Potential Fault Displacement Hazard Assessment Using Stochastic Source Models: A Retrospective Evaluation for the 1999 Hector Mine Earthquake

Katsuichiro Goda

doi:10.3390/geohazards2040022

Abstract

Surface fault displacement due to an earthquake affects buildings and infrastructure in the near-fault area significantly. Although approaches for probabilistic fault displacement hazard analysis have been developed and applied in practice, there are several limitations that prevent fault displacement hazard assessments for multiple locations simultaneously in a physically consistent manner. This study proposes an alternative approach that is based on stochastic source modelling and fault displacement analysis using Okada equations. The proposed method evaluates the fault displacement hazard potential due to a fault rupture. The developed method is applied to the 1999 Hector Mine earthquake from a retrospective perspective. The stochastic-source-based fault displacement hazard analysis method successfully identifies multiple source models that predict fault displacements in close agreement with observed GPS displacement vectors and displacement offsets along the fault trace. The case study for the 1999 Hector Mine earthquake demonstrates that the proposed stochastic-source-based method is a viable option in conducting probabilistic fault displacement hazard analysis.

Highlights

In the near-fault region, surface fault displacement due to an earthquake rupture can cause major damage to buildings and urban infrastructures, disrupting their services and functionalities [1,2]
This study presents an alternative approach for probabilistic fault displacement hazard analysis (PFDHA), which is based on stochastic source modelling [14]
The method predicts the fault displacement hazard potential at both on-fault and off-fault sites and brings in significant advantages over the state-of-the-art PFDHA approaches, including: (i) all faulting types can be accommodated by specifying rake angles; (ii) multisegment ruptures can be taken into account; (iii) fault displacements in E-W, N-S, and U-D

Summary

Introduction

In the near-fault region, surface fault displacement due to an earthquake rupture can cause major damage to buildings and urban infrastructures, disrupting their services and functionalities [1,2]. To evaluate the extent and likelihood of ground deformation, probabilistic fault displacement hazard analysis (PFDHA) has been developed in [5] for normal faulting earthquakes and has been extended to other faulting types, such as strike-slip events [6] and reverse events [7,8,9]. The key element of PFDHA is an empirical predictive relationship of surface fault displacement, which is established based on historical fault rupture data. Equations for predicting fault displacement distinguish on-fault (principal) and off-fault (distributed) surface ruptures [5,6,8,9,10,11]. To improve the predictive power of the empirical relationships, global efforts have been made to create more extensive surface rupture databases [12,13]

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