Abstract:Coulomb stress changes along the Xianshuihe fault induced by the Wenchuan, Lushan and Kangding earthquakes are calculated and compared with long term tectonic loading rates in order to assess seismic potential change on the fault due to these earthquakes. The results show that the Kangding earthquake was advanced and delayed by the Wenchuan and Lushan earthquakes, respectively.Most of the Coulomb stress changes along the Xianshuihe fault are due to the Wenchuan and Kangding earthquakes.Under a linear stress loading assumption, advance/delay times of earthquake recurrence are calculated along the fault.In the case assuming μ′=0, the earthquake recurring times could be advanced by approximately 0-5 years at locations between Bamei and Moxi〖JP2〗(except the rupture zone of the Kangding earthquake), and delayed by 0-4 years at the other regions, respectively.If μ′=0.4, the advance times of earthquake recurrence are estimated as 0-6 years in the range between Daofu and Zhuyaozihaizi, and the delay times are calculated to be 0-2 〖JP3〗years out of the range.As our knowledge is so limited about the rheological structures on both sides of the Xianshuihe fault, the impact of its variation on the results is also investigated.Our research shows that the lower the viscosities of the lower crust and the upper mantle, the larger the Coulomb stress change due to viscous relaxation would be, and the more rapidly it changes along fault strike.Furthermore, the contribution of the viscous relaxation is comparable to that of coseismic rupture, resulting in advance/delay times of earthquake recurrence of up to 3 years.
WANG Yanzhao,WANG Min,AN Yanfen. Coulomb Stress Changes Along the Xianshuihe Fault Induced by the Wenchuan,
Lushan and Kangding Earthquakes and Their Impacts on Seismic Potentials[J]. jgg, 2015, 35(4): 567-570.