Drone-Based Photogrammetry and Morphological Characterization of the Salse del Dragone Mud Volcanoes: Integrating Multidisciplinary Data for Future Exploration

This study investigates the Salse del Dragone mud volcanoes, located in the Apennine region of Italy, using an integrated approach that combines drone-based Structure-from-Motion (SfM) photogrammetry, morphological analysis, and the integration of diverse datasets. The primary focus is on high-resolution terrain mapping and characterization through SfM-derived data. Detailed surface features, including active gas emission points and surrounding topography, are thoroughly analyzed. The research also incorporates additional subsurface data obtained from passive seismic measurements, gas emission records, and satellite imagery to develop a comprehensive understanding of the area’s dynamics. These efforts aim to estimate the extruded mass volume and assess the spatial distribution of the phenomenon, which appears to be more extensive than previously thought. The study reveals significant morphological anomalies, highlighting the need for further investigation, which will soon be extended to neighboring areas. This research is part of the PROMUD project, funded by the National Institute of Geophysics and Volcanology (INGV)

DIVEnet: a local seismographic network monitoring the lower continental crust drilling activities for the ICDP-DIVE project

The 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

The use of the inversion of single-station Rayleigh wave ellipticity curve in routine site investigation: numerical inversion and case-studies

Non-invasive single-station ambient vibration recordings have become very common nowadays for microzonation studies. Usually, these records are processed using Nakamura’s method to determine the horizontal-to-vertical spectral ratio (H/V) curve, but the Rayleigh waves’ ellipticity curve can also be determined and inverted alone or combined with data acquired using other surface wave methods. Since single-station ambient vibration-based analyses are a very cost-effective technique, this paper studies the reliability of the shallow ground structure that results from the ellipticity curve inversion, with prior knowledge on the ground profile characteristics, as is common in urban areas. The inversion of the ellipticity curve of a large set of shear wave velocity profiles (Vs-profiles) was simulated numerically to characterize the uncertainty. Three normally dispersive case studies in Lisbon County were used to evaluate the technique. RayDec was used to obtain experimental ellipticity curves inverting the right flank and the complete curve. It is shown that the Rayleigh wave ellipticity curve inversion can be a valuable and cost-effective preliminary site investigation technique, adopting a constrained inversion (based on some prior knowledge), to support the preliminary design stage of geotechnical works)

A target-based, multi-hazard assessment approach as a tool for supporting decision-making in volcanic areas: a case study in Mt. Etna, Italy

Multi-hazard assessment aims at evaluating the potential impacts of various natural and humaninduced hazards in a given area of interest and time period. The analysis can include hazards of different nature – such as volcanic eruptions, earthquakes, floods, landslides, and industrial accidents – considering their interdependencies and cumulative effects. Multi-hazard assessments can provide critical insights into the potential impact of multiple hazards, enabling decision makers to adopt a wider view of the problem with respect to the approach of analyzing single hazards independently. Volcanoes are interesting targets for implementing multi-hazard analyses because they are intrinsically a multi-hazard source due to the variety of phenomena usually related to volcanic eruptions (e.g. volcano seismicity, lava flows, tephra fall, lahars, etc.). This paper presents a target-based approach for multi-hazard analysis at Etna volcano (Italy) in which the output of probabilistic single hazard assessment can be harmoniously integrated and used for assessing a wide number of scenarios. The findings underscore the advantages of adopting such a kind of approach for supporting decision makers when using the results of multiple probabilistic hazardsassessments for performing tasks of planning, mitigation, or emergency preparedness. This work has been performed in the framework of the INGV project “Pianeta Dinamico” – PANACEA, a project developed for implementing multi-hazard and multi-risk assessments at Etna volcano

Seismological Network in Hungary: Insights from the AdriaArray Operational Period

