Spaghetti Fault

This fault model is a variation of one invented by Paul Doherty of the San Francisco Exploratorium.

In the Earth, earthquakes occur as slip occurs along a fault plane.  The fault plane is not uniform in strength, so most of the energy is released from patches of the fault that are "stuck."  These patches are called "asperities."

In the model below, each piece of spaghetti acts as an asperity that must be broken for slip to occur.

Sometime just one noodle breaks, somewhat analogous a small earthquake.

Quite a few break (foreshocks) a few seconds prior to a "massive event" (main shock) in which many break in rapid succession.  This is followed by one or two remaining pops (aftershocks).

 

Spaghetti noodles lie in saw-cut groves in a board.  The arrows show the relative motion across the fault -- right-lateral strike-slip -- in response to tightening the vice. 

 

Click here for a video that illustrates faulting as the vice is tightened (3.4 MB in mpg format).

 

Click here for a modified version of the video that includes labels of the foreshocks, main shock, and aftershocks (3.6 MB in wmv format).

Back