Surface Displacement and Ground Motion from Dynamic Rupture Models of Thrust Faults with Variable Dip Angles and Burial Depths

Sirena Ulloa, & Julian C. Lozos

Published August 13, 2018, SCEC Contribution #8458, 2018 SCEC Annual Meeting Poster #210

Historic earthquakes and empirical studies show that thrust fault ruptures produce stronger ground motion than normal or strike-slip events of the same size. This is due to a combination of hanging wall effects, vertical asymmetry and higher stress drop due to compression. Surface displacement occurs with blind thrust ruptures in addition to those with surface expression. This poses a hazard since surface displacement can potentially break lifelines, such as water pipes and gas lines. Our 3D dynamic rupture modeling parameter study focuses on planar thrust faults of varying dip angles and burial depth, in order to establish a physics-based understanding of how these geometrical parameters affect surface displacement and ground motion. We vary dip angles from 20º to 70º, and burial depths from 0 km down to 5 km, and we conduct rupture models on these geometries under several different initial stress conditions. We analyze how systematic variation of these parameters affects peak particle velocity and surface displacement over the fault, with a particular focus on hanging wall versus footwall effects. Due to the simple geometry of a planar fault, our results can be applied to understanding basic behavior of specific real-world thrusts. The results of this study can also be used to aid in global hazard calculation.

Key Words
parameter study, dynamic rupture, thrust faults, ground motion, numeric modeling

Citation
Ulloa, S., & Lozos, J. C. (2018, 08). Surface Displacement and Ground Motion from Dynamic Rupture Models of Thrust Faults with Variable Dip Angles and Burial Depths. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)