Abstract: An M_S6.0 earthquake occurred on June 17, 2019 in Changning, Sichuan Province, which was followed by a series of strong aftershocks. In order to better analyze the sequence characteristics and predictability of the strong aftershocks, this paper focuses on the comparative study of the applicability of the “Epidemic Type Aftershock Sequence” (ETAS) model which have been widely adopted internationally for complex sequence, the Omi-R-J model which based on the Reseanberg-Jones (R-J) model. We compare the stability of model parameters, forecasting results by continuous sliding, fitting and aftershock occurrence rate forecasting, and evaluate the effectiveness of forecasting by using the N-test and T-test with multiple time windows. The results show that the sequence parameters αETAS of response excitation ability of Changning M_S6.0 earthquake sequence is obviously smaller than other parameters of moderate-strong earthquake sequence, while the pORJ value of response attenuation ability and the bORJ value of response stress accumulation level are relatively small, which are consistent with the rich and relatively long duration of this aftershock sequence. ETAS and Omi-R-J models still have certain forecasting ability for strong aftershocks of complex sequence at three magnitude ranges [3.0, 3.5, 4.0]. The overall “Information Gain Per Earthquake” (IGPE) calculation results show that the ETAS model is slightly superior to the Omi-R-J model, thus the former is more suitable for aftershock forecasting of complex earthquake sequences.

Key words: Epidemic Type Aftershock Sequence (ETAS) model, Omi-Reseanberg-Jones (Omi-R-J) model, Sequence parameters, Aftershock forecasting, Effectiveness evaluation