COMPARISON OF PREDICTED SIGNIFICANT STRONG MOTION DURATION WITH DATA FROM THE 2011 MINERAL, VIRGINIA EARTHQUAKE

The authors developed an empirical predictive relationship correlating significant duration to earthquake magnitude, site-to-source distance, and local site conditions (i.e., rock vs. stiff soil) for stable continental regions (e.g., central and eastern North America: CENA). The correlation was developed from data derived from 620 horizontal motions for stable continental regions, consisting of 28 recorded motions and 592 scaled motions. The data set encompasses earthquake magnitudes from 4.5 to 7.6 and distances from 0.1 to 199 km. The non-linear mixed-effects regression technique was used to fit the predictive model to the significant duration data. Similar to the trend observed from active shallow crustal region (e.g., western North America: WNA) motions, significant durations predicted for stable continental region motions increased with increasing earthquake magnitude and increasing site-to-source distance. However, the predicted significant durations for rock motions in CENA were consistently longer than those in WNA, while for soil motions, both CENA and WNA motions were estimated to have similar significant durations. To validate the proposed model, model predictions were compared with the significant durations of motions recorded during the 2011 Mineral, Virginia earthquake. The predicted durations are in good agreement with the recorded motions.