String of morning earthquakes rattles Bay Area

The Bay Area and Monterey region got a rude awakening Friday morning as a series of relatively small earthquakes shook up the region near Hollister just before 6 a.m. and was felt as far away as the North Bay.

The United States Geological Survey [USGS] records the largest of the morning earthquakes, a 4.1 in potency, just before 6 a.m. along the San Andreas Fault, originating south of the town of Tres Pinos. No injuries or damage were immediately reported.

More than 600 people self-reported feeling the shaking as far south as Salinas and as far north as Santa Rosa, affecting almost the entirety of the Bay Area, although most of the activity was focused nearer the point of origin.

And that was just the start of the morning’s geological gymnastics, as a series of five additional, smaller shakers followed, ranging from a 3.0 to a 3.6.

Small earthquakes or series of small earthquakes sometimes turn out to be what’s known as foreshocks, which presage larger pending quakes.

Foreshocks are fairly rare, but just in case, any small earthquake in or near the region is a good opportunity to drill on basic earthquake safety. USGS recommends:

If you are INDOORS--STAY THERE! Get under a desk or table and hang on to it or move into a hallway or against an inside wall.

STAY CLEAR of windows, fireplaces, and heavy furniture or appliances.

GET OUT of the kitchen, which is a dangerous place (things can fall on you).

DON’T run downstairs or rush outside while the bldg is shaking or while there is danger of falling and hurting yourself or being hit by falling glass or debris.

If you are OUTSIDE--get into the OPEN, away from buildings, power lines, chimneys, and anything else that might fall on you.

If you are DRIVING--stop, but carefully. Move your car as far out of traffic as possible.

DO NOT stop on or under a bridge or overpass or under trees, light posts, power lines, or signs. STAY INSIDE your car until the shaking stops.

USGS also notes that if you’re near the ocean or even near another large body of water such as the bay to head away away from the shoreline and towards higher ground.

Although records of California tsunamis indicate relatively small waves in such events, there is always some danger.

• Tres Pinos Quake [USGS]
• Intensity Map [USGS]
• What Should I Do? [USGS]
• California Tsunamis [Conservation CA]