Several small earthquakes struck the San Bernardino on Monday. Experts say this is normal activity, but they still urge the public to stay informed and prepared.
The three earthquakes hit throughout the day, with the largest quake – a 3.6 magnitude earthquake – striking around 10 p.m.
Elizabeth Cochran, a seismologist with the US Geological Survey (USGS), explained that there wasn’t anything particularly unusual about the specific sequence of smaller earthquakes in the area.
“Earthquakes like to cluster together in both time and in space,” said Cochran. “So in a particular area, if you have one earthquake, you're likely to then see several more earthquakes nearby happening over the next few hours or day.”
Cochran says it’s hard to predict whether a set of earthquakes like those in San Bernardino could trigger a larger event.
But there's still a 17% chance of a 7.5 or stronger quake on this section in the next 30 years, even though the San Andreas Fault is less active than the nearby San Jacinto Fault, Cothran explained.
“I certainly don't want to downplay the risk of the San Andreas fault, because it is the major source of hazard in California and for folks there in San Bernardino,” said Cothran.
The last major earthquake on the San Andreas Fault was in 1857 when the 7.9 magnitude Fort Tejon earthquake struck near the Tehachapi Mountains. It killed two people and destroyed many adobe buildings at the former U.S. Army outpost.
Cochran says people can prepare now by making emergency kits and plans.
“For example, everyone should have an emergency supply kit that's useful not only for earthquakes, but for any sort of emergency event,” she said. “That would be food and water, medications and pet food to keep you going for a couple of days.”
Before an earthquake (Preparation)
- Secure heavy objects: Bolt bookshelves, water heaters and large furniture to walls.
- Create an emergency plan: Identify safe spots in each room and practice “Drop, Cover and Hold On” drills.
- Assemble an emergency kit: Include water, non-perishable food, first-aid supplies, flashlights, extra batteries and important documents.
- Know how to turn off utilities: Learn how to safely shut off gas, electricity and water in case of leaks or damage.
- Reinforce your home: If possible, retrofit your home to withstand shaking, especially older buildings.
During an Earthquake
- Drop, Cover and Hold On:
- Drop to your hands and knees to prevent falling.
- Cover your head and neck under a sturdy table or desk. If none is available, use your arms to protect your head while staying against an interior wall.
- Hold On to your shelter until the shaking stops.
- Stay indoors if you’re inside: Move away from windows, mirrors and heavy furniture.
- If you’re outside, move to an open area away from buildings, trees, streetlights and power lines.
- If you’re in a car, pull over to a safe spot, away from overpasses, bridges and power lines. Stay inside the vehicle until the shaking stops.
After an Earthquake
- Check for injuries and hazards: Provide first aid if needed and watch for gas leaks, electrical damage or structural instability.
- Expect aftershocks: These can follow for hours, days or even weeks. Be prepared for additional shaking.
- Avoid damaged areas: Stay away from buildings with visible cracks or leaning structures.
- Listen to emergency updates: Use a battery-powered radio or your phone to get information from local authorities.
- Be cautious of tsunamis: If near the coast, move to higher ground if a tsunami warning is issued.
