The possible transition of brittle failure to an aseismic process due to alteration of juvenile fluids in the NW-Bohemia/ Vogtland earthquake swarm region

在目前的状态下，在西北波希米亚/Vogtland地区的地震群活动被解释为孔隙流体压力变化的结果，因为地震群的发生遵循扩散典型的签名。我们将这些结果应用于我们的震群触发模型，但我们阻止解释这些超压流体的触发效应起源于上地幔的岩浆储层。我们的初步调查表明显着的结果，必要的孔隙流体压力脉冲是从表面的压力瞬变引起的水文事件（大雨，融雪）。根据相互连通的管道（断层带）的局部水力扩散率，孔隙压力从最上层地下水库向震源扩散的过程需要几个月。我们的初步结果是基于两个长期数据集的分析和相关性：大约30年的Bad Brambach矿泉流量的连续记录和November Kostel震中区在此期间的震群活动。这一重要结果支持了水震活动是本区震群活动的主要触发机制的假设。该项目的主要目标是详细调查和验证这一假设，特别是针对每个震中群及其断层带。此外，额外的孔隙压力脉冲沿着剪切带的调查，由于在破裂过程中的热力学P-T条件的变化将被视为一个特定的目标，以了解完整的触发过程。除了触发过程外，还将利用当地震群周期的近似值作为进一步的重要假设，以建立一个简化的震群活动长期预报系统，从而减少该地区的灾害。

At the present state, the earthquake swarm activities at the NW-Bohemia/Vogtland region are interpreted as results of pore fluid pressure changes because the occurrence of earthquake swarms follow a diffusion-typical signature. We apply these results for our earthquake swarm trigger model but we prevent the explanation that these trigger effects of over-pressurized fluids are originated at magmatic reservoirs in the upper mantle. Our preliminary investigations suggest significant results that the necessary pore fluid pressure pluses are pressure transients from the surface which are induced by hydrological events (heavy rain, snowmelt). This pore pressure diffusion process from the uppermost groundwater reservoirs to the hypocenters needs several months according to the local hydraulic diffusivity of the interconnected conduits, the fault zones. Our preliminary results base on the analysis and correlation of two long term data sets: the continuously record of the Bad Brambach mineral spring discharge of about 30 years and the earthquake swarm activity of the Nový Kostel epicentral area at this period. The significant results give reason to the hypothesis that hydroseismicity can be considered as main trigger mechanism of the earthquake swarm activity at our area of investigation. The main goal of this project is to investigate and verify this hypothesis in detail, in particular for each epicentral cluster with their fault zones. Further, an investigation of additional pore pressure pulses along the shear zones due to the variations of the thermodynamic P-T-conditions during the rupture process will be considered as one specific target to understand the complete trigger processes. Besides the trigger processes, the approximation of the local earthquake swarm cycles will be used as a further important presumption to install a simplified long-term forecast system of the earthquake swarm activity for hazard reduction in that region.