Characteristics of the stress and barometric seismograms produced by the 2011 Tohoku Earthquake (M9.0) and vertical movements derived from barometric seismograms

Abstract

High-quality data concerning the Tohoku Earthquake (M9.0) on March 11, 2011, were obtained from the deep borehole observation network (maximum depth of 1030 m; epicentral distance of approximately 600 km) of the Tono Research Institute of Earthquake Science. In addition to data acquired via seismometers, stress meters, and strain meters, barometric seismograms were recorded by several barometers that are usually used for weather observations. We examined the characteristics of barometric and stress seismograms and compared them to the data obtained using broadband seismometers, finding a shared feature: large amplitudes and long-period waveforms began with the arrival of surface waves. We also investigated the relationship between vertical movements observed with GPS and barometric variations and discovered that the barometric variations were related to the differential of vertical movements, while the vertical movements corresponded to the integral of barometric variations. All these results demonstrate that vertical movements at observation points can be computed from the barometric variations observed at those points.