2 December 2000 11:00 AM PDT

The Nevada Seismological Laboratory recorded an earthquake of ML = 4.9 at 7:34 AM (PST) Saturday, December 2, 2000, west of Truckee, California. Aftershocks of M = 3.0 at 7:37 AM and 3.2 at 8:30 AM followed it. The preliminary location of the larger event is 39.38 degrees North and 120.46 degrees west. This location is about 4 miles north of the Kingvale exit on I80, or about 15 miles west-northwest of Truckee. The depth was computed to be approximately 12 km (5 mi). We are recording a sequence of small aftershocks.

The mechanism for this earthquake indicates strike-slip faulting. Seismicity catalogs show a diffuse trend of mostly small earthquakes in this area. One of the largest nearby events occurred on Nov 28, 1980. That event had a magnitude 5.2, and was located about 5 miles southeast of today’s event. Another event, on March 30, 1943, had a magnitude 5.3 and a location 4 miles northwest of today's event. Thus occasional events in this area are not a surprise.

We have received numerous felt reports. The earthquake was felt weakly throughout the Reno – Sparks metropolitan area, and sporadically in other western Nevada locations. To the west of the earthquake, the event was felt weakly in Sacramento, and widely in communities on the western foothills of the Sierra Nevada mountains. It was felt with moderate strength in the epicentral area.

The data reported here is preliminary. For more information, contact the Nevada Seismological Laboratory, (775) 784-4975. The free pamphlet "Earthquakes in Nevada and How to Survive Them," is available on request. The NSL operates a statewide network of seismographic stations and investigates the sizes, frequencies of occurrence, and distribution of earthquakes in the region, and other problems related to seismic risk in Nevada. Visit the NSL wb site at www.seismo.unr.edu for further information.

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