Variation of Radioactive Atmospheric Ion Concentration
Associated With Large Earthquakes
発表者
Hattori, K, Wadatsumi, K, Furuya, R, Yada, N, Yamamoto,
I, Ninagawa, K, Ideta, Y, Nishihashi, M
発表日時
12月19日10時50分〜11時05分(現地時間)
会場
The Moscone West
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Abstract
Tributsch (1978) pointed out the possibility
of anomalous atmospheric ion changes preceding large earthquakes.
Large and sudden changes in atmospheric ion concentration
(AIC) have been observed at Kobe 8 days before the 1995
Kobe Earthquake (M7.3) in Japan (Satsutani, 1996). In order
to evaluate the possibility of the short-term prediction
by monitoring AIC, we have started the continuous measurement
of AIC at Okayama, Japan, since 1998. Possible changes of
positive large AIC have been observed prior to the 2000
western Tottori (M7.3) and 2001 Geiyo (M6.7) Earthquakes
which occurred near the Okayama station. To clarify the
spatial and temporal variation of AIC, we have been established
the AIC measurement network since 2004 using Gerdien condensers
we developed. From July 2008, a most part of these sensors
has been replaced by new devices (COM SYSTEM, INC., COM-3700)
for more stable observation. There are 10 stations in operation
now. Meanwhile, in order to investigate the generation mechanism
of atmospheric ions associated with earthquakes, we have
measured the radiation of collected aerosols using three
methods: PSL method, Ge-LEPS method, and radioactive half-life
method with GM counter. We also monitor the Radon concentration
with AIC simultaneously at three stations. Recently we observed
the anomalous changes of
AIC prior to the 2008 Iwate-Miyagi Nairiku Earthquake (M7.2).
The results will be shown in the presentation.
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