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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

Strength analyses on the cylinder top at 6,000 m of depth.
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f7-sensors-12-03693: Strength analyses on the cylinder top at 6,000 m of depth.

Mentions: Buoyancy and drag calculations indicate a rise and fall rate of around 1 m/s, which agrees with initial observations. In Figure 2 is shown the UPC-SARTI’s OBS mechanical system designed by Carrack Measurement Technology. The pressure cylinders were designed using Finite Element Modeling (Unigraphics 2.0, by Siemens PLM Software) to give a safety factor of 1.4 at 6,000 m (Figure 7). The tubes were bored from solid bar and then heat treated T6 to give maximum strength before finish machining (T6 Heat Treatment is a specific heat treatment process which may be applied to aluminum/copper/silicon alloys to increase the strength of the alloy by as much as 30). After hard (sulfuric acid) anodizing, hydraulic tests were carried out at the Pressure Test facility at the National Oceanography Center in Southampton (UK) to the equivalent of 6,000 m depth in seawater, including a soak test at full pressure for 24 h. No leaks were detected. See Table 3 for the tube specifications.


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)

Strength analyses on the cylinder top at 6,000 m of depth.
© Copyright Policy
Related In: Results  -  Collection

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

f7-sensors-12-03693: Strength analyses on the cylinder top at 6,000 m of depth.
Mentions: Buoyancy and drag calculations indicate a rise and fall rate of around 1 m/s, which agrees with initial observations. In Figure 2 is shown the UPC-SARTI’s OBS mechanical system designed by Carrack Measurement Technology. The pressure cylinders were designed using Finite Element Modeling (Unigraphics 2.0, by Siemens PLM Software) to give a safety factor of 1.4 at 6,000 m (Figure 7). The tubes were bored from solid bar and then heat treated T6 to give maximum strength before finish machining (T6 Heat Treatment is a specific heat treatment process which may be applied to aluminum/copper/silicon alloys to increase the strength of the alloy by as much as 30). After hard (sulfuric acid) anodizing, hydraulic tests were carried out at the Pressure Test facility at the National Oceanography Center in Southampton (UK) to the equivalent of 6,000 m depth in seawater, including a soak test at full pressure for 24 h. No leaks were detected. See Table 3 for the tube specifications.

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