摘要：Periodical or temporary change of chlorine content is often observed in the thermal spring in coastal area. This change is generally classified into two types ; one is the periodical change closely related with tide and the other is a continuous change due to the intrusion of sea water caused by the overlifting of thermal water. Asamushi spa is in the coast of Aomori Bay, north end of Honshu island. At present, about 130 thermal springs and wells are distributed along the coast at the mouth of Asamushi River. These springs are chemically "sulfate springs" and had low salinity about eight years ago. Total amount of lifting had increased from 2000 tons/day in 1963 to 3000 tons/day in 1967, and then the content of chlorine ion increased. This increase in the content of chlorine ion was due to the intrusion of sea water caused by the lowering of thermal water pressure as a result of overlifting of thermal water. After August 1967, the total amount of lifting has been limited to below 1440 tons/day, the content of chlorine ion has decreased, and the intrusion of sea water has been reduced.
