Subduction Zone Structure and Earthquakes

Active-source seismic refraction across the Sumatra subduction zone

Historic earthquakes have ruptured distinct segments of the plate boundary megathrust at the Sumatra subduction zone. We use seismic refraction data to derive a velocity model for a  3-D area crossing the plate boundary near Nias and Siberut and to attempt to shed light on the factors controlling rupture segmentation [e.g., Tang et al., 2013].

Key Contact: Marianne Karplus

Controls on Megathrust Earthquake Segmentation

Great earthquakes rupture >1000km2 of a convergent margin with seismic slip of tens of meters. Marine seismic and bathymetry data across earthquake boundaries worldwide will be analysed to document structural and morphological variations of the upper overriding and the lower subducting plate which may impact on or reflect changes in the physical properties of the plate interface and thus control seismic rupture.

Key Contact: Jacob Geersen

Mapping physical properties using reflection coefficients, a global approach

This objective of this project is to create a globally standardised true amplitude analysis method (Dean et al. 2010) that can be used to rapidly assess variations in physical properties at undrilled subduction margins such as Sumatra and Hikurangi.

Key Contact: Dean Wilson

Segmentation, fault structure and tsunamigenesis of the Sumatran Subduction Zone

Earthquake rupture initiation requires strong coupling along a plate boundary interface. Variable along strike coupling of the plate boundary interface exerts a primary control on earthquake segmentation and across strike changes can affect the tsunamigenic potential.

Key Contact: Becky Cook (PhD Student), Tim Henstock

Structure, fluid flow and earthquake potential of the Makran Subduction Zone, Pakistan

An investigation into the structure and seismogenic potential of the Makran Subduction Zone using 2D seismic reflection data. This margin has been previously relatively understudied, however the occurrence of a Mw8.1 earthquake in 1945 raises questions about its true earthquake potential, and the Makran may pose a significant earthquake and tsunami hazard.

Key Contact: Gemma Smith (PhD Student), Lisa McNeill

Sumatran Earthquake Segment Boundaries Consortium

This project examines the structure and properties of barriers to earthquake rupture offshore Sumatra, Indonesia. This was the location of the devastating 2004 and 2005 earthquakes and tsunamis. The 5-year project (2006-2011) is led by Tim Henstock, and involves partners from 4 other UK institutions, plus a number of international partners. It is supported by a £2m grant from NERC.

Key Contact: Tim Henstock