地热温泉井与土壤逸出气中痕量氢的特征及差异性分析

地下氢气是反映地壳应力应变灵敏的气体地球化学组分,逸出气痕量氢是一项新型的气体地球化学观测手段,在我国很多省份进行了试观测。本项目实现逸出氢在高温自流井和土壤中的连续、并行观测,重点对痕量氢的动态变化特征进行分析,研究其差异性,并讨论温泉地热井逸出氢高值突跳异常的成因。经频谱分析发现地热温泉井中的逸出氢与土壤中逸出氢都存在日变,前者的浓度与井水位、水温有关,与地表环境因素无关,而后者主要受地表环境因素影响。庐江地震台地热温泉井逸出氢浓度的高值突跳来源于深部水体上涌过程中的气泡携带,为非震兆异常。

Characteristics and Difference of Trace Hydrogen in EscapeGas from Geothermal Hot Spring Well and Soil

Hydrogen is known as one of the most useful types of gas for detecting fault activity. The hydrogen concentration is susceptible to temperature, air pressure, and other factors because of its sensitivity. This study made the first attempt at continuous hydrogen observation in the geothermal hot spring well and the soil simultaneously. The differences in dynamic variation characteristics of trace hydrogen escaped from the geothermal hot spring well and the soil was analyzed, and the causes of hydrogen anomalies in geothermal hot spring well were discussed. Spectrum analysis showed that there arediurnal variations of hydrogen escaped from both the hot spring and the soil. The concentration of hydrogen escaped from the geothermal well is related to the well''s water level and temperature but has no relation to environmental factors on the soil. The trace hydrogen released from the soil is mainly influenced by the surface environmental conditions, it is positively correlated with air temperature and negatively correlated with air pressure. The abnormality of a sudden rise in hydrogen escaped from the geothermal hot spring well originated from the bubble carried by the upwelling fluid, which is a non-seismic precursor anomaly.