The prediction equation for the significant duration of strong motion in the Sichuan-Yunnan region of China

Abstract

The significant duration is a crucial intensity measure for earthquake-resistant design and seismic hazard assessment (SHA). The Sichuan-Yunnan region is characterized by a high level of seismic activity and possesses the most concentrated network of seismic stations in China. The ground motion prediction equation (GMPE) is the predominant approach to estimating significant durations. The existing prediction equations for the significant duration are not well-suited for the Sichuan-Yunnan region. This study used data from the National Strong Motion Observation Network System (NSMONS) of China in this region to develop prediction equations for significant durations of D_S5-75 and D_S5-95. The equations took into account variables including moment magnitude (M_w), fault distance (R_rup), average shear wave velocity of 30 m on the soil profile (V_S30), and depth to the top of the rupture (Z_tor). Our database has a singular instance of the Wenchuan earthquake with M_w > 7. The restricted data complicates the calibration of our model for events with M_w > 7. Therefore, we suggest the equations be valid in the Sichuan-Yunnan region for M_w between 4.2 and 7.0, R_rup from 0 to 300 km, and V_S30 values ranging from 139 to 900 m/s.