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On the Love Numbers of an Andrade Planet
No full textThe Andrade rheological model is often employed to describe the response of solar system or extra‐solar planets to tidal perturbations, especially when their properties are still poorly constrained. While for uniform planets with steady‐state Maxwell rheology the analytical form of the Love numbers was established long ago, for the transient Andrade rheology no closed‐form solutions have been yet determined, and the planetary response is usually studied either semi‐analitically in the frequency domain or numerically in the time domain. Closed‐form expressions are potentially important since they could provide insight into the dependence of Love numbers upon the model parameters and the time‐scales of the isostatic readjustment of the planet. First, we focus on the Andrade rheological law in 1‐D and we obtain a previously unknown explicit form, in the time domain, for the relaxation modulus in terms of the higher Mittag‐Leffler transcendental function Eα,β(z) that generalizes the exponential function. Second, we consider the general response of an incompressible planetary model — often referred to as the “Kelvin sphere” — studying the Laplace domain, the frequency domain and the time domain Love numbers by analytical methods. Through a numerical approach, we assess the effect of compressibility on the Love numbers in the Laplace and frequency domains. Furthermore, exploiting the results obtained in the 1‐D case, we establish closed‐form — although not elementary — expressions of the time domain Love numbers and we discuss the frequency domain response of the Kelvin sphere with Andrade rheology analytically.Publishede2024EA003779JCR Journa
Highlights on mantle deformation beneath the Western Alps with seismic anisotropy using CIFALPS2 data
No full textThere are still open questions about the deep structure beneath the Western Alps. Seismic velocity tomographies show the European slab subducting beneath the Adria plate, but all these images did not clarify completely the possible presence of tears, slab windows, or detachments. Seismic anisotropy, considered an indicator of mantle deformation and studied using data recorded by dense networks, allows a better understanding of mantle flows in terms of location and orientation at depth. Using the large amount of shear wave-splitting and splitting-intensity measurements available in the Western Alps, collected through the CIFALPS2 temporary seismic network, together with already available data, some new patterns can be highlighted, and gaps left by previous studies can be filled. Instead of the typical seismic anisotropy pattern parallel to the entire arc of the Western Alps, this study supports the presence of a differential contribution along the belt that is only partly related to the European slab steepening. A nearly north–south anisotropy pattern beneath the external Western Alps, a direction that cuts the morphological features of the belt, is clearly found with the new CIFALPS2 measurements. It is, however, confirmed that the asthenospheric flow from central France towards the Tyrrhenian Sea is turning around the southern tip of the European slab.Published827–835OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
Ground uplift and seismic activity at Campi Flegrei caldera (south Italy) during the unrest episodes: an overview
No full textA wide-ranging overview on the ground uplift and seismic activity during the 1969-1972,
1982-1984, and 2005-ongoing unrest episodes at Campi Flegrei caldera is delivered using
data reported in literature and those contained in the OV-INGV databases and surveillance
reports. In this study, an attempt to correlate the increase of the ground uplift rate and
the occurrence of seismic events with M ≥ 1.5 is made also by reporting some general
features on the ground deformations and seismic activity of the 1969-1972 and 1982
1984 unrest episodes. The original graphs, created to compare the ground uplift with
the seismic activity, highlight that the increment of the seismic activity, both in number
but especially in magnitude, occurs when in the presence of an increment of the ground
uplift rate. This feature appears to be common to both the large uplift episodes (1969
1972, 1982-1984, and 2005-ongoing) and the mini-uplift ones (e.g. 2000). Based on our
observations on the occurrence of the seismic events with M ≥ 3.5, we hypothesise that,
following an uplift rate of approximately 5 mm/day for a few days, seismic events with
M ≥ 4.5 may occur. Under such hypothesis, also considering the approximate migration
of the epicentres of the seismic events with M ≥ 2.5 of the ongoing unrest, we believe
that a reassessment of the seismic hazard for the area of Campi Flegrei could be useful.In pressJCR Journa
Seismic-electromagnetic signals from two monitoring stations in Southern Italy: Electromagnetic time series release
