Policymakers said unprepared for subduction earthquakes

Published 28 March 2007

A lack of historical data makes it impossible to predict when these rare disasters will occur; 2004 Indonesian tsunami an object lesson in being unprepared

Attentive readers will recall that we here at HSDW come from earthquake country, also known as the San Francisco Bay Area. Earthquake drills, earthquake preparedness, and even earthquake tours of famous fault lines make up a large part of our childhood memories, and so it is no coincidence that we left at the first opportunity. Now we have even more reasons not to return. According to professor Robert McCaffrey of Rensselaer Polytechnic Institute, scientists consistently underestimate the risk from earthquakes, most recently when seismologists failed to predict the 2004 Sumatra-Andaman earthquake and resulting tsunami. Policymakers, says McCaffrey, should now consider all subduction-type tectonic boundaries to be “locked, loaded, and dangerous.”

Seismologists have long tried to determine which subduction boundaries are more likely than others to break,” McCaffrey told Continuity Central, referring to the type of tectonic boundary where one plate is gently slipping underneath another plate. An earthquake can result by only twenty meters of slip, and although any particular boundry will do so only every 200 to 1000 years, a lack of historical data makes it almost impossible to predict if nearby residents are living in a safe or exceedingly dangerous historical era. As a result, McCaffrey argues that policymakers need to design warning systems with the long-term well in mind. “These systems need to be strong and they need to be maintained over the long term because we have no way of knowing when the next great earthquake will hit.”