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Carbon isotopes in OIB Mantle source

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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.

Dataset of wehrlitization process: insights from X-ray Micro-CT of Mt. Vulture (southern Italy) mantle xenoliths

The study of textural and chemical characteristics of mafic minerals from mantle xenoliths is essential to investigate the nature of the upper mantle in a continental geodynamic context, melts generation and their effects related to mantle metasomatism. Particular textures in mantle minerals, inclusions or secondary veins of different nature (silicates vs carbonates), bubbles, represent petrographic tools to investigate these processes within the mantle. Petrographic 2D thin sections might overlook these mineralogical features, and 3D textural analysis through X-ray computed microtomography (micro-CT) are crucial to overcome these limitations. We focused on the Mt. Vulture volcano (southern Italy) rare mantle xenoliths, brought to the surface by a melilitite-carbonatite magma (141 ka), with particular emphasis to spinel-wehrlite xenoliths and wehrlitization processes that is located close to an area of intense CO2 degassing associated to catastrophic earthquakes. Preliminary results showed interesting 3D textural distributions within the studied xenoliths-forming mantle minerals. In particular, the micro-CT allowed to furnish new constrains on the relationship between fluids entrapment and migration, and structural discontinuities. Indeed, some minerals (especially those from the wehrlite xenoliths) showed a well-correlated distribution of fluid inclusions along the secondary fracturing planes. This publication results from work conducted under the transnational access/national open access action at Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Vesuviano (INGV-OV) and supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005. The author thanks also Gianmarco Buono and Lucia Pappalardo for their support during the analyses and the post processing process.

∂13C data of picrite rock samples from St Helena Island (South Atlantic Ocean)

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The noble gas isotopic composition of the upper mantle in non-arc oceanic settings: Inferences from fluid inclusion studies

OIB localities (e.g., Tristan, Samoa) have been considered ideal natural laboratories for studying mantle heterogeneity. Indeed, Sr, Nd, and Pb isotopes of lavas collected from OIB systems have provided insights into the existence of distinct mantle reservoirs, the origins of which are closely related to local tectonic processes: DMM, HIMU, EM1, and EM2. In this context, we aim to investigate the isotopic composition of noble gases in fluid inclusions trapped in xenoliths and lavas from Samoa and Tristan islands, two well-known enriched mantle (EM) localities. Our goal is to evaluate the role of noble gas cycling and active tectonic processes on the composition of the upper mantle. Our results show that CO2 is the most abundant volatile in all samples (lavas and xenoliths) from both localities. The 4He/20Ne ratio in most samples is lower than 150, suggesting the presence of atmospheric components in the fluid inclusions. This is further confirmed by the relatively low 40Ar/36Ar ratios, particularly in Tristan samples, which show values below 360. It is worth noting that the Samoa sample exhibits a 40Ar/36Ar ratio of 1000.4, the highest of the dataset. The Rc/Ra values (3He/4He corrected for atmospheric contamination) observed in the Samoa samples align with the Ar ratios mentioned above, as the 3He/4He ratio is the highest reported (13.32Ra). This is above the MORB range, indicating a contribution from lower mantle fluids, likely derived from the Samoan hotspot. In contrast, Tristan samples exhibit low Rc/Ra values, with an average of 5.12Ra. These low helium ratios suggest the presence of a more radiogenic, 4He-rich mantle. The low helium ratios may be related to the EM nature of the mantle. Previous studies in the Canary Islands have shown a decrease in 3He/4He ratios in the eastern part of the archipelago, where EM components have been identified (Hoernle et al., 1993; Simonsen et al., 2001; Day and Hilton, 2011, 2021; Sandoval-Velasquez et al., 2021). However, it is confirmed that an EM component can show a wide range of variation for the 3He/4He ratio, ranging from low values of 5-6Ra to values beyond the typical MORB range, which overlaps (and complicates the distinction) with other OIB contexts with HIMU signature. This publication results from work conducted under the transnational access/national open access action at INGV-Palermo- Noble gas laboratory supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

A database of analogue models and geophysical data investigating caldera resurgence; DynamiCal project

In this dataset we provide data for 6 experimental models of caldera collapse and subsequent resurgence monitored through geophysical sensors (a force or “impact sensor”, Piezotronics PCB 104 200B02 and a Triaxial piezoelectric accelerometer, Model 356B18). The analogue modelling experiments were carried out at the TOOLab (Tectonic Modelling Laboratory), which is a joint laboratory between the Istituto di Geoscienze e Georisorse of the Consiglio Nazionale delle Ricerche, Italy and the Department of Earth Sciences of the University of Florence. The laboratory work that produced these data was partly supported by the European Plate Observing System (EPOS), by the Joint Research Unit (JRU) EPOS Italia and by the “Monitoring Earth's Evolution and Tectonics” (MEET) project (NextGenerationEU). Specifically, this work was performed in the frame of the DynamiCal project, funded by the 2° TNA-NOA call of the ILGE-MEET project.

Results of analogue tectonic models of rifting and tectonic lineament reactivation along the Main Ethiopian Rift

This data set includes results from a total of 13 analogue tectonic models aimed at simulating the activation of tectonic lineaments associated with the Main Ethiopian Rift in eastern Africa. We use a model set-up based on previous work by Zwaan et al. (2021, 2022). This set-up involves a velocity discontinuity (VD, i.e., the edge of a mobile base plate) to induce extension in the overlying brittle- and viscous model materials representing the upper and lower crust, respectively. Additional structural weaknesses (seeds) at the base of the brittle layer serve to represent activated tectonic weaknesses in nature. Model parameters (different VD and seed orientation, and different seed diameters) are summarized in Table 1. The model results presented in this data publication are obtained through Digital Image Correlation (DIC) and Structure-from-Motion (SfM) analyses. A more detailed description of model set-up, model results, and their interpretation can be found in Zwaan et al. (2025)

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.

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

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