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An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)

The Hebron fault scarp in southern Namibia is 45 km in length with an average height of 5.5 m and a maximum height of 8.9 m. Namibia is a Stable Continental Region (SCR) — a slowly deforming area within a continental plate. The country also has little recorded seismicity with the largest earthquake...

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Main Author: Salomon, Guy
Other Authors: Sloan, Alastair
Format: Thesis
Language:English
Published: Department of Geological Sciences 2020
Subjects:
Geological Sciences
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access_status_str Open Access
author Salomon, Guy
author2 Sloan, Alastair
author_browse Salomon, Guy
Sloan, Alastair
author_facet Sloan, Alastair
Salomon, Guy
author_sort Salomon, Guy
collection Thesis
description The Hebron fault scarp in southern Namibia is 45 km in length with an average height of 5.5 m and a maximum height of 8.9 m. Namibia is a Stable Continental Region (SCR) — a slowly deforming area within a continental plate. The country also has little recorded seismicity with the largest earthquake on the International Seismological Center (ISC) catalogue being MW 5.4. If the Hebron fault scarp was formed in a single event, this would represent a MW 7.3 earthquake. SCRs do occasionally experience large earthquakes, however, the recurrence intervals between these events is much larger than in rapidly deforming areas. Consequently, studying palaeo-earthquakes allows the record of seismicity to be extended and the characteristics of SCR events to be better understood. These studies may help refine the Mmax estimates required for seismic hazard assessment. Previous work on Hebron has been limited to field descriptions and theodolite survey scarp heights. Furthermore, there have been several interpretations of the fault mechanism and number of rupture events. This study produces a high-resolution Digital Elevation Model (DEM) via stereophotogrammetry using pan-sharpened Worldview-3 satellite imagery (0.31 m resolution). The DEM was used for several geomorphological analyses. These included measuring the scarp height at 160 locations along its length, measuring river channel displacements and identifying knickpoints along river profiles. Results indicate that the scarp formed from a normal, dip-slip fault that ruptured in a single event. This scenario would imply a high slip-to-length ratio. A comparison of other SCR fault scarps in the literature was made which shows that Hebrons’ slip-to-length ratio falls within the values found on other SCR faults. This study also discusses the implications of results for seismic hazard assessment in the region. Due a poor seismic record, probabilistic seismic hazard analysis (PSHA) will calculate a low seismic risk for Namibia. As large earthquakes can occur in SCRs, deterministic seismic hazard analysis (DSHA) can be used to inform policy makers of the worst case scenarios.
format Thesis
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institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:31:35.974Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2020
publishDateRange 2020
publishDateSort 2020
publisher Department of Geological Sciences
publisherStr Department of Geological Sciences
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/31710 An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM) Salomon, Guy Sloan, Alastair Geological Sciences The Hebron fault scarp in southern Namibia is 45 km in length with an average height of 5.5 m and a maximum height of 8.9 m. Namibia is a Stable Continental Region (SCR) — a slowly deforming area within a continental plate. The country also has little recorded seismicity with the largest earthquake on the International Seismological Center (ISC) catalogue being MW 5.4. If the Hebron fault scarp was formed in a single event, this would represent a MW 7.3 earthquake. SCRs do occasionally experience large earthquakes, however, the recurrence intervals between these events is much larger than in rapidly deforming areas. Consequently, studying palaeo-earthquakes allows the record of seismicity to be extended and the characteristics of SCR events to be better understood. These studies may help refine the Mmax estimates required for seismic hazard assessment. Previous work on Hebron has been limited to field descriptions and theodolite survey scarp heights. Furthermore, there have been several interpretations of the fault mechanism and number of rupture events. This study produces a high-resolution Digital Elevation Model (DEM) via stereophotogrammetry using pan-sharpened Worldview-3 satellite imagery (0.31 m resolution). The DEM was used for several geomorphological analyses. These included measuring the scarp height at 160 locations along its length, measuring river channel displacements and identifying knickpoints along river profiles. Results indicate that the scarp formed from a normal, dip-slip fault that ruptured in a single event. This scenario would imply a high slip-to-length ratio. A comparison of other SCR fault scarps in the literature was made which shows that Hebrons’ slip-to-length ratio falls within the values found on other SCR faults. This study also discusses the implications of results for seismic hazard assessment in the region. Due a poor seismic record, probabilistic seismic hazard analysis (PSHA) will calculate a low seismic risk for Namibia. As large earthquakes can occur in SCRs, deterministic seismic hazard analysis (DSHA) can be used to inform policy makers of the worst case scenarios. 2020-04-29T14:49:17Z 2020-04-29T14:49:17Z 2019 2020-04-28T14:08:44Z Master Thesis Masters MSc https://hdl.handle.net/11427/31710 eng application/pdf Department of Geological Sciences Faculty of Science
spellingShingle Geological Sciences
Salomon, Guy
An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
thesis_degree_str Master's
title An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
title_full An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
title_fullStr An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
title_full_unstemmed An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
title_short An investigation into the geomorphology of the Hebron Fault, Namibia, using a satellite-derived, high-resolution digital elevation model (DEM)
title_sort investigation into the geomorphology of the hebron fault namibia using a satellite derived high resolution digital elevation model dem
topic Geological Sciences
url https://hdl.handle.net/11427/31710
work_keys_str_mv AT salomonguy aninvestigationintothegeomorphologyofthehebronfaultnamibiausingasatellitederivedhighresolutiondigitalelevationmodeldem
AT salomonguy investigationintothegeomorphologyofthehebronfaultnamibiausingasatellitederivedhighresolutiondigitalelevationmodeldem

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