Exam 10: Earthquakes and Earth's Interior

On the basis of seismic evidence, the outer core is believed to be liquid.

List three criteria used to rank the intensity of an earthquake on the Mercalli scale.

What three factors are measured on a fault to determine the Moment Magnitude (MW)for the largest earthquakes?

The Cascadia Subduction Zone is typical in its earthquake activity for most young subduction zones.

If the S-wave arrival time was 4 minutes later than the P-wave arrival time for a distant earthquake on the same seismogram, what was the distance from the seismic station to the epicentre?

In general, P- and S-wave velocities increase abruptly as the waves pass downward across the crust-mantle boundary.

List three kinds of damage that can occur when a significant earthquake strikes a populated, well developed area.

Name three geologic changes that can be monitored and which may precede an earthquake?

Some large earthquakes are preceded by smaller magnitude foreshocks.

What is unusual about the seismicity of Canada's west coast, Cascadia subduction zone?

Note the length of rupture for Canada's largest historic earthquake of ML 8.1 on the Queen Charlotte Fault in Fig.10.20.Assuming that total rupture area is proportional to quake magnitude and energy released, what is the maximum size quake (ML)that could occur if the entire length of the Queen Charlotte Fault were to rupture all at once?

The ________ is directly related to the Richter earthquake-magnitude rating.

Earthquake intensity is a measure of damage related to shaking and not the energy released.

What was the smallest Richter magnitude that can be felt by a human?

The time between the first P-wave and S-wave arrivals is a measure of the distance from a receiving station to the epicentre of the earthquake.

In all materials, P waves are faster than S waves but S waves are faster than refracted P waves as a function of increasing depth.

Which one of the following statements concerning hypocentres and epicentres is correct?

The P-wave shadow zone is largely the result of ________.

Which is not a criterion for determining an earthquake's Mercalli intensity?

Do soft, unconsolidated, non-compacted, water-saturated sediments, or thin, compacted, dry, sand over competent bedrock, generally amplify seismic vibrations most and put buildings at risk.