Preliminary research on a probability-based medium term earthquake prediction in the Chinese mainland

Rui Yan, huaizhong Yu, Shiguang Deng, Jie Liu, Mengyu Xie, Yawei Ma, & Zhengyi Yuan

Published September 8, 2024, SCEC Contribution #13588, 2024 SCEC Annual Meeting Poster #203

Earthquake prediction is a controversial topic and is also one of the most challenging problems in the world. As a specialized organization that aimed for earthquake prediction, China Earthquake Administration (CEA) has been founded for a half century and achieved some success in medium-term earthquake prediction practice and the related methods research.Here, we would like to display the latest achievements made by CEA to show the feasibility of medium-term earthquake prediction. The proposed model is based on the routine work of CEA, but with important innovations with integrated probability technique.The method including two steps,
(1) Prepare candidate methods to determine annual seismic hazard regions(ASHR). We use the morphological analysis methods to identifies the anomalous annual variations, trend turnings, and marked increases or drops from the crustal deformation, seismometry, GNSS, groundwater, gravity, and electromagnetism observations. And the areas covered by the anomalies of each discipline are delineated as the predicted areas. In addition, many comprehensive calculation methods, such as the b-value, LURR, GPS strain rates, and so on, are also applied to test seismicity and produce the ASHR.
(2) Select sub-method with the optimal prediction performance from candidate methods and integrate their predictions with Bayesian formula. The prediction effectiveness of all candidate methods is tested rigorously using earthquakes over the last 5 years. The ones with the best performance for predicting the Ms≥5.0 earthquakes in the next year are selected as the sub-method for producing ASHR. We use the R-score which is similar to the “loss functions” associated with the Molchan error diagram for the evaluation. Then taking the performance (i.e. R-score) of each method as the weight, the occurrence probability of earthquake at any place can be calculated by Bayesian formula.
Every year, China should determine ASHR for earthquakes of Ms≥5 earthquakes in the next year. The ASHR is produced with the optimal methods selected by rigorous tests whose predictions are integrated through the Bayesian formula. Based on the above innovation work, more than 80% of Ms≥5 earthquakes in the Chinese mainland in 2022 occurred in ASHR, including Ms 6.9 Menyuan, Qinghai, and Ms 6.8 Luding, Sichuan earthquakes. It is suggested that the probability synthesis technique is valuable for earthquake prediction studies in areas with dense seismic monitoring networks worldwide.

Key Words
probability, medium term earthquake prediction, Chinese mainland

Citation
Yan, R., Yu, h., Deng, S., Liu, J., Xie, M., Ma, Y., & Yuan, Z. (2024, 09). Preliminary research on a probability-based medium term earthquake prediction in the Chinese mainland. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)