Fault displacement hazard: Predicting future coseismic rupture locations from mapped faults
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Chelsea Scott
Arizona State University
- Date & Time
- Location
- Online-only seminar via Microsoft Teams
- Host
- Belle Phillibosian & Stephen DeLong
- Summary
In surface-rupturing earthquakes, fault displacement can damage infrastructure that crosses fault zones. Geologists commonly predict future coseismic rupture locations from faults mapped based on landforms interpreted from remote sensing datasets like lidar topography and imagery. The effective use of fault maps for this purpose requires the following: Past earthquakes must create a persistent record in the landscape’s geology and/or geomorphology. Geologists must accurately identify and interpret surface features, understand how tectonic and surface processes modify the landscape, and integrate these interpretations into the fault map. The record of past earthquakes must serve as a dependable predictor of future earthquakes, requiring that earthquakes largely rupture pre-existing faults. Our work focuses on improving the fault mapping process and quantifying uncertainty in mapped fault location with the goal of improving engineering assessments, risk management, and the definition of fault study and exclusion zones.
I will discuss several projects:
1) We developed and evaluated a systematized approach for regional-scale fault mapping and geomorphic evidence documentation using remote sensing data (Adam et al., 2025: Geosphere).
2) Based on seven earthquakes with varying slip sense and in different climates, we found that the mapped faults predicted 12%- 68% of the principal surface ruptures, with median separation distances of 15–30 m between mapped faults and predicted ruptures (Scott et al., 2023: Geosphere).
(3) We investigated how tectonic landform types and surficial lithologic age influence fault location uncertainty. Certain tectonic landforms, such as fault scarps and range fronts, showed lower location error, while faults cutting Holocene units exhibited larger errors (Scott et al., 2024: GRL).
(4) We examined how mapper experience improves mapping outcome and found that even experienced mappers may miss future ruptures, and that fault maps produced by senior mappers and graduate students are often of similar quality (Zuckerman et al., in review: Seismica).