?

large subduction earthquakes

Can earthquakes be predicted

No

How is earthquake risk assessed

Probability of a magnitude within a certain time

What is the purpose of earthquake risk assessment

to inform public awareness, emergency plans, regulations, and enforcements

What is an aftershock?

an earthquake caused by a preceding earthquake

Which waves arrive first?

P waves

Which waves cause the most damage?

S waves and surface waves

What is earthquake early warning?

an alert triggered by detection of P-waves

Is shaking worse on strong or weak geology?

weak