Hayward Fault: Hazards and Preparedness

Hayward fault prob map

Bay Area Quake Probabilities

Different faults in the Bay Area and the probabilities for each one producing a magnitude 6.7 or greater earthquake. Click for more detail.

The Bay Area is home to many active faults that can erupt at anytime. Scientists have studied the faults extensively and determined that the Hayward is probably the most dangerous. It has a 31.7% chance of rupturing in a 6.7 magnitude earthquake or greater before 2036, and the Bay Area has a 63% chance of having at least a magnitude 6.7 earthquake in the same time period. Therefore, it is essential that every citizen in the area take a few moments and make sure they know what the potential hazards are, and what they can do to prepare.


Major active faults such as the Hayward Fault are associated with many hazards. The most obvious hazard is that of large earthquakes, which induce ground shaking over a large area that can cause heavy objects to fall and windows to shatter, and can cause structural damage to buildings and bridges. Strong shaking and fault rupture can also lead to many other problems, including landsliding, liquefaction, fires, disrupted transportation routes, broken water and gas pipes, downed electrical and phone lines, and many other dangerous conditions. The net effects of these are often more severe and more widespread than the damage directly caused by the shaking itself, and they complicate emergency response and clean-up. Faults, however, can also cause damage in much less noticeable and long term way through creep. The Hayward fault, for instance, moves at a rate of about 0.2 in. per year (about how fast your fingernails grow). If a building was unlucky enough to have been built on the fault, the fault will gradually warp and tear it apart.

The State of California's Department of Conservation website offers an application that displays fault, landslide, and liquefaction zones.

For more Department of Conservation geologic hazard maps, visit their website here.

KQED made a short video about the Hayward fault, The Hayward Fault: Predictable Peril, and its potential hazards. It is very well done and showcases some of the potential hazards the East Bay faces, as well as gives a nice overview of the Hayward fault.

SF damage after 1989 Loma Prieta quake

Loma Prieta Earthquake

Damage in San Francisco from the 1989 Loma Prieta earthquake.


There are very simple things that you and your family can do to get ready in the case of a major earthquake. Taking the time now can mean a major difference when the big one strikes. There are 3 main areas of preparedness.

  1. Make sure your house or apartment is retrofit to withstand the shaking from an earthquake
  2. Make sure that valuables and dangerous items are secure in your house and aren't likely to cause injury
  3. Create a Family Emergency Plan
The Association of Bay Area Governments has lots of great resources that show you how to do these things. They also have quizzes you can take to make sure you are prepared.

Some more links to help you prepare:

HayWired scenario logo

What if...
A 7.0 earthquake hit the San Francisco Bay Area? Are you, your family, and your business prepared to outsmart disaster?

Learn more at outsmartdisaster.com