PHILADELPHIA — Geological evidence of earthquakes and tsunamis aids in anticipating the timing and magnitude of future events. This natural warning system now influences building codes and planning in the United States, Canada and Japan, particularly where the geological record demonstrates prehistoric earthquakes larger than those known from written and instrumental records.
The National Science Foundation has awarded Benjamin Horton, associate professor of earth and environmental science in the School of Arts and Sciences and director of Penn’s Sea Level Research Laboratory, more than $1 million to investigate the geological record of earthquakes in Japan, Indonesia and the U.S. West Coast.
His lab, together with colleagues at Central Washington University and in Chile, has recently received a $500,000 grant to expand this research to a highly seismically active area of Chile.
“We will be working along the Peru-Chile trench that experienced two of the largest subduction zone earthquakes in the instrumental record, in 1960 and more recently in February 2010,” Horton said.
Horton and graduate student Tina Dura will investigate the magnitude and distribution of coastal land-level changes and tsunami deposits associated with subduction-zone earthquakes along the coast of south-central Chile. These deposits contain evidence of earthquakes and tsunamis that have occurred during the past 4,000 years.
“We indirectly measured how strain accumulates along the great megathrust fault between continental and oceanic plates by inferring coastal land-level changes,” Horton said. “This new information about how plate boundary deforms greatly assists the seismological community in improving assessments of earthquake and tsunami hazards.”
Horton’s group has previously studied vertical land movements caused by earthquakes and tsunami sediments associated with earthquakes greater than magnitude 8, including ones that struck the Pacific coasts of North America, Indonesia and Japan. The Indonesian earthquake produced the 2004 Indian Ocean tsunami, one of the deadliest natural disasters of all time. While the 2011 Tohoku-Oki earthquake off the coast of Japan was less deadly, it is now considered the costliest disaster in world history, causing an estimated $235 billion worth of damage. The unforeseen extent of these earthquakes underscores the practical importance of this kind of research in all subduction zones.
“Our research has many broader impacts in reducing the risk of earthquakes. We always involve students from local populations to directly communicate research results to coastal communities,” Horton said. “We take the results of our research to town hall meetings in coastal communities and interact with local media and policy makers.”