Global investigation of large earthquakes using InSAR and long-period seismic data

In this thesis I present the first comprehensive global archive of InSAR-determined source models (ICMT database) compiled from the literature, which I use to independently assess source parameters reported in global and regional seismic catalogues. In general there is good agreement between InSAR and seismic source models, but there are some large discrepancies, particularly in location and seismic moment. There is a large intra-event variability in source parameters in the ICMT database, which highlights the uncertainties introduced by errors in the data and by simplified assumptions used in the modelling. Large discrepancies for five earthquakes with magnitudes Mw 6.0 -Mw 8.1 are investigated in detail by comparing seismic data with theoretical seismograms calculated using two forward modelling techniques and 1-D and 3-D Earth models. For moderate magnitude events the InSAR location improves the fit to the seismic data, but this is not the case for the larger earthquakes, which is partly due to errors in the Earth models used. These findings motivated the development of a new seismo-geodesy joint source inversion technique that takes into account the effects of 3-D Earth structure when modelling the seismic data. It is tested on three synthetic events with different faulting mechanisms and for three real earthquakes in various tectonic settings (Mw 6.0 Eureka Valley, Mw 6.6 Aiquile and Mw 6.5 Zarand events). These tests clearly show the advantages of taking into account 3-D Earth structure in the modelling, and the combination of InSAR and seismic datasets reduces parameter tradeoffs and enables the robust characterisation of the earthquake source.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of East Anglia

Year dc:date.issued

2013

Author dc:creator

• Weston, Jennifer

Language dc:language

en