Seismo-Watch

More Special Earthquake Reports

September 3, 2002

An earthquake measuring M 4.8 occurred in eastern Orange County near Yorba Linda early this morning, jarring people from sleep and causing light items to topple from table or shelves. There have been no reports of serious damage or injuries.

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According to the Southern California Seismic Network (SCSN) the earthquake measured a Local magnitude (ML) of 4.8 occurred at 12:08 a.m. PDT, September 3, about 30 miles east of Los Angeles and three miles northeast of Yorba Linda in the Chino Hills. The quake was centered at the foot of Gilman Peak in Telegraph Canyon. See a Topozone topographic map or a MapQuest street map.

The focal depth was placed at 12.9 km beneath the surface and suggests that the quake was no related to the Whittier fault, which crops out at the surface at the base of the hills, but along a deeper structure probably related to many of the smaller fractures that crisscross the area. A fault plane solution has not been done at this point.

Aftershocks
The quake was followed by a couple dozen aftershocks, mostly in the M 1-2 range. The largest aftershock registered M 3.0 and occurred at 6:27 p.m. on September 5. It was widely felt in the epicentral area and as far away as Pasadena, Long Beach, Riverside and Mission Viejo. It was also felt on San Clemente Island.

It was the first M 4.0+ quake to strike the Southland in more than 14 weeks. Gaps this long are relatively uncommon.

Felt Reports
The quake was felt sharply in the epicentral region and as far away as San Diego, Palm Springs, Barstow and Mojave. In all, a few million people probably felt the temblor.

Reports near the epicenter told of light items topping from tables and shelves but there were no reports of any commercial retail store damage.

Many people were jolted from sleep while others said their children slept through it. Many people became excited, some were frightened and could not go back to sleep.

Additional seismic information links:

• Seismo-Watch - links for more Southern California information
• TRINet Preliminary Earthquake Page.
• USGS Community Intensity Report

Mainstream media news reports:

• No reports at this time.