Quake a Mile From City Hall Jiggles L.A.

A small earthquake whose epicenter was just a mile south of City Hall jolted downtown office workers Thursday, and scientists said the temblor may be related to an unnamed fault far below the city.

The 10:23 a.m. quake, measuring 2.6 on the Richter scale, caused no damage or injuries. However, it was felt throughout the Civic Center area and was centered only a few blocks away, near the city’s industrial sector, a spokeswoman for Caltech said.

Lucile Jones, a seismologist with the U.S. Geological Survey, said earthquakes with epicenters downtown are infrequent--perhaps one per year--”but what is really remarkable about this quake was that people felt it at all. It was just very, very small.”

Thomas L. Davis, who is studying the Whittier Narrows fault that caused last October’s major quake, said he suspects “there’s a fault deep under (the downtown) area that doesn’t come anywhere near the surface.”

Jones said the quake “is compatible with Tom Davis’ theory, but we just don’t know for sure. There has to be a fault somewhere to cause this, but it could be a fault that’s literally 1 foot long.”

The quake originated about 5 miles below the surface.

There are no mapped faults beneath downtown Los Angeles. The nearest are those in the Santa Monica-Raymond Hill fault zone that runs from Santa Monica through Hollywood to Pasadena and the Santa Monica Mountains, said Harold Weber, a state geologist.

Weber said: “You can have an epicenter that cannot be explained by a known fault. If you look at a map of epicenters, they do occur irregularly throughout the countryside.”