Several previously unknown geological faults, some of which may be active, have been discovered in the central and eastern Mojave Desert in California by geologists at the Jet Propulsion Laboratory and Louisiana State University analyzing images from an Earth-orbiting Landsat satellite.
The strike-slip faults were identified by images taken by the Thematic Mapper (TM) instrument on Landsat 5, which obtains images simultaneously in seven bands at optical and infrared wavelengths. Scientists used the TM images as "map" which pointed them in the right direction to locate and confirm the faults in the field.
JPL's Dr. John Ford, who helped locate and verify the faults in the field, said that "without Thematic Mapper images we would not have found the faults and TM images may enable us to find many more unmapped faults in the Mojave."
The newly observed faults are located in and near the unpopulated Bristol Mountains and Cady Mountains. Scientists have determined that the faults in the Bristol Mountains are overlain by unconsolidated alluvial fan debris (gravel) and are probably inactive. In contrast, faults lying to the west (Cady Mountains) cut all deposits and are seismically active. The faults all form part of complex regional network of right-slip faults that run between the Death Valley region and the San Andreas Fault System.
The newly observed faults are much smaller and less active than the San Andreas Fault but they all show evidence of strike slip, Ford said. During an earthquake, movement on strike-slip fault is dominantly horizontal and parallel to the trend of the fault. Scientists are now trying to determine how the newly observed faults fit into the regional structure in this part of the Earth's crust.
The faults add new pieces to the geological puzzle of how the Death Valley Fault zone and the San Andreas Fault system are related in space and time. The presence of these newly observed faults indicates that there are other yet-to-be discovered faults in the area.
The research is being conducted by geologists Dr. John P. Ford, Dr. Robert E. Crippen and Dr. Ronald G. Blom of JPL and Professor Roy K. Dokka of Louisiana State University's Department of Geology and Geophysics.
The project is funded by the Land Processes Branch of NASA's Office of Space Science and Applications.
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