ALBERT

Description: In January 2020, a swarm of earthquakes started under Thorbjorn volcano, Reykjanes, SW Iceland, associated to the uplift of up to 0.5 cm per day. Concern in Iceland is growing and the Iceland Meteorological Office suggested that possibly magma was intruded in the crust at shallow depth (3 to 9 km). The GFZ is starting a seismological Hazard and Risk Team (HART) in cooperation with IMO, ISOR and the University of Iceland. This dataset comprise a selection of waveforms recorded along a fibre length of 21 km. The interrogator is located in Grindavik and is connected to a standard telecom cable. Waveform data are available from the GEOFON data centre, under network code 5J.

Description: Imaging the internal structure of faults remains challenging using conventional seismometers. Here, the authors use deployed fibre-optic cables to obtain strain data and identify faults and volcanic dykes in Iceland. Such fibre-optic networks are pervasive for telecommu-nication and could be used for hazard assessment. Natural hazard prediction and efficient crustal exploration requires dense seismic observa-tions both in time and space. Seismological techniques provide ground-motion data, whose accuracy depends on sensor characteristics and spatial distribution. In the manuscript Jousset et al. (2018), we demonstrate that strain determination is possible with conventional fibre-optic cables deployed for telecommunication. Extending recently distributed acoustic sensing (DAS) studies, we present high resolution spatially un-aliased broadband strain data. We recorded seismic signals from natural and man-made sources with 4-m spacing along a 15-km-long fibre-optic cable layout on Reykjanes Peninsula, SW Iceland.

Description: The 208 km long profile 3B/MVE (West) was recorded in 1990 as part of the joint seismic reflection venture DEKORP 1990-3/MVE (Muenchberg-Vogtland-Erzgebirge) between the two former German Republics shortly before their unification. The aim of DEKORP 1990-3/MVE was to explore the structure of the crust from the Rhenish Shield through the Bohemian Massif to the Ore Mountains. The entire profile consists of DEKORP 3A, DEKORP 3B/MVE (West) and its prolongation to the east DEKORP 3B/MVE (East). Its total length amounts to about 600 km. 24 short seismic cross lines and associated 3D blocks with single fold coverage were also recorded. The seismic survey of 3B/MVE (West) was performed to investigate the deep crustal structure and the transition zone between the Rhenohercynian and Saxothuringian units with high-fold near-vertical incidence vibroseis acquisition. The results were compared with the results from the surveys DEKORP 1 and DEKORP 2, running nearly parallel to the line 3B/MVE (West). Details of the 3B/MVE (West) experiment, its preliminary results and interpretations may be obtained from DEKORP Research Group (A) et al. (1994) and DEKORP Research Group (C) et al. (1994). The Technical Report of line 3B/MVE (West) gives complete information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The mainly NW-SE running DEKORP 3B/MVE (West) runs perpendicular to the Variscan strike direction and traverses the southern part of the Rhenohercynian unit with the Northern Phyllite Zone and the northern part of the Saxothuringian unit including the Mid-German Crystalline High. Starting in the Kellerwald the profile crosses the Hessian Depression, the Tertiary volcanic Rhoen Mountains and the Mesozoic of the Franconian Basin (DEKORP Research Group (C) et al., 1994). East of Staffelstein the profile turns to the east and ends on the Franconian Line, the southwestern boundary fault zone of the Bohemian Massif. The line 3B/MVE (West) is intersected by ten cross lines along the profile and by DEKORP 3A at its northwestern end. To the east the profile is extended by DEKORP 3B/MVE (East).

Description: The profile 1C was recorded in 1988 as part of the joint reflection venture DEKORP 1 of DEKORP (German Deep Seismic Reflection Program) and BELCORP (Belgian Continental Reflection Seismic Program) groups. The seismic survey of the ca. 75-km long line 1C was conducted to investigate the deep crustal structure of the western Rhenish Massif with high-fold near-vertical incidence vibroseis acquisition. The objectives of the experiment were to analyse deep Variscan and post-Variscan crustal structures in the region and to compare them with the results from the eastern Rhenish Massif gathered from the survey DEKORP 2N. The first results were presented by DEKORP Research Group (1991) and supplemented by many other researches. The Technical Report of line 1C gives detailed information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Rhenohercynian Zone is a foreland fold-and-thrust belt cropping out in the Rhenish Massif which extends from the Ardennes to the Harz Mountains. This geological unit consists predominantly of Devonian and Lower Carboniferous rocks affected by very low-grade metamorphism (DEKORP Research Group, 1991). The survey 1C was carried out in the western part of the Rhenish Massif and intersects the Variscan main structures almost perpendicular. It stretches from the Mosel Syncline to the Saar-Nahe Basin (WNW-ESE) crossing the Devonian metamorphic rocks of the Hunsrueck Mountains, the Northern Phyllite Zone and the Hunsrueck Boundary Fault separating the Rhenohercynian and Saxothuringian Zones. In the northwest 1C joins line 1B which runs through the Hocheifel area. In the southeast the line continues with 9N running across the northern part of the Upper Rhine Graben.

