Annals of Geophysics (INGV, Istituto Nazionale di Geofisica e Vulcanologia)
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Spatial data and GIS for the assessment of the environmental impact at Mount Etna
Full text linkOne of the fundamental tasks for environmental impact assessment and natural risk management is the accurate and updated cataloging of road infrastructures and buildings. This is particularly important in volcanic areas, in order to predict the range of damage and disruption, and therefore losses and reconstruction costs that could result from an eruption. GIS allows immediate access to spatial data with the ability to overlay location-based information for easy interpretation, providing a critical tool for assessing and mitigating risk from natural phenomena. In this work, we present an innovative GIS‑based system for the identification of the values exposed to volcanic eruptions at Mount Etna, which can be used in both the readiness and response phases to a volcanic emergency. We carried out a precision mapping of buildings and road infrastructures on the flanks of the Etna volcano, giving particular attention to the exposed sensitive buildings (such as schools, barracks, hospitals, etc.) and to the construction and roofing characteristics. The result is an informative and dynamic platform that offers new opportunities and challenges to decision makers for the definition of both long‑term strategies, such as territorial planning, and short‑term strategies, for the prediction of the impact of eruptions or for managing evacuations during volcanic emergencies
DIVEnet: a local seismographic network monitoring the lower continental crust drilling activities for the ICDP-DIVE project
No full textThe ICDP DIVE project (Drilling the Ivrea‑Verbano zonE) addresses fundamental questions about the nature of the lower continental crust and its transition to the mantle. In its first phase, the project has drilled two, scientific, fully cored boreholes in the Ivrea Verbano Zone (IVZ) in Italy. The IVZ, considered the world’s best outcrop of lower crustal continental rocks, is structurally and historically connected to the underlying Ivrea Geophysical Body, a major, high density and high seismic‑velocity anomaly studied since the 1960s and a characteristic feature of the Western Alps. The two boreholes were conducted between 2022‑2024 in Val D’Ossola: the first in Ornavasso and the second in Megolo, 7 km apart. Within this framework, a dedicated seismographic network, named DIVEnet, has been monitoring natural earthquakes and possible operation‑related seismic activity for three years. Eleven seismographic stations (short period and broadband), provided by INGV and the University of Lausanne, were installed within a maximum distance of 15 km from the midpoint between the two drilling sites. All stations recorded data continuously and 10 provided data in real time. One broadband sensor was installed in a borehole, and its horizontal components’ orientation was determined by multiple methods. The stations occupied 14 different locations and operated from autumn 2021 to summer 2024, with varying recording durations. Being in an area characterized by low natural local seismicity and a relatively sparse distribution of seismographic stations, it is particularly important to record background activity and noise for as long as possible, especially before and after the start of drilling activities. Daily monitoring was conducted at INGV in quasi real time, and probabilistic power spectral density distributions (PPSD) have been computed.
In total, 28 events with magnitudes ranging from 0 to 2.6 MLv were recorded within a distance of about 20 km from the boreholes, most of them aligned with the Insubric Line, that is thought to be tectonically inactive, and 612 events were recorded in the larger study region. No events were related to the drilling activities, which have only very slightly increased noise levels, mostly in the in the 0.1-0.3 Hz frequency range
Stromboli 3 July 2019 Fire: what could have happened?
