|(Click on image for larger view.)|
Once again, I repeat the Eureka Alert report.
|Fault lines along the San Francisco region.|
Using a radar-like lasar imaging technology, known as LiDAR, scientists have identified a previously unrecognized active fault near the Martis Creek Dam just outside of Truckee, California, possibly representing a significant seismic risk to the greater Lake Tahoe area. Named after a 19th century town site that was located along the Truckee River, the Polaris Fault was identified during an evaluation by the U.S. Army Corps of Engineers, which owns and operates Martis Creek Dam. The approximate 22-mile fault may yield an estimated maximum earthquake magnitude of 6.4 to 6.9.
The estimate could increase should the fault connect with, or rupture at the same time as, other faults in the area. LiDAR, the aerial mapping technology, emits laser pulses from an instrument mounted in an airplane. Some of these near vertical laser pulses penetrate dense vegetation, allowing for the vegetation to be removed in data processing to yield high-resolution images of the Earth's surface. LiDAR is especially useful for analyzing rugged, poorly accessible, forested terrain. "LiDAR Assisted Identification of an Active Fault near Truckee, California," by authors Lewis E. Hunter and Ronn S. Rose of the U.S. Army Corps of Engineers and James F. Howle and Gerald W. Bawden of the U.S. Geological Survey.