THE EARTH INSTITUTE AT COLUMBIA UNIVERSITY -- Ordinarily, losing almost all of one's instruments would be considered a severe setback to any scientist. But when Maya Tolstoy, a marine geophysicist at the Lamont-Doherty Earth Observatory, a member of the Earth Institute at Columbia University, recently learned that two-thirds of the seismometers she placed on the floor of the Pacific Ocean were trapped more than 8,000 feet (2500 meters) underwater, it turned out to be an extremely good sign.
Tolstoy and Lamont-Doherty colleague Felix Waldhauser set an array of ocean bottom seismometers along a section of the East Pacific Rise off the coast of Mexico in 2003 to study the little-understood process of seafloor spreading--a process that is responsible for the formation of nearly three-quarters of the Earth's crust. When a team went back in April 2006 to retrieve the instruments, however, only four out of 12 responded to the coded release signal and bobbed to the surface; three more responded to the signal, but did not come up. The rest remained silent.
Tests of the water temperature and light-scattering near the sea floor revealed signs of a recent volcanic eruption. A second expedition led by James Cowen of the University of Hawaii on the research vessel R/V New Horizon in early May lowered a camera that confirmed what the scientists suspected: Their instruments had been directly on top of a section of the East Pacific Rise that erupted and were trapped in fresh lava flows.
Instead of bemoaning their fate, the group celebrated their fortune--no one has ever closely recorded the series of micro-earthquakes associated with the formation of new seafloor. Preliminary analysis of their data appears in an upcoming issue of the journal Science and will be released on the Science Express Web site November 23.
"It's amazing that we know so little about something so fundamental to the planet," said Tolstoy. "Even if we don't get t
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Contact: Ken Kostel
kkostel@ei.columbia.edu
212-854-9729
The Earth Institute at Columbia University
23-Nov-2006