SCEC INSTANeT News
	The World Didn't Come to an End- Despite some Big Shakes in Late 1999, globally speaking, 1999 was an average year for Earthquakes

By Susan Hough and Lucile M. Jones, Seismologists US Geological Survey, Pasadena, CA Special to SCEC INSTANeT News If there was a certain apocalyptic feeling to the spate of recent earthquake activity worldwide, rest assured, it sometimes felt that way to the Earth sciences community as well. While Earth scientists don't see recent worldwide activity as a biblical harbinger, they were reeling in late 1999 from having to deal with the scientific and media response to five significant earthquakes in Taiwan, Mexico, California and two in Turkey, in such close succession. However, the world did not ­ and is not ­ coming to an end. The Earth has been around for a few billion years and obviously didn't care that, according to a modern calendar, we clicked over to a nice, round number. In fact, globally speaking, 1999 shaped up to be an average year for earthquakes (see NEIC's statistics page for earthquakes at wwwneic.cr.usgs.gov/neis/eqlists/eqstats.html.) Late 1999 activity was somewhat unusual in that so many of the 7.0-plus earthquakes struck near populated areas, but we knew this was only a matter of statistics. And as the global population hits 6 billion and counting, the odds can only continue to worsen against us. Along the Pacific Rim--the so-called "ring of fire" ­ virtually all major cities are vulnerable to earthquakes of 7.0 or more. That includes Los Angeles, Seattle and Anchorage in the United States as well as cities in all of Japan and the west coast of South America. Earthquakes during 1999 that were larger than Magnitude 7.0 (map compiled by the NEIC Earthquake Search page, wwwneic.cr.usgs.gov/neis/epic/epic_global.html) Most earthquakes were on the "ring of fire."   In southern California, the southern San Andreas fault has been considered "ten months pregnant" for a long time, and earth scientists have been carefully monitoring a series of small earthquakes near the southern end that seem to have been triggered by the October 16, 1999 Hector Mine earthquake (see www.data.scec.org for updates on the Hector Mine and other earthquakes). The chance of a subsequent large earthquake still is considered low, but, at the same time, you don't have to be a seismologist to know that one can't stay ten months pregnant forever. Fortunately, where earthquakes and earthquake hazard are concerned, the new millennium heralds tremendous opportunities as well as terrific challenges. The 7.1 Hector Mine earthquake has been dubbed the first "cyberquake" because it is the first substantial earthquake to have struck southern California since the installation of the new, state-of-the-art "TriNet" seismic network (www.trinet.org). A collaborative effort among the U.S. Geological Survey, Caltech and the California Divisions of Mines and Geology, TriNet provides more, better and faster seismic data than ever before. A second important new instrumental initiative in Southern California ­ by the Southern California Earthquake Center, NASA and the USGS ­ involves installation of stations to record data from global positioning satellites tracking the slow, steady motion of the Earth's tectonic plates (see www.scign.org). Both TriNet and the new GPS network are integrated with, and dependent upon, the Internet. We are therefore not only collecting more and better data than ever before but also able to disseminate it ­ to scientists, policymakers and the public ­ much faster than before. Compared to the situation just seven years ago (the time of the 7.3 Landers earthquake) the quantity and quality of information making its way to the public is vastly improved. This is tax dollars at work. Major instrumental earth science programs do not come cheap, and recent efforts have been supported by a variety of federal and state government sources, sometimes in partnership with private industry. The initiatives in southern California also are pilot projects that were made possible because the 1992 Landers and 1994 Northridge earthquakes highlighted seismic hazard as a real and present danger in this region. Yet earthquake hazard is, of course, by no means restricted to southern California. If the next big earthquake strikes too soon in Northern California or elsewhere, scientists there will have far fewer integrated scientific/cyber-tools at their disposal.

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