The serene Lake Tahoe area was formed by seismic shifting and landslides. Lake Tahoe is the third deepest lake in North America. New data tells that significant seismic hazard exists in the Lake Tahoe Basin from earthquakes, ground shaking, faulting, landslides, liquefaction of sediments and waves known as seiches.

The Geology of Lake Tahoe Lake Tahoe is a popular place where most people go during vacations. Its crystal clear waters and characteristic blue color is unique from all lakes that exist. The common misconception that people have is that Tahoe was formed through volcanic activity. It is only recently that the Tahoe Basin is being mapped through a sonogram-which is a device that works like an ultrasound in a pregnant woman. Graham Kent, with the Scripps Institute of Oceanography in San Diego, said that the Lake Tahoe Basin was actually formed through a series of faulting and landslides. Lake Tahoe is located in the California-Nevada border where tectonic plates shearing past each other have resulted in the Sierra Nevada (Irion, 2001). In 1999, geologists documented that two earthquakes, with probable magnitudes of 7.2 and 7.5 struck within the last 2000 years along a fault within just 20 km east of the lake (Irion, 2001). New data tells that significant seismic hazard exists in the Lake Tahoe Basin from earthquakes, ground shaking, faulting, landslides, liquefaction of sediments and seismic waves known as seiches (Irion, 2001). New data about the basin can be seen in the Nevada News. The basin was formed through faulting, a process in which the earth's crust allows blocks of land to rise and sink. Several thousands of years ago, the Sierra Nevada Mountains were rising from the sea. Two principal faults were formed-the Carson Range on the eastern range and the Sierra Nevada mountains on the western side (Edson, 2001). Geologically speaking, this is a recent land development, occurring only these past few million years. One of the reasons for the movement of the fault is magma (Edson, 2001). Magma generates a whole lot of pressure and heat. Facts: 1. Lake Tahoe is the third deepest lake in North America and the tenth deepest lake in the world. 2. Two-thirds of the lake is in the state of California and one-third of it is in the state of Nevada. 3. Its surface elevation is 6225 feet above sea level, making it the highest lake of its size in the United States. VISIT: www.tahoecam.com/TahoeFacts.html for more facts and information. Just a few years back, the lake was so clear that objects could be seen up to the depths of 120 feet. However in the last three decades, more than thirty feet of visibility have been lost. Because of the lake's popularity, the population has increased. With this increase, pollution, of both water and air caused sediments to wash down the lake. The sediments contain nutrients which affect the water's ecosystem and clarity. Construction of roads and cars using these roads causes loose dirt to drift in the lake. --by Margarita Montes � � � �

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