Germany
Ocean Bottom Hydrophone/Ocean Bottom Seismometer
Operator: GEOMAR
Further Information
Ocean Bottom Hydrophones (OBH) and Seismometers (OBS) have been developed and operated by the MARINE GEODYNAMICS Group since 1991.
Since then, three types of instrument carriers have been developed. Modifications of data loggers and modularity of system components allow operating a variety of sensors used for active and passive seismic experiments, as well as for Tsunami detection purposes.
The mechanical construction of the OBH/S is available from the company "Umwelt- und Meerestechnik GmbH, KUM" (www.kum-kiel.de). Today, all metal parts of the system carrier as well as the pressure tubes of the acoustic release and data logger are made from Titanium. All buoyant bodies consist of syntactic foam, which has proven to be highly reliable even under harsh conditions. All components of the systems are designed for operation in 6000 m water depth. A few of OBS are rated for, 8000 m.
Own recorder development and the new 6D6 logger by KUM are available for active seismic or passive long-term monitoring projects with the lowest power consumption.
Seismic sources
Operator: GEOMAR
Further Information
At GEOMAR two types of airguns developed by the company Sercel are used to get seismic data, the G.GUN and the GI GUN.
The GI GUN is a pneumatic seismic source, made up of two independent air guns within the same casing, used to control and reduce bubble oscillations. The first air gun is called the generator, as it generates the primary pulse and creates the bubbles. The second one is called the Injector, as it injects air inside the bubble. Each gun has its own reservoir, its own shuttle, its own set of exhaust ports, and its own solenoid valve. GI GUN volumes can be varied from 105/250 cinch to 48/48 cinch volume. A common hydrophone provides both the time break and the shape of the near field signal. This gun phone is located inside the bubble and responds to the actual air blast of the GI GUN, without being affected by the neighbouring guns.
G GUNS are standard airguns with a single air chamber. For maximum energy output and signal consistency, G Guns are operated in clusters of the identical guns each. The GEOMAR G GUN array consists of two strings of two 1040 cinch (2* 520 cinch), and one 640 cinch (2* 320 cinch) clusters with a total volume of 5440 cinch per shot. Each gun is equipped with a shot sensor delivering the exact fire time for array tuning.
Both gun systems are operated with a Long Shot control system (Teledyne Real Time Systems) enabling individual tuning of each gun. Triggers are provided by a GPS time base.
Deployment of single or double GI GUNS can be done from any vessel of opportunity. G GUN deployment requires a U-rail deployment system provided by the survey vessel.
Netherlands
6 Channel Streamer Winch
Operator: NIOZ Further Information Oil filled hydrophone arrays for detecting reflections. |
Seismic Compressor Container
Operator: NIOZ Further Information Its goal is to produce high pressure air supply for the air guns. Two electrical compressors including accumulator tank and distribution system for airgun-array. |
United Kingdom
Air Gun
Operator: NOC Further Information Further Information to be supplied |
Seismic Compressor Container
Operator: NOC Further Information Further information to be supplied. |