Large Earthquake Shakes Bay Area This Morning

SAN LEANDRO, CA — A magnitude 3.8 earthquake shook San Leandro and surrounding East Bay communities Thursday morning, according to the U.S. Geological Survey.

The earthquake struck at 8:30 a.m. about 2.4 miles northeast of San Leandro and 5 miles east of Alameda. Two aftershocks followed.

The quake was initially reported by the USGS as 4.0, but was then upgraded to 4.1.

But the USGS is now reporting a magnitude of 3.8, having downgraded it two times approximately 20 minutes after the initial strike.

The quake rattled nearby residents in San Francisco County, as well as residents of Pleasanton, Livermore, Fremont, and according to initial reports.

Residents reported not receiving ShakeAlert notices on their phones this morning. The reason according to USGS is the quake was under 4.5, the threshold for the automatic alerts — even though it was originally reported by USGS as 4.1 before being downgraded.

Angie Lux, a project scientist on the early warning system at the Berkeley Seismological Laboratory, told KTVU that the system registers the quakes, but is designed to alert subscribers once the threshold is met.

Residents from Petaluma to Walnut Creek, as well as Pacifica and San Francisco, also reported feeling the tremblor.

"There was no double about it being an earth quake," a woman, Jenny, in downtown San Leandro at the time told KTVU on air. She described the earthquake as a "real hard shake" but quick — "bang, and that was it."

USGS recorded the earthquake at a depth of about 3.2 miles along the Hayward Fault.

Two aftershocks followed. The first registered 3.0 and the second 2.8.

The 3.0 aftershock struck at 9:07 a.m. about 2 miles north-northeast of San Leandro, near the Oakland-San Leandro border.

The magnitude 2.8 aftershock struck four seconds later in the same area, about 2 miles north of San Leandro.

A woman, Gretchen, who lives at the edge of the fault told KTVU it felt like being in a "big bowl of Jello." She said the shaking almost made her cry and she wondered if another massive earthquake like the Loma Prieta was happening. Her dog gave her a "sorrowful look."

Experts said the quake may have been felt so widely in part because it was a shallow one.

On Wednesday afternoon San Leandro officials asked residents to review proposed California Earthquake Fault Zone maps. by using the city's interactive map to better understand the proposed changes before the August 19 deadline. They can find more at SanLeandro.org/FaultZones.

The proposed maps affect the cities of Berkeley, Concord, El Cerrito, Fremont, Hayward, Milpitas, Oakland, Richmond, San Leandro, San Pablo, Union City, Walnut Creek, and the counties of Alameda, Contra Costa, and Santa Clara.

USGS has asked all who felt it to chime in on its Did You Feel It report.

No injuries or damages have been reported.

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