CONTRA COSTA COUNTY, CA — Friday morning, a 2.9 magnitude quake was detected near San Ramon, according to the U.S. Geological Survey.

The tremor shook at 8:14 a.m., with its epicenter situated roughly 2 miles east-southeast of San Ramon and a depth of 5 miles. Seismologists first reported it as a 3.0 event, but later downgraded it to 2.9.

Did you feel it?

If you noticed the earthquake, you can share your observations using the USGS Felt Report form. So far, the agency has collected 297 online responses from individuals indicating that they felt the quake. The USGS DYFI report indicates that weak shaking was registered, with people in Alameda, Hayward, Pleasanton and San Ramon among those who felt the tremor.

Did you capture the impact?

If you have photos showing the effects of the quake, we invite you to share them with us at sacbee.com/customer-service/submit-photo.

Past week’s quake

Last week, a magnitude 2.5 quake was reported in the region, with the event occurring close to Bayview-Montalvin three days ago.

What to know about earthquakes

Magnitude measures the energy released at the source of the earthquake, the U. S. Geological Survey says. It replaces the old Richter scale. Quakes between 2.5 and 5.4 magnitude are often felt but rarely cause much damage, according to Michigan Tech. Earthquakes below 2.5 magnitude are seldom felt by most people.

Earthquakes’ sudden, rapid shaking can cause fires, tsunamis, landslides or avalanches. They can happen anywhere, but are most common in Alaska, California, Hawaii, Oregon, Puerto Rico and Washington, according to the Department of Homeland Security.

It is estimated that there are 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and 100 of them cause damage.

What to do during an earthquake

If an earthquake strikes, it’s best to protect yourself right away. Here are tips from experts:

If you’re in a car: Pull over and stop. Set your parking brake.

If you’re in bed: Turn face-down and cover your head with a pillow.

If you’re outdoors: Stay away from buildings. Don’t go inside.

If you’re inside: Stay and don’t run outdoors. Stay away from doorways.

The best way to protect yourself during an earthquake is to drop, cover and hold on, officials say. “Wherever you are, drop down to your hands and knees and hold onto something sturdy,” officials say. “If you’re using a wheelchair or walker with a seat, make sure your wheels are locked and remain seated until the shaking stops.” Be sure to cover your head and neck with your arms, and crawl under a sturdy table if possible. If no shelter is available, crawl to an interior wall away from windows. Once under a table, officials say you should hold on with one hand and be ready to move with it.

“There can be serious hazards after an earthquake, such as damage to the building, leaking gas and water lines, or downed power lines,” officials say. “Expect aftershocks to follow the main shock of an earthquake. Be ready to Drop, Cover, and Hold On if you feel an aftershock.”

Source: The U.S. Geological Survey