Contribution to a Detailed Seismic Hazard Assessment in the Lower Tagus Valley

HR: 09:35h
AN: T31G-07 [Abstracts]
TI: Contribution to a Detailed Seismic Hazard Assessment in the Lower Tagus Valley
AU: * Simoes, J
EM: jose-simoes@fc.ul.pt
AF: Geophysical Center, University of Lisbon, Campo Grande, Ed. C8, Lisboa, PT 1749-01 Portugal
AU: * Simoes, J
EM: jose-simoes@fc.ul.pt
AF: Physics Department, Faculty of Sciences, University of Lisbon, Campo Grande, Ed. C8, Lisboa, PT 1749-01 Portugal
AU: Mendes-Victor, L
EM: lavictor@fc.ul.pt
AF: Infante D. Luis Geophysical Institute, Rua da Escola PolitＤnica 58, Lisboa, PT 1269-10 Portugal
AU: Carvalho, J
AF: Geological and Mining Institute, Estrada da Portela, Alfragide, PT 2720-46 Portugal
AU: Rio, I
AF: Infante D. Luis Geophysical Institute, Rua da Escola PolitＤnica 58, Lisboa, PT 1269-10 Portugal
AU: Teves-Costa, P
AF: Geophysical Center, University of Lisbon, Campo Grande, Ed. C8, Lisboa, PT 1749-01 Portugal
AU: Teves-Costa, P
AF: Physics Department, Faculty of Sciences, University of Lisbon, Campo Grande, Ed. C8, Lisboa, PT 1749-01 Portugal
AB: Several previous works have assessed the seismic hazard in the Lower Tagus River area, an industrialized and populated area, SE of Lisbon, using historical and instrumental data. In this study we gave a contribution to a more detailed study of the seismic risk, and we have tried to clarify the epicentral features and the fault characteristics as well as the seismogenetic behavior. This is particularly difficult in this case because, although we have strong evidence of past strong events in the historical data, no such events is recorded in the instrumental data. We have reinterpreted previous seismic prospecting work in the area, as well as other geophysical data gather in the last years. We believe that the reinterpretation of the seismic profiles, near the villages of Vila Franca and Azambuja, allows an identification of the seismogenetic structure, close to the surface, while some of the natural seismic events recorded seem to be generated by the deepest part of the same structure. This interpretation is with good agreement with the gravimetry data. We have also be able to calculate the probability of the top acceleration to exceed a certain value in a given time intervals, in each point of the area.
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting