Southampton scientist takes lead role in pioneering earthquake project

Geologist Dr Lisa McNeill, from the University’s School of Ocean and Earth Science based at the National Oceanography Centre, Southampton, is a Co-Chief Scientist on the second phase of the ambitious, multidisciplinary Earth science expedition – the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) – which aims to gain a better understanding of earthquakes.

For the first time scientists are drilling into the place deep in the Earth’s crust where earthquakes begin. Researchers are working on board the Japanese vessel Chikyu, the world’s most advanced scientific drilling ship.

“I am privileged to be part of this truly international experiment, one of the largest in Earth science and one of the most technologically challenging,” says Dr McNeill.

The Nankai Trough off the Japanese coast is where the Philippine Sea Plate slides or subducts beneath the Eurasian plate and is one of the most active earthquake zones on the planet. Such subduction zones are responsible for the most powerful earthquakes, such as the 2004 Boxing Day earthquake and tsunami in Indonesia and the Indian Ocean. Dr McNeill, who will be joining Chikyu (meaning ‘Planet Earth’) in June, has also worked on the Sunda Trench near Sumatra that ruptured with such devastating force in December 2004.

NanTroSEIZE is part of the Integrated Ocean Drilling Program (IODP), and this second-stage expedition will involve deep drilling, sampling and monitoring of the uppermost portion of the earthquake zone. The ultimate goal of this multi-year project will be to access, sample and monitor the deep fault zone that generates these destructive earthquakes. During NanTroSEIZE expeditions this year, more than 50 international researchers from the IODP participating countries will be on board the Chikyu.

The current expedition has just started and will continue until the end of August. This will be the first time that riser drilling technology is used in scientific ocean drilling: a method which allows drilling to greater depths below the seafloor and enables scientists to reach the deep fault zone. Data and rock samples will be collected to understand the composition, structure and physical properties of the subduction zone sediments and fault zones, including the frictional properties of the rocks and hydrological processes within the fault zones. During the expedition, equipment will be placed within the borehole to monitor changing properties such as pressure, temperature and deformation. These will be supplemented in future with many more instruments to observe the downhole conditions and earthquake generation process.

The research conducted at the Nankai subduction zone will not only contribute to the geological understanding of this particular region and its natural hazards, but will also be applicable to other subduction zones around the world, including the subduction zone in the eastern Indian Ocean (offshore Indonesia and parts of India). The earthquakes generated by this fault zone in 2004 and 2005 were recent reminders of the devastating impact of this type of natural hazard, but have also provided scientists with new data which are helping us to better understand the earthquake process.

The experiment can be followed at:

http://www.jamstec.go.jp/chikyu/eng/CHIKYU/status.html

http://www.jamstec.go.jp/chikyu/eng/Expedition/NantroSEIZE/index.html