怀4井氦气浓度异常与地震对应特征

运用原始日测值曲线法及一阶差分法,对河北省怀来后郝窑地震台4号观测井逸出氦气含量观测数据进行分析,定量计算几次震例发震前异常,认为怀4井氦气浓度异常变化能够反映当地地震活动变化趋势,即该地区地震活动性高,则观测井氦气浓度测值升高;氦气异常一般出现在地震发生前15—30天。     

河北省怀4井氦气观测集气装置改造

怀4井氦气观测初始采用井口至水面的井管静空间获取气体,氦气测值随水位发生变化,且井管静空间大,新旧气体易混合,进入测氦仪传感器的新鲜气体比例小,测值稳定,一些应力场作用信息被掩盖。为此,将不锈钢杯集气漏斗悬于水面上2 m处收集观测井自然逸出气,新鲜的逸出气及时有效地进入测氦仪传感器,有效避免水位涨落影响,观测数据有明显变化,观测效果较理想。     

五里营氦气受水位影响分析

延庆地震台五里营井逸出氦气受该井动水位异常变化影响,每日数据扰动大,影响原来的日变形态.对仪器的集气装置进行改造,把地面集气改为水下集气.既解决氦气受水位异常变化的影响问题,减小观测环境变化对氦气观测的影响,提高观测质量,对今后可能记录的地震前兆信息提供保障,对其他有此测项的台站有一定借鉴意义.     

怀4井新旧自动测氦仪比测分析

为验证新WGK-1型测氦仪在怀4井观测的可行性,在相同观测条件下,将新旧测氦仪串联并行观测,经动态稳定性、内在质量及观测曲线对比发现,新测氦仪能够捕捉到更多更完整的地下流体信息,观测数据日变化规则,动态特征明显,且2台测氦仪产出数据具有同步性变化特征。为进一步验证新旧测氦仪的相关性,与同台气温测项进行对比分析,发现2台测氦仪氦气测值与气温同时存在短期负相关变化。综合分析认为,新旧测氦仪产出观测数据真实可靠,均能反映怀4井地下流体中氦气的浓度变化。     

河北怀来台氦气集气装置改进及实验数据分析

怀4井氦气观测采用悬浮于水面之上的塑料集气漏斗获取逸出气体,受水位影响较大,造成新旧气体易混合。为全面研究地下流体氦气浓度动态变化过程,2021年7月3日对氦气集气装置进行改进,通过对改造前后观测数据进行对比分析,结果显示:观测值由改造前的0.011 9%～0.037 7%升高至改造后的0.041 7%～0.081 1%,且观测数据变化动态较之前更加稳定,抗干扰能力明显提高;改造后的氦气观测值的3倍σ值逐月减少,超差百分比显著下降。这说明怀来台氦气集气装置改进较为成功,氦气观测数据质量得到了显著提高,观测数据日变化更加规则,动态特征更加明显,可以及时有效地反映怀4井氦气浓度变化。     

哈萨克斯坦卡帕尔-阿拉善4号井氦气（He）含量映震特征

介绍了哈萨克斯坦卡帕尔-阿拉善4号井的水文地球化学环境,分析其17年氦气（He）含量变化映震特征,氦气（He）变化的地震前兆异常表现为：上升（或下降）幅度、速率变化超出正常范围,具有较好的重复性,测值遵循的是,背景值－趋势性上升（或突升）,趋势性下降（或突降）－恢复至背景值的变化过程。将该井氦气（He）观测数据经过滤波、差分处理后,以3倍均方差作为异常识别标准,结果表明：氦气（He）对监测点周围300km范围5级地震、400km范围6级地震的对映率分别为100％、66．7％,是较好的地震前兆手段之一。     

康定温泉逸出气短期预测研究

康定温泉逸出气气体百分含量的观测始于1986年,期间先后经历了多次甘孜州及邻区5.0级以上地震。地震前康定温泉逸出气观测资料均有不同程度的短临异常。本文在系统整理和深入剖析两泉点自有观测以来的在甘孜州及邻区发生的5.0级以上地震震例资料的基础上,借助多次“攻关”成果,排除观测资料的各种干扰因素及仪器标定变更情况,总结各观测资料短临异常特征、中短期异常特征及中短期异常特征随时间变化规律,提出康定温泉逸出气短临异常指标。     

