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Science Tour - 3D/4D mapping of the San Andreas Fault Zone

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Why do fault behave they way they do?

Large damaging earthquake are perhaps the most significant natural hazard to human populations rural and urban in California. With the development of the East Bay region following the Great San Francisco Earthquake and Fire of 1906, the Hayward Fault is now projected as the greatest earthquake threat in the region. Although surface observations provide fundamental clues about fault location, motion, and history, surficial information is not enough to characterize fault behavior. Geoscientists use a variety of methods to characterize faults and rocks they cross cut in the subsurface.

How does the 3-D geology of a fault zone affect earthquake fault behavior?

Using seismic record, geophysical measurement, and drilling, geoscientists are able to determine characteristics of rocks deep in the subsurface, and how they behave under strain and fracture before and during an earthquake. These subsurface measurements can help explain why are some faults segments are capable of producing great earthquakes whereas others produce only small ones. Measurements of the inheterogenious properties of rocks deep underground and the 3D geometry of fault zones can be used to help explain where earthquakes start and stop, and why some fault segments creep continuously whereas other segments fail only during earthquakes.
Hayward fault offsetting bricks at Contra Costa Community College
Contra Costa College campus
Hayward fault breaking asphalt in a parking lot at Contra Costa Community College
Contra Costa College campus
Satellite image of the San Francisco Bay Area showing the location of cities along the Hayward FaultMap and images from "Where's the Hayward Fault? A Green Guide to the Fault." The seismic connection:

Geoscientists work with seismologists and earthquake engineers to study and describe of earth materials behave during earthquakes. Scientists and engineers are collaborating to determine how rapidly earthquake energy propagates through the earth, how and where motion energy is transmitted, and how buildings and infrastructure on the surface will respond to earthquakes of different magnitudes and locations. Fortunately, most earthquakes are to small for humans to feel, but are strong enough to be recorded Modern earthquake sensor data, surficial geologic information, and subsurface geophysical information can be manipulated with computer modeling software to map the location and behavior of faults during earthquakes in three-dimensional detail.
Hayward Fault offset curb on Dwight Ave. in Berkeley
Dwight Avenue, Berkeley
Offset curb at Oakland Zoo
Oakland Zoo, San Leandro
Hayward Fault offset curb, Rose Street, Hayward
Rose Street, Hayward
Creeping Hayward fault damage on street in Fremont
Rockett Drive, Fremont
Hayward Fault offset curb in Central Park in Fremont, California
Central Park, Fremont
Hayward Fault offset curb
Simon Street, Hayward

Hayward Fault offset wall in Memorial Park in Hayward, California
Memorial Park, Hayward

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