長野県山口村の阿寺断層の土壌ガス中のラドン濃度とγ線スペクトロメトリーの違いについて
1993 年 34 巻 1 号 p. 1-13
詳細
1993 年 34 巻 1 号 p. 1-13
Dipole-dipole electric surveys, radon measurements in soil-gas and γ-ray spectrometry were carried out over the Atera active fault in Yamaguti village, Nagano Prefecture. The method for measuring radon in soil-gas are granular activated carbon in thin cylindrical canister.
The results of radon measurements are correlated with the underground structure by electric survey and the γ-ray spectrometry. The underground structures in a pseudo-profiles of specific resistance contour show faults as a trace connected margin to margin of high specific resistance zones. From similar specific resistance patterns, we could find out several faults.
Several peaks over Atera faults appeared in the profile of radon concentration along survey line A. The highest radon concentration peak corresponds to the one of faults estimated from electrical prospecting.
Comparing the radon concentration to equivalent γ-ray spectrometry shows a poor correlation between radon concentration and γ-ray activities of 214Bi.The poor correlation seems to be due to that γ-ray activities 214Bi is reflecting uranium content of soil particles and radon concentration is radon content of soil-gas in pore space of soil.
