Findings May Help Forecast Earthquake Severity
February 15, 2006 -- A new computer simulation indicates that a deep layer of sediment within ocean basins, specifically within subduction zones, may intensify the severity of earthquakes occurring in those regions. The results of the simulation increase our understanding of fault line characteristics and may contribute to the ability to forecast future earthquakes.
Subduction zones occur when one tectonic plate pushes under another to form a basin. Severe earthquakes often occur at fault lines within such basins. Researchers from University of Washington and Yale University developed a computer simulation to understand the cause of these high-magnitude earthquakes. The findings, published in the journal Geology, may help predict tectonic plate movements within the basins.
The simulation models suggest that sedimentation is the key to predicting earthquake severity. When a tectonic plate plows beneath another, the upper plate typically deforms and allows uninterrupted movement. However, the researchers hypothesize that in basins where sediment is greater than half of a mile deep, the sediment reinforces the upper plate, disrupts movement, and leads to a buildup in pressure. When the pressure eventually is released, rapid plate movement can occur, leading to a severe quake.
A number of National Research Council reports discuss the need for improved earthquake forecasts based on better scientific understanding of earthquake processes. Improved Seismic Monitoring - Improved Decision-Making: Assessing the Value of Reduced Uncertainty calls for increased seismic monitoring to reduce losses from earthquakes and improve damage prediction scenarios. Living on an Active Earth: Perspectives on Earthquake Science recommends using fault and deformation data gathered from new or proposed monitoring programs to improve earthquake forecasting.