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MARCH 26, 1872 (M=7.6)
[c6, p166-167]

The town of Lone Pine, Calif., was virtually leveled when the entire 100 to 110-km length of the Owens Valley fault ruptured on March 26, 1872, in one of the largest earthquakes in U.S. history. This fault, which lies in the middle of Owens Valley, is distinct from the normal faults bounding the front of the Sierra Nevada to the west. Considerable confusion has existed in the literature regarding the style of faulting in the 1872 earthquake, including interpretations of right-lateral, left-lateral, and normal-fault movement. A recent study of the earthquake offsets by Beanland and Clark (in press) unambiguously demonstrates that fault movement was predominately right-lateral strike slip, with an average horizontal displacement of 6 m (Figure 6.10). The vertical offsets were clearly smaller and averaged about 1 m down to the east. Beanland and Clark estimate a moment magnitude of M=7.5-7.7. Faulting in 1872 largely reactivated earlier Holocene scarps, as recognized by G.K. Gilbert when he visited the area in 1883.

The event was felt throughout most of California and Nevada, and as far east as Salt Lake City, Utah. Adobe and brick buildings in Owens Valley sustained the brunt of the damage. Minor damage also occurred in the San Joaquin and Sacramento Valleys on the opposite side of the Sierra Nevada, at distances of as far as 400 km. In Yosemite Valley, John Muir witnessed a spectacular rockfall triggered by the earthquake. As severe as the ground shaking must have been, it was noted in the Inyo, Calif., Independent of April 6, 1982, "*** that not a person would have been killed or hurt had their houses all been made of wood." It is of some historical interest that the first long-term earthquake forecast, made by G.K. Gilbert in 1883 to the citizens of Salt Lake City, was based in part on his observations of the 1872 earthquake. In it, he noted that the rebuilding of Independence with wood-frame buildings was an extravagance, because this great shock had relieved the accumulated strain, and so many generations would pass before conditions would permit another similar shock to occur (Gilbert, 1884):

The old maxim, "Lightning never strikes in the same spot twice" is unsound in theory and false in fact; but something similar might truly be said about earthquakes. The spot which is the focus of an earthquake (of the type here discussed [1872 Owens valley]) is thereby exempted for a long time.

Many comparisons have been drawn between the Owens Valley earthquake and the great San Andreas earthquakes of 1857 and 1906. The size of the regions shaken in all three events are comparable, as are the maximum fault displacements. The two San Andreas events have significantly longer rupture lengths, and their seismic moments are larger by a factor of 2 to 3. Whether or not any or all of these earthquakes can be classified as "great" earthquakes becomes a question of semantics. All of them can be classified as great on the basis of their rupture lengths of 100 km or more (Kanamori, 1977), but they all have seismic moments more than 100 times smaller than the largest known earthquakes, such as the M=9.2 Alaska earthquake of 1964. Practically speaking, these events are among the largest known strike-slip events, and they must be close to the size of the largest possible strike-slip events along the San Andreas fault system.