数字化测逸出氡替代模拟测水氡的理论与实践

模拟测水氡方法已有40年历史, 氡浓度异常变化预测地震取得了较好的效果, 在地震短临预报中发挥了重要作用。80年代中期, 人们逐渐认识到自流井中逸出气氡的信息量和异常量远远大于溶解氡, 随即开始对逸出气氡的微动态进行研究, 并在“九五”期间研制出目前国内功能、技术性能指标最佳的数字化测氡仪。然而数字化观测逸出氡能否代替模拟观测水氡存在不同意见, 通过理论上的分析和观测气氡实际震例的研究, 阐明模拟测水氡和测逸出氡的差异和一致性, 认为有逸出氡的井、泉测逸出氡完全可以代替模拟测水氡, 其效果更佳。     

聊古-井逸出气氦数字化观测资料分析及其映震能力的初步研究

简要介绍了一种新型测氦仪-GWK-201型测氦仪，分析了聊古一井1998年9月1日～1999年11月30日的逸出气氦观测资料。结果表明：该资料的正常动态为近直线型，并且在附近4.0级地震前有显的异常显示，对今后的地震预报探索研究具有一定的参考价值。     

延庆五里营井稀有气体地球化学特征

延庆五里营井逸出气体中主要组分是N2,微量组分含有He,CH4,Rn,CO2,Ar等.N2/Ar值为46.3,3 He/4 He为2.4 Ra,说明井热水中有深部幔源组分的加入;CH4含量为2.2％,CO2(TCD)为4.9 mg/L,显示了强还原环境下的热水释放活动,这与延怀盆地微量气体以还原性气体释放为主的气体背景场相符.五里营井气体释放更倾向于是热储库型气体释放而非断裂型释放,这可通过氦气动态观测及2次大震前后流体前兆氦气浓度异常释放得到体现.热储库型气体释放中深部气体上升进入热储并改变整个热储组成的时间较断裂型晚,消失的时间也会晚得多,这与处于八宝山断裂带的大灰场井氦气释放特征存在明显差异.五里营井气体释放特征与该区域地质、地球物理特征相符.     

2005年7月2S日黑龙江省林甸5．1级地震——地下流体前兆异常分析

分析了2005年7月25日林甸5．1级地震和2005年2月23日富裕3．7级地震前，林甸1井大地微电流、林甸04井的氦气和大庆地震台的地温异常变化。大地微电流在这2次地震前具有明显的异常变化，其异常幅度达正常背景值的10-20倍。氦气在林甸5．1级地震前具有明显前兆异常变化。     

山西临猗-永济5.0级地震前的地下流体异常

1998年 7月 1 1日山西临猗—永济之间发生 ML5.0地震 ,震前在晋陕豫交界地区存在水位、水氡、溶解氢气、氦气、气体总量及逸出氦气、氢气等多项地下流体异常。总结分析了该次地震前地下流体短临异常特征 ,并从中得到一些启示和新的认识     

Noble gas anomalies related to high-intensity methane gas seeps in the Black Sea

Dissolved noble gases and tritium were analyzed at a series of high-intensity methane gas seeps in the Black Sea to study the transport and gas exchange induced by bubble-streams in the water column. These processes affect marine methane emissions to the atmosphere and are therefore relevant to climate warming. The seep areas investigated are located in the Dnepr paleo-delta, west of Crimea, and in the Sorokin Trough mud volcano area, south-east of Crimea. Noble gas concentration profiles at active seep sites revealed prominent anomalies compared to reference profiles that are unaffected by outgassing. Supersaturations of the light noble gases helium and neon observed relatively close to the sea floor are interpreted as effects of gas exchange between the water and the rising bubbles. Depletions of the heavy noble gases argon, krypton and xenon that were detected above an active, bubble-releasing mud volcano appear to be related to the injection of fluids depleted in noble gases that undergo vertical transport in the water column due to small density differences. In both cases, the noble gas anomalies clearly document seep-specific processes which are difficult to detect by other methods. Helium is generally enriched in the deep water of the Black Sea due to terrigenic input. Although exceptionally high helium concentrations observed in one seep area indicate a locally elevated helium flux, most of the seeps studied seem to be negligible sources of terrigenic helium. Noble gas analyses of sediment pore waters from the vicinity of a mud volcano showed large vertical gradients in helium concentrations. The helium isotope signature of the pore waters points to a crustal origin for helium, whereas the deep water of the Black Sea also contains a small mantle-type component.     

