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Improvements to Fault Displacement Models: Examples From the 2023 M7.8 Pazarcık, Türkiye Earthquake

Description: 

Fault displacement models are used to predict fault surface rupture along strike as a function of earthquake magnitude. They are useful for numerous reasons, including, for instance, forecasting the displacement of an underground pipeline crossing a fault during a future earthquake scenario (i.e., a deterministic analysis). In addition, they are the backbone of probabilistic fault hazard displacement analyses, and thus, are important for advancing seismic design guidelines. Improving fault displacement model accuracy and precision requires collecting field data, and in particular, making high-quality fault displacement measurements with robust estimates of measurement uncertainty. With the foregoing motivation, we traveled to south Türkiye to complete ten days of fieldwork in June 2023 following the 6 February 2023 M7.8 Pazarcık Earthquake. In the field, wemeasured fault displacement and estimated uncertainty using traditional surveying techniques, GNSS, and terrestrial lidar scans. We also chose sites with varying quality of offset feature reconstructions to investigate the effect of quality on measurement uncertainty. Our fault displacement measurements led to numerous observations for how to improve fault displacement models. Our fieldwork highlighted the advantages and disadvantages of the measurement techniques as a function of piercing point definition. In particular, we determined some post-earthquake reconnaissance best practices for balancing the need to capture as many high-quality fault displacement measurements as possible with the correlative need to develop robust measurement uncertainty estimates. We compare our results to previous fault displacement models and make observations about magnitude scaling, the effects of geologic conditions, and faulting complexity. The results from our work have implications for improving post-earthquake reconnaissance practices and have produced data that can be used by future fault displacement modelers.

Session: Learning Across Geological, Geophysical & Model-Derived Observations to Constrain Earthquake Behavior - III

Type: Oral

Date: 5/1/2024

Presentation Time: 02:15 PM (local time)

Presenting Author: Henry

Student Presenter: No

Invited Presentation: 

Authors