Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia

A great number of the urban areas in Ethiopia are situated within the Great Rift Valley of Ethiopia, a system consisting of depressions and large faults. As a region with significant seismic activities, it is vital that careful planning is implemented to avoid constructing buildings on flat surfaces...

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Main Author: Laskar, Tasnim
Format: Others
Language:English
Published: Uppsala universitet, Geofysik 2019
Subjects:
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385893
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spelling ndltd-UPSALLA1-oai-DiVA.org-uu-3858932019-08-20T04:27:11ZDetermining shallow P-wave velocity and its engineering implication in Adama City, EthiopiaengLaskar, TasnimUppsala universitet, GeofysikUppsala universitet, Institutionen för teknikvetenskaper2019Ethiopiaseismic refractionearthquakeGeophysicsGeofysikA great number of the urban areas in Ethiopia are situated within the Great Rift Valley of Ethiopia, a system consisting of depressions and large faults. As a region with significant seismic activities, it is vital that careful planning is implemented to avoid constructing buildings on flat surfaces as they can amplify ground motion in the case of an earthquake.   This study was conducted in Adama, a city located within the rift system, to map and characterize the subsurface of a construction site with seismic refraction and investigate whether this is an optimal area to construct a building should an earthquake occur. Seismic refraction is based on Snell’s law, specifically the case of the critical angle, which is when the refracted angle is at 90 degrees and a number of the energy from the wave is rebounded back to the surface in accordance with Huygen’s Principle.       Seismic waves were generated with a sledgehammer and recorded with 24 vertical geophones. The acquired data was then analysed with SeisImager and produced a 2D-tomography of the site with the corresponding velocity layers for a P-wave. Comparing the P-wave velocities to a table of Seismic Velocities of Rocks and Various Materials, one could determine that the subsurface layers consisted of rock soils, sand and silt. These are incredibly loose materials that will amplify ground motion during earthquake crisis and are therefore not optimal or ideal for constructing buildings. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385893TVE-F ; 19005application/pdfinfo:eu-repo/semantics/openAccess
collection NDLTD
language English
format Others
sources NDLTD
topic Ethiopia
seismic refraction
earthquake
Geophysics
Geofysik
spellingShingle Ethiopia
seismic refraction
earthquake
Geophysics
Geofysik
Laskar, Tasnim
Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
description A great number of the urban areas in Ethiopia are situated within the Great Rift Valley of Ethiopia, a system consisting of depressions and large faults. As a region with significant seismic activities, it is vital that careful planning is implemented to avoid constructing buildings on flat surfaces as they can amplify ground motion in the case of an earthquake.   This study was conducted in Adama, a city located within the rift system, to map and characterize the subsurface of a construction site with seismic refraction and investigate whether this is an optimal area to construct a building should an earthquake occur. Seismic refraction is based on Snell’s law, specifically the case of the critical angle, which is when the refracted angle is at 90 degrees and a number of the energy from the wave is rebounded back to the surface in accordance with Huygen’s Principle.       Seismic waves were generated with a sledgehammer and recorded with 24 vertical geophones. The acquired data was then analysed with SeisImager and produced a 2D-tomography of the site with the corresponding velocity layers for a P-wave. Comparing the P-wave velocities to a table of Seismic Velocities of Rocks and Various Materials, one could determine that the subsurface layers consisted of rock soils, sand and silt. These are incredibly loose materials that will amplify ground motion during earthquake crisis and are therefore not optimal or ideal for constructing buildings.
author Laskar, Tasnim
author_facet Laskar, Tasnim
author_sort Laskar, Tasnim
title Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
title_short Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
title_full Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
title_fullStr Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
title_full_unstemmed Determining shallow P-wave velocity and its engineering implication in Adama City, Ethiopia
title_sort determining shallow p-wave velocity and its engineering implication in adama city, ethiopia
publisher Uppsala universitet, Geofysik
publishDate 2019
url http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385893
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