TOUR OF THE HAYWARD FAULT
Introduction to the Hayward Fault
The Hayward
fault extends from San Jose 120 km or about 74 miles northward along
the base of the East Bay Hills to San Pablo Bay. Two types of fault movement
occur along faults. One type is the catastrophic rupture of the ground
that generates large earthquakes. A large earthquake, estimated
to have been about magnitude 7, occurred on the Hayward fault in 1868 and
was the "great" earthquake of the Bay Area prior to 1906. Descriptions
from the 1868 Hayward earthquake report a meter
or about 3 feet of fault rupture in the City of Hayward. The other
type is a very slow movement of the fault, a few millimeters or a fraction
of an inch a year that does not generate earthquakes. This slow movement,
called fault
creep (or tectonic creep) can easily be observed where cultural features
such as streets, curbs, and buildings straddle the Hayward fault and are
deformed by the slow movement. Fault creep is most easily recognized
where curbs and other structures are bent in a specific direction called
right-lateral offset. Right lateral describes the horizontal movement of
one side of the Hayward fault relative to the other side of the fault.
This can be observed when you sight down along the curband the curb is
bent to your right. These
right-lateral offsets or bends produced by creep line up street after
street, identifying the precise location of the Hayward fault.
Tour of the Hayward Fault from Fremont to San Pablo Bay
This photographic tour will follow the Hayward fault, picturing some of
the most easily recognized surface features, from the City of Fremont toward
the southern end of the fault, northward to Point Pinole on the margin
of San Pablo Bay.
To enlarge any images to full screen, click on the image itself.
Fremont
to South Hayward
Downtown
Hayward
Residential
Area North of Downtown Hayward
Oakland-Berkeley
Region
San Pablo
to Point Pinole
1868 Hayward
Earthquake
Page design and creation by Don Hirschfeld
Modified February 2001
Copyright 1995 Dr. Sue Ellen Hirschfeld E-Mail:
shirschf@csuhayward.edu