More - Mofette Research

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Mofettes are gas emission sites where CO2 ascends through conduits from as deep as the mantle to the Earth’s surface and as such provide natural windows to magmatic/volcanic processes at depth. The primary objective of the proposed research on mofettes is to clarify the physical link between fluid properties, their pathways and earthquakes. The suggested state-of-the-art fluid monitoring techniques allow for a high temporal resolution and are completely different from the discrete sampling approach used in the last decades. Gas composition and its isotope signature will be continuously analysed in-situ at different depth levels. Unique in the world, ascending mantle fluids will be tracked along a vertical gradient in a set of drillings from a depth of a few hundred metres to the surface. This can provide hints on the origin of temporal variations related to the opening of fault-valves, admixture of crustal fluids to a background mantle-flow or the release of hydrogen during fault rupturing. As a test area the Hartoušov mofette has been chosen as a key site. Detailed measurements before, during and after drilling of a 300 m deep well will be carried out to realize possible influences of the drilling activity on the local and regional fluid regime. Periodically, samples for noble gas isotope analysis will be collected. This proposal is directly linked to the drilling of the fluid-borehole scheduled for 2019 in the frame of the ICDP project “Drilling the Eger Rift: Magmatic fluids driving the earthquake swarms and the deep biosphere”.