A terrestrial lidar-based workflow for determining three-dimensional slip vectors and associated uncertainties

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Three-dimensional (3D) slip vectors recorded by displaced landforms are difficult to constrain across complex fault zones, and the uncertainties associated with such measurements become increasingly challenging to assess as landforms degrade over time. We approach this problem from a remote sensing perspective by using terrestrial laser scanning (TLS) and 3D structural analysis. We have developed an integrated TLS data collection and point-based analysis workflow that incorporates accurate assessments of aleatoric and epistemic uncertainties using experimental surveys, Monte Carlo simulations, and iterative site reconstructions. Our scanning workflow and equipment requirements are optimized for single-operator surveying, and our data analysis process is largely completed using new point-based computing tools in an immersive 3D virtual reality environment. In a case study, we measured slip vector orientations at two sites along the rupture trace of the 1954 Dixie Valley earthquake (central Nevada, United States), yielding measurements that are the first direct constraints on the 3D slip vector for this event. These observations are consistent with a previous approximation of net extension direction for this event. We find that errors introduced by variables in our survey method result in <2.5 cm of variability in components of displacement, and are eclipsed by the 10–60 cm epistemic errors introduced by reconstructing the field sites to their pre-erosion geometries. Although the higher resolution TLS data sets enabled visualization and data interactivity critical for reconstructing the 3D slip vector and for assessing uncertainties, dense topographic constraints alone were not sufficient to significantly narrow the wide (<26°) range of allowable slip vector orientations that resulted from accounting for epistemic uncertainties.
Publication type Article
Publication Subtype Journal Article
Title A terrestrial lidar-based workflow for determining three-dimensional slip vectors and associated uncertainties
Series title Geosphere
DOI 10.1130/GES00714.1
Volume 8
Issue 2
Year Published 2012
Language English
Publisher Geological Society of America
Publisher location Boulder, CO
Contributing office(s) Geologic Hazards Science Center
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Geosphere
First page 431
Last page 442
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