Earthquakes Rattle California's South Bay Area; Felt in San Francisco and San Jose

The Internet is buzzing with activity this afternoon after several news sources reported an earthquake in California's South Bay. It was centered 16 miles southeast from San Jose, but was felt by many along the Peninsula, including San Francisco.

The magnitude 4.3 earthquake struck at 10:40 AM (Pacific Time) at a depth of 3.9 miles. According to the Earthquake Hazards Program at USGS, the earthquake was 11 miles from Morgan Hill, 12 miles from Seven Trees, 13 miles from Alum Rock and 15 miles from San Jose City Hall. The magnitude changed several times in the hour after the quake before the USGS settled on 4.3.

While the concept of earthquakes in California is old news to many, frankly, it's the last thing the state needs. Troubled by huge unemployment rates and growing tent cities, I can see how earthquakes would be the last straw for some.

Only yesterday, the L.A. Times reported a small earthquake that struck the Chino Hills area, the latest of many. The magnitude 1.5 quake hit at 6:32 AM, two miles west of the city and 8.3 miles below the surface. It was the seventh in a line of quakes that began on Friday. According to the L.A. Times, the largest quake that weekend was magnitude 1.9 on Friday, the next largest a magnitude 1.8 on Saturday.

Undoubtedly, the frequent quakes have many in the area shaken up, as it was only last year that a magnitude 5.4 quake hit below Chino Hills and was felt in Las Vegas. Hopefully, seismologists working in the desert area around the Salton Sea will be able to make progress on how to understand these swarms of small quakes and how they could build up and trigger seismic risk elsewhere.

The L.A. Times reported on the project only a few days ago, after over 200 small to moderate quakes troubled the area around the Salton Sea from Saturday to Wednesday last week. The seismologists have been recording the activity and observing that the quakes may have a pattern of moving to the southeast as time passes.

Scientists suspect the worse: that these small quakes could possibly trigger larger and more destructive earthquakes along the San Andreas fault, which could be devastating to Los Angeles. U.S. Geological Survey Scientist Doug Given told the L.A. Times, "Clearly [this week's swarm] wasn't sufficient" to trigger an event on the San Andreas. Does it mean that a San Andreas event will happen sooner? We don't know."

Here's hoping that scientists will make breakthroughs in how to understand the quakes and consequently, possibly be able to warn targeted cities before they hit.

4.4 Magnitude Earthquake Strikes California, CBS12.com

Ari B. Bloomekatz, Small Earthquakes Hit Chino Hills; No Damage or Injuries Reported, Los Angeles Times

Magnitude 4.3 Northern California, Earthquake.usgs.gov

Jia-Rui Chong, Salton Sea is Swarming with Earthquake Data, Los Angeles Times