Systematization of Karst Processes in Japan

1993-1997年，在日本的7个观测站（旭川、安熊、秩父、秋吉台、四国小野原、龙门和南大东）测定了石灰岩片的溶解失重，以阐明岩溶过程的区域性和年际波动性。这项研究在1995年、1996年和1997年得到了补助金的支持。结果表明：（1）在本州，日本南部地区的溶解速率较高。然而，南大渡是一个例外，因为在夏季存在干燥期。(2)各站A_3、B_2土层的溶解速率比1.5m高空高2-3倍。这意味着“覆盖岩溶过程”比“裸露岩溶过程”高2-3倍。(3)在5年的观测中，1993年为多雨年，溶解速率最大，1994年为干热年，溶解速率最小，几乎所有观测点都出现了这种现象。(4)5年的石灰岩溶解速率与水分盈余、WS-水分亏缺、WD的相关系数在距地面1.5m的空中最高。(5)土壤A_3层和B_2层石灰石的溶解速率与年降水量的相关系数最高。(6)在土壤中，高CO_2含量已被观察到在温暖的时期的年份。20 mm降雨后3-4天，土壤CO_2含量均表现出极高值。认为这些含水量和高CO_2值导致了强烈的岩溶作用。总之，如上述（1）-（6）所述，日本岩溶作用的系统性已经清楚。

Weight loss of limestone tablets by solution has been measured in order to clarify the regionality and year to year fluctuation of the karst processes at 7 observation stations (Asahikawa, abukuma, Chichibu, Akiyoshidai, Sikoku-onogahara, Ryugado and Minamidaito) in Japan during 1993-1997. This study was supported by Grant-in-aid in 1995,1996, and 1997. The results obtained are as follows :(1) In Honshu, solution rates are higher in the southern parts of Japan. However, Minamidaito is an exception, because of existence of dry period during summer.(2) In each station, the solution rates in A_3 and B_2 horizon of soil layrs are 2-3 times higher than 1.5m in the air above the ground. This means that the "covered karst processes" are 2-3 times higher than the "bare karst processes".(3) During the 5 years measured, the highest solution rates were occurred in 1993, a wet year and on the contrary, the smallest solution rates were occurred in 1994, a dry and hot year, which appeared at the almost all observation points.(4) Correlation coefficient between (solution rate of limestone) and (water surplus, WS-water deficit, WD) for the 5 years is the highest in the air, 1.5m above the ground.(5) Correlation coefficient between (solution rate of limestone in A_3 horizon and B_2 horizon of soils) and (annual precipitation) is the highest for the 5 years measured.(6) In the soils, high CO_2 contents have been observed during the warmer period of the years. After 3-4 days of 20mm rainfall, CO_2 contents in the soils show extremely high value. It is considered that these water contents and high CO_2 values resulted in karstification strongly.In conclusion, the systematization of karst processes in Japan has been made clear as written in (1)-(6) above.