An international team of scientists has found evidence suggesting that the dehydration of minerals deep below the ocean floor influenced the severity of the Sumatra earthquake, which took place on 26 December 2004.
The earthquake, measuring magnitude 9.2, and the subsequent tsunami, devastated coastal communities of the Indian Ocean killing over 250,000 people.
Research into the earthquake was conducted during a scientific ocean drilling expedition to the region in 2016, as part of the International Ocean 福利着片y Program (IODP), led by scientists from the University and Colorado School of Mines.
During the expedition, for the first time researchers sampled sediments and rocks from the oceanic tectonic plate which feeds the Sumatra subduction zone.聽A subduction zone is an area where two of the Earth鈥檚 tectonic plates converge, one sliding beneath the other, generating the largest earthquakes on Earth, many with destructive tsunamis.
, expedition co-leader and professor of Tectonics at the University, said:
The 2004 Indian Ocean tsunami was triggered by an unusually strong earthquake with an extensive rupture area. We wanted to find out what caused such a large earthquake and tsunami and what this might mean for other regions with similar geological properties.
The researchers found that the sediments on the ocean floor eroded from the Himalayan mountain range and Tibetan Plateau and transported thousands of kilometres by rivers on land and in the ocean. The sediments are thick enough to reach high temperatures and drive the dehydration process to completion before reaching the subduction zone. This creates unusually strong material, allowing earthquake slip at the subduction fault surface to shallower depths and over a larger fault area 鈥� causing the exceptionally strong earthquake seen in 2004.
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