Full text linkOn 3 July 2019, paroxysmal activity at the Stromboli volcano ignited a fire in the south-western sector of the island. This fire burnt the entire southern and eastern area. Thanks to the intervention of the firefighters, the fire did not spread northward, thus avoiding further damage. What could have happened if there had been no intervention? Would the fire have stopped its spread on its own, orwould it have burnt the entire island? We show through numerical simulations what could have happened if the fire had not been put out by firefighters and how numerical modelling can help plan preventive actions to avoid worst-case scenarios
Scenario impact assessment for volcanoes using the OpenQuake engine
Full text linkThis study introduces a unified framework for evaluating the physical impacts of earthquakes and volcanic eruptions on buildings, leveraging upon the existing capabilities of the OpenQuake engine for earthquake risk assessment and various existing packages for computing volcanic hazard footprints. We illustrate the capabilities of the new OpenQuake volcanic scenario module using two case studies: a VEI (Volcanic Explosivity Index) 3-4 eruption of Nevado del Ruiz volcano in Colombia and a VEI 6 eruption of Mount Pinatubo in the Philippines, employing various methods for simulating hazard footprints for tephra fall, lava flows, pyroclastic density currents, and lahars. The findings demonstrate the versatility of OpenQuake in managing diverse geohazards and its potential for further extension to other hazards, while this integration advances our ability to assess and manage disaster risk
Performance of a seismicity model based on three parameters for earthquakes (M ? 5.0) in Kanto, central Japan
Full text linkWe constructed a model of earthquakes (M ? 5.0) in Kanto, central Japan, based on three parameters: the a and
b values of the Gutenberg-Richter relation, and the ?- parameter of changes in mean event size. In our method,
two empirical probability densities for each parameter, those associated with target events (conditional density
distributions) and those not associated with them (background density distributions), are defined and assumed to
have a normal distribution. Therefore, three parameters are transformed by appropriate relations so that new parameters
are normally distributed. The retrospective analysis in the learning period and the prospective test of
testing period demonstrated that the proposed model performs better by about 0.1 units in terms of the information
gain per event than the value summed up with those of the three parameters. The results are confirmed by
a simulation with randomly selected model parameters
DSEBRA - the German Seismological Broadband Array and its contribution to AdriaArray – Deployment and performance
Full text linkThe German Seismological Broadband Array (DSEBRA) comprises 100 mobile seismological stations, which are currently contributing to the multidisciplinary international AdriaArray project, launched in 2022 to comprehensively study the Adriatic plate and its surrounding regions. The data collected in this project enable detailed monitoring of seismic activity and imaging of the crustal and upper mantle structures in the Central Mediterranean. DSEBRA stations are deployed across a wide range of geographical locations, including the Alpine foreland of Germany and Austria, the high Alps of Austria, the Pannonian Basin in Hungary, the southern Dinarides in Montenegro, Kosovo, and Albania, North Macedonia, as well as the mainland of Greece. Equipped with state‑of‑the‑art technology and featuring innovative station design and remote monitoring capabilities, these stations enable the acquisition of high‑quality data in near real‑time, which is essential for early warning systems in this seismically active region. In this study, the noise characteristics of the stations are analyzed in both the frequency and time domains, revealing significant variations that can be attributed to differences in geographical and geological settings, as well as levels of urbanization. In the frequency range of the secondary microseisms, a split in the double frequency peak is observed at the Balkan stations. This split is attributed to the simultaneous activation of two distinct source regions in the surrounding oceans. This article provides an overview of the distribution and performance of DSEBRA stations within the AdriaArray project. The contribution of DSEBRA to AdriaArray underscores the importance of well‑equipped station pools and international collaboration in achieving the scientific objectives of large‑scale seismic networks
Predict part 2: Building a Geo-Database and a 3D subsurface model for the historical center of Rome
Full text linkIn many countries, the subsurface is increasingly recognized as an integral part to urban planning, requiring detailed knowledge of the 3D subsurface geometry and properties of both natural sediments and artificial deposits. The underground data are essential for visualizing and analyzing geological features in combination with artificial structures, assessing risks related to groundwater protection, seismic hazard, and preserving archaeological heritage. Geographic information systems offer powerful tools for managing and visualizing spatial data, facilitating the creation of detailed subsurface models. In this work, a novel geo‑lithologic database has been implemented in a GIS environment to provide a comprehensive understanding of the subsurface of the Roman urban area. The Roman area, despite being located in a moderate seismic hazard zone, is exposed to a significant level of seismic risk, also due to the unique cultural heritage of its historical center. Over 800 boreholes, with average depths of 50‑60 m, were georeferenced and interpreted from a large database of civil engineering boreholes. This geodatabase (hereafter GDB) served as the basis for developing a 3D subsurface model, finalised to seismic response analyses in the framework of the INGV Dynamic Planet ST‑Predict project. In addition, the development of an implicit 3D geological model for Rome, based on stratigraphic correlations and lithofacies analysis, provides crucial input for future analyses on the Quaternary deposits of the Roman area
Application of the relocation-error distribution on geomagnetic databases. Analyses on the «Historical Italian Geomagnetic Data Catalogue»
Full text linkThe reliability of the Historical Italian Geomagnetic Data Catalogue, comprising 536 directions and 393 intensities,
has been assessed by comparing the historical geomagnetic measurements with the GUFM1 model predictions.
