Can modeling the geologic record contribute to constraining the tectonic source of the AD 1755 Great Lisbon earthquake?

Earth and Space Science
By: , and 

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Abstract

The precise location of the seismic source of 1755 CE Great Lisbon earthquake is still uncertain. The aim of this work is to use an onland sedimentary record in southern Portugal to test and validate seismic sources for the earthquake. To achieve this, tsunami deposit thicknesses from over 150 cores collected at Salgados in southern Portugal were compared to the results of a tsunami sediment transport model (Delft3D-FLOW) that simulates tsunami propagation, inundation, erosion, and deposition. Five different hypothetical seismic sources were modeled with varying bed roughness coefficients to assess how well they reproduced observed patterns of tsunami deposit thicknesses and dune. Modeled and observed historical tsunami arrival times were also used to test different earthquake sources. Based on these comparisons, three modeled earthquake sources were able to reproduce the observed data, suggesting they should be regarded as somewhat more likely sources for the 1755 earthquake in contrast to four other modeled sources. The fault closest to shore (Marquês de Pombal) yielded the best correlations between model and observations.

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Publication type Article
Publication Subtype Journal Article
Title Can modeling the geologic record contribute to constraining the tectonic source of the AD 1755 Great Lisbon earthquake?
Series title Earth and Space Science
DOI 10.1029/2020EA001109
Volume 8
Issue 4
Year Published 2021
Language English
Publisher American Geophysical Union
Contributing office(s) Pacific Coastal and Marine Science Center
Description e2020EA001109, 11 p.
Country Portugal
City Lisbon
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