Installing a Hydroacoustic Station at the Crozet Islands

• Main Authors: Ray, Terrill W, Grenard, Patrick
• Other Authors: DEPARTMENT OF STATE WASHINGTON DC
• Format: Text
• Language: English
• Published: 2012
• Subjects: Acoustics; *UNDERWATER ACOUSTICS; HYDROPHONES; MONITORING; NETWORKS; OCEANS; STATIONS; HYDROACOUSTIC STATION; Fernandez; Indian; Triplets; Crozet Islands
• Online Access: http://www.dtic.mil/docs/citations/ADA569872; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA569872

The CTBT IMS has the objective of providing global monitoring to detect nuclear explosions in any environment. The eleven stations comprising the hydroacoustic network principally look for explosions in the water column of the Earth s oceans and above the ocean surface. The efficient transmission of acoustic energy through the SOFAR channel allows a small number of stations to effectively cover most of the world s oceans. Six of the IMS stations are hydrophone stations, where moored hydrophones float in the SOFAR channel suspended above the seafloor on vertical risers suspended by submerged buoys. Such stations require major installation efforts because of the remote sites where they are deployed and the challenges of deep undersea cable laying operations. Five of the six hydrophone stations in the IMS have been certified and four are currently part of IDC operations. One of the two stations not in operation is HA03 in Juan Fernandez, Chile, which is awaiting repair after having been destroyed by a Tsunami in 2010. The other station, designated HA04 and located on Ile de la Possession in the Crozet archipelago in the southwestern Indian Ocean, will be re-established after having suffered damages during repair and successive anchoring incidents. The re-establishment requires removal of the previous equipment and reinstallation of an entirely new shore component, trunk cables and hydrophone triplets. Given the particularly harsh conditions that prevail in the area, the successful installation of a sustainable certified International Monitoring System hydrophone station at Crozet requires careful consideration of the particular environment in the area. Published in the Proceedings of the 2012 Monitoring Research Review - Ground-Based Nuclear Explosion Monitoring Technologies, 18-20 September 2012, Albuquerque, NM. Volume II. Sponsored by the Air Force Research Laboratory (AFRL) and the National Nuclear Security Administration (NNSA).