Exam 7: Earthquakes

Most earthquakes occur at great depths.

The effects of ground motion caused by an earthquake do not include _____.

The time interval between the first arrival of P-waves and the first arrival of S-waves ____ with distance from the focus of an earthquake.

Earthquakes occur most commonly in the plate boundaries.

Paleoseismology studies the past record of earthquakes.

___ stations are the minimum needed to determine the location of an earthquake epicenter.

_____ maps are useful for assessing how different areas respond to seismic waves and provide valuable information for earthquake planning.

Earthquakes occur more or less uniformly throughout the Earth in the recent past.

Body waves are seismic waves that travel through the Earth's interior.

Richter scale values above 7 are not accurate.The ______ scale is a more objective method of measuring the energy of a large earthquake.

Perhaps 90 percent of the destruction in the 1906 San Francisco earthquake was caused by ____.

An earthquake of Richter magnitude 5 releases 32 times more energy than an earthquake of magnitude 4.

Small earthquakes following the main surface wave arrival are called foreshocks.

By studying seismograms of an earthquake on a distant fault,geologists can tell which way rocks moved along that fault.

The greatest loss of life in the 1964 southern Alaska earthquake was from _________.

Rupture begins at the _____ and then spreads rapidly along the fault plane.

First motion studies of mid-ocean ridges show that the faults there are ____,and parallel to the rift valley.

______ would be associated with Benioff zones.

_____ can occur when water-saturated soil turns from a solid to a liquid as a result of an earthquake.

P-waves are compressional waves in which the rock vibrates back and forth parallel to the direction of wave propagation.