The importance of detail fault geometry in modelling the stress change caused by large earthquake: Case Study of 2017 Mw 6.7 Poso earthquake

Abstract

One of the criteria that can describe the stress condition under which a fault can rupture is the Coulomb Failure Criterion. One technique to calculate the Coulomb Failure Stress (∆CFS) is through the specified orientation approach that requires the strike, dip, and rake of fault geometry parameters. Most studies use planar fault which could degrade the accuracy of the stress calculation. In this study, we present the fault model with variable geometry in order to produce a more detailed stress calculation. We implement the 2017 Mw 6.7 Poso earthquake to model the stress transfer into Poso Fault which has a bent geometry. We compare the stress result with three different cases: planar and curve fault geometries. The result from curve fault geometries is sufficiently different than using the former one. The Coulomb stress distribution is generated in a more detail way when using multi-strike geometry as this parameter is more sensitive to the Coulomb stress change calculation. As demonstrated from this study, fault geometry plays an important role in the Coulomb stress imparted to highly orientated faults.