FluSO - The Fluid Flow Seabed Observatory; a first demonstration mission in a seismically active region in Greece
Abstract
Earthquakes are the most common trigger for submarine landslides. Ground movement due to earthquakes can change the pore pressure of marine sediments either instantaneously or through seismic loading, and may therefore destabilise submarine slopes. In order to test the hypothesis that earthquakes induce fluid migration in the shallow subsurface the National Oceanography Centre, Southampton (NOCS) and IFM-Geomar designed the FluSO observatory as part of a demonstration mission within the EuroSITES project. The main instrumentations on the observatory are a 3-component seismometer, a water flow meter, a data logger, and battery packs housed in a trawl-resistant bottom mount. The instrument configuration can be easily changed and additional instruments, e.g. geochemical sensors, added; and with sufficient power of between 8-12 months making it an autonomous multi-purpose tool for long-term seabed measurements. The instrument was deployed on a pockmark outside Patras Harbour, Eastern Ionian Sea, in Greece. Both, the seismicity and the fluid/water escape within the active pockmark, were measured directly, and later on merged with information from a regional earthquake catalogue. Preliminary examination of the data covering two 4-months periods in summer 2009 and spring 2010, during which both, the seismometer and the flow meter, worked without any problems, suggests that for many earthquakes ground shaking triggered an almost instantaneous response of fluid flow from the pockmark. However, during the end of the summer deployment for a period of almost 3 weeks the flow meter showed almost continuous activity of the pockmark indicating that also other geological factors except earthquakes may induce discharge.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMOS51D..03H
- Keywords:
-
- 3050 MARINE GEOLOGY AND GEOPHYSICS / Ocean observatories and experiments;
- 3094 MARINE GEOLOGY AND GEOPHYSICS / Instruments and techniques;
- 7212 SEISMOLOGY / Earthquake ground motions and engineering seismology