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For more information on these science news and feature story tips, please contact the public information officer at the end of each item at (703) 292-8070. Editor: Bill Noxon Contents of this News Tip:
CALM BEFORE THE QUAKE?A new theory maintains that periods of "seismic quiescence" -- months or years when there are far fewer small earthquakes in an area than normal -- sometimes precede the world's strongest and most damaging earthquakes. In a recent study, researchers Max Wyss of the University of Alaska Geophysical Institute and Walter Arabasz of the University of Utah Seismographic Station, searched for periods of seismic quiescence before seven large earthquakes recorded in Utah from 1974 to 1996. Quiet periods preceded at least three of those earthquakes. Wyss and Arabasz conducted the study through the National Science Foundation-supported National Center for Atmospheric Research in Boulder, Colorado. Wyss also studied why large earthquakes don't always follow seismic quiescence. In Japan, where much has been published in support of the quiescence hypothesis, Wyss found that seismically quiet periods precede significant earthquakes only when sufficient underground stress has accumulated. Wyss believes his research tends to confirm the theory of seismic quiescence as an indicator of earthquakes to come, despite "false alarms" to the contrary in places like Tokyo. "Scientists who predict the weather experience false alarms quite frequently," says Wyss, "which just means the hypothesis doesn't work in those few cases." [Cheryl Dybas] SCIENTISTS DETECT DEEP-SEA EARTHQUAKES OFF OREGON COASTUsing a military system designed to track submarines, scientists supported in part with NSF funds have detected and are monitoring intense earthquake activity on the sea floor about 300 miles off the northern Oregon coast, indicating an ongoing seafloor volcanic eruption. Researchers have detected more than 6,000 small earthquakes since seismic activity began on January 28th on the summit and southern flank of Axial Seamount on the Juan de Fuca Ridge, an underwater mountain range off the U.S. Pacific northwest coast. Axial Seamount rises 1,100 meters (3,610 feet) above the surrounding ocean floor to a depth of approximately 1,400 meters (4,595 feet) below sea level. The activity is the most intense recorded since scientists began monitoring the area in 1991. Scientists with the National Science Foundation's Ridge Program and with the National Oceanic and Atmospheric Administration's Vents Program will continue to monitor the ongoing eruption, and have dispatched the research vessel Wecoma to the site to conduct further studies. Similar to volcanoes on land, seafloor volcanoes erupt episodically. Their effects on the ocean environment are most profound during the early stages of eruption, making it critical to detect them early so that these effects can be observed. Although deep-sea volcanic eruptions account for more than 80 percent of the earth's volcanic activity, there was no means of detecting these eruptions until the U.S. Navy's SOSUS (Sound Surveillance) system was adapted for other uses in the early 1990s. [Cheryl Dybas] REVIEW FINDS HABITAT CONSERVATION PLANS LACK BASIC SCIENCECertain habitat conservation plans that promote timber-cutting accords -- new ways of timber-harvesting in exchange for concessions in the requirements of the Endangered Species Act -- often are based on few hard scientific results, an in-depth review of these plans has found. In the review, funded in part by the NSF and the American Institute for Biological Sciences, biologists and graduate students at universities across the country found inconsistencies in the quality of science and the degree to which wildlife habitat is protected, according to zoologist Peter Kareiva of the University of Washington. Some 100 graduate students and 13 scientists from eight universities participated. Students plan to publish the results in scientific journals. Kareiva found widely varying degrees of scientific accuracy in the plans. For a large portion, perhaps half, of the plans reviewed, Kareiva and his colleagues believe that the plans lack enough data and "basic biology" to conduct adequate scientific studies of a given habitat; others, especially those that looked at species well-studied by biologists, like the northern spotted owl, were the most "scientifically solid." Habitat conservation plans influence industrial forestry practices, with large companies like Weyerhaeuser now participating in plans that cover hundreds of thousands of acres and attempt to protect a wide range of species. [Cheryl Dybas]
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