The October 26, 1998 Whiskey Springs Earthquake

At 5:08 PM PST (13:34 GMT) a moderate earthquake (Magnitude 4.9) occurred 4 miles north of Big Bear City.  Since this event is NOT considered an aftershock to the 1992 M6.4 Big Bear Earthquake we've decided to reference it to Whiskey Springs, a location closer to the epicenter to avoid confusion. The earthquake is not considered an aftershock because it's been 6 years since the sequence produced comparable earthquakes and also because it occurred outside (slightly north of) the 1992 Big Bear aftershock zone. It had a strike-slip mechanism with nodal planes striking N40W and N50E. This is just one of many M4.5 to M5 earthquakes we've had in the San Bernardino mountains in the past few months. Typically strike-slip earthquakes that occur in the San Bernardino mountains infer they, the mountains, are being deformed along the many microblocks they're composed of.

There have been a number of small aftershocks, the largest being a M3.2 at 5:42PM.

The event was felt across a wide area of southern California, from Pasadena to San Diego, but there has been no reported damage.

Report prepared by US Geological Survey, Pasadena and Caltech Seismological Laboratory.
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