Scientists reveal first photographic evidence of cause of Asian tsunami
Todd McLeish, 401-874-7892
KINGSTON, R.I. -- June 2, 2005 -- An international team of the world's leading scientists, led by a University of Rhode Island oceanographer, has just returned from the first scientific expedition to dive 4,500 meters into the Indian Ocean to explore the seabed site of the 2004 Asian tsunami. They have revealed dramatic photographic evidence of seafloor ruptures that contributed to the deadly December 26 tsunami.
Beginning May 10, scientists spent 17 days at sea exploring the seafloor off the coast of Sumatra in order to gain a better understanding of the forces that led to the devastating tsunami. Led by URI's Kate Moran accompanied by URI researchers Stephan Grilli and Yang Shen, the expedition's results will help piece together the dramatic sequence of events of how the giant earthquake caused the tsunami.
"We gathered an experienced and diverse team of specialists for this expedition because it was one of the essential ingredients for this challenging goal to find evidence of the sources that created this devastating tsunami," said Moran.
Using geophysical survey tools, operated by the Geological Survey of Canada, and a unique deep-water remotely-operated vehicle, operated by Oceaneering International Inc., the Sumatra Earthquake and Tsunami Offshore Survey (SEATOS) team's mission is the first time that marine scientists have been able to find and film such critical ruptures at such an incredible depth in the Indian Ocean.
The project was filmed for a BBC, Discovery and ProSieben documentary, by award-winning UK production company Darlow Smithson Productions, for broadcast later this year.
The mosaic of photographs the team has released today show a 3 meter high x 8 meter wide section of compacted sediment, only a small part of a huge cliff that was faulted and upthrust during the enormous earthquake and which undoubtedly contributed to the creation of the tsunami.
Don Fisher from Pennsylvania State University said: "The faults are absolutely fresh and it's mind-blowing that we were fortunate enough to find these faults nearly 3 miles down."
The faults, which were found on the outer edge of the continental shelf, provide important evidence for reconstructing the events of December 26. The observed seafloor fault surface is referred to by geologists as striated because it is smoothed by rocks moving against each other as the seafloor is ripped open. Leading the Census of Marine Life biologists, Professor Paul Tyler of the National Oceanography Centre, UK, was surprised to find absolutely no evidence of deep-sea animals at the site during a 14 hour dive with the ROV submersible. This is unprecedented in 25 years of sampling the deep sea."
"This discovery is a critical piece of the puzzle for reconstructing the December 26 tsunami," said Dave Tappin, co-chief scientist of the expedition from the British Geological Survey. Seafloor models that re-create the motions from the measured earthquake energy are crude in terms of their ability to pinpoint exact locations of fault movements at the seabed. The SEATOS expedition is specifically designed to explore the seafloor in search of direct evidence for the critical locations where the seabed moved and generated the giant wave.
The SEATOS team comprises a group of 22 from six countries combining a variety of scientific disciplines, including tsunami model experts, geophysicists, biologists, seismologists, engineers, geologists, and visualization experts. This unique range of experts enabled a fully integrated approach to the expedition.
The data from the expedition will take months to analyze, and the full implications of the results will also take some time to gauge, but the scientific team are all delighted with the mission's success and are confident that their findings will enable them a far greater and detailed understanding of the forces that led to the tsunami. The team will re-convene later this year to draw their conclusions after initial analysis has taken place.
David L. Mearns, director of Blue Water Recoveries Ltd UK, who conceived the expedition and is acting as marine coordinator, says: "Everyone involved in the project is thrilled that we have made such a significant scientific discovery in the relatively short period of time we have been at sea. We had a good scientific plan and our share of good fortune but we owe a great deal to the UK Hydrographic Ship HMS Scott, which surveyed the area earlier this year and provided a roadmap of seabed features that allowed us to zero-in with our high-resolution cameras on the most likely fault areas."
The expedition was filmed on location for Journey To The Heart Of The Tsunami
by Darlow Smithson Productions. Directed by Ed Wardle with Julian Ware as the executive producer, it will be broadcast later this year on BBC ONE, Discovery US, ProSieben in Germany and Discovery International. Also supporting the expedition is the National Science Foundation's ARMADA Project, the Alfred P. Sloan Foundation for the Census of Marine Life Program, Oceaneering Inc, BP Marine Limited and Science Application International Corporation (SAIC).
Image by UK production company Darlow Smithson Productions: Lines of strata snapped 4.4 kilometres below sea-level are evidence of the massive upheaval in the seabed, which lifted one layer above the other (Sumatra Earthquake and Tsunami Offshore Survey)