Transcript for Computer Animation of Loma Prieta Aftershocks, segment 08 of 12


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The next animations show a transparent box with the aftershocks represented as dots and spheres inside the box. The earthquakes are selected from the first month of aftershocks and are the same in all of the three following animations. The main shock is shown by a focal sphere where the compressional quadrants are colored dark blue. The yellow and red dots indicate different magnitude aftershocks. The two Lake Ellsman preshocks are in green. The aftershocks lie mostly in a plane dipping at an angle of seventy degrees to the southwest. The aftershock plane extends from three kilometers below the surface trace of the San Andreas Fault to eighteen kilometers' depth. The rupture began at the main shock hypocenter and broke upward and along the fault in both directions. Note that the dipping aftershock plane coincides with one of the main shock noble planes.

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The next animation shows the same earthquake data but seen from a camera flying perpendicular to the fault plane. The camera starts looking at the aftershocks from overhead, then swings through the aftershock plane to see the fault plane end on and finally views the aftershocks from below the surface to the northeast.