IMPERIAL COUNTY, CA — Thursday morning, a 4.1 magnitude quake was detected close to Holtville, according to the U.S. Geological Survey.

A tremor shook the region at 1:54 a.m. The earthquake’s epicenter was located approximately 4 miles west-southwest of Holtville and occurred at a depth of 10 miles. Seismologists first reported it as a 4.6 event, but later downgraded it to 4.1.

Did you feel it?

Those who experienced the quake are encouraged to report it via the USGS Felt Report form. The agency has received 109 responses on its online form so far, from people indicating they felt the tremor. The USGS DYFI report shows that people in a few cities, including Yuma and Somerton, experienced light to moderate shaking from the earthquake.

Did you capture the aftermath?

Help us tell the story — share your images illustrating how the quake affected your area at sacbee.com/customer-service/submit-photo.

Impact and estimated losses

Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage. Recent earthquakes in this area have caused secondary hazards such as landslides and liquefaction that might have contributed to losses.

Structure information summary
Overall, the population in this region resides in structures that are resistant to earthquake shaking, though vulnerable structures exist. The predominant vulnerable building types are unreinforced brick masonry and reinforced masonry construction.

Last week’s quakes

During the last week, there have been two quakes, greater than magnitude 2.5, in the region. The largest, a 3.4 magnitude earthquake, was recorded in the same area prior to this quake, while a smaller 2.7 magnitude quake occurred near Ocotillo on January 11.

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