The Hungarian National Seismological Network has experienced significant advancements in its monitoring capabilities due to the increasing density of seismic stations across the country, leading to improved earthquake detection and localization. This paper presents an analysis of the noise characteristics, detection capabilities, and seismic events registered by the Hungarian National Seismological Network, utilizing data from both permanent and temporary stations, including those from international projects such as AlpArray, PACASE, and AdriaArray. The noise characteristics of the network were analyzed through probabilistic power spectral densities, highlighting the diverse noise conditions across Hungary. The stations were grouped based on their installation dates and geographical locations, revealing significant differences in noise levels due to geological conditions, anthropogenic influences, and seasonal variations. Noise conditions at high frequencies, crucial for detecting low‑magnitude local earthquakes, were particularly influenced by both geological factors and human activity. The study also investigated the horizontal‑to‑vertical spectral ratios and found correlations between sediment thickness, resonance frequencies, and noise levels at different stations. The paper assesses the detection capability of the seismic network, focusing on its ability to identify earthquakes of varying magnitudes. We estimated the maximum background noise displacement, providing insights into the detection thresholds of the network. The results showed that the network is capable of detecting events as small as magnitude ML = 0.5 during the night in northern Hungary and events larger than ML = 1.25 throughout the country during all day. A case study of the Szarvas cluster in 2023, a notable seismic swarm demonstrates the network’s ability to accurately localize earthquake sequences using advanced localization algorithms. This event highlighted the enhanced seismic monitoring capability of the expanded network and its ability to capture small local seismic events that were previously undetectable. The paper concludes with an overview of ongoing research and future developments, including studies on the crust and mantle structure of the Pannonian Basin and wider region, advancements in seismic hazard mapping, and the role of the AdriaArray stations in refining earthquake localization. The continuous development of the Hungarian National Seismological Network and its integration into international cooperations are expected to further enhance high quality seismological structural research and contribute to a more detailed understanding of regional seismicity

Water level and volume estimations of the Albano and Nemi lakes (central Italy)

In April 2006 an airborne laser scanning (LIDAR) survey of the Albano and Nemi craters was carried out to obtain a high resolution digital terrain model (DTM) of the area. We have integrated the LIDAR survey of the craters and the recent bathymetry of the Albano lake to achieve a complete DTM, useful for morphological studies. In addition, with a GPS RTK survey (July 2007) we estimated the Albano and Nemi mean lake levels respectively at 288.16 m and 319.02 m (asl). Based on the integrated DTM and the newly estimated water level values, we evaluated about 21.7·106 m3 the water volume loss of the Albano lake from 1993 to 2007, with an average rate of about 1.6·106 m3/yr

A multidisciplinary strategy based on geophysicaland geochemical data to investigate hydrothermalcirculation along the rift zones of Mt. Etna volcano(Italy)

We surveyed the South Rift and Northeast Rift of Mt. Etna volcano in order to assess the presence and the spatial extent of shallow hydrothermal activity linked with magma degassing along the main feeder systems of the volcano. Surveys were carried out across the two rift zones at altitude between 1500 and 2500 m a.s.l. Soil CO2 effluxes, soil heat fluxes, self‑potential intensity, simultaneously with magnetic surveys, were measured for the first time together in 2017, both along profiles of measurement points and over networks of points. Several convective hydrothermal cells were found close together, particularly on the South Rift where they occupied a large portion of this rift. This suggested the existence of a complex plexus of volcano‑tectonic structures, highly permeable to volcanic fluids, that are all potential pathways for new magma intrusions, as they appear well connected with the portions of the central feeder conduits that allow for efficient magma degassing. Gravity measurements acquired successively along the South Rift strongly support this hypothesis. The Northeast Rift showed only one major hydrothermal convective cell, centered along the 2002 eruptive fissure, and a minor one a few hundred meters west of it. These surveys were repeated in 2018, although only partially. The 2018 measurements showed a strong decrease in the overall intensity of hydrothermal circulation along the Northeast Rift area and in most of the South Rift areas surveyed in 2017. This was explained as indication of strong migration of high‑enthalpy fluids from the two rift zones following magma transfer along the main conduits of the volcano towards its summit. Similar conclusions were drawn from the observed variations in gravity data from 2020 to 2021. The hypothesized magma transfer episodes seem to be coherent with the subsequent occurrence of the December 2018 flank eruption and of the 2020‑2021 sequence of paroxysmal summit eruptions

