Earthquakes are unpredictable events which can lead to significant disruptions in daily life.

While large scale earthquakes (M4.5+) are historically not prevalent in the San Joaquin County area, there can be a chance of damage resulting from earthquakes. Many bay area earthquakes have been felt along the western portions of San Joaquin County.

However, there is a chance that citizens may find themselves traveling outside of San Joaquin County were the risk may be greater. In addition, San Joaquin County may be affected secondary to an earthquake, as a staging location for supplies or additional shelters for those impacted by a large scale earthquake in the bay area.

For these reasons, OES is sharing the following preparedness information to help you to identify available resources and current information in the event of an earthquake with consequences in San Joaquin County.

Earthquake Warning California

Earthquake Warning California is the country’s first publicly available, statewide warning system that could give California residents crucial seconds to take cover before you feel shaking. Managed by the Governor’s Office of Emergency Services (Cal OES), Earthquake Warning California uses ground motion sensors from across the state to detect earthquakes before humans can feel them and can notify Californians to “Drop, Cover and Hold On” in advance of an earthquake.

MyShake App: Free smartphone app that provides iPhone and Android users with audio and visual warnings [magnitude 4.5 or higher and Modified Mercalli Intensity III (weak) shaking].

Available in the Apple App Store and Google Play.


Before the next big earthquake we recommend these four steps that will make you, your family, or your workplace better prepared to survive and recover quickly:
Drawing of two people securing a bookshelf and water heater to prevent them from falling in an earthquake Step 1: Secure your space by identifying hazards and securing moveable items.
Drawing of a family discussing their emergency plan at a dining table. Step 2: Plan to be safe by creating a disaster plan and deciding how you will communicate in an emergency.
Drawing of a parent and child organizing disaster supplies in a backpack and a larger container. Step 3: Organize disaster supplies in convenient locations.
Drawing of a couple discussing their financial preparedness, while workers retrofit the foundation of their home. Step 4: Secure your space by identifying hazards and securing moveable items.


During the next big earthquake, and immediately after, is when your level of preparedness will make a difference in how you and others survive and can respond to emergencies:

Drawing of a family protecting themselves during an earthquake, under a table and in a wheelchair. Step 5: Drop, Cover, and Hold On when the earth shakes or you get an alert.
Drawing of people after a quake cleaning up debris, helping the injured, and moving to high ground in case of tsunami. Step 6: Improve safety after earthquakes by evacuating if necessary, helping the injured, and preventing further injuries or damage.


After the immediate threat of the earthquake has passed, your level of preparedness will determine your quality of life in the weeks and months that follow:

Drawing of people reconnecting with family, repairing a damaged window, and reopening a school. Step 7: Restore daily life by reconnecting with others, repairing damage, and rebuilding community.

Here is a model with forecasts of earthquakes and their severities throughout California.

United States Geological Survey (USGS) - UCERF3: A New Earthquake Forecast for California’s Complex Fault System (PDF) PDF. Opens in new Window.

A Map of recent earthquakes and their epicenters can be found at the USGS: Latest Earthquakes Map

Within a few minutes after an earthquake, you can check the USGS Site to verify the earthquake, and see the magnitude.

Being prepared can mitigate the negative consequences created by earthquakes. The Southern California Earthquake Center's (SCEC): Seven Steps to Earthquake Safety will provide helpful and useful tips for earthquake preparedness.

For some basic information about Earthquakes and Faults visit the SCEC Earthquakes Basics Page.