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Giovanni Macedonio

Publications and source records attributed to Giovanni Macedonio.

6 recordsLinked to original sources
arXiv2025

Updates on MURAVES Project at Mt. Vesuvius

The MUon RAdiography of VESuvius (MURAVES) project aims to use muography imaging techniques to study the internal structure of the summit of the Mt. Vesuvius, an active volcano near Naples, Italy. This paper presents recent advancements in both data analysis and simulation tools that enhance the quality and reliability of the experiments results. A new track selection method, termed the Golden Selection, has been introduced to select high quality muon tracks by applying a refined Chi2 based criterion. This selection improves the signal to background ratio and enhances the resolution of muographic images. Additionally, the simulation framework has been upgraded with the integration of the MULDER (MUon simuLation for DEnsity Reconstruction) library, which unifies the functionalities of pervious used libraries within a single platform. MULDER enables efficient and accurate modeling of muon flux variations due to topographical features. An agreement is shown between simulated and experimental flux map.

physics.ins-det↗
arXiv2024

Simulation tools, first results and experimental status of the MURAVES experiment

The MUon RAdiography of VESuvius (MURAVES) project aims at the study of Mt. Vesuvius, an active and hazardous volcano near Naples, Italy, with the use of muons freely and abundantly produced by cosmic rays. In particular, the MURAVES experiment intends to perform muographic imaging of the internal structure of the summit of Mt. Vesuvius. The challenging measurement of the rock density distribution in its summit by muography, in conjunction with data from other geophysical techniques, can help model possible eruption dynamics. The MURAVES apparatus consists of an array of three independent and identical muon trackers, with a total sensitive area of 3 square meters. In each tracker, a sequence of 4 XY tracking planes made of plastic scintillators is complemented by a 60 cm thick lead wall inserted between the two downstream planes to improve rejection of background from low energy muons. The apparatus is currently acquiring data. This paper presents preliminary results from the analysis of the first data samples acquired with trackers pointing towards Mt. Vesuvius, including the first relative measurement of the density projection of two flanks of the volcano at three different altitudes; we also present the workflow of the simulation chain of the MURAVES experiment and its ongoing developments.

hep-ex↗
arXiv2023

On the seafloor horizontal displacement from cGPS and compass data in the Campi Flegrei caldera

Seafloor deformation monitoring is now performed in the marine sector of the Campi Flegrei volcanic area. MEDUSA infrastructure consists of 4 buoys at depths of 40-96m equipped with cGPS receivers, accelerometers and magnetic compasses to monitor buoy status and a seafloor module with a bottom pressure recorder. We study the seafloor deformation in the caldera. Previously we show that cGPS onland network and MEDUSA timeseries for the years 2017-2020 are in agreement with the deformation predicted by a Mogi model describing the observed deformation of an active volcano. Only for buoy A data differ significantly from model, at 6.9sigma and 23.7sigma for the horizontal speed (v) and direction. We devised a new method to reconstruct the sea bottom displacement including cGPS and compass data. The method, applied to buoy A and validated also on C, uses compass data to correct cGPS positions accounting for pole inclination. Including systematic errors, the internal consistency, within 3sigma (2sigma) for the speed (angle), between the results derived for different maximum inclinations of the buoy pole up to 3.5deg shows that the method allows to significantly reduce the impact of the pole inclination which can alter the estimation. We find good convergence of the velocity and deformation angle for increasing values of the buoy pole inclination. We found v=3.521+-0.039(stat)+-0.352(syst)cm/yr and an angle -115.159+-0.670(stat)+-7.630(syst)deg. The relative impact of potential systematics (statistical) effects increases (decreases) with cutoff. Our analysis gives v consistent with Mogi at 5.2sigma(stat) or 0.5sigma(stat and syst), and a deformation angle consistent at 4.3sigma(stat) or at 0.3sigma. The module of the vectorial difference between v from the data and Mogi diminishes by a factor 7.65+-1.23(stat) or +-5.78(stat+syst) compared with previous work. Potential improvements are discussed.

physics.geo-ph↗
arXiv2005

Numerical simulation of lava flows based on depth-averaged equations

Risks and damages associated with lava flows propagation (for instance the most recent Etna eruptions) require a quantitative description of this phenomenon and a reliable forecasting of lava flow paths. Due to the high complexity of these processes, numerical solution of the complete conservation equations for real lava flows is often practically impossible. To overcome the computational difficulties, simplified models are usually adopted, including 1-D models and cellular automata. In this work we propose a simplified 2D model based on the conservation equations for lava thickness and depth-averaged velocities and temperature which result in first order partial differential equations. The proposed approach represents a good compromise between the full 3-D description and the need to decrease the computational time. The method was satisfactorily applied to reproduce some analytical solutions and to simulate a real lava flow event occurred during the 1991-93 Etna eruption.

physics.geo-ph↗
arXiv2003

Nonlinear phenomena in fluids with temperature-dependent viscosity: an hysteresis model for magma flow in conduits

Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. As a consequence, this system may show an hysteresis effect, and the transition between the two branches can occur quickly when certain critical points are reached. In this paper we describe a model to study the relation between the pressure at the inlet and the volumetric magma flow rate in a conduit. We apply this model to explain an hysteric jump observed during the dome growth at Soufrière Hills volcano (Montserrat), and described by Melnik and Sparks [1999] using a different model.

physics.geo-ph↗