Physical and mathematical models of the occurrence of earthquake fluid anomalies in hydrogeochemical fields of seismically active areas

Comprehensive monitoring of seismic activity over the last 40 years at the special Almaty Forecasting Polygon (AFP) in Kazakhstan has demonstrated that the physical, mathematical and chemical mechanisms of fluid anomalies in the groundwater regime are quite convincingly substantiated by the example of tracking many strong earthquakes. The purpose of this research – to analyse the system “water-rock-gas”, in particular the genetic features of the manifestation of exotic unstable time anomalies. The research methods used in this work include systematic data analysis, and their interpretation and evaluation based on dilatant-diffuse (DD) and avalanche unstable fracturing (AUF) models. The first results of research of such anomalies preceding major earthquakes in the main earthquake-prone areas of the USSR, China, and Japan were manifested in sudden increases or decreases in the concentration of a wide range of components of the ion-salt composition of groundwater and its gas components: HCO–3, CO2–3, Cl, SO2–4, Ca2+, Mg2+, Na, K+, pH, He, Rn, CO2, CH4, H2, and Hg. They varied in the time interval from hours, days and the first weeks and months before the earthquake. In addition, the changes were explained by theoretically generally accepted models of DD or AUF earthquake occurrence. The proposed studies demonstrate and state the main genetic features of the manifestation of these exotic unstable temporal anomalies in the hydrogeochemical system “water-rock-gas”. Based on the results of long-term studies of hydrogeochemical and hydrogeodynamic precursors in the fluid regime of the Earth’s crust in Kazakhstan, Kyrgyzstan, Uzbekistan and Xinjiang Uygur Autonomous Region of People’s Republic of China, a more convincing physical and chemical model of the development of fluid anomalies in the process of preparation of strong earthquakes is proposed. The practical significance lies in the following aspects: the development of accurate models can help in predicting possible earthquakes based on fluid anomalies in hydrogeochemical fields; using physico-mathematical models can help in establishing systems for monitoring seismic activity based on the analysis of hydrogeochemical parameters; the research can help in assessing the risks associated with earthquakes in seismically active areas and in better understanding of the physical processes occurring in hydrogeochemical fields; and the research can help in assessing the risks associated with earthquakes in seismicallyactive areas and in better understanding the physical processes occurring in hydrogeochemical fields

Ionospheric error analysis in gps measurements

The results of an experiment aimed at evaluating the effects of the ionosphere on GPS positioning applications are presented in this paper. Specifically, the study, based upon a differential approach, was conducted utilizing GPS measurements acquired by various receivers located at increasing inter-distances. The experimental research was developed upon the basis of two groups of baselines: the first group is comprised of "short" baselines (less than 10 km); the second group is characterized by greater distances (up to 90 km). The obtained results were compared either upon the basis of the geometric characteristics, for six different baseline lengths, using 24 hours of data, or upon temporal variations, by examining two periods of varying intensity in ionospheric activity respectively coinciding with the maximum of the 23 solar cycle and in conditions of low ionospheric activity. The analysis revealed variations in terms of inter-distance as well as different performances primarily owing to temporal modifications in the state of the ionosphere

Earthquakes in Bosnia and Herzegovina from 2022 to 2023 recorded on the Bosnian Adria Array temporary network

As part of the Adria Array initiative, the seismic network in Bosnia and Herzegovina was augmented with 20 additional broadband stations between June 2022 and December 2024. In this study, we describe the characteristics and deployment of this temporary network, highlighting its impact on seismic catalog quality, including a lowered detection threshold to approximately magnitude 1.0. Beyond improving event detection, we provide a comprehensive seismic catalog from June 2022 to December 2023 that demonstrates enhanced constraints on location and magnitude for larger earthquakes. Additionally, we discuss the critical role of open data sharing in this seismically active region, emphasizing its importance for accurate seismicity monitoring and reliable seismic hazard assessment