Description: The 50 km long profile 1B was recorded in 1987 as part of the joint reflection venture DEKORP 1 of DEKORP (German Deep Seismic Reflection Program) and BELCORP (Belgian Continental Reflection Seismic Program) groups. It was surveyed to investigate the deep crustal structure of the western Rhenish Massif with high-fold near-vertical incidence vibroseis acquisition. The objectives of the experiment were to analyse deep Variscan and post-Variscan crustal structures in the region and to compare them with the results from the eastern Rhenish Massif gathered from the survey DEKORP 2N. The first results were presented by DEKORP Research Group (1990, 1991) and supplemented by many other researches. The Technical Report of line 1B gives detailed information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Rhenohercynian Zone is a foreland fold-and-thrust belt cropping out in the Rhenish Massif which extends from the Ardennes to the Harz Mountains. This geological unit consists predominantly of Devonian and Lower Carboniferous rocks affected by very low-grade metamorphism (DEKORP Research Group, 1991). The survey 1B was carried out in the western part of the Rhenish Massif and trends nearly N-S starting in the western volcanic zone of the Eifel, the Tertiary Hoch Eifel Volcanic Field represented by alkali basalts and fractionated volcanics. The line also runs over a positiv magnetic anomaly, the Kelberg Magnetic High which is located on the southern flank of the East Eifel Main Anticline. Afterwards, 1B crosses the SE-dipping Siegen Main Thrust and ends in the Mosel Syncline, the northern border of the Hunsrueck Mountains (DEKORP Research Group, 1991). The profile joins line 1A in the north and continues to the southeast with line 1C.

Description: The 128 km long profile 3A was recorded in 1990 as part of the joint seismic reflection venture DEKORP 1990-3/MVE (Muenchberg-Vogtland-Erzgebirge) between the two former German Republics shortly before their unification. The aim of DEKORP 1990-3/MVE was to explore the structure of the crust from the Rhenish Shield through the Bohemian Massif to the Ore Mountains. The entire profile consists of DEKORP 3A, DEKORP 3B/MVE (West) and its prolongation to the east DEKORP 3B/MVE (East). Its total length amounts to about 600 km. 24 short cross lines and associated 3D blocks with single fold coverage were also recorded. The seismic survey of 3A was conducted to investigate the deep crustal structure of the Hessian Depression with high-fold near-vertical incidence vibroseis acquisition, and thus to connect DEKORP 3B/MVE (West) to oil industry seismic profiles in the Leinegraben area. Details of the experiment, preliminary results and interpretations may be obtained from DEKORP Research Group (A) et al. (1994) and DEKORP Research Group (C) et al. (1994). The Technical Report of line 3A gives complete information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The N-S trending DEKORP 3A line aimed at a seismic characterisation of the crust beneath the Permo-Mesozoic to Tertiary Hessian Depression. Running from the Solling Dome in the Rhenohercynian through the Kassel Graben and the late Tertiary volcanic fields of the Reinhardswald and Soehrewald, the 3A line ends in the Northern Phyllite Zone north of the Vogelsberg Volcano, the largest of the Cenozoic volcanoes in Europe (DEKORP Research Group (C) et al., 1994). DEKORP 3A is intersected by six short cross lines along the profile and by DEKORP 3B/MVE (West) at its southern end.

Description: DEKORP 2S was the first profile carried out in 1984 as part of the DEKORP project, the German deep seismic reflection program. The seismic line has a length of 250 km and was the first and only DEKORP line to be acquired using explosives as source energy. The objectives of the experiment were to explore the deep crustal structure of the Saxothuringian Zone and of its transitions into the adjacent Moldanubian and Rhenohercynian Zones of the Variscan Belt, to obtain evidence about vertical tectonic processes during the Variscan orogenesis, to understand the causes of observed gravity and magnetic anomalies and to recognize and define the Variscan front to the north. In addition, the survey contributed to the International Lithosphere Program (ILP) and the former European Geotraverse (EGT). Details of the experiment, preliminary results and interpretations may be obtained from DEKORP Research Group (1985) or Meissner et al. (1987). The Technical Report of line 2S gives complete information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The SE-NW striking DEKORP 2S line runs perpendicular to the Variscan strike direction and crosses the tectonic boundaries between the Moldanubian, Saxothuringian and Rhenohercynian units, which are predominantly covered by Permian and younger sediments (DEKORP Research Group, 1985). Extending from the Danube river to the Taunus Mountains line 2S crosses the Franconian Platform passing through the Noerdlinger Ries, where the impact excavated crystalline basement slivers of the Moldanubian zone, the Spessart Mountains, a part of the Mid German Crystalline High and the NE trending Hessian Through (DEKORP Research Group, 1985). Ending beyond the northeast branch of the Rhine Graben within the Taunus Mountains the profile is extended by line 2N to the northwest.

