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Near‐Surface Characterization of the Lisbon and Lower Tagus Valley Area, Portugal, for Seismic Hazard Assessment: VS30 and Soil Classification Maps

2018; Seismological Society of America; Volume: 108; Issue: 5A Linguagem: Inglês

10.1785/0120170340

1943-3573

J. Carvalho, R. Dias, Ranajit Ghose, Paula Teves‐Costa, José Fernando Borges, J. Narciso, César Braga-Pinto, Jaime Leote,

Seismic Waves and Analysis

Research Article| September 11, 2018 Near‐Surface Characterization of the Lisbon and Lower Tagus Valley Area, Portugal, for Seismic Hazard Assessment: VS30 and Soil Classification Maps J. Carvalho; J. Carvalho aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt Search for other works by this author on: GSW Google Scholar R. Dias; R. Dias aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt Search for other works by this author on: GSW Google Scholar R. Ghose; R. Ghose bDepartment of Geoscience and Engineering, Delft University of Technology, P.O. Box 5028, 2628 GA Delft, The Netherlands, r.ghose@tudelft.nl Search for other works by this author on: GSW Google Scholar P. Teves‐Costa; P. Teves‐Costa cInstituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa, 1749‐016 Lisbon, Portugal, mpcosta@fc.ul.pt Search for other works by this author on: GSW Google Scholar J. Borges; J. Borges dInstitute of Earth Sciences, University of Évora, R. Romão Ramalho, 59, 7000 Évora, Portugal, jborges@uevora.pt Search for other works by this author on: GSW Google Scholar J. Narciso; J. Narciso eInstituto Superior Técnico, R. Rodovisco Pais, 1, 1040‐001 Lisbon, Portugal, joao.narciso@tecnico.ulisboa.pt Search for other works by this author on: GSW Google Scholar C. Pinto; C. Pinto aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt Search for other works by this author on: GSW Google Scholar J. Leote J. Leote aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt Search for other works by this author on: GSW Google Scholar Author and Article Information J. Carvalho aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt R. Dias aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt R. Ghose bDepartment of Geoscience and Engineering, Delft University of Technology, P.O. Box 5028, 2628 GA Delft, The Netherlands, r.ghose@tudelft.nl P. Teves‐Costa cInstituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa, 1749‐016 Lisbon, Portugal, mpcosta@fc.ul.pt J. Borges dInstitute of Earth Sciences, University of Évora, R. Romão Ramalho, 59, 7000 Évora, Portugal, jborges@uevora.pt J. Narciso eInstituto Superior Técnico, R. Rodovisco Pais, 1, 1040‐001 Lisbon, Portugal, joao.narciso@tecnico.ulisboa.pt C. Pinto aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt J. Leote aLaboratório Nacional de Energia e Geologia, Estrada Portela‐Zambujal, Apartado 7586‐Alfragide, 2610‐999 Amadora, Portugal, joao.carvalho@lneg.ptruben.dias@lneg.ptcdcpinto@gmail.comjaime.leote@lneg.pt Publisher: Seismological Society of America First Online: 11 Sep 2018 Online Issn: 1943-3573 Print Issn: 0037-1106 © Seismological Society of America Bulletin of the Seismological Society of America (2018) 108 (5A): 2854–2876. https://doi.org/10.1785/0120170340 Article history First Online: 11 Sep 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. Carvalho, R. Dias, R. Ghose, P. Teves‐Costa, J. Borges, J. Narciso, C. Pinto, J. Leote; Near‐Surface Characterization of the Lisbon and Lower Tagus Valley Area, Portugal, for Seismic Hazard Assessment: VS30 and Soil Classification Maps. Bulletin of the Seismological Society of America 2018;; 108 (5A): 2854–2876. doi: https://doi.org/10.1785/0120170340 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract The Lower Tagus Valley (LTV) region includes the metropolitan area of Lisbon and has the highest population density in Portugal, with about 3.5 million inhabitants. The LTV has been struck by several historical earthquakes that caused significant economic and human losses, and therefore, earthquake damage mitigation is of great importance. The present research was directed toward preparation of the first detailed VS30 and soil classification maps for the LTV region using in situ shear‐wave velocity (⁠VS⁠) measurements. These maps were built using P‐ and S‐wave seismic velocities in the shallowest surface, obtained mostly from seismic refraction and a few crosshole datasets, together with lithostratigraphic studies and analyses of boreholes drilled for water supply and geotechnical investigations. Borehole data were used to confirm layer thicknesses and lithologies, and to overcome the limitations of traditional refraction interpretation. Our results (⁠VS30 and soil classification maps) show that lithological changes within each formation prevent simple generalization of geophysical data/interpretations based solely on geological mapping. Contrary to previously available VS30 maps based on proxies or gross geological generalizations, different classes are obtained inside the Holocene alluvial sediments and the Miocene units, for instance. Certain areas with Miocene outcropping, such as the district capital of Santarém, unexpectedly fall into a moderate risk class, albeit showing hard‐rock outcrops. Though there is scope for further improvements in the future, the maps presented results from the first rigorous near‐surface characterization campaign undertaken in the region. Velocity information assembled in this work can be further used to correct earthquake records from a number of seismological stations and to update velocity models used in ground‐motion simulations. Furthermore, seismic refraction interpretation was compared among different acquisition geometries for seismic noise measurements at three geologically distinct sites to evaluate the use of these techniques for future S‐wave data acquisition. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.