Attention:
Ocean Bottom Seismometer are part of the Marine Seismic Equipment.
Please note that operations with the Seismic Equipment can only be operated upon request. Request operations with the Seismic Equipoment to AWI-Geophysics and AWI-Logistics in sufficient time prior to the cruise. The operations of the system require experienced scientific staff on board.
Summary
Ocean-bottom seismometers (OBS) are used offshore to explore architecture and structure of the earth's crust and mantle, e.g at passive continental margins, subduction zones oder mid-ocean ridges. The registration of earthquakes (seismology) or of artificial sound waves (seismic refraction) yields conclusions about the properties of the subsurface in different depths.
Contacts
| Role | Name |
|---|---|
| Engineer in Charge | Henning Kirk |
| Data Scientist | Mechita Schmidt-Aursch |
Components
The OBS is assembled on the vessel, provided with an ballast weight (anchor), and lifted with a crane into the water. After being released from the crane, the OBS sinks freely to the sea floor. The maximum deployment depth ranges between 4500 m and 6000 m depending on the type of construction. On the sea floor, the instrument records ground movements (e.g. earthquakes) with a seismometer and change of water pressure (sound) with a hydrophone. For most long-term deployments, the battery-powered OBS remains about one year on the sea floor, the data are recorded by an internal data logger. To stop the measurement, an acoustic signal is sent to the OBS, the anchor weight is released and the OBS rises due to its flotations back to the sea surface. An VHF-transmitter, a flashlight and a flag help to locate the OBS. After recovery of the instrument, the seismic data can be retrieved, processed and interpreted. The AWI operates the marine part of the "German Instrument Pool for Amphibian Seismology" (DEPAS, "Deutscher Geräte-Pool für amphibische Seismologie"). This pool is not only used by AWI, but it is available for all scientist from German universities or research institutes. Please find further information about the instruments, costs, application procedure, etc. on DEPAS homepage.
