Correlation between Strain Rate and Seismicity in Different Tectonic Settings

Abstract

Geodetic strain rate characterizes present-day crustal deformation and therefore may be used as a spatial predictor for earthquakes. However, the reported correlation between strain rates and seismicity varies significantly in different places. Here, we systematically study the correlation between strain rate, seismicity, and seismic moment in six regions representing typical plate boundary zones, diffuse plate boundary regions, and continental interiors. We quantify the strain rate–seismicity correlation using a method similar to the Molchan error diagram and area skill scores. We find that the correlation between strain rate and seismicity varies with different tectonic settings that can be characterized by the mean strain rates. Strong correlations are found in typical plate boundary zones where strain rates are high and concentrated at major fault zones, whereas poor or no correlations are found in stable continental interiors with low strain rates. The correlation between strain rate and seismicity is also time dependent: It is stronger in seismically active periods but weaker during periods of relative quiescence. These temporal variations can be useful for hazard assessment.