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Ocean bottom seismometer: design and test of a measurement system for marine seismology.

Mànuel A, Roset X, Del Rio J, Toma DM, Carreras N, Panahi SS, Garcia-Benadí A, Owen T, Cadena J - Sensors (Basel) (2012)

Bottom Line: Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years.In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface.The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

View Article: PubMed Central - PubMed

Affiliation: SARTI Group, Electronics Department, Universitat Politècnica de Catalunya, UPC.Vilanova i la Geltrú 08800, Spain. antoni.manuel@upc.edu

ABSTRACT
The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal-to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth's crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

No MeSH data available.


Related in: MedlinePlus

Different parts of the OBS preliminary design using glass sphere. Hydrophone detail from Hytech Company.
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f6-sensors-12-03693: Different parts of the OBS preliminary design using glass sphere. Hydrophone detail from Hytech Company.

Mentions: In our first design, the miniDOBS, a polyethylene structure protected a single glass sphere (432 mm diameter and 17.7 kg mass in air). The sphere contained the acquisition electronics, data storage, instrument release and the batteries for the electronic system [11] (Figure 6), thus providing both the buoyancy and the housing. In the new UPC-SARTI design the volume available for electronics and batteries has been considerably increased, and the use of glass spheres as instrument housings has been abandoned to make access to electronics and batteries at sea safer and easier. The design uses two sealed 430 mm diameter glass floats for buoyancy, giving a total available buoyancy of 50 kg. By using a high strength aluminum alloy we have been able to provide two instrument/battery housings of 150 mm internal diameter and 850 mm length each with a housing net weight in water of around 5 kg, giving about 20 kg available payload for the tubes (Figure 2). See Table 2 for details of the system weights and buoyancy calculations.


Ocean bottom seismometer: design and test of a measurement system for marine seismology.

Mànuel A, Roset X, Del Rio J, Toma DM, Carreras N, Panahi SS, Garcia-Benadí A, Owen T, Cadena J - Sensors (Basel) (2012)

Different parts of the OBS preliminary design using glass sphere. Hydrophone detail from Hytech Company.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376630&req=5

f6-sensors-12-03693: Different parts of the OBS preliminary design using glass sphere. Hydrophone detail from Hytech Company.
Mentions: In our first design, the miniDOBS, a polyethylene structure protected a single glass sphere (432 mm diameter and 17.7 kg mass in air). The sphere contained the acquisition electronics, data storage, instrument release and the batteries for the electronic system [11] (Figure 6), thus providing both the buoyancy and the housing. In the new UPC-SARTI design the volume available for electronics and batteries has been considerably increased, and the use of glass spheres as instrument housings has been abandoned to make access to electronics and batteries at sea safer and easier. The design uses two sealed 430 mm diameter glass floats for buoyancy, giving a total available buoyancy of 50 kg. By using a high strength aluminum alloy we have been able to provide two instrument/battery housings of 150 mm internal diameter and 850 mm length each with a housing net weight in water of around 5 kg, giving about 20 kg available payload for the tubes (Figure 2). See Table 2 for details of the system weights and buoyancy calculations.

Bottom Line: Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years.In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface.The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

View Article: PubMed Central - PubMed

Affiliation: SARTI Group, Electronics Department, Universitat Politècnica de Catalunya, UPC.Vilanova i la Geltrú 08800, Spain. antoni.manuel@upc.edu

ABSTRACT
The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal-to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth's crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

No MeSH data available.


Related in: MedlinePlus