11:00 AM - 11:15 AM
[J07-2-03] Laboratory experiments for evaluating long-term characteristics of pressure sensors used for seafloor pressure monitoring
Lots of precise pressure sensors are currently used for seafloor pressure monitoring to detect tectonic movements. Although the pressure sensors show high resolution and good stability, long-term fluctuations have been observed in the sensors' outputs during seafloor measurements, and their magnitudes are at the same level as the pressure change caused by tectonic movements of interest. Evaluating and compensating the effects of the long-term characteristics of the sensors are indispensable to improve the accuracy of the seafloor pressure measurement over years.
In this study, the long-term characteristics of quartz Bourdon-tube pressure sensors have been evaluated at the pressure calibration laboratory in National Metrology Institute of Japan. The pressure of 100 MPa has been applied to the test pressure sensors for a long period of time, during which calibrations are repeated at 100 MPa using a pressure balance as the standard. The calibration results, the deviation of the sensor's output from the standard value, at 100 MPa rapidly changed immediately after the pressure application, and then, the change rate became small and almost constant as time proceeded. This long-term behavior was quite different from that obtained for the same kind of sensors used under normal, atmospheric pressure conditions. The changes in the sensor's outputs at atmospheric pressure, intermittently obtained during the pressure application, showed that the observed long-term behavior at 100 MPa can mainly be attributed to the zero drift of the sensor.
On the basis of the results from laboratory experiments for over two years, measures are proposed and discussed to appropriately compensate the long-term characteristics of pressure sensors used for seafloor pressure monitoring.
In this study, the long-term characteristics of quartz Bourdon-tube pressure sensors have been evaluated at the pressure calibration laboratory in National Metrology Institute of Japan. The pressure of 100 MPa has been applied to the test pressure sensors for a long period of time, during which calibrations are repeated at 100 MPa using a pressure balance as the standard. The calibration results, the deviation of the sensor's output from the standard value, at 100 MPa rapidly changed immediately after the pressure application, and then, the change rate became small and almost constant as time proceeded. This long-term behavior was quite different from that obtained for the same kind of sensors used under normal, atmospheric pressure conditions. The changes in the sensor's outputs at atmospheric pressure, intermittently obtained during the pressure application, showed that the observed long-term behavior at 100 MPa can mainly be attributed to the zero drift of the sensor.
On the basis of the results from laboratory experiments for over two years, measures are proposed and discussed to appropriately compensate the long-term characteristics of pressure sensors used for seafloor pressure monitoring.