Seismo-Watch, Your Source for Earthquake Information EARTHQUAKE EPICENTER MAP (Topaz Lake M4.8) TRACK GLOBAL AND REGIONAL SEISMIC ACTIVITY WITH SEISMO-WATCH EARTHQUAKE REPORTS 
GLOBAL 
NORTHERN CALIFORNIA 
WESTERN GREAT BASIN 
SOUTHERN CALIFORNIA
Other Seismo-Watch Special Earthquake Reports
- Notations:
- TOPAZ LAKE, NEVADA, September 26, 2000 (Seismo-Watch) -- Preliminary data indicates that the largest of a series of earthquakes along the California-Nevada border southeast of Lake Tahoe near Topaz Lake registered ML 4.8, Mw 4.5.
- The main earthquake occurred at 7:20 UTC or 12:20 a.m. PDT about 30 miles southeast of Lake Tahoe, 12 miles east of Markleeville and about 1 mile east of Topaz Lake beneath the Gray Hills in Antelope Valley. The focal point was placed at 10 km beneath the surface and the preliminary fault plane solution from the U.C. Berkeley suggested strike-slip motion along either a northwest (preferred) or northeast trending plane.
- It was preceded by three foreshocks, a M1.7 a 11:56 p.m., September 25 and a pair of M2.9's at 2 and 9 minutes past midnight, September 26. It was quickly followed several aftershocks, including another temblor in the M4 range, a M4.2 at 12:27 a.m. Preliminary data showed the M4.2 quake had occurred about 3.5 miles southwest of Topaz Lake in Slinkard Valley, California, but reanalysis of the data indicated this not to be true and it was centered in the same location at the initial M4.8 jolt. Some of the aftershocks were also located in Slinkard Valley but this may be an artifact of the remote location of the activity and they probably are miss located. Perhaps further analysis will adjust the locations as well (See Seismo-Watch Regional Earthquakes for updated information). In all, 13 aftershocks were recorded, including three M3's and the M4.2 event.
- The initial M4.8 earthquake was widely felt at Topaz Lake, Holbrook Junction, Smith Valley and Markleeville jarring many people from sleep. It was felt as far away as Lake Tahoe and Carson City, and we have a few unconfirmed reports from locations along the western side of the Sierra, including Paradise, Placerville, and Stockton. There have been no reports of items toppling from tables and shelves and there was no indications of injuries. There has been no word from the Highway Patrol or the Department of Transportation of fallen rocks on road ways. The Reno Gazette-Journal reported some additional information.
- The main M4.8 shock was the first M4+ earthquake to occur in Nevada since a M4.2 struck Upper Fish Lake Valley (northeast of Bishop, CA and just inside the NV border) on March 14, 2000.
- Seismo History:
- A M6.0 earthquake occurred on September 12, 1994 about 11 miles northwest of Topaz Lake at Double Springs Flats. Robust aftershock sequence from that quake consisted of thousands of events, including several in Topaz Lake area as well with one as large as M4.7 on December 23, 1995 which caused a rock to topple off the hill and strike a truck near the California Inspection Station but in Nevada, causing it to crash and seriously injure the driver. It was the first earthquake related injury in Nevada in more than 30 years.
Sources: USGS, UCB, personal communications.
Update: 7:40 a.m., September 28, 2000.
Information contained within this report may not be disseminated without prior written consent from Advance Geologic Exploration, Inc. and Seismo-Watch.
Copyright (c) Advanced Geologic Exploration 2000
Did you feel
this tremor?
Send
us a quick note on what you felt.
A
Seismo-Watch
Earthquake email Alert Bulletin
sent to subscribers within an minutes of the event. You should
subscribe too! Click
here for more info.
Feel
free to browse other Seismo-Watch
Special Earthquake Reports.
Stay
informed, Stay Safe. Subscribe to Seismo-Watch
Global and Regional Earthquake Reports. Eight global and
regional earthquake reports to choose from, including four FREE Brief Regional Reports. Stay
informed with FREE e-mail updates to the Seismo-Watch
Online Earthquake Reports.
Don't forget our
FREE Brief
Central California Earthquake Report! Covering all the earthquake
activity for the Central California region, including the ever
active creeping segments of the San Andreas and Calaveras faults.
Updated
weekly. Subscribe to our FREE Update
e-mail messages NOW.
Have you seen our
FREE Brief
Western Great Basin Earthquake Report! Covering earthquake
activity for the California/Nevada border region, including detailed
activity of the Mammoth Lakes area.
Updated
weekly. Subscribe to our FREE Update
e-mail messages NOW.
You can't miss
our FREE Coachella
Valley Earthquake Report! Covering magnitude M1+ earthquake
activity in the Palm Springs area from the southern Landers aftershock
zone to the locked Coachella Valley segment of the San Andreas
fault.
Updated
weekly. Subscribe to our FREE Update
e-mail messages NOW.
