This dataset documents surface deformation and fracture evolution on Mount Thorbjörn during the 2023 - 2024 volcano-tectonic unrest in the Svartsengi volcanic system on the Reykjanes Peninsula (SW Iceland). The data consist of four cm-resolution orthophotos and digital elevation models (DEMs) derived from four drone photogrammetric surveys conducted on 23 July 2022, 18 November 2023, 25 April 2024 and 20 August 2024. The drone images were processed using Agisoft Metashape software to generate products for structural mapping and temporal comparison. The drone data evidences fracture reactivation processes and associated new surface fractures and sinkholes. The dataset includes maps of these structures, carried out using QGIS, and describes their temporal evolution. A full description of the data can be found in the file description.
The western Eger Rift in the Czech Republic is a currently inactive volcanic area characterized by earthquake swarms and degassing of mantle-derived fluids. Gases obtained from minerals and from repeatedly sampled free gases are used to trace the origin and evolution of volatiles and determine the conditions of the magma reservoir. Helium isotopes in fluids and minerals are up to 5.95 RA, with 20Ne/22Ne ratios up to ~11.0 and 21Ne/22Ne ratios up to ~0.048, suggesting a mixed atmospheric-mantle source for neon. Some crustal input may also be present. The slightly lower-than-mantle He isotopic ratios and the variability in Ne isotopic compositions indicate that these gases may have been impacted by a subduction-related crustal component during the Variscan (or Hercynian) Orogeny. 40Ar/36Ar ratios are higher than atmospheric levels and arrive up to 4680, indicating a mixture of atmospheric and mantle sources. Thermobarometry of pyroxene mineral grains reveals temperatures and pressures suggesting that the crystallization started at ~75 km depth and ended at ~20 km depth following a smooth p-T course. This implies diverse magma ascent conditions.
A total of 56 gas samples were collected from two intensively degassing areas in the western Eger Rift (Czech Republic), namely the mofette fields of Bublák and Hartoušov. From the Hartoušov mofette field, 24 gas samples of fluids ascending in two boreholes (F1:∼28 m depth and F2: ∼108 m depth) and 22 samples of gases emerging in two nearby ponds [surface expressions Hartoušov Mofette (HM) and Hartoušov Mofette South (HMS)] were taken. Ten samples were collected from a pond in the Bublák mofette field (Bbl). In addition to the gas samples, ten rock samples were collected from rock exposures [i.e. Libá (LI) and Číhaná (CI) in quarries, Horní Slavkov (HS1&2), Pila (PI), Dolní Dražov (DD), Kadaň (KN), Horní Paseky (HP), and Slapany (SL) in natural cliffs, and Hlinky (HL) in an outcrop] within the western Eger rift area. In addition, six samples of ultramafic nodules/xenoliths were obtained from the Quaternary tephra deposit of the Mýtina maar and from Železná hůrka scoria cone.
Gas and rock sampling:
This data set includes videos depicting the surface evolution of 29 analogue models on crustal extension, as well as 4D CT imagery (figures and videos) of two of these experiments. The experiments examined the influence of the method for driving extension (orthogonal or rotational) on the interaction between rift segments using a brittle-viscous set-up.
All experiments were performed at the Tectonic Modelling Laboratory of the University of Bern, Bern, Switzerland (UB). Brittle and viscous layers are both 4 cm thick, extension velocities are 8 mm/h so that a model duration of 5 h yields a total extension of 40 mm (e = ca. 13%, given an initial model width of ca. 30 mm). Next to the mode of extension (orthogonal or rotational), we also test the effect of the degree of onderlap (angle φ). Detailed descriptions of the experiments and monitoring techniques can be found in Zwaan et al. (2020).
This dataset includes the results of 5 lithospheric-scale, brittle-ductile analogue experiments of extension and subsequent shortening performed at the Geodynamic Modelling Laboratory at Monash University (Melbourne, Australia). Here we investigated (1) the influence of the mechanical stratification of the model layers on rift basins during extension and (2) the influence of these basins on shortening-related structures. This dataset consists of images and movies that illustrate the evolution of topography (i.e., model surface height) and cumulative and incremental axial strain during the experiments. Topography and strain measures were obtained using digital image correlation (DIC) which was applied to sequential images of the model surface. This dataset also includes orthophotos (i.e., orthorectified images) of the model surface, overlain with fault traces and basins that were interpreted using QGIS. The experiments are described in detail in Samsu et al. (submitted to Solid Earth), to which this dataset is supplementary.