Abstract：Using ALOS-2 and Sentinel-1 satellites SAR images based on the InSAR technology, we extract the coseismic surface deformation fields of the four MW>6.0 earthquakes that occurred between October to December of 2019 in Mindanao Island, Philippines. Then, we use the InSAR data to estimate the coseismic faulting model of these four earthquakes. The inversion result shows that the rupture of three individual faults are responsible for these four earthquakes. The dextral strike rupture of two adjacent segments of the same southeast dipping fault caused the two earthquakes occurred on 2019-10-16 and 2019-10-31, respectively. The maximum slip magnitude of the 2019-10-31 earthquake is about 1.1 m, which is two times of that of the 2019-10-16 earthquake. Another fault for the earthquake occurred on 2019-10-29, and the maximum slip magnitude is about 2.0 m. An additional fault characterized by predominant sinistral strike slip is the seismogenic fault of the 2019-12-15 earthquake, with a maximum slip magnitude of about 3.0 m. The calculation of the Coulomb failure stress (CFS) change indicates that the 2019-10-16 earthquake has caused significant positive CFS change in the high-slip area of the 2019-10-29 earthquake. Moreover, the 2019-10-29 earthquake also increased the CFS in the hypocenter area of the 2019-10-31 earthquake. Finally, the cumulated CFS change on the seismogenic fault of the 2019-12-15 earthquake due to the previous three earthquakes is less than zero, which suggests that the static CFS changes may be not the main triggering factor of the 2019-12-15 earthquake.
WU Shaojie,YANG Yinghui,WANG Zegen et al. Research of the Coseismic Faulting Models and Coulomb Stress Transfer of the Four MW>6.0 Earthquakes in Mindanao Island, Philippines in 2019[J]. jgg, 2022, 42(3): 240-246.
