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Mechanical data of rotary shear experiments in bituminous dolostones

Mirror-like Surfaces (MSs) are ultra-polished fault surfaces widespread in carbonate seismic terrains, but their formation process is still debated. We deformed gouge samples from exposed fault surfaces hosted in bituminous dolostone rocks in a rotary shear apparatus (SHIVA) at seismic slip rates (1 m/s). By changing the water availability (water-pressurised and room-humidity conditions) and the organic matter/dolomite content (> 35%, dark gouge DG; < 30% bright gouge BG) we investigated the mechanical behaviour leading to MSs formation in fault gouges. We run tests at 15 MPa effective normal stress, 2 MPa confinement and 1 MPa pore pressure for the water-pressurised experiments and a total displacement of 0.13 m. Mirror-like fault surfaces were obtained in all successful experiments; mirrors were more developed under room-humidity conditions. Bituminous dolostones under room-humidity conditions had a slip neutral behaviour with a low friction (0.3). Bituminous dolostones under water-pressurised conditions showed a slip weakening behaviour with an initial peak effective friction μp = 0.65, followed by a drop to effective friction μss DG than in BG (i.e., μss of 0.25 vs 0.28). Future work will focus on the microstructural analysis of the experimental products and the investigation of the slip behaviour of bituminous dolostones at sub-seismic slip rates for a complete study of the slip behaviour spectra. This publication results from work conducted under the national open access action at SHIVA (Slow to High Velocity Apparatus) - HP-HT laboratory of experimental Volcanology and Geophysics (INGV, Roma 1 section) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Carbon isotopes in OIB Mantle source

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Microstructure and mechanical properties of massive and porous of lavas from S. Miguel Island (Azores, Portugal)

The role of elongated pores and crystals of lavas influences their mechanical and physical behaviour, providing a first microstructural clue. In the context of a doctoral project, two samples – a trachyte and a basalt/andesite (s.l.) - representative of Fogo Volcano (S. Miguel Island, Azores, Portugal) were collected as part of an intact rock study. They were microstructurally assessed in the INGV-OV (Naples) using the ZEISS Xradia Versa 410 X-ray computed microtomography to obtain high-resolution 3D images, as well as to perform real-time in-situ mechanical tests (uniaxial – 7 mm diameter cylinders - and Brazilian – 13 mm diameter discs) to assess how elongated pores/crystals control strength. In addition to 3D images of the samples, which allow segmentation of the pore space and crystals, mechanical tests show that trachytes are more competent than vesicular basalts/andesites. Both pores and crystals control the development of the crack pattern.

CAMSIZER Particle Size Data from Explosive Paroxysms of Mt. Etna (2011–2025)

Mt. Etna in Catania, Italy, is an active volcano that has served as a natural laboratory for many volcanologists worldwide. Its paroxysms are unique eruptive events caused by a complex magmatic system that, despite being one of the most studied volcanoes, there is still an open field to contribute to the understanding of magma dynamics and degassing. This data set is a compilation of grain-size and shape measurements of 14 tephra samples of Mt. Etna. The tephra samples correspond to some of the most explosive cycles and events of the volcano from 2011 to 2025. The measurements were obtained using CAMSIZER through the ILGE TNA grant funding at INGV sezione di Catania. This dataset is the basis for a research project investigating the controls on the volume of gases and magma emitted during an eruption of Mt. Etna. This publication results from work conducted under the transnational access/national open access action at Sedimentology Laboratory – INGV sezione di Catania supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Trace element concentration of minerals in the Morro São João malignites (Serra do Mar, Brazil)

