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Know the West

Lots to see in Carrizo

  Dear HCN,

Sam Kennedy, in his article on the grazing controversy in the new Carrizo Plain National Monument in California (HCN, 6/4/01: California monument welcomes cattle) starts by saying "The first thing you notice ... is, well, there's not much to see." How wrong he is! Carrizo Plain is a premier world site for seismology, and probably has more earthquake fault phenomena more starkly displayed in one place than anywhere else in the world.

The San Andreas Fault, which is the boundary between the North American and Pacific tectonic plates, runs for 30 miles through the monument, and was the location of the giant 8+" magnitude earthquake of 1857, which moved the Pacific plate over 30 feet northwest of the North American plate in the monument. Because of the arid conditions, the earthquake trace is still fresh and easily seen and followed. The Carrizo Plain is probably the only place in the world where you can stand with one foot on one tectonic plate and the other foot on a separate tectonic plate. The monument is full of old fault traces, earthquake scarps, sag ponds, canyons that abruptly detour 90 degrees to the right as they meet the fault, and other signs of great seismic activity, all vividly displayed.

President Clinton's decree establishing the monument mentions the unique geology of the Plain, but the BLM has done almost nothing in its publicity to mention the geology on view there. That is probably why Mr. Kennedy returned from there saying there is nothing to see. Properly developed, Carrizo Plain could be the most important place in the United States, if not the world, for viewing earthquake faults and seismic phenomena, but that will not happen while the monument is under current management.

I suggest that the U.S. Geological Survey should be added to the monument management, and given the assignment of making its marvels of seismic activity available to the public for their delight and education. Or, if that cannot be done, the managers of the monument for the state of California should get the geology departments of some of the universities in California to identify the geological features of the monument for public appreciation.

William G. Rhoads
Arlington, Virginia