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在地壳岩石中,由于化学的和机械的变化可释放氢气。氢一经释放,就非常容易迁移,有浮力,而且几乎不溶于地下水。一个断层系可充作通道,使氢在它的地表显示附近的土壤气中聚集。因环境大气中缺乏氢,它在土壤气中以高水平出现,可作为断层测绘的手段。为了评价这一手段,我们调查了11个不同断层,在每一断层附近采集了2至21个土壤气样,测量了氢和甲烷的浓度。其中,4个断层的活动方向是正向的(美国西部、希腊),5个是平移或倾滑的(加利福尼亚,科罗拉多,日本),两个是逆向的(加利福尼亚)。在其中的4个断层(希伯津湖、黄石、山崎、巴勒山)上,最高氢浓度范围从80ppm到70％,甲烷从300ppm到5％。除了一个取自爱达荷,鲍惹奇山的样品有2％甲烷外,所有其它测点的两种气体只有背景水平。据此初步研究,尚难了解氢的出现与断层位置是唯一相关,还是出于偶然。产生和聚集氢所需要的条件也不清楚。过量的氢完全可能在不同地质情况下由不同机理产生。例如,局部岩石里有氢氧化亚铁,它可起化学反应产生氢。为了阐明氢和构造断层活动之间的关系需要进行广泛的、详细的研究。
In crustal rocks, hydrogen can be released due to chemical and mechanical changes. Once released, hydrogen is very migratory, buoyant and practically insoluble in groundwater. A fault system can be used as a channel to accumulate hydrogen in the soil gas near its surface display. Due to the lack of hydrogen in the ambient atmosphere, it appears at a high level in the soil gas and can be used as a means of fault mapping. To evaluate this approach, we surveyed 11 different faults, collected 2 to 21 soil samples near each fault, and measured hydrogen and methane concentrations. Of these, the four faults have a positive direction of motion (western United States, Greece), five are translating or tilting (California, Colorado, Japan) and two are backward (California). The highest hydrogen concentration ranges from 80 ppm to 70% on four of these faults (Hibino, Yellowstone, Yamazaki, Balleh) and 300 ppm to 5% for methane. Except for 2% methane from a sample taken from Idaho and Bowjacan, both gases at all other stations have a background level only. Based on this preliminary study, it is difficult to understand whether the occurrence of hydrogen and the location of the fault are the only correlations, or by chance. The conditions required for the production and accumulation of hydrogen are also not clear. It is entirely possible that excess hydrogen may be produced by different mechanisms under different geological conditions. For example, local rocks contain ferrous hydroxide, which can react chemically to produce hydrogen. Extensive and detailed studies are needed to elucidate the relationship between hydrogen and tectonic activity.