Description: The c. 93 km long profile 1A was recorded in 1987 as part of the joint seismic reflection venture DEKORP 1 of the DEKORP (German Deep Seismic Reflection Program) and BELCORP (Belgian Continental Reflection Seismic Program) project steering groups. It was surveyed to investigate the deep crustal structure of the western Rhenish Massif with high-fold near-vertical incidence vibroseis acquisition. The objectives of the experiment were to analyse deep Variscan and post-Variscan crustal structures in the region and to compare them with the results from the eastern Rhenish Massif gathered from the survey DEKORP 2N. The first results were presented by DEKORP Research Group (1990, 1991) and supplemented by many other researches. The Technical Report of line 1A gives detailed information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Rhenohercynian Zone is a foreland fold-and-thrust belt cropping out in the Rhenish Massif which extends from the Ardennes to the Harz Mountains. This geological unit consists predominantly of Devonian and Lower Carboniferous rocks affected by very low-grade metamorphism (DEKORP Research Group, 1991). The nearly NW-SE running survey 1A starts at the Dutch-Belgian border southeast of Maastricht on the southern flank of the London-Brabant Massif. The seismic line also crosses the northern rim of the Rhenish Massif passing through the Aachen Thrust, a part of the North Variscan Deformation Front. 1A runs over the Stavelot-Venn Anticline into the Northern Eifel intersecting the N-S trending axial depression of the Eifel North-South Zone nearly perpendicularly to its strike direction. The eastern flank of the depression was affected by volcanic activity of the High Eifel Volcanic Field during Early Tertiary times (DEKORP Research Group, 1991). Near Adenau the southern end of line 1A crosses the northern beginning of line DEKORP 1B, which proceeds through the Kelberg Magnetic High farther to the south.

Description: The profile 9N was recorded in 1988 as part of the DEKORP project, the German deep seismic reflection program. The seismic survey of the ca. 92-km long line 9N was conducted to investigate the deep crustal structure of the northern Upper Rhine Graben with high-fold near-vertical incidence vibroseis acquisition. The objectives of the survey were to delineate the geometry of the major faults, which control the graben subsidence, to map the geometry of deep crustal reflection patterns and to reveal variations of the seismic signature of the lower crust in the context of rift formation. The first results were discussed by Wenzel et al. (1991), summarized by Brun et al. (1992) and supplemented by many other researches. Since the Eocene the Upper Rhine Graben has represented an active rift system. It obliquely intersects the Saxothuringian and the Moldanubian domains, which are separated by the NW vergent and dextrally sheared Lalaye‐Lubine‐Baden‐Baden fault. In the northern Vosges and Black Forest massifs the shear zone is characterized by low-grade Devonian metasediments. The profile starts in the crystalline Odenwald in the east, intersects the Tertiary and Quaternary fill of the Rhine Graben and ends in the late Palaeozoic sequences of the Saar-Nahe Basin in the west, where it crosses the Permian rhyolitic Donnersberg intrusion. The profile 1C creates a continuation of the survey to the west. The seismic section of 9N shows different crustal structures on both sides of the graben and some indications of dipping reflections in the mantle on the western side, which could refer to the genesis of the Upper Rhine Graben.

Description: This data publication contains a seismic survey which was acquired in the Mont Terri Underground Rock Laboratory (URL) in January 2019. The aim of the SI-A experiment (Seismic Imaging Ahead of and around underground infrastructure) is to provide a seismic characterization at the meso scale and to investigate the feasibility of tomographic and reflection imaging in argillaceous environments. The survey covered the different facies types of Opalinus Clay: shaly facies, carbonate -rich sandy facies and sandy facies (Bossart et al. 2017). Three different seismic sources (impact, vibro, ELVIS) were used to acquire the seismic data. The impact and magnetostrictive vibro sources were particularly designed for seismic exploration in the underground (Giese et al. 2005, Richter et al. 2018). The ELVIS source was mainly designed for near-surface investigations on roads or in open terrain (Krawczyk et al. 2012). All data were recorded on 32 3-component geophones (GS-14-L3, 28 Hz) which were deployed in 2 m deep boreholes, fixed at the tip of rock anchors. The data publication covers raw and preprocessed data stored in SEG-Y format.