Two awarded postdoctoral NKFIH OTKA proposals at EPSS

Two EPSS researchers have won postdoctoral OTKA grants. A short description of the proposals:

Dániel Kalmár: Lithosphere and upper mantle structure in the Alpine-Carpathian-Pannonian region: receiver function analysis of seismological data and geodynamic interpretation

The main goal of my present research project is clearly to determine the location of the seismic discontinuities in the upper mantle with high accuracy in the Alpine-Carpathian-Pannonian region. Before this project, these estimations were not provided of these geophysical parameters. The dynamically evolving seismological network allows the use of such methods that have already been available, but have not yet been applied in this region by the seismologists. By performing S receiver function analysis, which is widely used in seismological investigation, we can provide reliable and more exact information about the location and extension of the Lithosphere-asthenosphere boundary (LAB). Determining the precise depth of this interface is crucial because it has an essential role in the understanding of many geodynamic and geochemical processes, furthermore it is an input parameter in the mantle scales numerical model simulation. The phase boundaries of the deeper transition zone (~410 and ~660 km) can be determined by calculating the P receiver functions. Due to the complexity of the Pannonian Basin, these phase boundaries are certainly not of the same depth below the study area. But at present, these phase transitions are completely unknown for the whole Alpine-Carpathian-Pannonian region, but they also play a very major role in the most accurate understanding of the slab properties and in the interpretation of the asthenosphere flows. At the end of my research project, I would like to extend, revised and update the defined discontinuity parameters into new geodynamic models in the framework of international cooperation, thereafter we can get answers to many hitherto unknown geological and geodynamical problems.

Kristóf Porkoláb: The role of dehydration reactions in triggering intermediate-depth seismicity: development and application of cutting edge numerical models

Solid rocks beneath the surface have a deformable pore space and fractures that accommodate fluids. Coexisting rocks and fluids chemically react with each other, which may induce changes in the physical characteristics of the rocks. For example, water-bearing minerals in the lithosphere can dehydrate (release their water content) due to elevated temperature and pressure. The released water increases the pressure in the pore space of the rocks, which may induce the formation of fractures, and sometimes, earthquakes. The understanding of rock-fluid interactions that may lead to earthquake nucleation is still incomplete, hence representing a significant knowledge gap in geodynamic research. This research project aims to fill this knowledge gap by developing state-of-the-art numerical simulation techniques that can model rock deformation, fluid flow, and chemical reactions all together. Such models can show us how water release modifies the physical-chemical characteristics of the subsurface, and specifically, how does it contribute to earthquake nucleation. The project aims to apply the newly developed models for revealing the causes of the enigmatic and large earthquakes that nucleate between 100and 170 km depth beneath the Eastern Carpathians. Furthermore, these models can also be used for a large variety of other research fields in Earth Science, including timely challenges in energetics and industry. These are for example geothermal fields, and underground storage sites for carbon-dioxide, hydrogen and nuclear waste, where predicting rock deformation, fluid flow, and chemical processes are essential for successful operation.