The University of Southampton
University of Southampton Institutional Repository

Crustal thickness estimates beneath four seismic stations in Ethiopia inferred from p-wave receiver function studies

Crustal thickness estimates beneath four seismic stations in Ethiopia inferred from p-wave receiver function studies
Crustal thickness estimates beneath four seismic stations in Ethiopia inferred from p-wave receiver function studies
Moho depths beneath four stations of the Ethiopian Seismic Station Network (ESSN) are estimated from P-wave receiver functions (RF). We used high quality seismic data recorded at ANKE (Ankober), DILA (Dilla), HARA (Harar) and SEME (Semera) stations for earthquakes located at epicentral distances ranging from 30 to 100° with magnitude mb ≥ 5.5. We applied a frequency domain deconvolution technique to remove source and propagation path effects from the earthquakes waveforms to make the RFs dependent only on the structure beneath the seismic stations. The minimum number of teleseismic earthquakes used is 14 for HARA while the maximum is 39 for SEME station. A linearized-iterative inversion is applied on the generated radial component of the receiver functions to obtain P-wave velocity models beneath the stations. We achieved a reasonably good fit between the observed and synthetic RFs, which demonstrated the high quality of the inversion process. From the obtained models we estimated Moho depths of 26 ± 2 km for SEME, 36 ± 2 km for DILA, 38 ± 2 km for HARA and 42 ± 1.7 km for ANKE. The lowest Moho depth is observed at Semera station which implies a thinned crust while the highest crustal thickness is observed at Ankober, which lies along the North western plateau margin. Our results agree with previous observations which strengthen the hypothesis that Moho depths estimated for stations that lie within the rift and rift margins are lower than those located in the plateaus. Our RFs inversions show a low velocity gradient at about 16 km depth at Semera station, interpreted as evidence for lower crustal storage of partial melt.
Anomalous Moho, Crustal structure, Moho, Partial melt, Receiver functions, Velocity model
1464-343X
264-271
Kibret, Birhanu A.
353b131c-0ca4-4063-9c62-60a407d0c862
Ayele, Atalay
5b4eeb35-d229-4325-8940-d934dab7563d
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Kibret, Birhanu A.
353b131c-0ca4-4063-9c62-60a407d0c862
Ayele, Atalay
5b4eeb35-d229-4325-8940-d934dab7563d
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65

Kibret, Birhanu A., Ayele, Atalay and Keir, Derek (2019) Crustal thickness estimates beneath four seismic stations in Ethiopia inferred from p-wave receiver function studies. Journal of African Earth Sciences, 150, 264-271. (doi:10.1016/j.jafrearsci.2018.11.005).

Record type: Article

Abstract

Moho depths beneath four stations of the Ethiopian Seismic Station Network (ESSN) are estimated from P-wave receiver functions (RF). We used high quality seismic data recorded at ANKE (Ankober), DILA (Dilla), HARA (Harar) and SEME (Semera) stations for earthquakes located at epicentral distances ranging from 30 to 100° with magnitude mb ≥ 5.5. We applied a frequency domain deconvolution technique to remove source and propagation path effects from the earthquakes waveforms to make the RFs dependent only on the structure beneath the seismic stations. The minimum number of teleseismic earthquakes used is 14 for HARA while the maximum is 39 for SEME station. A linearized-iterative inversion is applied on the generated radial component of the receiver functions to obtain P-wave velocity models beneath the stations. We achieved a reasonably good fit between the observed and synthetic RFs, which demonstrated the high quality of the inversion process. From the obtained models we estimated Moho depths of 26 ± 2 km for SEME, 36 ± 2 km for DILA, 38 ± 2 km for HARA and 42 ± 1.7 km for ANKE. The lowest Moho depth is observed at Semera station which implies a thinned crust while the highest crustal thickness is observed at Ankober, which lies along the North western plateau margin. Our results agree with previous observations which strengthen the hypothesis that Moho depths estimated for stations that lie within the rift and rift margins are lower than those located in the plateaus. Our RFs inversions show a low velocity gradient at about 16 km depth at Semera station, interpreted as evidence for lower crustal storage of partial melt.

Text
Accepted-Manuscript-AES6163 - Accepted Manuscript
Restricted to Repository staff only until 16 November 2019.
Request a copy

More information

Accepted/In Press date: 7 November 2018
e-pub ahead of print date: 16 November 2018
Published date: February 2019
Keywords: Anomalous Moho, Crustal structure, Moho, Partial melt, Receiver functions, Velocity model

Identifiers

Local EPrints ID: 427888
URI: https://eprints.soton.ac.uk/id/eprint/427888
ISSN: 1464-343X
PURE UUID: eb540042-dee8-4ed0-a17e-267aea4b99fa
ORCID for Derek Keir: ORCID iD orcid.org/0000-0001-8787-8446

Catalogue record

Date deposited: 01 Feb 2019 17:30
Last modified: 15 Jul 2019 16:45

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×