A Wavelet-Domain Seismic Source Inversion Method for Submarine Earthquakes Based on 3-D Green’s Functions

Determining source parameters of submarine earthquakes is fundamental to geotechnical and geodynamic research. However, these remote areas are usually poorly monitored, posing challenges in characterizing seismic behaviors. Here, we propose a wavelet-domain seismic source inversion method based on 3-D Green’s functions for modeling teleseismic body waves to obtain locations and focal mechanisms of submarine earthquakes. We adopt the heat bath algorithm to implement inversions. The wavelet transform allows us to simultaneously investigate source features in different frequencies. Numerical experiments conducted on synthetic data show our method is efficient and suggest that, for ~M6 earthquakes, lower-frequency waveforms (<0.1 Hz) are more sensitive to focal mechanisms, while higher frequencies (0.1~0.2 Hz) work better in constraining source locations. Application to a ~M6 earthquake in the Japan Trench suggests that our approach can provide reliable source parameters (locations and focal mechanisms) for submarine earthquakes.