Broadband seismological data studies : validity of assumptions in surface wave studies and detailed structure of the upper mantle

Abstract

The work described in this thesis is aimed at improving the knowledge of the upper mantle structure beneath specific regions of the Earth. In addition, it seeks to contribute to better understanding of surface wave propagation and to test assumptions generally made in surface wave studies which have implications for the interpretation of upper mantle velocity models. In this context, four different aspects of seismological research have been addressed in this thesis. A point in common between these four different studies is that each of them employs seismological broadband data (either body waves, surface waves and/or surface wave coda) recorded at a regional array of stations, or at stations well distributed across the region of study. Broadband seismic sensors have a larger dynamic range and allow the retrieval of more waveform information than short-period or long-period instruments. In this way, broadband data can reveal detailed information of the complex upper mantle structure, and can be used to study some aspects of surface wave propagation in the upper mantle. For each study, the size of the array or the spatial distribution of stations has been chosen depending on the type of information to be extracted from the data.