Simulació numèrica del moviment del sòl produït per terratrèmols. Aplicació a moviments febles i forts.

Resumen

This Thesis is produced in the framework of the seismic risk studies developed by the Geological Survey of Catalonia, the contribution of this work has been the seismic ground motion characterisation thought the application of different numerical simulation methods and comparing the synthetic results with real data. With the application of different numerical simulation techniques we can analyse the seismic soil response and to know their relations with the seismic wave generation and propagation. In this work, the theory of different 1D and 2D ground motion modelling methods are described, ones of them are seismological methods, used in this Thesis as a first time in our country, and the others are engineering methods, more usually used in our country. Special attention is done to the wave amplification in relation with the local geological and geometrical characteristics. A set of programs based on this methods have been implemented and they have been applied to several cases and the synthetic results compared with the real ones. The application of several methods to the same problem gives us to have a complete definition of the processes involved in the soil seismic motion, and is useful as much for the field of the Seismology like from the Seismic Engineering. The numerical methods have been applied to the following cases: - Ground motion numerical simulation for one Ml=4.2 earthquake, with epicentre in South Barcelona (15/12/1991), in Poblet station (3 components) and Vandellós (1 component), both at 100 km of distance form the epicentre. The influence of focal parameters and propagation have been studied and a good structural model and focal parameters obtained, similars to the obtained with classical methods. - Modelling of ground motion in different soil sites in Ashigara-Valley (Japan), considering two earthquakes (strong and moderate) a point source and a realistic structural and topographical model of the local sites. This study is the result of our participation, with the LGIT (Grenoble), in one international experiment for the calibration of numerical site effects estimation. The later comparison between predictions and real records in soil sites it allows the methods calibration and their validation. - Experimental study of the soil response and their dependency with the input ground motion in rock (possible non linear behaviour), in the Smart-1 accelerometer array in Taiwan. The empirical study is completed with a numerical one to verify if the observed behaviour can be predicted.