Magmatic volatiles can be considered as the surface fingerprint of active volcanic systems, both during periods of quiescent and eruptive volcanic activity. The spatial variability of gas emissions at Earth’s surface is a proxy for structural discontinuities in the subsurface of volcanic systems. We conducted extensive and regular spaced soil gas surveys within the Los Humeros geothermal field to improve the understanding of the structural control on fluid flow.Surveys at different scales were performed with the aim to identify areas of increased gas emissions on reservoir scale, their relation to unknown/knows volcano-tectonic structures on fault scale favoring fluid flow, and determine the origin of gas emissions. Herein, we show results from a carbon dioxide efflux scouting survey, which was performed across the main geothermal production zone together with soil temperature measurements. We identified five areas with increased carbon dioxide emissions, where further sampling was performed with denser sampling grids to understand the fault zone architecture and local variations in gas emissions.We show that a systematic sampling approach on reservoir scale is necessary for the identification and assessment of major permeable fault segments. The combined processing of CO2 efflux and carbon/helium isotopes facilitated the detection of permeable structural segments with a connection to the deep, high-temperature geothermal reservoir, also in areas with low to intermediate carbon dioxide emissions. The results of this study complement existing geophysical datasets and define further promising areas for future exploration activities in the north- and southwestern sector of the production field.The data are presented as one zip folder with 4 data tables (tab delimited text format) according to the measurement variable. The columns are defined in each data file.
Petrophysical properties are key to populate numerical models of subsurface process simulations and for the interpretation of many geophysical exploration methods. They are characteristic for specific rock types and may vary considerably as a response to subsurface conditions (e.g. temperature and pressure). Hence, the quality of process simulations and geophysical data interpretation critically depend on the knowledge of in-situ physical properties that have been measured for a specific rock unit.Inquiries for rock property values for a specific site might become a very time-consuming challenge given that such data are (1) spread across diverse publications and compilations, (2) heterogeneous in quality and (3) continuously being acquired in different laboratories worldwide. One important quality factor for the usability of measured petrophysical properties is the availability of corresponding metadata such as the sample location, petrography, stratigraphy, or the measuring method, conditions and authorship.The open-access database presented here aims at providing easily accessible, peer-reviewed information on physical rock properties in one single compilation. As it has been developed within the scope of the EC funded project IMAGE (Integrated Methods for Advanced Geothermal Exploration, EU grant agreement No. 608553), the database mainly contains information relevant for geothermal exploration and reservoir characterization, namely hydraulic, thermophysical and mechanical properties and, in addition, electrical resistivity and magnetic susceptibility.The uniqueness of this database emerges from its coverage and metadata structure. Each measured value is complemented by the corresponding sample location, petrographic description, chronostratigraphic age and original citation. The original stratigraphic and petrographic descriptions are transferred to standardized catalogues following a hierarchical structure ensuring intercomparability for statistical analysis. In addition, information on the experimental set-up (methods) and the measurement conditions are given for quality control. Thus, rock properties can directly be related to in-situ conditions to derive specific parameters relevant for modelling the subsurface or interpreting geophysical data.