Alba Simona Zappone

Last Name

Zappone

First Name

Alba Simona

ORCID

0000-0003-0965-7271

Organisational unit

03476 - Giardini, Domenico (emeritus) / Giardini, Domenico (emeritus)

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Publications 1 - 10 of 24

Gas equilibrium membrane inlet mass spectrometry (GE-MIMS) for water at high pressure
Brennwald, Matthias S.; Rinaldi, Antonio Pio; Gisiger, Jocelyn; et al. (2024)
Geoscientific Instrumentation, Methods and Data Systems
Gas species are widely used as natural or artificial tracers to study fluid dynamics in environmental and geological systems. The recently developed gas equilibrium membrane inlet mass spectrometry (GE-MIMS) method is most useful for accurate and autonomous on-site quantification of dissolved gases in aquatic systems. GE-MIMS works by pumping water through a gas equilibrator module containing a gas headspace, which is separated from the water by a gas-permeable membrane. The partial pressures of the gas species in the headspace equilibrate with the gas concentrations in the water according to Henry's Law and are quantified with a mass spectrometer optimized for low gas consumption (miniRUEDI or similar). However, the fragile membrane structures of the commonly used equilibrator modules break down at water pressures ĝ‰33ĝ€¯bar. These modules are therefore not suitable for use in deep geological systems or other environments with high water pressures. To this end, the SysMoG® MD membrane module (Solexperts AG, Switzerland; "SOMM") was developed to withstand water pressures of up to 100ĝ€¯bar. Compared to the conventionally used GE-MIMS equilibrator modules, the mechanically robust construction of the SOMM module entails slow and potentially incomplete gas-water equilibration. We tested the gas equilibration efficiency of the SOMM and developed an adapted protocol that allows correct operation of the SOMM for GE-MIMS analysis at high water pressures. This adapted SOMM GE-MIMS technique exhibits a very low gas consumption from the SOMM to maintain the gas-water equilibrium according to Henry's Law and provides the same analytical accuracy and precision as the conventional GE-MIMS technique. The analytical potential of the adapted SOMM GE-MIMS technique was demonstrated in a high-pressure fluid migration experiment in an underground rock laboratory. The new technique overcomes the pressure limitations of conventional gas equilibrators and thereby opens new opportunities for efficient and autonomous on-site quantification of dissolved gases in high-pressure environments, such as in research and monitoring of underground storage of CO2 and waste deposits or in the exploration of natural resources.
Structural Evolution, Exhumation Rates, and Rheology of the European Crust During Alpine Collision: Constraints From the Rotondo Granite—Gotthard Nappe
Ceccato, Alberto; Behr, Whitney M.; Zappone, Alba Simona; et al. (2024)
Tectonics
The rheology of crystalline units controls the large-scale deformation geometry and dynamics of collisional orogens. Defining a time-constrained rheological evolution of such units may help unravel the details of collisional dynamics. Here, we integrate field analysis, pseudosection calculations and in situ garnet U–Pb and mica Rb–Sr geochronology to define the structural and rheological evolution of the Rotondo granite (Gotthard nappe, Central Alps). We identify a sequence of four (D1–D4) deformation stages. Pre-collisional D1 brittle faults developed before Alpine peak metamorphism, which occurred at 34–20 Ma (U–Pb garnet ages) at 590 ± 25°C and 0.9 ± 0.1 GPa. The reactivation of D1 structures controlled the rheological evolution, from D2 reverse mylonitic shearing at amphibolite facies (520 ± 40°C and 0.8 ± 0.1 GPa) at 18–20 Ma (white mica Rb–Sr ages), to strike-slip, brittle-ductile shearing at greenschist-facies D3 (395 ± 25°C and 0.4 ± 0.1 GPa) at 14–15 Ma (white mica and biotite Rb–Sr ages), and then to D4 strike-slip faulting at shallow conditions. Although highly misoriented for the Alpine collisional stress orientation, D1 brittle structures controlled the localization of D2 ductile mylonites accommodating fast (∼3 mm/yr) exhumation rates due to their weak shear strength (<10 MPa). This structural and rheological evolution is common across External Crystalline Massifs (e.g., Aar, Mont Blanc), suggesting that the European upper crust was extremely weak during Alpine collision, its strength controlled by weak ductile shear zones localized on pre-collisional deformation structures, that in turn controlled localized exhumation at the scale of the orogen.
Use of Distributed Acoustic Sensing and Distributed Strain Sensing Technologies for Geomechanical Characterization of Rock Mass Response in Mesoscale Experiments in Underground Laboratories: Lessons Learned
Rodríguez Tribaldos, Verónica; Hopp, Chet; Rinaldi, Antonio Pio; et al. (2024)
Geophysical Monograph Series ~ Distributed Acoustic Sensing in Borehole Geophysics
