GEOL 1001 : Geology 1001 Test 3
Document Summary
Chapter 13: earthquakes: stress: local force per unit area, strain: amount of distortion due to stress, strength: critical stress at which rocks break. Focus: a focus is a point where things start to break. Seismic waves radiate from this point: strain: propagates outward and begins offsetting the surface. Just after earthquakes there are after-shocks releasing left over energy. These little earthquakes/shocks also occur before the earthquake. Studying earthquakes: epicenter, seismograph: seismic wave recorder, measures earth"s movement by a ball on a spring and recording its motion on a drum. Vertical and lateral ripples: the three different types of seismic waves move at different speeds. Seismic waves: velocities: where the three seismograph lines converge is the epicenter. What type of fault: field data: direct observation of the fault scarp, sometimes scarps are not visible and all movement is subsurface, seismographs. Push and pull-compressional (shear stress)-secondary waves: we can measure.
