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<div>Sharp decrease of entropy production rate (EPR) is observed in the
process of the Great East Japan Earthquake (GEJE) of magnitude 9. The
EPR, a thermodynamic property of a fluctuating system, is calculated
from the binarized velocity deviation of the background vibration. The
background signal of the GEJE process includes a micron / second scale
velocity signal that exhibits the dominant frequency of 1 Hz to 10 Hz in
the Fourier amplitude spectrum. Paying attention to the negative
curvature of the spectrum in the frequency range, we define alpha-tremor
as the degree of negative curvature of the spectrum in the frequency
range from 2.97 Hz to 9.80 Hz. The positive and non-positive
alpha-tremor represent an arbitral weak velocity signal. The
alpha-tremor has been shown to be invariant in binarizing the velocity
fluctuation signal. Therefore, the binarized velocity and the raw
velocity signal are equivalent as long as the background vibration is
considered as the alpha-tremor fluctuation. The binarized velocity
signal is divided into sets with 10 data, and the vibration state is
defined for each set considering the degree of dispersion of the 10
signals. Then the transition rate from one state to the other is
calculated, followed by the EPR calculation. The EPR is evaluated for
ground vibration data acquired every 0.05 seconds from 2008 to 2014 at
the seismic station 188 km away from the epicenter of GEJE which
occurred in 2011.</div>