BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
Contribution to the seismic microzonation of Lisbon based on the integration of geological, geophysical, and geotechnical data

Participants in the publication
Liliana Oliveira (Author)
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal
Rui Carrilho Gomes (Author)
INSTITUTO SUPERIOR TÉCNICO
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal
Paula Teves-Costa (Author)
Instituto Dom Luiz (IDL), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749–016, Lisboa, Portugal

Summary
Lisbon has been affected by several moderate to strong earthquakes that caused considerable damage and produced significant economic and social impacts (e.g., the November 1st, 1755, earthquake). Studies on the potential damage due to a seismic event have been done considering Lisbon's moderate to high seismic hazard, but the seismic site effects have not yet been investigated at the city scale. The local ground conditions can locally modify the characteristics of surface seismic motion. Based on a multidisciplinary dataset composed of surface geology, a geotechnical database, and a geophysical database that compiles all the available geophysical tests carried out in Lisbon, an integrated approach to seismic ground characterisation was performed. A regression analysis of the shear-wave velocity values compiled in the geophysical database was done for each geological unit. The peak frequency distribution in the city, assessed from the ambient vibration measurements, showed a pattern in peak frequency variation. It decreases from the oldest to the most recent geological formations that outcrop in the SW-NE direction. Three zones based on peak frequency value distribution were proposed. An estimation of the impedance contrast depths was computed through two processes, considering the previous results: (i) the shallower contrast depth was assessed through a sharp variation of NSPT values available in the geotechnical database, and (ii) the deeper contrast depth was estimated based on geology data and deep borehole information. The results showed that for the upper ∼100 m of depth, a consistent relationship between the contrasts identified through different data was obtained, even if uncertainty increased with depth.


Institution
UNIVERSIDADE DE LISBOA

Where published
Soil Dynamics and Earthquake Engineering

Publication Identifiers
ISSN - 0267-7261

Publisher
Elsevier BV



Document Identifiers
DOI - https://doi.org/10.1016/j.soildyn.2023.107965
URL - http://dx.doi.org/10.1016/j.soildyn.2023.107965

Rankings
SCIMAGO Q1 (2021) - 1426 - Geotechnical Engineering and Engineering Geology
SCOPUS Q1 (2021) - 6.8 - Geotechnical Engineering and Engineering Geology
Web Of Science Q2 (2021) - 4.250 - ENGINEERING, GEOLOGICAL - SCIE