Paper summaries 2017

Re-evaluating seismic hazard along the southern Longmen Shan, China: Insights from the 1970 Dayi and 2013 Lushan earthquakes

Z. Li, J. Liu-Zeng, R. Almeida, J. Hubbard, C. Sun, G. Yi (2017). Re-evaluating seismic hazard along the southern Longmen Shan, China: Insights from the 1970 Day and 2013 Lushan earthquakes. Tectonophysics 717, p. 519-530, https://doi.org/10.1016/j.tecto.2017.09.001.

Highlights

• Isoseismal maps and intensity-derived epicenters define the approximate locations of instrumental and historical earthquakes.

• The RFBT is the seismogenic fault of the 1970 Ms 6.2 Dayi and 2013 Mw 6.6 Lushan earthquakes.

• The accumulation rate of seismic moment is 8.04 (± 2.09) × 1017 N·m/yr for the main active thrusts on the southern LMS.

• The entire southern LMS is capable of generating much larger earthquakes (Mw 7.3–7.7), with an average frequency of once every 1000–1400 years.

Building Objective 3D Fault Representations in Active Tectonic Settings

M. Riesner, P. Durand-Riard, J. Hubbard, A. Plesch, J. H. Shaw (2017). Building objective 3D fault representations in active tectonic settings. Seismological Research Letters 88 (3), p. 831-839, https://doi.org/10.1785/0220160192.

Abstract: Developing 3D 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 3D 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 an implicit modeling approach. This method enables us to control the weights assigned to the different constraints, increasing the accuracy of the fault 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, California, that is imaged by high‐quality seismic reflection data and that generated the 1987 Mw 6.0 Whittier Narrows earthquake. Then, we apply our new workflow to the Xianshuihe–Anninghe left‐lateral strike‐slip fault systems, China. Implementing this workflow allows for the development of improved fault surface representations that can contribute to Community Fault Models and support fault system modeling, rupture simulations, and regional hazard assessments.