Recurrence interval of the 2008 Mw 7.9 Wenchuan earthquake inferred from geodynamic modelling stress buildup and release

- The earthquakes-stress buildup and release associated to the 2008 Wenchuan earthquake are simulated.
- The recurrence interval of the 2008 Wenchuan earthquake is estimated to be 4200-6500 years.
- Sensitivities relying on model dependent parameters are discussed.
- It provides a method of geodynamic modelling to estimate recurrence interval of large earthquakes.

The destructive 2008 Mw 7.9 Wenchuan earthquake ruptured the Longmen Shan (LMS) fault zone and devastated cities in Sichuan province, China. Estimates of the recurrence interval of the large earthquake is important to understand the feature of seismic activity and to analyze the seismic hazard in the fault area. In this research we introduce the method of geodynamic modelling to estimate the recurrence interval of the Mw7.9 earthquake based on the basic physics of earthquakes-stress buildup and release on fault. The inter-seismic stress accumulation prior to the 2008 Wenchuan earthquake is extracted from our previous study, which developed 3D finite element visco-elastic lithospheric model of the LMS fault zone. The co-seismic stress release and the post-seismic stress relaxation of the earthquake are simulated through dislocation source models. The recurrence interval, which is the duration needed to accumulate the magnitude of the stress drop of the Mw7.9 earthquake, is estimated to be about 4200-6500 years. Sensitivities of the estimated recurrence interval relying on model dependent parameters, such as the viscosity and slip models, are discussed. This research provides a preferred method to estimate recurrence interval of large earthquake in fault zone.