Unformatted text preview: down rolling motion and the side-to-side vibration. 8.) The point on the Earth’s surface above the focus is the epicenter. Geologists used a time-travel curve to calculate the distance between an earthquake epicenter and a seismograph. To make this curve, a number of seismic stations at different locations record the time of arrival of seismic waves from an earthquake with a known epicenter and occurrence time. Then a graph is drawn using this data. This graph can then be used to measure the distance between a recording station and an earthquake whose epicenter is unknown. 11.) Only shallow earthquakes occur along the Mid-Oceanic Ridge because here the asthenosphere rises to levels as shallow as 10 to 15 kilometers below Earth’s surface and is too hot and plastic to fracture....
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- Fall '08
- Seismology, Seismic wave, Love wave, S-wave, Crystal Cozart