Dec. 23, 2004
An earthquake with a preliminary magnitude of 8.1, the year's strongest, shook the ocean floor today about 1,000 miles southwest of New Zealand, with the potential to release tsunamis that were unlikely to reach Pacific coastlines.
The quake struck about 1:59 a.m. at the epicenter and was the first this year to exceed a magnitude of 8. An 8.1 quake in Mexico City in 1985 killed about 9,500 people and left extensive damage.
``This was a strike-slip earthquake, where two plates move sideways to each other, as opposed to colliding head on,'' research geophysicist Stuart Sipkin said of the Pacific quake by telephone from Golden, Colorado, at the U.S. Geological Survey. A sideways quake limits the extent of tsunamis, Sipkin said.
The U.S. government's Pacific Tsunami Warning Center said on its Web site that ``widely destructive'' tsunamis from the quake were possible in the open ocean.
The nearest human outpost is MacQuarie Island, a small, rocky isle 305 miles to the south that Australian researchers share with seals. Today's quake was located at 50.24 degrees south latitude, 160.13 degrees east longitude.
The quake occurred about six miles below the seafloor, according to the U.S. quake center's analysis. The next largest quake in 2004 was a magnitude 7.5 temblor that struck eastern Indonesia on Nov. 11, killing 23 people and leaving almost 8,000 homeless, according to the national government.