Coyote Flat Landslide W.J. Elliott, CPG-04194, Engineering Geologist Abstract
The Coyote Warp, or Coyote Flat Landslide, is a physiographic feature located on the east side of the Sierra Nevada, between Bishop and Big Pine, California. Its origin has been described as an artifact of structural warping. An alternative explanation is a mega-landslide.
Introduction
What follows is an alternative to Bateman’s (1965, p. 174) explanation of the geology and geomorphology he observed in the eastern Sierra Nevada, between Bishop and Big Pine. He proposed that the old (Eocene?) erosion surface had, by some mysterious and unexplained tectonic process, been warped down to the north, northeast, and east.
Matthes (1930 and 1960) recognized four stages of erosion in the central Sierra Nevada, the oldest being a nearly completely destroyed surface of presumably Eocene age. Although the age of the surface is clearly a subject for spirited debate, based on regional considerations, it seems an Eocene age makes the most sense at this preliminary level of review.
Bateman (1965, p. 174) includes the Tungsten Hills, west of Bishop, as a part of his Coyote Warp, as well as a similar- sized area south of Big Pine Creek. For simplicity, these two flanking areas are herein acknowledged as likely appendages
to the main, obvious, landslide mass, but attention to them will be left for another essay.
Phillips (2017-a) offered a listric fault solution to explain the Coyote Warp. In this interpretation, the Sierra block would slide westward away from the White Mountains fault, leaving a series of fault blocks to fall into what is now Owens Valley.
Discussion Coyote Warp
The Coyote Warp is described in great geological and geomor- phic detail in Professional Paper 470 (1965, p. 174-181). The warp was characterized as having little in common with the adjacent Sierra escarpment. Instead, it was suggested that it represented a dissected old erosion surface (perhaps of Eocene age, Wahrhaftig and Birman, 1965, p. 305) that has been cut by faults and dissected by erosion of numerous steep-sided canyons and arroyos.
Additionally, several normal faults, some with valley side down and some with Sierra side down were described. Horsts and grabens abound between these discontinuous, curvilinear fault sets; all of which seemed to have baffled Dr. Bateman not familiar with engineering geology, at least not the same way as we are today.
Coyote Flat Landslide
Imagine an approximately 14½ mile wide, by approximately 17-mile-long, short-run-out block-glide-landslide or rotational been suggested that this feature may be a sackung (or sagging) by Kim Bishop, (personal communication, 2018; Radbrunch- Hall and others, 1976).
The Owens Valley graben provided an amply deep (approxi- mately 7,000’) and wide hole into which the slide could move (Pakiser and others, 1964; Hollett and others, 1991; Danskin, 1998).
Figure 1 - Unedited Google Earth image of the Coyote Flat landslide. (cf. Figure 6.)
www.aipg.org
Earthquakes along the Sierra frontal fault system would have released enough energy to get the earth moving, even if only a little bit at a time (Hough and Hutton, 2008).
Jul.Aug.Sep 2021 • TPG 3
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