The Natural Environment Research Council (NERC) has awarded £2m to a research team to combine data recorded during the earthquakes in south east Asia, with new observations of the seafloor and sub-seafloor plate boundary zone. The team, led by the National Oceanograhy Centre, Southampton is to survey the region to determine how the structure of major faults affects the size of large earthquakes.
The project will provide critical information about what happened during the 2004/2005 Sumatran earthquakes and whether similar events might have happened in the past. This could have important implications for understanding the risks from future earthquakes.
All plate boundaries are divided into segments, which are sections of fault that are distinct and behave differently from one another. Barriers between these segments often limit how far a particular earthquake ruptures. But it is not known what determines whether an earthquake ruptures only a single segment, staying relatively small, or jumps across the barriers between segments to become a major event.
The project aims to understand this behaviour and combine it with measurements of the faults beneath the seafloor, linking the dynamics of the rupture to the static structure of the plate boundary. The data will improve understanding of the shape of the two tectonic plates and the properties of the sediments and fluids within them, all of which influence how an earthquake propagates along a fault.