The Morro São João intrusion is located in the easternmost part of the Serra do Mar province, along the Cabo Frio lineament (Fig. 1) and has an area of approximately 10 km². It is a Late Cretaceous intrusion formed by clinopyroxenites, melagabbros, shonkinites, malignites, nepheline syenites, and phonolite dikes, without olivine, and is thought to have formed by closed system crystallization of a fairly evolved tephritic melt of potassic/ultrapotassic affinity (cf. Brotzu et al., 2007). We have analyzed two malignites, and specifically, their liquidus phases (clinopyroxene, titanite, garnet, amphibole). Analyzing the trace elements in these minerals helps us to better understand the different fractionation of the elements in these coexisting phases, and the implications for the evolution processes that occurred in the Morro São João magma reservoir. These analyses also provided important information about the concentration of rare earth elements (REEs) and high field strength elements (HFSEs), and their change with the magmatic evolution of the suite. This publication results from work conducted under the transnational access/national open access action at Mass spectrometry la-icp laboratory (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Horizontal-to-Vertical Spectral Ratios (HVSR) of NW Italy seismic stations elaborated during the "FOCUS-HVNEA" NOA-ILGE project

This data set consists of Horizontal-to-Vertical Spectral Ratios (HVSR) resulting from the application of the software package HVNEA (HV Noise and Earthquake Automatic Analysis) with the aim of comparing them with those resulting from the application of another method, namely STATION (Seismic sTATion and sIte amplificatiON). The results, relative to more than 24,000 HVSR, derive from the processing of 700,000 seismograms recorded over different time periods by 8 stations of the networks IV (Italian Seismic Network), GU (Regional Seismic Network of North Western Italy) and GV (Mobile RSNI). To compare the results of the two methods as accurately as possible, the waveforms were subjected to the same preprocessing already used to elaborate the results stored in the STATION database. To this end, the methodological workflow applied with HVNEA for station IV.MURB involved the selection of segments from continuous recordings for each event reported in the INGV catalogue located within a radius of 120 kilometres from the station. Starting from the automatically picked S-wave onsets, 12-second windows were then extracted and used for the analysis of earthquake recordings. Regarding the noise analysis, it should be noted that STATION again considers 12-second windows selected before the P-wave onset, while HVNEA requires the use of a signal window of at least 60 seconds. A window of 3,600 seconds was used for the analysis. The comparison of the HVSR was performed in the frequency band 0.1–15 Hz. All analysed curves, for both earthquake and noise recordings, show generally similar shapes and identify significant peaks in correspondence of the same frequency ranges, although the amplitudes obtained with STATION are systematically higher than those obtained with HVNEA. To obtain a quantitative comparison, various statistical metrics commonly used to measure the discrepancy between data sets were applied, namely the Mean Squared Error, the Mean Absolute Error and the Pearson Correlation Coefficient. This publication results from work conducted under the transnational access/national open access action at the Site effects Laboratory – INGV L’Aquila supported by WP3 ILGE–MEET project, PNRR–EU Next Generation Europe program, MUR grant number D53C22001400005.

Dense Seismic Array of Ambient Vibrations Applied for Site Characterization to a Liquefiable Site in the Po Plain at San Felice sul Panaro

The dataset consists of microtremor recordings collected from multiple arrays in mid-September 2024 at San Felice sul Panaro, located in the Quaternary deposits of the Po Plain (Emilia-Romagna, Italy). Data collection was performed using seismic nodes and six-component seismic stations: five stations Reftek recorders provided by INGV - Sezione Roma 1 (Italy) and six Certimus seismic stations from Cerema, as part of a collaboration between the Istituto Nazionale di Geofisica e Vulcanologia and Cerema. Five concentric arrays, with radii of 50, 100, 200, 300, and 400 meters, were installed, each consisting of five stations. These arrays were active for a few days, centered around the SAN0 seismic station, which recorded the second shock of the Emilia Romagna seismic sequence in 2012. The Certimus seismic stations, co-located with nodes, were placed at the 400-meter radius and at the center, while INGV stations, also co-located with nodes, were installed on the 200-meter circle. Nodes alone were used for the remaining circles. Additionally, 46 single-station recordings were performed. The project proposal “SISFelice: Towards the Identification of the Physical Mechanisms Driving Nonlinear Soil Behavior Using Accelerometric Data: Site Characterization of San Felice” (PI: Julie Régnier) aims to study the impact of nonlinear soil behavior on site response during earthquakes. Within the framework of Joya El Hitti’s PhD, our research seeks to differentiate the physical mechanisms behind nonlinear soil behavior for more accurate earthquake predictions based on seismological observations. In this project, we plan to utilize earthquake recordings from the 2012 Emilia Romagna earthquake sequence at SAN0, San Felice sul Panaro, a site known for liquefaction. Despite nearby geotechnical tests, there remains a gap in characterizing the variability of site response and shear wave velocity profiles. Our project aims to address this by conducting single-station H/V measurements to assess spatial variability in site response and characterize the shear wave velocity profile down to bedrock. This publication results from work conducted under the transnational access/national open access action at INGV – lab Effetti di SITO (ESITO) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005

