By Becky Oskin, Staff Writer | January 10, 2014
There are tantalizing hints some faults issue warning signals in the days and months before a big earthquake, according to new research.
A study of squeaky glass beads squeezed between powerful pistons offers one explanation for how these earthquake warning signals form. The findings were published online Nov. 4 in the journal Geophysical Research Letters.
The signals range from tiny shocks along the fault, which may be beyond the limit of detection by today’s seismic monitors, to earthquakes large enough to rattle houses. The common thread is that the final rip — the main earthquake — strikes at or near the site of the smaller, earlier breaks.
“They are associated with small failures along the fault patch that is going to fail catastrophically,” said Paul Johnson, a geophysicist at Los Alamos National Laboratory in New Mexico and lead study author.
Making a link between these earthquake precursors and the “big one” is controversial in the world of earthquake research. While many laboratory studies indicate there are seismic warning signals to watch for, in the real world, not all earthquakes have foreshocks, as these preliminary shakers are known. Still, geoscientists hope that by better understanding what happens before an earthquake, they may one day have a means of warning the public of increased earthquake risk.
“I think we’re seeing the beginning of something potentially really exciting for characterizing an area of increased hazard,” Johnson said. “We’re not going to predict when an event takes place. [But] this kind of observation can be tested to see whether or not this information will be useful for earthquake hazard and predicting intervals of increased seismic risk.” [13 Crazy Earthquake Facts]