Interactive Earthquake Map: Get to Know Your Local Faults

Zoom in and mouseover this interactive USGS map to locate local fault lines and recent earthquakes.

Call it nature's alarm clock (sans snooze button).

A 4.0 earthquake, centered in the Oakland Hills just north of Piedmont, rattled much of the East Bay and other areas of the central Bay Area this morning, jolting thousands of residents out of bed. Located on the Hayward Fault, the quake struck at 6:49 a.m. and was followed by a series of minor aftershocks, according to the U.S. Geological Survey. No serious damage was reported.

The Hayward Fault runs from San Pablo Bay to Fremont. It passes through parts of Berkeley, Oakland, Hayward and Fremont before branching into a set of surface faults that connect it to the central part of the Calaveras Fault, according to the USGS. Some scientists predict that the Bay Area's the next major quake will occur on this fault.

The last major quake on the Hayward Fault hit on Oct. 21, 1868. The estimated 6.8-magnitude quake killed roughly 30 people and caused extensive property damage in a handful of East Bay's nascent cities. At the time, the population of the East Bay was roughly 100 times smaller than it is today.

As the USGS describes in its report on the quake:

"Shaking from the 1868 quake was the strongest that the new towns and growing
cities of the Bay Area had ever experienced. Until overshadowed by the 1906 earthquake, the 1868 event was known as the “great San
Francisco quake.”