Fig. 2From: Precise tilt measurement by seafloor borehole tiltmeters at the Nankai Trough subduction zoneDepth and installation conditions for the two tiltmeters. Schematic illustration of tiltmeters in boreholes. The electrolytic tiltmeter was installed 6 m below the seafloor and surrounded by sand. The pendulum tiltmeter was installed 19 m below the seafloor and cemented with mortar to couple the tiltmeter with the surrounding mediaBack to article page