Monte Carlo waveform inversion and deep continental structure

Abstract

The study of the three dimensional structure of the earth is limited by the uneven distribution of earthquake sources and seismic stations. The distribution of the earthquakes is fixed as most earthquakes occur along the plate boundaries. The use of artificial sources can improve the distribution of seismic sources but such experiments are not popular as they require sources with the strength of a nuclear explosion in order to probe the mantle. The distribution of seismic stations is mainly concentrated in regions with a significant earthquake risk. In Europe the availability of seismic data has also been restricted by political borders. The politically changes in the 1980's and 1990's in Eastern Europe lead to increased scientific communication which has resulted in the NARS-DEEP (Network of Autonomously Recording Seismographs Deployed on the East European Platform) project. The NARS-DEEP project has been initiated to increase the data coverage in Eastern Europe and to investigate the geodynamic history of the region. Starting in the summer of 1995 eleven modern digital seismic stations have been installed in Russia, Belarus, Ukraine and Finland, see Figure 1.1. Other organizations such as IRIS and GEOFON also installed several seismic stations in the region. In this thesis the velocity structure of Eastern Europe is investigated using these newly available data.