Dec. 13, 2005 A geophysicist from the U.S. Department of
Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab)
has identified possible seismic precursors to two recent
California earthquakes, including the 1989 Loma Prieta
earthquake that wreaked havoc throughout the Bay Area. After
sifting through seismic data from the two quakes, Valeri Korneev
found a spike in the number of micro-earthquakes followed by a
period of relative calm in the crust surrounding the quakes’
epicenters — months before the quakes occurred. Although more
work needs to be conducted to determine whether other large
quakes are foreshadowed by a similar rise and subsequent decline
in small-magnitude tremors, Korneev’s analysis suggests that
these peaks may be indicative of the total set of geological
stresses that affect the timing and location of large
earthquakes. Understanding this total stress picture may
eventually make it be possible to predict destructive
earthquakes within a much shorter time frame than currently
possible.