Abstract:On March 11,2011, an earthquake of magnitude of 9.0 occurred at Japan. Earth’s free oscillation and teleseismic surface waves caused by this earthquake are recorded by both tiltermeters and seismometers in Yunnan province, China. Some low-frequency signals, which are out of the seismometer’s pass-band, appear in seismic data and cannot be easily interpreted by classic seismological theory. By assuming the trigger signals as translation motion and tilt motion individually, the records of seismometer are simulated by a mathematic seismometer model. We argue that the signal out of the seismometer’s pass-band recorded at Eryuan station, of which the period is 390 s(6.5 min), is the response of seismometer to tilt motion, not to translating motion.
HUANG Qijin,CUI Qinggu,LI Danning. Interpretation to Out of Pass-Band Signals in Broadband Seismometer Data for the Tohoku Earthquake of M9.0 in 2011[J]. jgg, 2019, 39(4): 421-424.