Alteration in active faults application to geothermal reservoirs
The project focuses on the process of maturation of active faults in the upper crust by chemical alteration of their fault walls, and on the feedback between alteration and tectonic activity. The main research hypothesis is that the fault activity induces new fractures that enhance fluid-rock interactions and associated fault zone alteration. The focus is on granitoid rocks, which is the lithology of both the Rhine Valley geothermal reservoirs and that of the wall rocks of the Nojima fault responsible for the 1995 Nanbu-Kobe earthquake in Japan. It will be used core samples from the GSJ-Hirabayashi scientific borehole intersecting the Nojima fault to obtain a continuous alteration profile through the fault by combining core and downhole geophysical data as well as to perform laboratory alteration experiments at various differential stresses to assess the intertwined effects of tectonic loading and fault alteration.
Funded by: French National Research Agency (ANR)
Project leader: ISTerre Grenoble, France
Project partners:
Géosciences Montepellier
IC2PM Poitier
ITES Strasbourg
ITES budget: 174 437€
Project duration: 2024-2027