Characterization of the boiling sand and water liquefied by the Western Tottori Earthquake, 2000

Abstract

An earthquake (M=7.3) hit the western part of Tottori Prefecture on the 6^th October on 13 : 30, 2000. Liquefaction occurred on reclaimed lands in Tottori and Shimane Prefectures. A large amount of the boiling sands and water are found at Takenouchi industrial area and at Nishikihama. The character of the boiling sand and water were chemically, physically and mineralogically studied. High NaCl contents in the boiling sand and water correspond to pH 6-7 and high EC. The boiling sand consisting mainly of silicate minerals and feldspars, with grain size of approximately 30-40 μm at Takenouchi and 130-178 μm at Nishikihama were examined. After ethylene glycol treatment, swelling smectite and halloysite identified by XRD method. In the boiling sand crater, coccus and bacillus bacteria inhabited in yellowish-brown biofilms at Takenouchi. The microorganisms in the biofilms are capable of concentrating of heavy metals in the boiling sand crater.