Research Shows L.A. Quake Faults Squeezed

By Associated Press

May 19, 2005, 9:17 PM EDT
PASADENA, Calif. -- The San Gabriel Mountains and downtown Los Angeles are being squeezed at such a rate that the strain could cause a moderate temblor, according to new research.
Scientists cannot forecast when the earthquake might occur, but said the strain will be released in quakes similar to the 6.7-magnitude temblor that hit the Northridge area of Los Angeles in 1994.
"These findings remove uncertainty about the rate at which strain is building up in northern metropolitan Los Angeles," Donald Argus of NASA's Jet Propulsion Laboratory said in a statement Thursday.
More studies are needed because scientists do not yet fully understand the consequences of such stress accumulation, Argus said.
According to Argus' research, the region is being compressed at a rate of 0.2 inch a year, straining an area between the Puente Hills fault located beneath downtown, and the Sierra Madre Fault running along the base of the San Gabriel Mountains.
The research was published in the Journal of Geophysical Research last month.
The compression was monitored by a network of more than 250 global positioning instruments, part of a satellite-based network to track tiny creeps of the Earth's crust with unprecedented accuracy.