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5.4 earthquake in Southern California – july 7 2010

Posted by on Jul 08, 2010 | Leave a Comment

On July 7, 2010 a moderate 5.4 earthquake jerked Southern California at 4:53 p.m. about 30 miles south of Palm Springs, 25 miles southwest of Indio, and 13 miles north-northwest of Borrego Springs.

The seismic activity reportedly started at 4:53 p.m. PST near Borrego Springs which is situated 30 miles south of Palm Springs. According to the first report from the Los Angeles Times, local residents said the Wednesday quake was strong enough to shatter glass, and was followed by numerous smaller aftershocks. There are reports that items fell off shelves in the Palm Springs area, but no reports of any injuries or damages will be received. Residents say the quake felt like a rolling motion and lasted about 15 seconds in the desert areas.

Residents reported feeling the quake across a wide area from the Mexican Border to Ventura County. The earthquake happened near the Coyote Creek segment of the San Jacinto fault, which is one of the strands of the San Jacinto fault. The earthquake exhibited sideways horizontal motion to the northwest, consistent with slip on the San Jacinto fault. It was followed by more than 60 aftershocks of M1.3 and greater during the first hour. Seismologists expect continued aftershock activity.

The earthquake had no effect on the Palm Springs Tramway, which takes tourists and hikers to the top of Mt. San Jacinto. But the seismic action activated a rock slide on a nearby ridge, tramway spokeswoman Lena Zimmerschied said. Disneyland spokeswoman Suzi Brown said all rides was being inspected before guests would be allowed back on, in line with resort policy after any earthquake. She said, “The rides come back on as they’re inspected, so some within a matter of minutes, some a little longer depending on the attraction“.

Mary Jane Laws, an assistant manager at Center Market Grocery Store in Borrego Springs, said that a lot of products fell of the store shelves – but there was no major damage. “I’ve been here 30 years and it was bigger than any of us have experienced,” Laws said. “It shook up and down really hard. That was the big jolt, then back and forth. It feels like forever, but it was probably only 10 to 15 seconds.”

There weren’t many customers in the store when the quake hit, but Laws said, “The employees, they bolted. The cash registers are right by the door.” The residents are accustomed to an occasional temblor, but Laws said, “It was a little bit more than we’re comfortable.” At least for the evening, it will give the sleepy town something to chat about in the off season. “This place is going to be just atwitter,” Laws said. “We’ll be in the coffee shop, talking about all kinds of things.”

The San Jacinto fault, along with the Elsinore, San Andreas, and other faults, is part of the plate boundary that accommodates about 2 inches/year of motion as the Pacific plate moves northwest relative to the North American plate. The largest recent earthquake on the San Jacinto fault, near this location, the M6.5 1968 Borrego Mountain earthquake April 8, 1968, occurred about 25 miles southeast of the July 7 M5.4 earthquake.

This M5.4 earthquake follows the 4th of April 2010, Easter Sunday, Mw7.2 earthquake, located about 125 miles to the south, well south of the US Mexico international border. A M4.9 earthquake occurred in the same area on June 12th at 8:08 pm (Pacific Time). Thus this section of the San Jacinto fault remains active.

Recent airborne analysis by the NASA Jet Propulsion Laboratory found that the Easter quake put increased pressure on the San Jacinto Fault and neighboring Elsinore Fault. JPL geophysicist, Eric Fielding said, “There’s certainly a little higher level of activity than we’ve seen before” along the two faults. The upshot is that the Easter quake appeared to have decreased the stress on the southernmost San Andreas Fault — slightly lowering the chance of a quake on the mother of California faults. Fielding said, that’s “good news for us living in Southern California“.

Earthquake Details:

Magnitude: 5.4
Date-Time:

  • Wednesday, July 07, 2010 at 23:53:33 UTC
  • Wednesday, July 07, 2010 at 04:53:33 PM at epicenter

Location: 33.420°N, 116.489°W
Depth: 14 km (8.7 miles)
Region: SOUTHERN CALIFORNIA

Parameters:

  • Nph=144, Dmin=10 km, Rmss=0.27 sec, Gp= 18°,
  • M-type=regional moment magnitude (Mw), Version=6

Location Uncertainty: horizontal +/- 0.2 km (0.1 miles); depth +/- 0.4 km (0.2 miles)
Distances:

  • 20 km (15 miles) NNW of Borrego Springs, California
  • 40 km (25 miles) SW of Indio, California
  • 45 km (30 miles) S of Palm Springs, California
  • 730 km (455 miles) SE of SACRAMENTO, California

Event ID: ci10736069

Video of South California Earthquake from YouTube:

Video of California Earthquake from YouTube:

Video of 5.9 Earthquake at work from YouTube:

Video of Earthquake in Borrego Springs from YouTube:


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