EPS 20 Lecture Notes - Lecture 10: Magma Chamber, 1992 Landers Earthquake, Synthetic Aperture Radar
26 Apr 2016
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Friction along fault prevents slip, elastic deformation instead. Stress exceeds rupture strength, fault slips and an earthquake occurs. Triangulation: measuring angles between peaks and note change in angle over time. Trilateration: measuring distances between peaks and noting change over time. By using trilateration we can map the total deformation of an area (bay area) Uses trilateration (3 satellites provide lat and long, a 4th gives elevation as well) Handheld devices have accuracy of several meters. Differential gps is used for research and has accuracy of a few millimeters. Plate motion between pacific and north american plates. Time until la reaches sf: 500 kilometers/5 cm/yr= 10 million years. Sar (synthetic aperture radar) and insar (interferometric ) Sar: bounce a radar beam off earth"s surface and measure travel time until the energy returns. Insar: measure the difference between a before and after image. The difference in the phase provide millimeter accuracy. Can make measurement everywhere (not just where there are gps receivers)
