Ruth Harris, a Senior Scientist with the U.S. Geological Survey’s Earthquake Science Center, along with her colleague Robert Simpson, examined the static stress change effects of the 1992 Landers earthquake and one of its larger aftershocks on Hector Mine. “We showed that depending on small changes in the assumed Earth parameters, the 1992 Landers earthquake may have triggered 1999 Hector Mine or may have delayed 1999 Hector Mine, and that the answer had a big range of possible values, compared to what we usually think of in terms of earthquake triggering—or delaying, also known as shadowing,” Harris said. “That is why in general, it is good to include the range of possibilities—the uncertainty—when presenting results."
Studying the stressing relationships among earthquakes was already a popular research topic by 1999, “but with each new well-recorded large earthquake we do always learn something new,” Harris noted.
“One of the new things with 1999 Hector Mine was that it made us quite aware that we could have multiple large earthquakes in this particular region of California,” she added. “It also reminded us that we need ourselves and the public to remain focused on the idea that large earthquakes, in both remote and populated areas, can occur in most parts of California, not just on the famous faults, so we need to always be prepared, in both the short term and the longer term.” |
