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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

Measurement system block diagram.
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f21-sensors-12-03693: Measurement system block diagram.

Mentions: In an experiment, we placed the crystal oscillator inside a VC4060 environmental chamber where temperature is controlled. In order to measure the temperature close to the Seascan module, a temperature sensor is placed beside it and 4-wire measurements of the sensor are carried out. The available version of the VC4060 chamber does not allow humidity control below 10 °C inside the chamber. A humidity sensor is used to measure the humidity near the crystal. A HP34970A datalogger is used to measure the temperature and an Agilent 53132A universal counter with a temperature stability of 2.5 × 10−9 was used to measure the Seascan output frequency (125Hz). In order to obtain an improved resolution, frequency is measured within a time gate of 1 s. The overall measurement system is controlled by a PC through a GPIB bus, where software in LabVIEW 8.5 takes measurements every 20 seconds. Figure 21 shows the measurement system in the lab:


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)

Measurement system block diagram.
© Copyright Policy
Related In: Results  -  Collection

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

f21-sensors-12-03693: Measurement system block diagram.
Mentions: In an experiment, we placed the crystal oscillator inside a VC4060 environmental chamber where temperature is controlled. In order to measure the temperature close to the Seascan module, a temperature sensor is placed beside it and 4-wire measurements of the sensor are carried out. The available version of the VC4060 chamber does not allow humidity control below 10 °C inside the chamber. A humidity sensor is used to measure the humidity near the crystal. A HP34970A datalogger is used to measure the temperature and an Agilent 53132A universal counter with a temperature stability of 2.5 × 10−9 was used to measure the Seascan output frequency (125Hz). In order to obtain an improved resolution, frequency is measured within a time gate of 1 s. The overall measurement system is controlled by a PC through a GPIB bus, where software in LabVIEW 8.5 takes measurements every 20 seconds. Figure 21 shows the measurement system in the lab:

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