£2 million to study earthquake region
University of Southampton scientists are part of a major research consortium which has just started to investigate the causes of devastating earthquakes in south-east Asia. The research team, led by the National Oceanography Centre, Southampton, is surveying the region struck by the 2004 and 2005 Sumatran earthquakes and tsunami to determine how the structure of major faults affects the size of large earthquakes.
The team has been awarded more than £2 million by the Natural Environment Research Council (NERC) to carry out the research, which will combine data recorded during the earthquakes with new observations of the seafloor and sub-seafloor plate boundary zone.
The project will provide critical information about what happened during the 2004 and 2005 Sumatran earthquakes, and whether similar events might have happened in the past. This will have important implications for understanding the risk from future earthquakes both in Sumatra and elsewhere.
All plate boundaries are divided into segments - 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 Sumatran earthquakes provide a unique framework to tackle this problem", explains Dr Tim Henstock, a NOCS geophysicist at the University of Southampton and Principal Investigator for the project. "The southern boundary of the major 2004 earthquake stopped the rupture and therefore limited the earthquake magnitude, but we don't yet know why this boundary is there and how it controls the earthquake rupture process."
The project aims to understand this behaviour, and was designed to combine observations of the earthquakes with measurements of the faults beneath the seafloor, linking the dynamics of the rupture to the static structure of the plate boundary. The study will collect many different geophysical and geological datasets around the earthquake rupture barriers exploring different properties at many different scales. 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.
A complementary experiment on land will record earthquakes by installing instruments for up to one year on Sumatra and the islands overlying the plate boundary zone. They will record waves from earthquakes all over the world to image deep into the subduction system and will show which faults are currently most active.
The 130-day shipboard programme started this week, using the German R/V Sonne. Dr Mike Webb of the NERC said "This is the largest exchange of marine facilities that we have ever undertaken. As well as providing an excellent platform for this important study, we hope the project will demonstrate the expanding cooperation between European research fleets. Because the Sonne is already working in the area, this exchange is logical and more efficient."
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The UK consortium comprises Tim Henstock, Lisa McNeill, Simon Dean, Jon Bull, Doug Masson and Russell Wynn from the National Oceanography Centre, Southampton; Philip England, Shamita Das and David Robinson, from the University of Oxford; Frederik Tilmann, Penny Barton and Keith Priestly from the University of Cambridge; Andreas Rietbrock from University of Liverpool, and Dave Tappin from the British Geological Survey. They will be working closely with colleagues from BPPT and LIPI in Indonesia, as well as scientists from Germany, France, and the US.
The Natural Environment Research Council (NERC) funds world-class science, in universities and its own research centres, that increases knowledge and understanding of the natural world. It is tackling major environmental issues such as climate change, biodiversity and natural hazards. NERC receives around £400 million a year from the government's science budget, which is used to provide independent research and training in the environmental sciences.
The National Oceanography Centre, Southampton is a collaboration between the University of Southampton and the Natural Environment Research Council. It is one of the world's leading institutions devoted to research, teaching and technology development in ocean and earth science.
The University of Southampton is one of the UK's top 10 research universities, offering first-rate opportunities and facilities for study and research across a wide range of subjects in health, humanities, science and engineering.
The University, which has over 22,000 students, 5000 staff, and an annual turnover in the region of £325 million, is one of the country's top institutions for engineering, computer science and medicine, and home to a range of world-leading research centres. These include the National Oceanography Centre, Southampton, the Institute of Sound and Vibration Research, the Optoelectronics Research Centre, the Centre for the Developmental Origins of Health and Disease, and the Mountbatten Centre for International Studies.