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

由于对与2000年和2008年震群有关的地幔流体进行了详细的同位素地球化学研究，可以在Pocatky Plesna断裂带(PPZ)和Marianske Lazne断层(MLF)的脱气地点发现地震引起的地壳衍生成分的临时释放，但也在Vogtland地区观察到。在2000年和2008年的震群之后，都在大约两年的时间里反复探测到地壳衍生成分与稳定的地幔衍生流体的混合物。此外，至少自2000年以来，在CHAB盆地的一些地方观察到了来自地幔的氦(高达6Ra)的明显增加。这一增加表明在切布盆地下的上地幔中存在活动的岩浆储集层。在2000年和2008年地震群之前，在Novy Kstel震源区(NKFZ)附近观察到地幔氦的比例在时间上进一步增加(达到6.3Ra)，叠加了地幔氦的逐渐增加。记录的异常表明，2000年和2008年的震群似乎都与上地幔较少脱气的储集层提供的新鲜岩浆有关。这意味着从流体的角度来看，这两个岩群似乎都是由岩石圈内隐藏的岩浆侵入引发的。2011年的震群没有记录到任何流动的数据。因此，目前尚不清楚埃格裂谷西部地区的地幔气体比例与最近一次震群的关系是增加还是减少，以及是否有迹象表明，随着埃格裂谷西部地区地幔气体比例的增加，该地区的空间进一步扩大？因此，该提案主要集中在两个目标上：(1)评估和比较2011年震群后切布盆地(CB)、马里安斯克·拉兹内(Marianske Lazne)及其周围地区(ML)和卡洛维瓦利(Karlovy Varie)三个脱气中心(Cb)、Marianske Lazne及其周围地区(ML)和Karlovy Varie(KV)的地球动力学状况。以及(2)在靠近规划的地震和地电剖面的脱气位置一起评价流体特征。作为计划中的流体研究的结果，预计与大约20年前的情况相比，地幔衍生气体的分布模式将会更新。新的流体数据，包括区域和近距离的地球物理研究剖面，允许根据流体运移路径在地表的气体特征来评估供应相应地点的流体运移路径的渗透率，并提供关于岩浆油藏当前状态的信息。对所有数据的最后讨论将有助于解释地球物理研究中分别确定的空间异常和上升流体路径指示，并将为今后在西部Eger裂谷进行的ICDP钻探提供基本信息。

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.