Earth Planets Space, Vol. 64 (No. 4), pp. e5-e8, 2012
Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan
(Received July 11, 2011; Revised February 5, 2012; Accepted February 15, 2012; Online published April 16, 2012)
The present paper proposes a technique for
low-frequency and trend compensation of broadband seismograms,
which involves frequency-band broadening using digital filtering
and background-trend compensation based on a Heaviside-type tilt
signal estimated using a stochastic trend model. Applying this
method to the east-west component of broadband seismograms, recorded
using VSE355G3 broadband seismometers at the KSN site of F-net for
the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0), allowed a sharpened velocity waveform to be obtained and the static
displacement associated with the earthquake to be determined.
Key words: Broadband seismograms, strong motion, band broadening, digital compensation filter, background trend.