For 25 years, geophysicist Rob McCaffrey has been monitoring earthquake activity and plate convergence at subduction zones around the world, including the Sumatra subduction zone in Indonesia where December’s devastating magnitude 9 earthquake occurred.

“Large earthquakes are common in South Asia, generating smaller tsunamis every few decades. But a magnitude 9 is very rare,” says McCaffrey, professor of earth and environmental sciences. “This is about as big as it could get along that fault line. It will likely be many centuries before a magnitude 9 quake hits that section of the fault again, but a quake of similar size could occur along the fault south of Java or Sumatra.”

Scientists have yet to develop a reliable system to predict earthquakes. Still, McCaffrey says tsunami warning systems, which can predict tsunami arrival times at coastal communities, can and should be improved and expanded.

McCaffrey estimated that about three hours passed by between the time the earthquake occurred off the coast of Sumatra and when the resulting tidal wave struck Sri Lanka more than 1,000 miles away.

“If there was a warning system in place in the Indian Ocean, people in Sri Lanka surely would have had time to get to higher ground,” McCaffrey told the Albany Times Union newspaper.

An extensive tsunami warning system has been installed on the floor of the Pacific Ocean, but not in the Indian Ocean.

McCaffrey’s research interests include the analysis of geological, seismological, gravity, and geodetic data from convergent margins with attention to the structure, tectonics, and dynamics of subduction and collision. “We examine earthquake statistics to understand what factors control when and where large earthquakes occur, measuring temperature of the faults, earthquake magnitude distributions, fault slip rates, etc.,” McCaffrey says. “The goal is to see how much we can learn about future earthquakes from what has happened in the past.”

Originally published in Rensselaer Magazine, Spring 2005
Photo by Mark McCarty

Published April 1, 2005