Trace element analysis of the main minerals in the Salitre lamprophyre (APIP, Brazil)

The Upper Cretaceous Salitre intrusion, subdivided into Salitre I and Salitre II and dated to ~86-82 Ma by Sonoki and Garda (1988), is part of the Alto Paranaíba Igneous Province (APIP, Fig. 1) in Brazil, which is one of the largest ultrapotassic / carbonatitic / kimberlitic provinces in the world. The intrusion is characterized by the presence of lamproites, carbonatites and one lamprophyre (analyzed here), as well as along with a variety of intrusive cumulitic rocks. Among the Salitre studied samples, this alkaline lamprophyre is characterized by low SiO2 (35.6 wt%), ultrapotassic (K2O/Na2O = 5; K2O = 4.4 wt%) and peralkaline (PI = 1.3). It exhibits variable MgO content (14 wt%) and is enriched in REEs (∑REE=~1,300 ppm) and other trace elements (Nb, Ta, Zr, Hf, Sr, Ba). This lamprophyre is characterized by olivine and phlogopite phenocrysts set in a fine-grained groundmass of clinopyroxene, apatite, phlogopite, magnetite, chromite, and perovskite, with rare titanite and garnet; kalsilite is absent. Analyzing the trace elements of the main minerals in this lamprophyre helped us learn more about the origin and evolution of these magmas, as well as their possible genetic link with the other Salitre rocks. This analysis also provided important information about their enrichment in rare earth elements (REEs) and high field strength elements (HFSEs). This publication results from work conducted under the transnational access/national open access action at Mass spectrometry la-icp laboratory (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Crystal Size Distribution Analyses of Isothermal Deformation Experiments

In this work we aimed to investigate and quantify the relative importance of dynamic conditions (e.g., stirring in a Concentric Cylinder apparatus) on the crystallization kinetics of basaltic magmas (Stromboli). This was achieved by observing the final textures of the samples, analysing the resulting SEM images, and finally relating the resulting parameters to specific growth and nucleation rates. The dataset is made of: 1) A folder called "SEM Images" with two sub-folders inside, representative of the two experiments carried out, called "CG1" and "CG2.3" 2) An Excel file, consisting in 4 data sheets, where all results of image analysis are included, divided in sections. The sheets are also available in CSV format. This publication results from work conducted under the transnational access/national open access action at High Pressure - High Temperature Laboratory (HPHT Lab), Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

3D textural characterization of rocks representing S. Miguel Island (Azores, Portugal)

The role of the physical and microstructural properties of lavas impacts the dynamics of magma ascent and of the volcanic edifice itself. In the context of a doctoral project, ten samples representative of the central volcanoes of S. Miguel Island (Azores, Portugal), priorily collected in available outcrops in the island, were microstructurally assessed for the first time in the INGV-OV (Naples). Imaging was processed by the ZEISS Xradia Versa 410 X-ray computed microtomography. This tool enables accurate and complete textural characterization of rocks by providing 3D images of the samples. Posteriorly, the rocks were analysed with a dedicated image analysis software to resolve the internal microstructure of the samples. determining several key properties (porosity, permeability, fracturation, and crystal content) that are of major relevance for a posterior physical and mechanical assessment. This publication results from work conducted under the transnational access/national open access action at magLab, INGV-OV (Naples, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

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