A permanent network designed to monitor the microseismic activity at Soultz-sous-Forêts was installed by EOST (Ecole et Observatoire des Sciences de la Terre) from the Strasbourg University in 2003. It consisted of nine stations, six one-component and three three-component sensors. A temporary network of four three-component stations completed the permanent network during the 2004 and 2005 episodes. In addition to the permanent and temporary surface network, a broad-band Güralp sensor was used mostly for waveform analysis. Two other accelerometers completed the surface monitoring system too. The coordinates of the stations have been obtained from RESIF (https://www.resif.fr/">https://www.resif.fr). Last update of data: 03/02/2020

The surface network was installed by EOST, University of Strasbourg, and contained different types of seismological stations. Three of them were permanent stations, belonging to the ReNaSS (French National Seismic Network) and designed to monitor the local, natural seismicity. One broad-band sensor (Güralp type) was also permanently installed at Soultz-sous-Forêts. In addition, fourteen temporary stations were set up during the stimulation test. Eight were continuously recording, telemetered, 1 Hz, single vertical seismometers. Five were autonomous three-component seismometers recording by triggering. Finally one three-component station (CARO) was also continuously recording (Cuenot et al., 2008, Analysis of the Microseismicity Induced by Fluid Injections at the EGS Site of Soultz-sous-Forêts (Alsace, France): Implications for the Characterization of the Geothermal Reservoir Properties). The temporary stations of the surface network were removed on the 11th of July, five days after the shut-in of the GPK2 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK2) well. Unfortunately, several seismic events occurred after that date and were then only recorded by the permanent surface network. The coordinates of the stations have been obtained from RESIF (https://www.resif.fr) and from the Ph. D. of N. Cuenot (Réponse du granite fracturé de Soultz-sous-Forêts à des injections massives de fluide : Analyse de la microsismicité induite et du régime de contraintes). Last update of data: 03/02/2022

In 1996, three new accelerometers (4-component sensors) built by the CSMA and one hydrophone were deployed. As in past years, the 4-component sondes were located in boreholes 4616 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4616), 4601 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4601) and 4550 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4550) within the granite and the hydrophone was deployed in EPS1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-EPS1). Unlike the previous episodes, the accelerometers were not grouted in the boreholes. The X,Y,Z coordinates in the file refer to the local coordinate system with the GPK1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK1) wellhead as origin: X: Easting in meters from GPK1 wellhead (toward UTM32 East) Y: Northing in meters from GPK1 wellhead (toward UTM32 North) Z: Depth in meters from GPK1 wellhead The local coordinate system is based on the UTM32 system. The coordinates of the stations in the local coordinate system have been obtained from the CSMA report for Socomine by Jones and Jupe, 1997 (Microseismic results from the Soultz 1996 experimental programme). The latitude, longitude and elevation in the WGS84 coordinate system have been derived from the local coordinate system. Last update of data: 16/02/2021

The downhole seismic network in 2000 consisted of three accelerometers (4-component sensors) built by the CSMA and two hydrophones. The two first accelerometers were placed in boreholes 4550 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4550) and 4601 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4601) and were assumed to have the same locations as in 1996. The last one was placed in OPS4 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-OPS4), an additional observation well drilled in early 2000 to improve the efficiency of the network. The three accelerometers were deployed at around 1500 m depth. The hydrophones were deployed much deeper at around 2000 m depth in borehole EPS1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-EPS1) and at 3500 m depth in borehole GPK1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK1). The detection of seismic events was performed by trigerring. Each recorded signal has a duration of 2 s. The X,Y,Z coordinates in the file refer to the local coordinate system with the GPK1 wellhead as origin: X: Easting in meters from GPK1 wellhead (toward UTM32 East) Y: Northing in meters from GPK1 wellhead (toward UTM32 North) Z: Depth in meters from GPK1 wellhead The local coordinate system is based on the UTM32 system. The coordinates of the stations in the local coordinate system have been obtained from the Semore Seismic report for Socomine by B. Dyer, 2001 (Soultz GPK2 stimulation June/July 2000. Seismic monitoring report). The latitude, longitude and elevation in the WGS84 coordinate system have been derived from the local coordinate system. Last update of data: 11/06/2021

During the 1991 episode, two 50 hours hydraulic injection tests were carried out at the bottom of the well GPK1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK1). The fresh water was injected at a flowrate of 7 l/s during the first test and 15 l/s during the second test. New seismic probes composed of 3-axis accelerometers built by the CSM (Camborne School of Mines) monitored the induced seismicity. Two of them were deployed in new recovered wells 4550 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4550) and 4601 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-4601). In addition, two hydrophones were installed in a new borehole EPS1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-EPS1), drilled in 1990 and sited at about 600m SSE of GPK1. The network permitted to detect more than 400 induced seismic events during the two tests of the episode. About 60% of them were located. The following report from BRGM in the link gives details about the experiments and presents the results about the seismic monitoring and the location of the events. Some hydraulic data are presented as well with figures.

The Hot Dry Rock (HDR) site of Soultz-sous-Forêts in Alsace was chosen in 1986 for scientific investigations. During the first phase of the project (1987-1988), a first borehole GPK1 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK1) was drilled. It reached a final depth of 2000 m and various investigations were undertaken during that period. In December 1988, an injection test was made at the bottom zone of this borehole with a relatively low flow rate of 3.3 l/s for a period of three days. Induced seismicity recorded was detected by 3-axis geophone probes deployed in three old recovered oil wells at depth ranging from 850 to 1350 m. A small amount of the detected seismicity could be located and showed a trend to grow towards greater depths than the injection zone. The following report from BRGM in the link gives details about the experiments and presents the results about the seismic monitoring and the location of the events. Some hydraulic data are presented as well with figures.

