Comparison of Near-Fault Displacement Interpretations from Field and Aerial Data for the M 6.4 and M 7.1 Ridgecrest Earthquake Sequence Ruptures

Christine A. Goulet, Yongfei Wang, Chukwuebuka Nweke, Bo-xiang Tang, Pengfei Wang, Kenneth S. Hudson, Sean K. Ahdi, Xiaofeng Meng, Martin B. Hudson, Andrea Donnellan, Gregory A. Lyzenga, Scott J. Brandenberg, Timu Gallien, & Maria A. Winters

Submitted June 22, 2020, SCEC Contribution #10180

Surface fault displacement presents a serious potential hazard for civil infrastructure. Roads, shallowly buried pipelines and electrical transmission lines, due to their distributed nature, tend to cover large distances and are bound to go through several fault crossings, making them more susceptible to fault-displacement induced damage. Strain-induced damage to any component can render a whole system inoperable for long periods of time. This therefore constitutes an important source of seismic hazard, yet fault displacement measurements for engineering applications are sparse, making the development of predictive models extremely difficult and fraught with large uncertainties. Detailed fault geological mapping exists for a few documented cases, but they do not tend to capture the full width of deformations that are likely to impact distributed infrastructure. The 2019 Ridgecrest Earthquake Sequence presented an ideal case to collect data and evaluate the ability of different techniques to capture coseismic deformations on and near fault ruptures. Both the M 6.4 and M 7.1 events ruptured the surface in sparsely populated areas in the desert where little vegetation was present to obscure the surface features. We selected focus study areas around each fault rupture trace for this purpose. We coordinated data collection campaigns to gather field measurements and photographs as well as imagery from small uninhabited aerial systems and from airborne light detection and ranging. Each technique requires a different level of resources in terms of labor, processing and interpretation efforts and deployment costs. In this paper, we summarize the data collection methodologies along with qualitative and quantitative assessments of the methods used in our two study areas. Our validation shows that the use of remote sensing methods in combination with some field measurements for calibration presented a strong advantage over the use of a single technique, but that the resolution of each approach must be considered.

Citation
Goulet, C. A., Wang, Y., Nweke, C., Tang, B., Wang, P., Hudson, K. S., Ahdi, S. K., Meng, X., Hudson, M. B., Donnellan, A., Lyzenga, G. A., Brandenberg, S. J., Gallien, T., & Winters, M. A. (2020). Comparison of Near-Fault Displacement Interpretations from Field and Aerial Data for the M 6.4 and M 7.1 Ridgecrest Earthquake Sequence Ruptures. Bulletin of the Seismological Society of America, (submitted).