By Sid Perkins
Shallow coral reefs around islands west of Sumatra chronicled the uplift and subsidence that resulted from massive quakes that struck that region recently, a new study shows. From data recorded in this biological database, scientists may learn why two undersea ruptures stopped where they did.
On Dec. 26, 2004, a magnitude 9.3 temblor beneath the Indian Ocean spawned killer tsunamis (SN: 1/8/05, p. 19: Tsunami Disaster: Scientists model the big quake and its consequences) and a flood of scientific interest (SN: 8/27/05, p. 136: Earthshaking Event). Researchers rushed to the affected region to install sophisticated instruments, many of them in time to record the effects of a magnitude 8.7 quake in March 2005 (SN: 4/2/05, p. 211: Available to subscribers at Hit Again: December temblor probably caused new Sumatran quakes). But some of the best sensors—the reefs surrounding the region’s islands—had been in place all along, says Richard W. Briggs, a geologist at the California Institute of Technology in Pasadena.