Limited preservation of strike-slip surface displacement in the geomorphic record

Journal of Geophysical Research: Solid Earth
By: , and 

Links

Abstract

Offset geomorphic markers are commonly used to interpret slip history of strike-slip faults and have played an important role in forming earthquake recurrence models. These data sets are typically analyzed using cumulative probability methods to interpret average amounts of slip in past earthquakes. However, interpretation of the geomorphic record to infer surface slip history is complicated by slip variability, measurement uncertainty, and modification of offset features in the landscape. To investigate how well geomorphic data record surface slip, we use offset measurements from recent strike-slip surface ruptures (n = 39), faults with geomorphic evidence of multiple strike-slip earthquakes (n = 29), and synthetic slip distributions with added noise (n>10,000) to examine the constraints of the geomorphic record and the underlying assumptions of the cumulative offset probability distribution analysis method. We find that the geomorphic record is unlikely to resolve more than two paleo-slip distributions, except in specific cases with low slip variability, high slip-per-event, and semiarid climate. In cases where site-specific conditions allow for interpretation of more than two earthquakes, lateral extrapolation along a fault is not straightforward because on-fault displacement and distributed deformation may be spatially variable in each earthquake. We also find that average slip in modern earthquakes is adequately recovered by probability methods, but the reported prevalence of strike-slip faults with characteristic slip history is not supported by geomorphic data. We also propose updated methods to interpret slip history and construct uncertainty bounds for paleo-slip distributions.

Publication type Article
Publication Subtype Journal Article
Title Limited preservation of strike-slip surface displacement in the geomorphic record
Series title Journal of Geophysical Research: Solid Earth
DOI 10.1029/2024JB028692
Volume 129
Issue 11
Year Published 2024
Language English
Publisher American Geophysical Union
Contributing office(s) Geologic Hazards Science Center - Landslides / Earthquake Geology
Description e2024JB028692, 24 p.
Google Analytic Metrics Metrics page
Additional publication details