Field surveys were carried out at the Kakkonda geothermal field, where the location of the neutral hydrothermal reservoir has been identified, to investigate the shadow effect of the pH distribution in the actual geothermal development field. Methods using the electrical conductivity (EC)–pH relation and catchment area were employed, and the validity of the data was evaluated to select the most appropriate data for verifying the shadow effect. Results consistent with the concept of a shadow effect were obtained because acidic surface waters strongly affected by volcanic gases were not distributed above the neutral hydrothermal reservoir.

中文翻译：

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日本Kakkonda地热田周围地表水pH分布的阴影效应

在Kakkonda地热田进行了实地调查，确定了中性热液储层的位置，以调查实际地热开发田中pH分布的阴影效应。采用了利用电导率（EC）-pH关系和集水面积的方法，并对数据的有效性进行了评估，以选择最合适的数据来验证阴影效果。获得的结果与阴影效应的概念一致，因为受火山气体强烈影响的酸性地表水没有分布在中性热液储层上方。