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ES Chapter 19
Term | Definition |
---|---|
stress | is the total force acting on crustal rocks per unit of area. |
strain | the deformation of materials in response to stress. |
elastic deformation | is caused when a material is compressed bent or stretched. |
plastic deformation | when stress builds up past a certain print called the elastic limit rocks undergo this. |
fault | is any fracture or system of fractures along which earth moves. |
seismic wave | the vibrations of the ground produced during an earthquake. |
primary wave | this squeezes and pushes rocks in the direction along which the waves are traveling. |
focus | the point where were the waves originated. |
epicenter | the point on Earth's surface directly above the earth's surface |
seismometer | most of the vibrations caused by seismic waves cannot be felt at great distances from an earthquake's epicenter but they can be detected by sensitive instruments. |
seismogram | the record produced by a seismometer. |
richter scale | devised by a geologist named charles rigter is numerical rating system that measures rating system that measures the energy of the largest seismic waves. |
magnitude | hat are produced during an earthquake. |
moment magnitude scale | is a rating scale that measures the energy released by an |
modified mercalli scale | the measure called the intensity of an earthquake. |
soil liquefaction | in areas can cause the ground to behave like a liquid in a phenomenon |
tsunami | a large ocean wave generated by vertical motions motions of the seafloor during an earthquake. |
seismic gap | are sections located along faults that are known to be active but which have not experienced significant earthquakes for a long period of time. |