The distribution of slip on the Hebron Fault, Namibia: Implications for earthquakes in stable continental regions.
Abstract
The 45 km long and up to 9.6 m high Hebron fault scarp is a dramatic representation of neotectonic activity in a stable continental region (southern Namibia). Previous studies have disagreed on the number of events that formed this scarp, and style of deformation that it records. Existing quantitative descriptions of the offset on the fault are limited to a small number of theodolite transects. Understanding the nature of large earthquakes in such stable regions is of considerable societal interest, but only a small number of such events have occurred in the instrumental period and comparatively few paleo-ruptures have been quantitatively described. In this study we present a high-resolution DEM of the scarp obtained from 0.31 m resolution Worldview3 stereoscopic satellite imagery. We further characterize the fault through a three month geophone deployment which recorded significant microseismic activity associated with the structure. We find that the scarp formed through normal faulting, with no geomorphological evidence of oblique motion. We further find no evidence of a multiple event origin for the scarp suggesting that this feature may have formed in a single Mw>7 paleo-earthquake. This hypothesis would require a relatively large slip-to-length ratio ( 1x10-4), but we demonstrate that such a slip-to-length is comparable with other large events in very slowly deforming regions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.S41D0584S
- Keywords:
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- 4314 Mathematical and computer modeling;
- NATURAL HAZARDSDE: 7215 Earthquake source observations;
- SEISMOLOGYDE: 7221 Paleoseismology;
- SEISMOLOGYDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS