The current state of the hidden magmatic process beneath the western Eger Rift after the 2011 earthquake swarm traced by isotope studies

通过同位素研究追踪 2011 年群震后埃格尔裂谷西部隐藏岩浆过程的现状

• 批准号: 252970106
• 负责人: Dr. Karin Bräuer
• 金额: --
• 依托单位: Department Hydrogeologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/252970106?language=en
• 关键词: current; state; hidden; magmatic; process

As a result of the detailed isotope-geochemical studies of the mantle-derived fluids related to the 2000 and 2008 earthquake swarms the temporal seismically induced release of crustal derived components could be identified at degassing locations along the Pocatky Plesna Fault Zone (PPZ) and at degassing sites along the Marianske Lazne Fault (MLF), but was also observed in the Vogtland area. Both, after the swarms 2000 and 2008, the admixture of crustal derived components to the steady mantle-derived fluid flow were repeatedly detected for about two years. Besides that a clear increase of mantle-derived helium (up to 6 Ra) was observed at locations in the Cheb basin at least since 2000. This increase indicates the existence of an active magmatic reservoir in the upper mantle beneath the Cheb basin. Superimposed to the progressive increase of mantle-derived helium further temporal increased portions of mantle-derived helium (to 6.3 Ra) were observed before the 2000 and 2008 earthquake swarms at locations close to the Novy Kostel focal zone (NKFZ). The recorded anomalies indicate that both, the 2000 and the 2008 swarm, seems to be linked with supply of fresh magma from a less degassed reservoir in the upper mantle. That means from the view of fluids both swarms seems to be triggered by hidden magma intrusions within the lithosphere. No fluid data could be recorded accompanying the earthquake swarm 2011. Thus, it is yet unknown whether the portion of mantle-derived gas has increased or decreased in the western Eger Rift area in relation to the latest earthquake swarm, and whether indications exist for a further spatial expansion of the area with increased portions of mantle-derived gas in the western Eger Rift, respectively?Therefore, the proposal is mainly focussed on two aims: (1) to evaluate and compare the geodynamic situation within the three degassing centres Cheb Basin (CB), Marianske Lazne and surroundings (ML) and Karlovy Vary (KV) after the earthquake swarm 2011, and (2) to evaluate the fluid signatures at the degassing locations close to the piece of the planned seismic and geoelectric profile together. As a result of the planned fluid studies an update of the distribution pattern of mantle-derived gas is to expect in comparison to situation about 20 years ago. The new fluid data, regional and close of the profiles of geophysical research, allow the evaluation the permeability of fluid migration paths supplying the respective sites by their gas characteristic at the surface and provide information on the current state of the magmatic reservoir. The final discussion of all data will assist the interpretation of spatial anomalies and indications of ascending fluid paths, respectively identified in geophysical studies and will supply essential information for a future ICDP drilling in the western Eger Rift.

As a result of the detailed isotope-geochemical studies of the mantle-derived fluids related to the 2000 and 2008 earthquake swarms the temporal seismically induced release of crustal derived components could be identified at degassing locations along the Pocatky Plesna Fault Zone (PPZ) and at degassing sites along the Marianske Lazne Fault (MLF), but was also observed in the Vogtland 区域。在2000年和2008年群体之后，在稳定的地幔衍生的流体流中的地壳衍生成分的混合均反复检测到大约两年。除此之外，至少自2000年以来，在Cheb盆地的位置观察到地幔衍生的氦气明显增加（最多6 ra）。这种增加表明在Cheb盆地下面的上地幔中存在活跃的岩浆储层。叠加到地幔衍生的氦气的逐渐增加，进一步增加了地幔衍生的氦气（至6.3 ra），在2000年和2008年的地震群之前，在靠近Novy Kostel焦点区域（NKFZ）的地点的地震群之前观察到。记录的异常表明，2000年和2008年群似乎都与上地幔中脱气较低的水库的新鲜岩浆供应有关。从液体的角度来看，这意味着两个群似乎是由岩石圈中隐藏的岩浆入侵触发的。因此，与最新的地震群相关的地幔衍生气体的一部分是否增加或减少是未知的。 (1) to evaluate and compare the geodynamic situation within the three degassing centres Cheb Basin (CB), Marianske Lazne and surroundings (ML) and Karlovy Vary (KV) after the earthquake swarm 2011, and (2) to evaluate the fluid signatures at the degassing locations close to the piece of the planned seismic and geoelectric profile together.由于计划中的流体研究，与大约20年前的情况相比，地幔衍生天然气的分布模式的更新是期望的。新的流体数据，地球物理研究曲线的区域和关闭，允许评估流体迁移路径的渗透性，从表面上通过其气体特征为各自位点提供的渗透性，并提供有关岩浆储层的当前状态的信息。所有数据的最终讨论将有助于解释空间异常和上升流体路径的指示，分别在地球物理研究中确定，并为西部Eger Rift的未来ICDP钻探提供必要的信息。