First Installation of an Optical Ocean-Bottom Seismometer, Cabled Offshore Les Saintes, Lesser Antilles
Year: 2024
Type: article
Abstract: The detection and analysis of offshore seismic processes worldwide often require the use of ocean-bottom seismometers (OBSs). However, most OBS deployments are done with stand-alone stations, with data recovery delayed by months. On the other hand, electrically cabled OBS, which allows for real-time monitoring, remains exceptional due to the high cost of manufacturing, installation, and maintenance. Here, we present a new perspective for cabled array of OBSs, using purely optical seismometers, plugged at the end of long fiber-optic cables, aimed at reducing their cost for observatories requesting real-time data. The optical seismometer was developed in the last decade by the École Supérieure d’Électronique de l’Ouest, based on the Fabry–Perot interferometer, tracking at high resolution the displacement of the mobile mass of a mechanical geophone (no electronics nor feedback). A prototype was successfully installed at the top of La Soufrière volcano of Guadeloupe in 2019. We replicated this sensor and installed it 5 km offshore Les Saintes islands, at 43 m depth (Guadeloupe, Lesser Antilles) to characterize the swarm-type activity persistent after the 2004 M 6.3 earthquake (Interreg Caraïbe PREST project). The installation cruise, FIBROSAINTES, was supported by the Flotte Océanographique Française. A plow designed by GEOAZUR carried the cable and was pulled on the seafloor by the vessel ANTEA. The landing cable was connected to the interrogator, with a real-time telemetry to the Institut du Physique du Globe de Paris/Observatoire Volcanologique et Sismologique de Guadeloupe. The OBS has been qualified with local land-based velocity broad band stations. The analysis of local earthquake swarms suggests transient creep on the major normal faults. This successful installation opens promising perspectives for real-time monitoring in on-land or offshore sites, presenting harsh environmental conditions, in which commercial, electrical seismic sensors are difficult and/or costly to install and maintain.
Source: Seismological Research Letters
DOI: 10.1785/0220240037
Authors: Pascal Bernard, Yann Hello, Guy Plantier, Philippe Menard, Guillaume Savaton, Sébastien Bonnieux, Marie-Paule Bouin, Alexandre Nercessian, Mathieu Feuilloy, Romain Feron, Claudio Satriano, Sébastien Deroussi, Roberto Moretti, Anthony Sladen, Jean-Claude Roca, Mathieu Camusat, Judicaël Rivier, Bastien Gaucher, Frédérick Boudin, Thierry Kitou, Tristan Didier, Jean-Bernard De Chaballier, Valérie Clouard
Institutions: Géoazur, École Supérieure d'Électronique de l'Ouest, Laboratoire d'Acoustique de l'Université du Mans, University of Campania "Luigi Vanvitelli", Observatoire Océanologique de Banyuls-sur-Mer, Centre National de la Recherche Scientifique, Station Biologique de Roscoff, École Normale Supérieure - PSL, Observatoire Midi-Pyrénées
Language: English
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4403837106