Unit 3 - Earthquake Prediction and Mitigation

Question 1

The influence of geology on earthquake shaking.

Answer 1

Consolidated rocks or sediments amplify earthquake shaking (solids that behave like liquids during the earthquake).
kind of like jello

Question 2

What Mercalli intensities measure

Answer 2

Mercalli intensities quantify the shaking that people and buildings field, which is influenced by the magnitude of an earthquake, its distance, and the local geology.

Question 3

That the biggest magnitude earthquakes are generally not the deadliest.

Answer 3

The biggest earthquakes (M8+) are not the deadliest
it’s the M7-M8 earthquakes that occur in heavily populated regions with poor building practices that are the deadliest
M9s are more likely to happen in subduction zones (which are usually out at sea)

Question 4

foreshock

Answer 4

are smaller earthquakes that sometimes occur before a bigger mainshock

Question 5

aftershock

Answer 5

are smaller earthquakes that always occur after a bigger mainshock

Question 6

How GPS measurements of surface deformation can help estimate earthquake potential

Answer 6

GPS measurements enable us to measure a slip deficit
the amount an earthquake will need to slip in order to relieve elastic stress built up since the last earthquake

Question 7

What forced resonance is.

Answer 7

structures are particularly vulnerable to damage if the forces excite a natural frequency inherent to a structure which can greatly amplify deformation this is called forced resonance

Question 8

What liquefaction is.

Answer 8

Buildings can fall over during an earthquake due to liquefaction, where water saturated soils lose all strength during shaking
occurs when water saturated sediments are shaking, causing the grain the lost contact and more easily slide
Once shaking stops, ground becomes strong again