GEO 102 Lecture 14: Chapter 8 Geology

• School: Stony Brook University
• Department: Geosciences
• Course: GEO 102
• Professor: Timothy Glotch

Document Summary

Earthquakes are caused by a rapid release of energy: tectonic stresses that cause rocks to break, energy moves outward as an expanding sphere of waves, waveform can be measured, can destroy buildings, and cause loss of life. Seismicity: motion along a newly formed crustal fracture or fault, a sudden change in mineral structure, inflation of a magma chamber, volcanic eruptions, giant landslides, meteorite impacts, nuclear detonations, motion on an existing fault. Most quakes occur on faults: common crustal fracture that moves rock masses, amount of movement is termed displacement, offset, slip. Faults are like planar breaks in blocks of crust. On sloping fault: footwall(below fault, hanging wall (above fault) Normal fault: hanging wall moves down, results from extension. Reverse fault: hanging wall moves up, results from compression/shortening/squeezing, slope dip is steep. Thrust fault: special kind of reverse fault, slope dip is not steep. Strike-slip fault: blocks slide laterally past one another, no vertical.