bluuebunny/crossref_metadata_2025 huggingface dataset:
Technologies and new approaches used by the INGV EMERGEO Working Group for real-time data sourcing and processing during the Emilia Romagna (northern Italy) 2012 earthquake sequence
Authors: Giuliana Alessio  , Laura Alfonsi  , Carlo Alberto Brunori  , Pierfrancesco Burrato  , Giuseppe Casula  , Francesca Romana Cinti  , Riccardo Civico  , Laura Colini  , Luigi Cucci  , Paolo Marco De Martini  , Emanuela Falcucci  , Fabrizio Galadini  , Germana Gaudiosi  , Stefano Gori  , Maria Teresa Mariucci  , Paola Montone  , Marco Moro  , Rosa Nappi  , Anna Nardi  , Rosa Nave  , Daniela Pantosti  , Antonio Patera  , Arianna Pesci  , Maurizio Pignone  , Stefania Pinzi  , Stefano Pucci  , Paola Vannoli  , Alessandra Venuti  , Fabio Villani
Published: June 2021

On May 20, 2012, a Ml 5.9 seismic event hit the Emilia Po Plain, triggering intense earthquake activity along a broad area of the Po Plain across the provinces of Modena, Ferrara, Rovigo and Mantova (Figure 1). Nine days later, on May 29, 2012, a Ml 5.8 event occurred roughly 10 km to the SW of the first main shock. These events caused widespread damage and resulted in 26 victims. The aftershock area extended over more than 50 km and was elongated in the WNW-ESE direction, and it included five major aftershocks with 5.1 ≤Ml ≤5.3, and more than 2000 minor events (Figure 1). In general, the seismic sequence was confined to the upper 10 km of the crust. Minor seismicity with depths ranging from 10 km to 30 km extended towards the southern sector of the epicentral area (ISIDe, http://iside.rm.ingv.it/). […]
Preliminary results of ground-motion characteristics
Authors: Francesca Bozzoni  , Carlo Giovanni Lai  , Laura Scandella
Published: June 2021

The preliminary results are presented herein for the engineering applications of the characteristics of the ground motion induced by the May 20, 2012, Emilia earthquake. Shake maps are computed to provide estimates of the spatial distribution of the induced ground motion. The signals recorded at the Mirandola (MRN) station, the closest to the epicenter, have been processed to obtain acceleration, velocity and displacement response spectra. Ground-motion parameters from the MRN recordings are compared with the corresponding estimates from recent ground-motion prediction equations, and with the spectra prescribed by the current Italian Building Code for different return periods. The records from the MRN station are used to plot the particle orbit (hodogram) described by the waveform. The availability of results from geotechnical field tests that were performed at a few sites in the Municipality of Mirandola prior to this earthquake of May 2012 has allowed preliminary assessment of the ground response. The amplification effects at Mirandola are estimated using fully stochastic site-response analyses. The seismic input comprises seven actual records that are compatible with the Italian code-based spectrum that refers to a 475-year return period. The computed acceleration response spectrum and the associated dispersion are compared to the spectra calculated from the recordings of the MRN station. Good agreement is obtained for periods up to 1 s, especially for the peak ground acceleration. For the other periods, the spectral acceleration of the MRN recordings exceeds that of the computed spectra.
The Emilia 2012 sequence: a macroseismic survey
Authors: Andrea Tertulliani  , Luca Arcoraci  , Michele Berardi  , Filippo Bernardini  , Beatriz Brizuela  , Corrado Castellano  , Sergio Del Mese  , Emanuela Ercolani  , Laura Graziani  , Alessandra Maramai  , Antonio Rossi  , Manuela Sbarra  , Maurizio Vecchi
Published: June 2021

On May 20, 2012, at 4:03 local time (2:03 UTC), a large part of the Po Valley between the cities of Ferrara, Modena and Mantova was struck by a damaging earthquake (Ml 5.9). The epicenter was located by the Istituto Nazionale di Geo-fisica e Vulcanologia (INGV) seismic network [ISIDe 2010] at 44.889 ˚N and 11.228 ˚E, approximately 30 km west of Ferrara (Figure 1). The event was preceded by a foreshock that occurred at 01:13 local time, with a magnitude of Ml 4. The mainshock started an intense seismic sequence that lasted for weeks, counting more than 2,000 events, six of which had Ml >5. The strongest earthquakes of this sequence occurred on May 29, 2012, with Ml 5.8 and Ml 5.3, recorded at 9:00 and 12:55 local time, respectively. The epicenters of the May 29, 2012, events were located at the westernmost part of the rupture zone of the May 20, 2012, earthquake (Figure 2). The May 20 and 29, 2012, earthquakes were felt through the whole of northern and central Italy, and as far as Switzerland, Slovenia, Croatia, Austria, south-eastern France and southern Germany. Historical information reveals that the seismic activity in the Po Valley is moderate […]
Geological evidence of pre-2012 seismic events, Emilia-Romagna, Italy
Authors: Riccardo Caputo  , Kyriaki Iordanidou  , Luca Minarelli  , Giorgos Papathanassiou  , Maria Eliana Poli  , Dimitra Rapti-Caputo  , Sotiris Sboras  , Marco Stefani  , Adriano Zanferrari
Published: June 2021

