A UC Berkeley seismologist reports that the number of tremors along the San Andreas Fault has increased by as much as 80 percent over the last four years. Using evidence gathered from seismic tools buried near Parkfield to measure the phenomenon, Robert Nadeau explains that these tremors “can signal that there are deep stress changes going on that we hadn’t detected before.”
A UC Berkeley seismologist reports that the number of tremors along the San Andreas Fault has increased by as much as 80 percent over the last four years. Using evidence gathered from seismic tools buried near Parkfield to measure the phenomenon, Robert Nadeau explains that these tremors “can signal that there are deep stress changes going on that we hadn’t detected before.”
While earthquakes are considered to cause tremors, increasing evidence suggests that they might precede earthquakes as well. The level of tremors should have dropped after the 2003 San Simeon quake and the 2004 Parkfield quake, once stress levels declined along the fault. The fact that they did not may suggest that stress is actually building up along this segment and that the fault is at risk of breaking. When that last occurred in 1857, the result was the 7.8 magnitude Fort Tejon earthquake.
Nadeau’s observations are not to be interpreted as some prediction of an impending, catastrophic earthquake at some precise time in the immediate future. They do show that tremors are far more common that previously believed, and could help scientists move one step closer to the elusive goal of predicting major earthquakes. Read More at InsideBayArea.com. http://www.insidebayarea.com/top-stories/ci_12803538