No full textThe seismic-electromagnetic phenomenon entails the generation of transient electromagnetic signals, which can be observed both simultaneously (co-seismic) and preceding (pre-seismic) a seismic wave arrival. Following the most accredited hypothesis, these signals are mainly due to electrokinetic effects, generated on microscopic scale in porous media containing electrolytic fluids. Thus, the seismic-electromagnetic signals are expected to be suitable for the detection and tracking of crustal fluids. Despite the growing interest in this phenomenon, there is a lack of freely available observational database of earthquake-related electromagnetic signals recorded at co-located seismic and magnetotelluric stations. To fill this gap, we set up two multicomponent monitoring stations in two seismically active areas of Southern Italy: the Gargano Promontory and the High Agri Valley. This work is both aimed to systematically analyse earthquake-generated seismic-electromagnetic recordings and to make the collected database accessible to the scientific community.Published863-872JCR Journa
Multi-Proxy Environmental Reconstruction of the Covacha de los Zarpazos in Galería Site (Atapuerca, Spain)
No full textMagnetic properties of iron oxides provide invaluable data for environmental reconstruction during
sediment deposition. Encouraged by the results of our previous studies in the near Gran Dolina site, we investigate the GI waterlain facies sediments that fill Galería Complex cave (Sierra de Atapuerca, Spain), in particular the Covacha de los Zarpazos cave considering two vertical profiles at different walls and comparing them with two profiles previously analysed. For the first time in this cave, we propose a correlation among these two walls based on the low field susceptibility values. An environmental reconstruction is proposed based on the pedogenesis and weathering processes, and water activity influencing the composition, concentration and grain size of magnetic minerals. In order to have a more comprehensive interpretation, elemental geochemistry was also analysed. The results allow to identify three different sections with the alternation of environmental characteristics.Published60-81OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioN/A or not JC
Performance Comparison of CFD Microbenchmarks on Diverse HPC Architectures
No full textOpenFOAM is a CFD software widely used in both industry and academia. The exaFOAM project aims at enhancing the HPC scalability of OpenFOAM, while identifying its current bottlenecks and proposing ways to overcome them. For the assessment of the software components and the code profiling during the code development, lightweight but significant benchmarks should be used. The answer was to develop microbenchmarks, with a small memory footprint and short runtime. The name microbenchmark does not mean that they have been prepared to be the smallest possible test cases, as they have been developed to fit in a compute node, which usually has dozens of compute cores. The microbenchmarks cover a broad band of applications: incompressible and compressible flow, combustion, viscoelastic flow and adjoint optimization. All benchmarks are part of the OpenFOAM HPC Technical Committee repository and are fully accessible. The performance using HPC systems with Intel and AMD processors (x86_64 architecture) and Arm processors (aarch64 architecture) have been benchmarked. For the workloads in this study, the mean performance with the AMD CPU is 62% higher than with Arm and 42% higher than with Intel. The AMD processor seems particularly suited resulting in an overall shorter time-to-solution.Published115OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Displacements of Fushun west opencast coal mine revealed by multi-temporal InSAR technology
No full textIn this paper, the Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technology
is adopted to monitor the Line of Sight (LOS) displacement of Fushun West Opencast Coal
Mine (FWOCM) and its surrounding areas in northeast China using Sentinel-1 Synthetic
Aperture Radar (SAR) images acquired from 2018 to 2022. The spatial-temporal evolution of
urban subsidence and the south-slope landslide are both analyzed in detail. Comparison with
ground measurements and cross-correlation analysis via cross wavelet transform with monthly
precipitation data are also conducted, to analyze the influence factors of displacements in
FWOCM. The monitoring results show that a subsidence basin appeared in the urban area near
the eastern part of the north slope in 2018, with settlement center located at the intersection of
E3000 and fault F1. The Qian Tai Shan (QTS) landslide on the south slope, which experienced
rapid sliding during 2014 to 2016, presents seasonal deceleration and acceleration with
precipitation, with the maximum displacement in vicinity of the Liushan paleochannel. The
