click below
click below
Normal Size Small Size show me how
Ch 19 Vocab.
Term | Definition |
---|---|
stress | the total force acting on crustal rocks involved, movement occurs along fractures in the rocks |
strain | the deformation of materials in response to stress |
elastic deformation | caused when a material is compressed, bent, or stretched |
plastic deformation | permanent deformation caused by strain when stress exceeds a certain value |
fault | any fracture of system of fractures along which earth moves |
seismic wave | the vibrations of the ground produced during an earthquake |
primary wave | squeeze and push rocks in the direction along which the waves are traveling |
secondary wave | are named with respect to their arrival times |
focus | point where the waves originate |
epicenter | the point on earth's surface directly above the focus |
seismometer | record produced by a seismometer that can provide individual tracking of each type of seismic wave |
seismogram | record produced by a seismometer |
Rickter scale | devised by a geologist named Charles Richter, is a numerical rating system that measures the energy of the largest seismic waves |
magnitude | the measure of the energy released during an earthquake |
amplitude | the size of the seismic waves; an increase of 1 in the scalere represents an increase in amplitude of a factor of 10 |
moment magnitude scale | is a rating scale that measures the energy released by an earthquake, taking into account the size of the fault rupture. the amount of movement along the fault, and the rocks' stiffness |
modified Mercalli scale | is used to measure earthquake intensity on a scale form I-XII (1-10) |
soil liquefaction | process associated with seismic vibrations that occur in areas of sand that is nearly saturated; resulting in the ground behaving like a liquid |
tsunami | large, powerful ocean wage generated by the vertical motions of the seafloor during an earthquake; in shallow water, can form huge, fast-moving breakers exceeding 30 m in height that can damage coastal areas |
seismic gap | sections located along faults that are known to be active, but which have not experienced significant earthquakes for a long period of time |