There are 5 to 6 large fault lines that run through the San Francisco Bay Area region and many other smaller fault lines that branch out from these larger ones. The San Andreas fault is the most well known in the San Francisco area. It is believed to have caused both the 1906 Earthquake & Fire and the 1989 Loma Prieta Earthquake. It runs under the Santa Cruz Mountains, up through the Peninsula, near the Golden Gate Bridge, through part of Marin County, and then out to the Pacific Ocean.
Another notable fault line in the area is the Hayward fault. This one runs through the east side of the San Francisco Bay Area. It runs from Hayward up through Berkeley (the UC Berkeley football stadium sits right on top of it!) and north into the bay. This is the fault scientists are watching closely because it has been so long since the last big earthquake on it.
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.
- Drop, Cover, and hold when the ground starts shaking.
- If you are inside-Drop to the ground, take cover under a sturdy table or other piece of furniture, and hold on.
- Stay away from glass, windows, outside doors and walls, and anything that could fall on you, such as lights.
- Stay inside until the shaking stops and it is safe to go outside. Do not exit the building during shaking.
- If you are outdoors, move away from buildings, streetlights, and utility wires.
- If you are in a moving vehicle-Stop as quickly as safety permits and stay inside the vehicle. Avoid stopping under overpasses and utility wires.
- Once the shaking stops-Proceed with caution. Avoid overpasses, bridges, and ramps until you know it is safe to do so.
- Know your building: Know where your exits and any additional emergency exits are located.
- Know your Stairwells: Some stairways in CCSF buildings do not connect to all floors. Try to note the stairways that connect.
- Elevators won't work: During and after an earthquake, do not use elevators to escape-even they are working.
- Aftershocks are common after major earthquakes. Do not evacuate immediately until you feel safe to do so.
- Assist those you can, otherwise notify first responders who needs help evacuating and where they are located.
- After evacuating a building, do not re-enter until it is deemed safe to do so by a trained professional.
- Emergency services will be limited, and you may not get immediate help.
- Emergency Kits: Include in your kit-emergency food, battery powered flashlights, and radios.
- Use a tool to get someone's attention. Whistles are a great tool to have when needing to call for help. Phone lines and cellular lines will likely be backed up and you may not be able to call for help from a phone.