Chapter 15-Earthquakes

                         Physical Geology Illustrated Vocabulary
Cochise College                                                     
Geology Home Page 
EARTHQUAKES 
Roger Weller, geology instructor
wellerr@cochise.edu   
copyright 2018-Roger Weller   3/30/18  

Vocabulary

special link
Richter Scale- equivalent energies (Wikipedia)
 

aftershocks

-are earthquakes that occur just after an earthquake and are structurally related to
the main earthquake.
-aftershocks

 

animal behavior

-It has been often noted that many species of animals behave strangely just prior to a major
earthquake.  Studies are being conducted to see if this phenomenon can be used as a reliable
method of predicting earthquakes.
-animal behavior

 

Benioff zone

-is the earthquake zone associated with a subduction zone.
-Benioff zone

 

Circum Pacific belt

-is the collection of earthquake epicenters that encircle the Pacific ocean.

 

compression wave

-is a seismic wave in which particles oscillate back and forth in the same direction as the
propagation of the wave.  In seismology, this wave is the faster of the two seismic waves and so it
is called the Primary wave or P-wave.

 

earthquake

-is a sudden release of energy underground usually associated with fault or magma movement.

earthquake disaster recovery training  (link)

 

earthquake education resources (link)

earthquake engineering

-is the branch of engineering dedicated to designing buildings that are earthquake resistant.

earthquake family safety (link)

 

earthquake lights

-Just prior to some large earthquakes, lights have been seen coming out of the ground. 
This type of light is probably created by the breaking of chemical bonds of minerals as the ground
is being stressed.

 

earthquake occurrence pattern

-is one of the ways of predicting earthquakes is to study the rate of occurrence of earthquakes
along a particular fault; if a pattern is detected in the sequence of earthquakes, a prediction might
be made as to when another earthquake might occur.

earthquake recovery (link)

 

epicenter

-is the place at the surface of the earth directly above the focus of an earthquake.
-epicenter
-focus and epicenter

 

focus

-is the point below the surface of the earth where an earthquake wave originates.
-focus and epicenter

 

foreshock

-is a small earthquake that precedes a larger earthquake in the same area.

 

Mercalli scale

-is a system of numerical values, expressed in Roman numerals, that indicates the degree of
surface damage caused by an earthquake.
-Mercalli scale
 

New Madrid, Missouri earthquakes

-are a series of major earthquakes that occurred in 1811 to 1812 in the extreme southeastern corner
of Missouri at the northern end of the Mississippi Embayment.

 

P-wave (Primary Seismic Wave)

-is a seismic compression wave, so named because it travels faster and thus arrives earlier than the
S-wave.
-P and S waves

 

Richter scale

-is a numerical value in decimal form that is a rating of the amount of energy released by an
earthquake.
Richter Scale- equivalent energies (Wikipedia)

 

San Francisco earthquake

-In 1906 a large movement along the San Andreas Fault in California produced a major earthquake
that destroyed most of San Francisco.

 

seismic sea wave

-is the correct term to use in referring to large ocean waves created by earthquakes.  Earlier terms
applied to these waves were tidal waves and tsunamis.

 

seismograph

-is a device that records an earthquake.

 

seismogram

-is a record of an earthquake produced by a seismograph.
-seismogram

 

seismologist

-is a scientist who studies earthquakes.

 

seismology

-is the science of studying earthquakes.

 

seismometer

-is a device that detects earthquakes.

 

shear wave

-is a seismic wave in which particles oscillate at right angles to the direction of propagation of the
wave.  In seismology, this slower moving wave is known as the Secondary wave or S-wave.

 

surface wave

-is a seismic wave that travels along the surface of the Earth; it resembles an ocean wave, but it
is moving through sediments.

 

S-wave (Secondary Seismic Wave)

-is a seismic wave in which the motion of disturbed particles is at right angles to the direction of
propagation of the wave; a shear wave. This type of wave is called a secondary wave because it
travels slower than a P-wave and so arrives second.

-P and S waves
 

travel-time graph

-The time of travel of P and S seismic waves waves is plotted versus distance.  Using this graph,
the difference in arrival times between the P-wave and the S-wave can be used to calculate the
distance from the focus of the earthquake to the seismograph.

 

tsunami

-is the Japanese word for seismic sea wave.  Tsunami actually means harbor wave.

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