Probabilistic seismic-hazard assessment for Eritrea

Berhe Goitom, Maximilian J. Werner, Katsuichiro Goda, J. Michael Kendall, James O.S. Hammond, Ghebrebrhan Ogubazghi, Clive Oppenheimer, Agnes Helmstetter, Derek Keir, Finnigan Illsley-Kemp

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

To date little is known about seismic hazard in Eritrea, despite its location in a volcanically and tectonically active region, and the gathering pace of major infrastructure projects. In response, we report the findings of a comprehensive probabilistic seismic-hazard assessment for Eritrea and adjacent areas. Seismic source and groundmotion models are constructed separately; we use an adaptive spatiotemporal smoothing method to map expected patterns of seismicity. To construct a consistent earthquake catalog from different data sets, we use orthogonal regression to convert and unify different magnitude scales. A sensitivity analysis of the different input parameters helps constrain them and disaggregation of site-specific hazard estimates yields insights into the relative contribution from seismic sources of different magnitudes and distances. The results highlight seismic hazard in proximity to the Red Sea, Gulf of Aden, Afar depression, and along the boundaries of the Danakil microplate. We estimate a 10% chance over 50 years of observing pseudospectral accelerations (PSAs) at 0.2 s exceeding 0:16g in the port city of Massawa (population ∼32;000) and the town of Bada (population ∼4000). For the capital, Asmara (population ∼520;000), we calculate a PSA of 0:11g at 0.2 s. Compared with previous studies, our results provide greater spatial resolution, use more recent ground-motion models, and benefit from a smoothed seismicity method. Our aims are to stimulate further studies and contribute to the safe development of the region in light of its exposure to seismic hazards.
Original languageEnglish (US)
Pages (from-to)1478-1494
Number of pages17
JournalBULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
Volume107
Issue number3
DOIs
StatePublished - Mar 21 2017
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-08
Acknowledged KAUST grant number(s): OSR-2015-CRG4-2643
Acknowledgements: B. G. is funded through a Ph.D. scholarship by the University of Bristol and Engineering and Physical Sciences Research Council (EPSRC; Grant Number DTG EP/L504919/1). We would like to thank Eastern and Southern African Regional Seismological Working Group(ESARSWG) for providing us with their catalog that we used in our analysis. The local earthquake catalog during 2011-2012 was generated from data collected using the facilities of Seismic Equipment Infra-Structure in the UK (SEIS-UK) supported by the Natural Environment Research Council under Agreement R8/H10/64. Fieldwork support was provided by the Natural Environment Research Council (NERC; Award Number NE/J012297/1 “Mechanisms and implications of the 2011 eruption of Nabro volcano, Eritrea”). C. O. acknowledges support from the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics. D. K. is supported by NERC Grant Number NE/L013932/1 and Grant Number OSR-2015-CRG4-2643 from King Abdullah University of Science and Technology; and F. I. K. is funded through NERC studentship NE/L002531/1 and a grant to Graduate School of the National Oceanography Centre of Southampton(GSNOCS) from Roy Franklin O.B.E. We thank the two anonymous reviewers and Associate Editor Mark Stirling for their valuable comments on the original article.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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