Distributed fiber-optic sensing (DFOS) is a promising technology for efficient, high-resolution monitoring and characterization of rock mass response to stimulation during subsurface operations. However, uncertainties in its implementation and the impact of experimental components on the measurements remain. Underground research laboratories (URLs) provide opportunities to test and optimize DFOS approaches through controlled experiments in relevant conditions. Here, we present practical observations gathered from implementing downhole DFOS for geomechanical monitoring during fluid injection experiments conducted in the Sanford Underground Research Facility (SURF) in the United States and the Mont Terri Rock Laboratory (MTRL) in Switzerland, as part of the EGS Collab (at SURF) and the Carbon Sequestration Series D and Fault Slip B (at MTRL) projects. We investigate the performance of low-frequency distributed acoustic sensing (DAS) and distributed strain sensing (DSS) for strain-rate and strain monitoring and evaluate the effect of contrasting cable designs, installation methods, and acquisition parameters. Results suggest that cable construction and installation affect noise levels and measured strain magnitudes. We also discuss experimental and logistical constraints imposed by URLs. Observations are summarized as lessons learned that we hope will guide future investigations and encourage implementing borehole-based DFOS for geomechanical characterization and monitoring in URLs and beyond.
The structural evolution of the Rotondo granite (Gotthard nappe, Central Alps): constraints on the strength and timing of weakening of the European upper crust during Alpine collision
Ceccato, Alberto; Behr, Whitney M.; Zappone, Alba Simona; et al. (2024)
16th EGU Emile Argand Conference on Alpine Geological Studies: Alpine Workshop. Abstract Book and List of Authors
The Effect of Fault Architecture on Slip Behavior in Shale Revealed by Distributed Fiber Optic Strain Sensing
Hopp, Chet; Guglielmi, Yves; Rinaldi, Antonio Pio; et al. (2022)
Journal of Geophysical Research: Solid Earth
We use Distributed Strain Sensing (DSS) through Brillouin scattering measurements to characterize the reactivation of a fault zone in shale (Opalinus clay), caused by the excavation of a gallery at ∼400 m depth in the Mont Terri Underground Laboratory (Switzerland). DSS fibers are cemented behind casing in six boreholes cross-cutting the fault zone. We compare the DSS data with co-located measurements of displacement from a chain potentiometer and a three-dimensional displacement sensor (SIMFIP). DSS proves to be able to detect in- and off-fault strain variations induced by the gallery excavated 30–50 m away. The total permanent displacement of the fault is ∼200 microns at rates up to 1.5 nm/s. DSS is sensitive to longitudinal and shear strain with measurements showing that fault shear is concentrated at the top and bottom interfaces of the fault zone with little deformation within the fault zone itself. Such a localized pattern of strain relates to the architecture of the fault that is characterized by a thick “layer” including an anastomosing network of polished surfaces where clay-rich rock splits into progressively smaller flakes conferring the entire zone very little cohesion and friction (weak zone), and favoring slipping at the edges of the “layer”. Overall, DSS shows that slow slip may activate everywhere there is a weak fault within a shale series. Thus, our work demonstrates the importance of shear strain on faults caused by remote loading, highlighting the utility of DSS systems to detect and quantify these effects at large reservoir scales.
The response of a fractured crystalline reservoir to natural pressure buildup: Experiment results from the Bedretto Lab
Shakas, Alexis; Gholizadeh Doonechaly, Nima; Hertrich, Marian; et al. (2021)
EGUsphere
Swiss Potential for Geothermal Energy and CO2 Storage
Driesner, Thomas; Gischig, Valentin; Hertrich, Marian; et al. (2021)
Selection and Characterisation of the Target Fault for Fluid-Induced Activation and Earthquake Rupture Experiments
Achtziger-Zupančič, Peter; Ceccato, Alberto; Zappone, Alba Simona; et al. (2024)
EGUsphere
Performing stimulation experiments at approximately 1 km depth in the Bedretto Underground Laboratory for Geosciences and Geoenergies necessitates identifying and characterizing the target fault zone for on-fault monitoring of induced fault-slip and seismicity, a current challenge in understanding seismogenic processes. We discuss the multidisciplinary approach for selecting the target fault zone for the experiments planned within the Fault Activation and Earthquake Ruptures (FEAR) project, aiming to induce fault-slip and seismicity up to a magnitude 1.0 earthquake while enhancing monitoring and control of fluid-injection experiments. Structural geological mapping, remote sensing, exploration drilling and borehole logging, ground-penetration radar, and laboratory investigations were employed to identify and characterize the target fault – a ductile-brittle shear zone several meters wide with intensely fractured volume persisting over 100 m. Its orientation in the in-situ stress field favors reactivation in normal to strike-slip regimes. Laboratory tests showed slight velocity strengthening of the fault gouge. The fault's architecture, typical for crystalline environments, poses challenges for fluid flow, necessitating detailed hydraulic and stress characterization before each of the FEAR experiments. This multidisciplinary approach was crucial for managing rock volume heterogeneity and understand implications for the dense monitoring network. Successfully identifying the fault sets the stage for seismic activation experiments commencing in spring 2024.