During February/March 2005 a hydraulic stimulation program was conducted in the well GPK4 (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSF-GPK4) at European Hot Dry Rock Project, Soultz-sous-Forêts, France. It is the second stimulation of GPK4, after the previous one, performed in September 2004. The hydraulic stimulation was followed a few days later by a program of chemical stimulation (injection of diluted HCl). This program involved the chemical stimulation itself and two identical step-rate injection tests. The first injection test was performed before the chemical stimulation and the second after, in order to observe the efficiency of the chemical stimulation. Dates of the 2005 hydraulic programme: - Second hydraulic stimulation of GPK4: from 18:05 07/02/2005 to 18:00 11/02/2005. - First step-rate injection test of GPK4: from 15:30 22/02/2005 to 15:30 25/02/2005. - Chemical stimulation of GPK4 with HCl: from 13:30 02/03/2005 to 06:00 05/03/2005. - Second step-rate injection test of GPK4: from 10:00 13/03/2005 to 09:55 16/03/2005. The Episode contains several datasets which you can find further down the page in "Links".

The 2004 stimulation was aimed at improving the hydraulic performances of the well GPK4 (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSF-GPK4). This borehole was stimulated twice. The 2004 episode corresponds to the first stimulation of GPK4. 9300 m3 of water were injected during the test at a constant flowrate of 30 l/s, with peaks up to 45 l/s. A low flow injection test of GPK4 was performed before the stimulation to evaluate the initial injectivity of the well. The data from the injection test are included too. Dates of the 2004 hydraulic programme: - GPK4 low flow injection: from 10:38 08/09/2004 to 10:00 12/09/2004. - GPK4 stimulation: from 08:32 13/09/2004 to 20:00 16/09/2004. The Episode contains the following datasets: - Microseismic catalogue of the downhole network by B.C. Dyer - Soultz-sous-Forêts 2004 Stimulation (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSFS2004-Catalogue_downhole); - Microseismic downhole network - Soultz-sous-Forêts 2004 and 2005 Stimulations (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSFS2004-Downhole_network); - Seismological waveforms - Soultz-sous-Forêts 2004 Stimulations (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSFS2004-Waveforms); - Hydraulic data - Soultz-sous-Forêts 2004 Stimulation (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSFS2004-Hydraulic); - Velocity model and station corrections used by B.C. Dyer to locate seismic events recorded by the downhole network - Soultz-sous-Forêts 2004 and 2005 Episodes (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/SSFS2004-velocity_model_downhole);

Before the 2003 episode, a permanent network designed to monitor the microseismic activity at Soultz-sous-Forêts was installed by EOST (Ecole et Observatoire des Sciences de la Terre) from the Strasbourg University. It consisted of nine stations, six one-component and three three-component sensors. The network was operational just before the 2003 stimulation of GPK3 (https://cdgp.u-strasbg.fr/geonetwork/srv/fre/catalog.search#/metadata/SSF-GPK3). A temporary network of fourteen seismometers (six three-component and eight one-component) was added to this permanent network. Contrary to the 2000 episode, all the fourteen stations of the temporary network were continuously recording. In addition to the network under the responsibility of EOST, a broad-band Güralp sensor was used mostly for waveform analysis. Two other accelerometers completed the surface monitoring system too. The coordinates of the stations have been obtained from RESIF (https://www.resif.fr/">https://www.resif.fr). Last update of data: 03/02/2020

Geoven (http://www.geoven.fr) is a geothermal powerplant project led by Fonroche Géothermie now Arverne (https://arverne.earth/). The project is implemented on the site of the Rhenan Ecoparc at Vendenheim, north of Strasbourg. The geothermal powerplant produced 6 MW of electrical energy and 40 MW of thermal energy. To this end, two wells were used to draw the hot water and reinject it at more than 4000 meters deep. The two wells VDH-GT1 (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/VDH-GT1) and VDH-GT2 (https://cdgp.u-strasbg.fr/geonetwork/srv/eng/catalog.search#/metadata/VDH-GT2) had been drilled and some tests had been conducted (5 injectivity and productivity cycles between 02/2018 and 11/2019). A first interruption occured after a first period of seismicity (11/2019 – 01/2020, MLv=3.0 max) at Strasbourg and Vendenheim, to allow a third-party scientific expertise. During this period, the well was deepened of 450m to reach 5000m. New tests were authorized starting 10/2020, but were stopped on 28/10/2020 after a new period of seismicity with quake reaching 3.6MLv (04/12/2020). Authority decided on 07/12/2020 to definitely stop the project. Another earthquake of 3.9 ML (https://www.franceseisme.fr/donnees/intensites/2021/210626_0300/Rapport_BCSF-RENASS_2021R1_EVT210626-DPT67.pdf) occured on 26/06/2021. Authorities set up a committee of experts that delivered a first report (https://www.bas-rhin.gouv.fr/Politiques-publiques/Environnement/Geothermie/Rapport-du-comite-d-experts-cree-en-appui-a-l-administration-sur-la-boucle-geothermique-GEOVEN).