results of this paper have fully taken in account for the complications of large topographic
relief, geological conditions, spatial distribution and temporal evolution characteristics of
surface displacements in opencast mining area. The wide range and long time series dynamic
monitoring of opencast mine are of great significance to ensure mine safety production and
geological disaster prevention in the investigated mining area.Published585-601OSA5: Energia e georisorseJCR Journa
Exploration of the 2021 Mw 7.3 Maduo Earthquake by Fusing the Electron Density and Magnetic Field Data of Swarm Satellites
No full textEarthquake is a complex and multivariate problem. Using a single parameter to extract anomalies is difficult to completely and truly reflect the preparation activity before earthquakes. In this paper, we develop a fusion anomaly extraction method based on principal component analysis (PCA) and non-negative tensor decomposition (NTD). It extracts anomalies by combining features of different parameters, which can obtain earthquake-related signals from dataset and reveal some weak anomalies hidden in individual parameters. By PCA-NTD, we fused the electron density and magnetic field data from the Swarm satellites to explore the possible precursors of 2021 M7.3 Maduo earthquake and compared the results with those of the single-parameter analyses. The cumulative value of fusion anomalies indicates two acceleration stages before the mainshock: from -51 to -24 days, following a sigmoid trend, and from -21 to the earthquake occurrence, following a power-law behavior. The second acceleration is more pronounced than the first one, and its critical point occurs near the date of the Maduo earthquake. Spatially, these anomalies are located around important fault zones (Altun fault, Jiali fault, and Red River fault) and the epicenter region, which likely reflect the northward stress and eastward stress experienced in the seismogenic area before the mainshock. As the earthquake approaches, the anomalies become more concentrated and closer to the impending epicenter. Furthermore, the ionospheric anomalies correspond well with the anomalous phenomena of lithospheric activity and atmospheric thermal radiation, which support a multi-channel lithosphere-atmosphere-ionosphere coupling (LAIC).Published2002424OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa
ESM processing tool users’ manual
No full textThe behaviour of the ground surface and of structures subjected to earthquakes can be
estimated analysing the accelerograms of seismic records. The ground motion is strongly
dependent on several factors and the ability to record, characterize and extract the main features
of waveforms is essential to better understand these dependencies. One of the most difficult
steps of this analysis is the waveforms’ processing. Its purpose is the estimation and the removal
of noise in the records, to evaluate reliable ground motion.
In this framework a processing tool fully integrated within the Engineering Strong Motion (ESM)
database was designed [Paolucci et al., 2011; Luzi et al., 2016].
In the last decade the number of waveforms is sharply increased and so is the time it takes to
process them. To solve this issue a possible solution is to broaden the number of qualified people
involved in the processing. The main aim of this tutorial is to teach the largest number of people
how to use the ESM processing tool and to provide some important guidelines for the thresholds
of the parameters to set. In the text a step by step processing routine is depicted with a
description of the purpose for each parameter. In addition, a suite of explanatory examples with
peculiar situations is given.INGV | Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Milano
Swiss Seismological Service at ETH Zurich, Zurich, Switzerland
ORFEUS and Swiss Seismological Service at ETH Zurich, Zurich, SwitzerlandPublished1-34OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoN/A or not JC
Coseismic hydrological effects associated with historical earthquakes in Southern Italy: data retrieval, classification, and seismotectonic clues
No full textEarthquake-induced hydrological effects, such as changes in streamflow, water levels, springs, and water properties, have long been observed and documented
across vast distances. This study focuses on hydrological changes caused by historical earthquakes in Central-Southern Italy from 1688 to 2020, with data collected as
part of the Further Project at INGV. The research method differs for events before and after the 18th Century, using historical records, reports, and diaries for older
events, and more detailed observations and instrumental data for recent ones. A classification method for hydrological data is also proposed, with an analysis showing
its potential for identifying causative faults of past seismic events lacking constrained instrumental dataPublishedCorfù Greec