Geophysical Site Characterization and monitoring of CO2 mineralization in Basaltic Complexes, Helguvik, Iceland
Junker, Jonas; Obermann, Anne; Zappone, Alba Simona; et al. (2024)
EGUsphere
In a pilot project (DemoUpStorage) in Helguvik, Iceland, CO2 is injected into basaltic strata using seawater instead of freshwater for CO2 dissolution. The aim is to obtain permanent storage of the CO2 by mineral carbonation. We aim to observe the precipitation of Mg and Fe carbonates in the porosity of the reservoir at depth. Additional to geochemical observations, we use geophysical methods (ERT, seismics) to monitor the mineralization process. Here, we present the overall project, the geophysical characterization of the site and the first time-lapse monitoring results. We performed a cross-hole seismic traveltime tomography and single-hole electrical resistivity (ERT) measurements to characterize the study site in the target depth of 150m to 400m and to record a geophysical baseline for the time-lapse measurements. The seismic and geoelectric data are in good agreement, highlighting multiple basaltic layers of tens of meters in thickness with sedimentary interlayers. With the CO2 injection starting in early 2024, we will also show the first results from the (daily) time-lapse ERT surveys.
Characterization and 3D geometrical modelling of a complex fault zone for earthquake rupture experiments
Ceccato, Alberto; Achtziger-Zupančič, Peter; Pozzi, Giacomo; et al. (2024)
EGUsphere
Fault zone geological and geometrical complexities are prime parameters playing a fundamental role in controlling the characteristics of both natural and induced seismicity. In the Bedretto tunnel (Switzerland), the Fault Activation and Earthquake Rupture (FEAR) project aims at triggering a Mw = 1 seismic event through fluid injection and stimulation of a natural fault zone situated in a large-scale (> 106 m3) fractured granite reservoir. The limited exposure of the fault zone in the tunnel, however, restricts the possibility to constrain in detail the geometrical and geological characteristics of the experimental target. Therefore, in order to constrain the geological and geometrical characteristics of the target fault zone, we have integrated structural analyses, borehole and core logging, and borehole ground penetrating radar (GPR). Preliminary field investigations in the tunnel allowed to identify the complex fault structure characteristics, fault rock properties, and slip tendency in the current stress field of the selected fault zone. These results were compared to the structural observations obtained from field surveys and remote sensing, constraining the slip history, and lateral extent of the set of natural fault zones occurring on the surface above the Bedretto tunnel. Indeed, the lateral extent of the selected fault has been confirmed through the logging (optical/acoustic televiewer, fracture intensity, fracture typology) of exploration boreholes and the analyses of the related cores. The comparison between the geological characteristics of fault zones in the cores and the characteristics of the selected fault zone exposed in the tunnel allowed to confirm the occurrence of the same typology of fault zone further away from the exposure in the tunnel. In addition, GPR logging of the exploratory boreholes provided fundamental insights on the lateral continuity of the identified fault zones on the tunnel wall, as well as those identified in the borehole/core logging. All geological and geometrical information have been integrated into a preliminary 3D geometrical model (in Leapfrog Geo), representing the overall geometry of the selected fault zone. This preliminary geometrical model has been validated against synthetic GPR profiles, computed through GPR forward modelling along the exploration boreholes. The integrated results define the selected fault zone as a 3-7 m wide zone of higher density (up to 5/m), of variably oriented secondary fractures, and bounded by two main slip surfaces. The slip surfaces are irregularly decorated by phyllosilicate-rich gouge patches, filling the roughness of the fault surface. The lateral extension of each discrete fracture does not exceed 30 m in length, but the overall lateral continuity of the fault zone exceeds several hundreds of meters. The presented integrated characterization approach allowed us to constrain a geologically-sound, first-order 3D geometrical model of a complex natural fault zone, validated against geophysical forward modelling. These preliminary results have fundamental implications for the expected experimental planning and outcomes, modelling and injection strategies, project logistics, as well as the design and deployment of the monitoring network around the stimulated fault zone.

Publications 1 - 10 of 24

Alba Simona Zappone

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