Skip to Main content Skip to Navigation
Journal articles

Microevents produced by gas migration and expulsion at the seabed: A study based on sea bottom recordings from the Sea of Marmara

Abstract : Different types of 4-component ocean bottom seismometers (OBS) were deployed for variable durations ranging from 1 week to about 4 months in 2007, over soft sediments covering the seafloor of the Tekirdag Basin (western part of the Sea of Marmara, Turkey). Non-seismic microevents were recorded by the geophones, but generally not by the hydrophones, except when the hydrophone is located less than a few tens of centimetres above the seafloor. The microevents are characterized by short durations of less than 0.8 s, by frequencies ranging between 4 and 30 Hz, and by highly variable amplitudes. In addition, no correlation between OBSs was observed, except for two OBSs, located 10 m apart. Interestingly, a swarm of ∼400 very similar microevents (based on principal component analysis) was recorded in less than one day by an OBS located in the close vicinity of an active, gas-prone fault cutting through the upper sedimentary layers. The presence of gas in superficial sediments, together with analogies with laboratory experiments, suggest that gas migration followed by the collapse of fluid-filled cavities or conduits could be the source of the observed microevents. This work shows that OBSs may provide valuable information to improve our understanding of natural degassing processes from the seafloor.
Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-00714611
Contributor : Adminhal Univbrestbu <>
Submitted on : Thursday, January 10, 2013 - 9:53:52 AM
Last modification on : Wednesday, October 14, 2020 - 3:49:31 AM
Long-term archiving on: : Friday, March 31, 2017 - 10:17:18 AM

File

GJI-Tary-2012.pdf
Files produced by the author(s)

Identifiers

Citation

J.-B. Tary, L. Geli, Claude Guennou, P Henry, Nabil Sultan, et al.. Microevents produced by gas migration and expulsion at the seabed: A study based on sea bottom recordings from the Sea of Marmara. Geophysical Journal International, Oxford University Press (OUP), 2012, 190 (2), pp.993-1007. ⟨10.1111/j.1365-246X.2012.05533.x⟩. ⟨insu-00714611⟩

Share

Metrics

Record views

835

Files downloads

1023