Probabilistic Fault Displacement Hazard Analysis Based On Dislocation Theory In A Half-space

With the increasing development of economy in China,Construction of Economic Corridor and ‘Belt and Road' are proposed and implemented.The priority of 'Belt and Road' is to improve infrastructure construction and enable it connectivity with neighboring countries.Because the transition between the Eurasian and Indian plates is the southwest region of China,so the increasing demand for infrastructure in this region year by year.However,with the complex geological structure,large-scale active faults and high seismicity,southwestern region faces the high risk of large earthquakes occurrence.Surface deformation due to the large earthquake usually cause serious damage to infrastructure,such as railways,bridges,tunnels,inevitably pass through high intensity area.Therefore,it is of great engineering significance to propose appropriate method to estimate the risk of surface permanent deformation.Based on OKADA model,deformation field simulation was performed and the deformation prediction equations was deprived for a high intensity area in Sichuan.By using PFDHA,we assessed the seismic permanent deformation of probabilistic risk and give the seismic hazard curves for Milin fault.Firstly,this article presents the methodology and procedure of PFDHA based on surface deformation simulation and the elastic dislocation theory.And the OKADA dislocation theory was used to calculate the surface displacement field in Kumamoto earthquake(2016).Then,we simulate the surface displacement in a high-intensity area.For parameters with significant variability,we consider the effects of aleatory uncertainty,treating each key parameter as a probability distribution for simulation.Model parameters and their probability distribution characteristic were determined by regional geological and seismicity data.Surface deformation for differences sites and magnitudes were simulated for a high intensity area in Sichuan.Based on these results,Regression was used to obtain the deformation prediction equation.The seismic hazard curves in Milin fault were calculated using PFDHA by the deformation prediction equation.This article also compared these results with seismic hazard curves used traditional empirical relations,the results show that both our result and the traditional risk curve show almost the same attenuation trend,but when displacement value is in the(1m,10m),the results of the traditional risk curve are more conservative.