中国火山温泉气体地球化学特征及其在火山监测中的应用

中国火山温泉主要分布在吉林长白山、云南腾冲和黑龙江五大连池等火山区。这些火山虽然处于休眠状态,但大面积的温泉分布指示着岩浆房存在的可能性。本文总结了前人研究成果,分析了中国主要火山区温泉气体地球化学特征,并探讨了温泉气体在火山监测中的应用。长白山、腾冲和五大连池火山区温泉气体地球化学性质类似,都以CO₂为主要气体,含量在80%以上,最高可达99%以上,其它气体组分包括CH₄、N₂、O₂、SO₂、H₂S、He和H₂等。长白山火山温泉气体中氦同位素比值（3He/4He）最高,约为4—6R_A,CO₂中碳同位素比值（δ13C）为-7.9‰—-1.3‰,CH₄中碳同位素为-48.0‰—-28.7‰;腾冲火山温泉气体氦同位素比值为3—5.5R_A,CO₂中的碳同位素为-6.49‰—-2.07‰,CH₄中碳同位素为-23.5‰—-9.3‰;五大连池火山温泉气体氦同位素比值约为3R_A,CO₂中的碳同位素比值为-9.6‰—-3.1‰,CH₄中碳同位素为-47.2‰—-44.4‰。3个火山区的温泉气体均显示地幔来源的岩浆气体特征,并在上升运移过程中受地壳或古俯冲物质的影响。     

北京五里营井流体前兆观测到的两次异常及讨论

In this paper, the precursor response characteristics of digital fluid caused by the Wenchuan M8.0 and Yushu M7.1 earthquakes are studied, and the response difference of the observations of Wuliying well to the two strong earthquakes is compared. The result shows that the abnormal fluid response has a certain relationship with earthquake size and epicenter distance. The greater the earthquake, and the closer it is to the epicenter from the observatory, the more sensitive the response will be to fluid anomalies. Abnormal Helium release was first observed before both strong earthquakes in the fluid precursor observation. The release intensity is related to earthquake magnitude; the larger the magnitude, the stronger the abnormal changes. The large change in He release in a short period after the Wenchuan earthquake may be related to the continuous activity of strong aftershocks and the structural adjustment after the earthquake. Helium release increased significantly after both earthquakes, as contributed by the abnormal deep-sited Helium release. However, this process may be connected to the annual change from July to September or the hot-reservoir type gas release in the Wuliying well. In the earthquake preparation process, a large number of deep-derived Helium is released into the geothermal system and the entire composition is changed. Temporally, this gas release appears later than fault-type gas release, and the disappearance time of this anomaly is also much later. The response difference of the fluid precursor to the two strong earthquakes may be related to differences of deep structural setting and dynamic mechanism. It also shows there is a stronger correlation between Wenchuan M8.0 earthquake in the North-South Seismic Belt and North China region than the Yushu M7.1 earthquake in the internal Qinghai-Tibetan plateau. Helium gas can be a sensitive indicator for monitoring abnormal deep-gas activity of the region where the observation station is located. Hence, observation and research should be strengthened in the future.     

The statistical study of precursory anomalies observed in Chinese Seismological Network

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濮阳2次ML4.0级地震前兆异常研究

介绍了濮阳2次ML4.0级地震的基本参数.2次地震前出现了电磁波、水位、逸出气氦等异常.对前兆资料的异常特征进行了分析研究.异常出现的起始时间、持续时间、异常幅度等不同手段、不同台站在地震前的表现各不相同,表现出异常的复杂多样性.