|Geology of Lake Tahoe and the Sierra Nevada|
The most recent earthquake in the Tahoe region was about 575 years ago, on the Incline Fault, which becomes active about every 10,000 to 15,000 years.
There have been more recent earthquakes north and east of the lake.
The biggest recent quake was on the northern part of the West Shore fault.
In the event of an earthquake move away from windows and doors that face the lake.
The West Tahoe fault may be the most dangerous:
Earthquakes strike every 3,000 to 4,000 years on the fault.
The West Tahoe Fault last moved 4,500 years ago causing a large part of the west shore shelf to move down into the lake and creating a 30 ft high tsunami.
Actually earthquake-caused large waves in a lake or closed body of water is called seiche (pronounced say'sh).
Some of the debris from the slide in the middle of the lake are 65 ft high.
It is due to strike again with up to a level 7.3 earthquake, this time it is estimated that the seiche (tsunami) waves will be 30 ft. high and it will slosh from shore to shore for hours.
Because the fault crosses the lake, scientists worry a future earthquake will cause a tsunami in Lake Tahoe. The monster waves could form in two ways: by the fault displacing ground under the lake, similar to Japan's Tohoku tsunami, or by causing landslides that displace the water. A combination of both could also create an even bigger wave.
The eastern side of the fault could drop 10 feet or more causing a wave which would bounce off the east shore 4 minutes after the quake and come back reaching the west shore 6 minutes after the quake. The water will continue to rise on the west shore until 10 minutes after the quake then start washing back out into the lake where it will rise on the north and south shores 14 minutes after the quake.
Shallow-water waves move at a speed, c, that is dependent upon the water depth and is given by the formula:
where g is the acceleration due to gravity (= 9.8 m/s2) and H is the depth of water.
Tahoe is about 450 m deep so the speed would be 66 m/sec or 150 MPH.
on the central and northern segments of the West Tahoe fault (5600-5330 cal. yr B.P.); and on the West Tahoe fault (between 7890 and 7190 cal. yr B.P.).
The McKinney Bay (MB) landslide extends 5.5 miles to middle of the lake.
The large blocks in the center of the lake are the result of a massive megaslide failure that created the McKinney Bay reentrant A smaller earthquake in the southern part of the West Tahoe fault occurred between 4510 and 4070 cal. yr B.P. See:
(PDF) Paleoseismic history of the Fallen Leaf segment of the West Tahoe-Dollar Point fault reconstructed from slide deposits in the Lake Tahoe Basin, California-Nevada | \0x2002Geosphere - 2013
Holocene subaqueous paleoseismology of Lake Tahoe | Geological Society of America Bulletin - 2013
Lake Tahoe overdue for an earthquake | NBC News
A tsunami at Lake Tahoe? - KRNV, Reno, NV
websites.pmc.ucsc.edu/~ward/Tahoe-Tsunami-Tube.mov Simulation video
Lake Tahoe in Depth Video created for the UC Davis Tahoe Environmental Research Center by Stephen McQ
Steven N. Ward's main index Cross Section Wave - websites.pmc.ucsc.edu/~ward/Tahoe-Tsunami-Tube.mov Mega-Tsunami
A 2006 USGS study led by internationally recognized tsunami expert James G. Moore2 found that a giant landslide in McKinney Bay on Tahoe’s west shore dropped several cubic miles of the West Shore 1,500 feet to the bottom of the lake and likely generated enormous seiche waves between 7,000 and 15,000 years ago (Moore et al., 2006).
Gene Ichinose3 of the UNR seismological laboratory studied the faults underneath the lake and they estimated that the probability of such an event would be around 2-4% in the next 50 years,
North Central California Faults
Lake Tahoe Tsunami & Earthquake Risk | US Earthquake Hazards | Live Science 60 k.y. record of extension across the western boundary of the Basin and Range province: Estimate of slip rates from offset shoreline terraces and a catastrophic slide beneath Lake Tahoe | Geology | GeoScienceWorld
1. Schweickert, R. A.; M. M. Lahren. (2002). Glacial Geology of Blackwood Canyon, Lake Tahoe, California; Implications for Landslides and Tsunamis. Abstracts with Programs – Geological Society of America 34(6):130-131.
2. Tsunami-generated sediment wave channels at Lake Tahoe, California-Nevada, USA | USGS.gov
3. Ichinose, G. A., J. G. Anderson, K. Satake, R. A. Schweickert, M.L. Lahren. (2000). The potential hazard from tsunami and seiche waves generated by large earthquakes within Lake Tahoe, California-Nevada. Geophysical Research Letters 27(8):1203-1206