Detectability of crustal deformation by using ocean bottom pressure gauges deployed to DONET system

One of the observation targets of Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET), which deployed in the Nankai trough, is the monitoring of the crustal deformations caused by the ordinary earthquakes, low frequency earthquake and the slow slip event. Although it is possible that the vertical deformations of the crustal deformations are measured by using the quarts type pressure gauge on the oceanfloor, the pressure changes recorded by those sensors include several kinds of the signals such as ocean surface changes and sensor drift other than crustal deformations. We estimated the vertical component of the crustal deformation from pressure changes by subtracting the average pressure changes taking into the adjacent stations, it is possible that we detect more than 1.1 [cm] vertical movements of the crustal deformations from those changes.