摘要：Through forward multiple-event analysis of teleseismic P-waves using source time functions (STFs), derived by non-negative time-domain deconvolution, we inferred the rupture features of the 2018 Hualien earthquake. At least six sub-events composed the Hualien earthquake, with the largest one (corresponding to M w = 6.3) occurring 4.8 s later than the initiation of rupture. The total seismic moment ( M 0 ) of 6.48 × 10 18 Nm (M w = 6.5) and radiated seismic energy ( E S ) of 1.76 × 10 14 Nm led to the E S / M 0 ratio ~2.72 × 10 -5 . A static stress drop (Δσ S ) of 5.03 MPa was also derived for the earthquake. On average, the rupture parameters of the 2018 Hualien earthquake from this study were similar to globally average values. From M 0 and source duration (10.9 s), this implied an average rupture velocity (Vr) less than 2.0 km s -1 . The forward multiple-event modeling showed that Δσ S varied with the sub-events and increased with E S / M 0 to imply the frictional strength being heterogeneous along the fault. From the highest STF peak (6.9 s after the initiation) near the land-sea interface, we suggested that the Hualien earthquake be divided into two rupture processes. One with low Δσ S , low E S / M 0 , and high Vr occurred at sea; the other with high Δσ S , high E S / M 0 , and low Vr occurred on land. Both seawater and local velocity structures probably played crucial factors behind these rupture discrepancies during the 2018 Hualien earthquake.
