Cover illustration: anelastic observations of upper mantle sensitive mode 2S12 and lower mantle sensitive mode 1S9, figure by SATS using Paraview (Ahrens et al., 2005).The facilities of IRIS Data Services, and specifically the IRIS Data Management Centre, were used for access to waveforms, related metadata, and/or derived products used in this thesis. We also acknowledge the 'Global CMT project' webpage for the earthquake source parameters used in this thesis Dziewonski et al., 2012). GraphClick (http://www.arizona-software.ch/graphclick/) was used to digitalise data. Preand post-processing were done using ObsPy (Beyreuther et al., 2010) and FrosPy (Schneider et al., in prep.). The figures were generated using FrosPy and GMT (Wessel et al., 2013).