MLBP Application: the 2019 Ridgecrest earthquakes
We apply the MLBP method to the 2019 Mw 6.4 and Mw 7.1 Ridgecrest, California earthquakes to resolve their kinematic process, with the dense seismic network in California. To increase the objectivity of stations selection criteria and to be prepared for future real-time BP implementations, we improve MLBP with an automatic procedure to group stations based on waveform coherence.
The Mw 6.4 Event
Our MLBP highlights the rupture complexity in a multi-fault system. The Mw 6.4 quake initiates on a 5-km-long NW-trending segment, then ruptures the primary SW-trending fault at the speed of ~ 1.3 km/s.
The Mw 7.1 Event
The Mw 7.1 quake ruptures bilaterally for 10 km and 22 km, on the NW and SE portion of the fault, respectively, at the speed of 1 to 1.6 km/s.
The rupture paths agree with aftershock distributions and surface rupture estimated from satellite imagery. The slow rupture propagation may be driven by the low structural maturity of the fault. This case study demonstrates the effectiveness of MLBP for earthquake source imaging and rapid hazard assessment.