Characteristics of bottom pressure sensors of the dense ocean-floor network system for earthquakes and tsunamis

Abstract

DONET, i.e., the dense ocean-floor network system for earthquakes and tsunamis has started in operation in the Nankai Trough in the early of 2010. DONET consists of various sensors such as broadband seismometer, seismic accelerometer, tsunami meter, etc. This paper focuses on bottom pressure sensors being used as tsunami meters. Long-term sensors' stabilities have been evaluated before/after the deployment into the deep-sea, and tide assimilation has been carried out in order for detection of crustal deformation with high accuracy. As a result, sensor drift of ~20 hPa per month could be measured in the laboratory experiment, and it may continue after the deployment. This paper also reports that the tsunami from the Tohoku-oki earthquake on 11 March 2011 could be detected by DONET with those peak-to-peak amplitudes of 20~40 cm.