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Surveying Active Fault Zones in California Using Quakes-I Wide-Swath Airborne Stereoimagery

Description: 

We present new and continuing results from fault surveys collected by the QUAKES-I airborne stereoimager. Recent decades have seen a proliferation of stereoimaging techniques for mapping fault zone structure, measuring offset geomorphic features, and characterizing earthquake dynamics by correlating images collected before and after surface ruptures. Despite the merits of such studies, stereoimaging surveys are often expensive, logistically difficult, and/or time-consuming to carry out. For example, stereoimaging is often accomplished at fine scales (kilometers or less) by drone surveys, or at broad scales through purchase of high-resolution satellite imagery. Additionally, airborne lidar surveys can be flown to cover > 100-km-long ruptures, but are often confined to a narrow (~1 km) swath width due to limitations of the scanner, and may consequently miss distributed deformation. In contrast, the Quantifying Uncertainty and Kinematics in Earth Systems Imager (QUAKES-I) presents an instrument for capturing high-resolution (~1 m pixel) imagery over a wide swath (up to ~12 km) aboard a taskable aircraft that can cover a few thousand km of fault length in a single day. Using commercial photogrammetric software, the stereoimages can be converted to a 3D point cloud, a color orthomosaic, and a digital surface model (DSM). In some cases (e.g., sparse vegetation), the point cloud can be reliably classified and a digital terrain model (DTM) can be produced. The results presented here showcase examples from surveys of > 1,500 km of active fault traces in CA and the western U.S., collected in June 2021 and October 2022. Faults and fault systems surveyed include the San Andreas fault, the Hayward-Calaveras fault system, and parts of the eastern California shear zone. Using these image products, we map primary and subsidiary fault features, and displaced geomorphic markers. These images further constitute a “before” data set for comparison following potential future large earthquakes.

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

Type: Oral

Date: 5/1/2024

Presentation Time: 02:00 PM (local time)

Presenting Author: Robert

Student Presenter: No

Invited Presentation: 

Authors