Nov 04, 2009

Project to deploy seismic monitoring system

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Researchers partially funded by the European Union will be using state-of-the-art technology to look into building underwater observatories that will monitor underwater seismic activity in the eastern Mediterranean. As populations grow in the region, scientists have been developing ways of looking for signs of earthquakes before they happen.

The work is part of the ‘European Seas Observatory Network’ (ESONET) project, which was launched in March 2007 with EUR 7 million in funding from the Sixth Framework Programme (FP6). ESONET’s main objective is the creation of an organisation capable of implementing, operating and maintaining a network of ocean observatories in deep waters around Europe from the Arctic Ocean to the Black Sea. These observatories are to be connected to the shore with data and power links via fibre optic cables. Constant monitoring has the goal of allowing resolution of quasi-instantaneous hazardous events such as slides, earthquakes, tsunamis and benthic storms.

One of the sites in the ESONET project is in the Sea of Marmara, which connects the Black Sea to the Mediterranean south of Istanbul, Turkey. The size and location of the Sea of Marmara means that not only seismic activity, but also water quality need to be monitored. It is also an ideal area for ESONET to conduct demonstrations and testing.

During November and December 2009, ESONET researchers, led by Louis Geli of the French Research Institute for Exploitation of the Sea (IFREMER) and Pierre Henry of France’s National Centre for Scientific Research (CNRS) will be aboard the oceanographic vessel Le Suroît. The activity has two objectives: to determine a possible link between seismicity and fluid expulsion along the North-Anatolian Fault and to conduct preliminary studies for the introduction of permanent underwater observatories. The Bubbles OBservatory module (BOB), a system of surveillance of gas bubble expulsion on the seabed, will be deployed.

Along active undersea faults, gas, mainly in the form of methane, seeps from the bottom sediment. The North-Anatolian Fault, which runs through the Sea of Marmara, has produced 12 earthquakes since 1942, including the Izmit earthquake of 1999 which killed over 17,000 people. The segment south of Istanbul, say scientists, is the only one along the fault’s 1,600 kilometre length which has not ruptured in several centuries. It is also the only part of the fault which does not have gas seepage. This, they continue, means that during the next earthquake, the gas trapped in the sediment will be expelled. The question to be answered is whether gas release priming will occur just before a rupture.

Underwater observatories are comparable to laboratories placed on the ocean floor. Equipped with a set of measuring tools, they are capable of recording different types of data to help understand oceanic phenomena. The technology of deep-water scientific cabled observatories is still in its beginning stages, and the ESONET project will facilitate the development and implementation of permanent observation capabilities. Observatories will provide information on global change, warnings of natural hazards and a basis for sustainable management of the European Seas. The undersea laboratories will be a segment of the Global Monitoring for Environment and Security (GMES) and Global Earth Observation System of Systems (GEOSS) initiatives.

Work at other ESONET sites currently includes the observation of hydrothermal flows and volcanism in the Azores and slope instability and sedimentary and biogeochemical flows for the Ligurian Sea.

For more information on ESONET, please click

For more information on French Research Institute for Exploitation of the Sea (IFREMER), please click

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