Such measurements were assessed at three selected relocation centres. For all the data contained in the
Catalogue it has been calculated the discrepancy between the relocated data and the GUFM1-model prediction
at the relocation centres. There is a correlation between relocation distance and the mean discrepancy. The upper
limit of discrepancy assumable as relocation error has been selected using error distributions previously calculated
using geomagnetic field models. Angular and intensity threshold lines have been slightly shifted upwards
to account for the estimated error of GUFM1 model itself at the considered region, mainly due to the crustal
field. The Italian database proved to contain reliable data, as only a very low percentage of data (namely 14 directions
and 20 intensities) can be considered anomalous. Possible explanations for such questionable data are
suggested. All the remaining data of this catalogue could thus be added to the databases used to produce regional
or global geomagnetic models
A Multi-method Geophysical Approach for Complex Shallow Landslide Characterization
No full textThis case study demonstrates the value of combining multiple non-invasive geophysical methods to characterize a landslide along Highway 7 near Jasper, Arkansas, USA. Geophysical testing was conducted using Multichannel Analysis of Surface Waves (MASW), Horizontal to VerticalSpectral Ratio (HVSR), and Electrical Resistivity Tomography (ERT), supplemented by select soil borings. The geophysical investigation aimed to provide a high-resolution, near-continuous view of subsurface conditions, including bedrock depth and the location of the groundwater table or highly saturated zones within the slide area. These factors are important contributors to slope instability. The MASW results revealed a highly variable depth to weathered bedrock along the observed displacement zone, with the bedrock becoming shallower downslope. The ERT data detected saturated zones associated with observed seeps and springs in the area, which were feeding water into the unstable zone. A low resistivity zone on the north side correlated to wet spots, while south of the highway, saturation occurred near the deeper bedrock interface. Additionally, a grid-based HVSR approach generated a high-resolution image of the shallow and complex bedrock topography across the slide area, providing valuable information for the slope repair design. Overall, the integrated geophysical approach offered a more sustainable, rapid, and cost-effective solution for comprehensive landslide characterization and slope stability assessment, compared to relying solely on conventional methods. The combined geophysical results provided a detailed, high-resolution understanding of the subsurface conditions influential for stability analyses and slope repair design
Geometric scaling of felsic sheet intrusions in the brittle upper crust, eastern Elba Island, Italy, with implications for host-rock strain distribution and strain rates
No full textSheet intrusions (dikes and sills) represent the most viable mode of magma transport and emplacement within the brittle upper crust. The thickness-to-length aspect ratio of such intrusions provides information about magma emplacement mechanisms and provides information on intruded magma volumes. Within the brittle upper crust, the mobility of magma is governed by magma cooling and solidification rates. The cooling rate of sheet intrusions depends on the temperature difference between magma and its host rocks, the thickness of the intrusion and the thermal diffusivity of the surrounding crust. The cooling rate of magma in the upper crust can be expected to be faster than the tectonic strain rate. In eastern Elba Island Italy, well exposed, late Miocene leucogranite sheets that intrude schistose host rocks within the contact aureole of the Porto Azzurro pluton provide a natural laboratory for analysing sheet intrusion geometries (length, thickness, spacing between intrusions). The thickness-to-length ratios of the intrusions define a power law dimensional scaling relationship with exponent ~1. Using this length versus thickness scaling we estimate that the total volume of leucogranite that intruded the Porto Azzurro pluton contact aureole was 4‑15 × 106 m3.Moreover, by analysing the spacing between sheet intrusions along with the size distribution of their thicknesses, we estimate that their emplacement was accommodated by an average bulk strain (volumetric strain) of 13-15% of the Porto Azzurro pluton contact aureole host rocks. Our observations also highlight how host rock brittle structures may control the location and mode of magma emplacement. Well exposed sections of sheet intrusions and their host rocks, as observed on Elba Island, are natural laboratories where geometries of intrusions can be analysed to provide important clues on the mechanisms of magma emplacement within the brittle crust, and interactions between magmatic and deformation processes