An approach to building 3D fault representations in active tectonic settings.

Magali Riesner and Pauline Durand-Riard and Judith Hubbard and John H. Shaw and Andreas Plesch and Maomao Wang. ( 2012 )
in: Proc. 32nd Gocad Meeting, Nancy

Abstract

Developing 3-D representations of active faults is an important step to improve seismic hazard assessment. However, the geometries of faults can be difficult to constrain at depth, and building representations is often subjective. We present a new, objective workflow to build 3-D fault geometries from surface and subsurface data that are generally available in active tectonic environments. We use surface traces, focal mechanism orientations, and relocated hypocenters as geological constraints in the implicit modeling approach. This method enables us to control the weights assigned to the different constraints, increasing the accuracy of the model. We evaluate and refine our method by applying it to a well-known natural case study: the Puente Hills thrust fault, a blind thrust beneath Los Angeles, CA, that is imaged by high-quality seismic reflection data and generated the Mw 6.0, 1987 Whittier Narrows earthquake. We then apply our new workflow to thrust systems in the Sichuan basin and Longmenshan, China. Implementing this workflow allows us to improve and standardize fault surfaces that are being developed as part of our efforts to develop a Community Fault Model in this region.

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BibTeX Reference

@inproceedings{RiesnerGM2012,
 abstract = { Developing 3-D representations of active faults is an important step to improve seismic hazard assessment. However, the geometries of faults can be difficult to constrain at depth, and building representations is often subjective. We present a new, objective workflow to build 3-D fault geometries from surface and subsurface data that are generally available in active tectonic environments. We use surface traces, focal mechanism orientations, and relocated hypocenters as geological constraints in the implicit modeling approach.
This method enables us to control the weights assigned to the different constraints, increasing the accuracy of the model. We evaluate and refine our method by applying it to a well-known natural case study: the Puente Hills thrust fault, a blind thrust beneath Los Angeles, CA, that is imaged by high-quality seismic reflection data and generated the Mw 6.0, 1987 Whittier Narrows earthquake. We then apply our new workflow to thrust systems in the Sichuan basin and Longmenshan, China.
Implementing this workflow allows us to improve and standardize fault surfaces that are being developed as part of our efforts to develop a Community Fault Model in this region. },
 author = { Riesner, Magali AND Durand-Riard, Pauline AND Hubbard, Judith AND Shaw, John H. AND Plesch, Andreas AND Wang, Maomao },
 booktitle = { Proc. 32nd Gocad Meeting, Nancy },
 title = { An approach to building 3D fault representations in active tectonic settings. },
 year = { 2012 }
}