ORIENTATION DETERMINING DEVICES FOR BOREHOLE SEIEMIC ACCELERATION INSTALLED TRUE NORTH DIRECTION

摘要

The present invention relates to an orientation determining device which corrects an azimuth of a borehole acceleration seismometer to match a direction of a Y-axis of the borehole acceleration seismometer underground with a true north direction indicated by a compass, comprising: a pipe-shaped casing made from steel, into which the borehole acceleration seismometer is inserted, which protects the borehole acceleration seismometer and guides the borehole acceleration seismometer to the underground to measure earthquake underground; and an azimuth control unit which penetrates the casing, which is connected to the borehole acceleration seismometer, installed in a top end unit of the casing which matches the direction of the Y-axis of the borehole acceleration seismometer with the true north direction of the compass. The present invention is able to precisely measure the azimuth of an earthquake underground by inserting the borehole acceleration seismometer into the casing and burying the casing underground; and matches the direction of the Y-axis of the borehole acceleration seismometer with the true north direction measured by the compass using the azimuth control unit.