 by Jim Erickson Scripps Howard News Service December 30, 2004
Those are a few of the claims that surfaced after last weekend's magnitude 9.0 earthquake and the killer tsunami that followed. Pretty amazing stuff. Problem is, those claims aren't true, according to the National Earthquake Information Center in Golden, Colo. The information center has been overwhelmed by calls from reporters and the public since the devastating megathrust earthquake ruptured a 600-mile-long slab of sea floor off the coast of Sumatra. The center-run Web site (earthquake.usgs.gov) received an unprecedented 15 million hits Sunday, 18 million hits Monday and 10 million hits Tuesday, according to David Wald, a seismologist at the U.S. Geological Survey center. "I hesitate to use the word inundate. But it's been chaotic here," Wald said. When interacting with the public and the media, the center's 20 staff members invariably spend part of their time clearing up misconceptions. Some points of confusion are addressed in a new Frequently Asked Questions list on the survey's earthquake Web site. Rumor 1: The Earth was knocked off its axis. Not true. But the redistribution of the Earth's crustal mass caused by the earthquake likely will have a tiny effect on the planet's rate of rotation, and therefore the length of a day. Using computer models, Richard Gross of NASA's Jet Propulsion Laboratory has calculated that the earthquake shortened the length of a day by 2.676 microseconds - that's less than three one-millionths of a second. Gross also calculated that the Earth's rotation axis was changed by an exceedingly small and probably undetectable amount. "The effect on the Earth's rotation is infinitesimal and obviously inconsequential," Wald said. "You shouldn't lose sleep over it." Rumor 2: Sumatra moved 100 feet. Not true. It was widely reported, based on information supplied by a U.S. Geological Survey scientist in California, that Sumatra moved 100 feet to the southwest. The Los Angeles Times reported it Monday but later issued a correction, citing incorrect information. The quake occurred along the boundary between the Burma and India tectonic plates. The northwest corner of Sumatra sits on the Burma plate and may have moved southwest several yards, Wald said. Rumor 3: Global sea levels surged. Somewhat true. Energy from the Indian Ocean tsunami did, in fact, leak into the Pacific, causing minor sea-level fluctuations there, according to the Pacific Tsunami Warning Center in Hawaii. The greatest increase - 8.6 feet - was seen in Manzanillo, on Mexico's west coast, according to the tsunami center. While there were temporary, regional surges in sea level, there was no global sea-level rise.
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