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Probing the Crustal Structure Around Deep Geothermal Reservoirs with Ambient Seismic Noise: the Estof Pilot Study
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
In the framework of the EstOF pilot study, a passive temporary seismic network of 288 sensors was deployed homogeneously over a 25km wide disc centered on the Soultz-sous-Forêts and Rittershoffen geothermal sites (Northern Alsace, France). We analyze the one-month records of ambient seismic noise in the 1–5s period range and show an imprint of the local geology on the noise level. We also compute the ambient noise cross correlation functions between the ∼41 000 pairs of sensors to estimate the empirical Green functions between them. We extract the group dispersion curves for the Rayleigh wave and invert them to produce tomographic maps at different periods that highlight the major geological features of the region from the surface down to ∼3km depth. This suggests that ambient noise correlation is a reliable and affordable solution to probe the crustal structure in the depth range targeted for deep geothermal reservoirs.