BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
A sanity check for earthquake recurrence models used in PSHA of slowly deforming regions: the case of SW Iberia

Participants in the publication
Margarida Ramalho (Author)
Luis Matias (Author)
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal
Dep. Engenharia Geográfica, Geofísica e Energia
Marta Neres (Author)
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal
Michele M. C. Carafa (Author)
Alexandra Carvalho (Author)
Paula Teves-Costa (Author)
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal

Summary
Probabilistic seismic hazard assessment (PSHA), despite its deep criticism, is still the most common tool used to decide on the acceptable seismic risk and corresponding mitigation measures. We propose two consistency tests to address the variability of earthquake generation models found in PSHA studies: (i) one rule-of-thumb test where the seismic moment release from the model is converted to an average slip on a typical fault and compared with known plate kinematics or GNSS deformation field and (ii) a test where using a neotectonic model the computed deformation is converted into seismic moment release and to a synthetic earthquake catalogue. We apply these tests to W and SW Iberia slowly deforming region, where two earthquake source areas are investigated: (1) the Lower Tagus Valley, one of the largest seismic risk zones of Portugal; and (2) the offshore SW Iberia area, considered to be the source for the 1 November 1755 event (M ∼ 8.7). Results show that some of the earthquake source models should be considered suspicious, given their high/low moment release when compared to the expected values from GNSS observations or neotectonic modelling. This analysis allowed for a downgrade of the weight of poorly compliant models in the PSHA analysis, and thus for a more realistic hazard assessment, and can be integrated in other studies of similar settings.


Where published
Natural Hazards and Earth System Sciences

Publication Identifiers

Publisher
Copernicus GmbH



Document Identifiers
DOI - https://doi.org/10.5194/nhess-22-117-2022
URL - http://dx.doi.org/10.5194/nhess-22-117-2022