In May 2012, two moderate (-to-strong) earthquakes that were associated with a noticeable aftershock sequence affected the eastern sector of the Po Plain, Italy, in correspondence with a buried portion of the Apennines thrust belt. The Provinces of Ferrara, Modena and Bologna (Emilia Romagna Region), Mantua (Lombardy Region), and Rovigo (Veneto Region) were affected to different extents. The first shock (Ml 5.9 according to the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), and Mw 6.1 according to the US Geological Service) occurred on May 20, 2012, at 2:03 a.m. (GMT); this was the strongest of the sequence, and it was followed by several aftershocks (up to Ml 5.1). This first event produced secondary ground deformation effects, which were mainly associated with liquefaction phenomena that were spread across the broader epicentral region, and particularly in the western sector of the Ferrara Province [Papathanassiou et al. 2012, this volume]. A few weeks after the earthquake, a paleoseismological trench was excavated south of San Carlo village, where earthquake-induced effects were widely documented. This report presents the preliminary results of the paleoseismological investigation and documents the occurrence in the same area of paleo-events older than the May 2012 earthquakes. […]
Preliminary results from EMERSITO, a rapid response network for site-effect studies
Authors: Paola Bordoni  , Riccardo M. Azzara  , Fabrizio Cara  , Rocco Cogliano  , Giovanna Cultrera  , Giuseppe Di Giulio  , Antonio Fodarella  , Giuliano Milana  , Stefania Pucillo  , Gaetano Riccio  , Antonio Rovelli  , Paolo Augliera  , Lucia Luzi  , Sara Lovati  , Marco Massa  , Francesca Pacor  , Rodolfo Puglia  , Gabriele Ameri
Published: June 2021

On May 20, 2012, at 02:03 UTC, a Ml 5.9 reverse-fault earthquake occurred in the Emilia-Romagna region, northern Italy, at a hypocentral depth of 6.3 km (http://iside.rm.ingv.it/), close to the cities of Modena and Ferrara in the plain of the Po River. The epicenter was near the village of Finale Emilia where macroseismic intensity was assessed at 7 EMS98 [Tertulliani et al. 2012, this issue], while the closest accelerometric station, MRN, located less than 20 km west-ward at Mirandola (Figure 1) recorded peaks of ground accelerations of about 300 cm/s2 (www.protezionecivile.gov.it/resources/cms/documents/Report_DPC_1_Emilia_EQSd.pdf). The mainshock triggered liquefaction phenomena a few kilometers eastwards of the epicenter, around the village of San Carlo. On the same day, two other shocks of Ml 5.1 followed (02:07, 13:18 GMT; http://iside.rm.ingv.it/). On May 29, 2012, at 07:00 UTC another Ml 5.8 earthquake hit the region (http://iside.rm.ingv.it/), with the epicenter close to the village of Mirandola (Figure 1). Three other strong aftershocks occurred afterwards, of Ml 5.3 (May 29, at 10:55), Ml 5.2 (May 29, at 11:00) and Ml 5.1 (June 3, at 19:20). For a detailed description of the seismic sequence, see Moretti et al. [2012], Scognamiglio et al. [2012], and Massa et al. [2012], in this issue. The Emilia seismic sequence resulted in 25 casualties, several of whom were among the workers in the many factories that collapsed during working hours, and there was extensive damage to monuments, public buildings, industrial sites, and private homes. […]
Seismic hazard in the Po Plain and the 2012 Emilia earthquakes
Authors: Carlo Meletti  , Vera D'Amico  , Gabriele Ameri  , Andrea Rovida  , Massimiliano Stucchi
Published: June 2021

The Emilia earthquakes of May 20, 2012 (Ml 5.9, INGV; Mw 6.11, http://www.bo.ingv.it/RCMT/) and May 29, 2012 (Ml 5.8, INGV; Mw 5.96, http://www.bo.ingv.it/RCMT/) struck an area that in the national reference seismic hazard model [MPS04; http://zonesismiche.mi.ingv.it, and Stucchi et al. 2011] is characterized by expected horizontal peak ground acceleration (PGA) with a 10% probability of exceedance in 50 years that ranges between 0.10 g and 0.15 g (Figure 1), which is a medium level of seismic hazard in Italy. The strong impact of the earthquakes on a region that is not included among the most hazardous areas of Italy, and the ground motion data recorded by accelerometric networks, have given the impression to the population and the media that the current seismic hazard map is not correct, and thus needs to be updated. Since the MPS04 seismic hazard model was adopted by the current Italian building code [Norme Tecniche per le Costruzioni 2008, hereafter termed NTC08; http://www.cslp.it/cslp/] as the basis to define seismic action (the design spectra), any modification to the seismic hazard model would also affect the building code. The aim of this paper is to briefly present the data that support the seismic hazard model in the area, and to perform some comparisons between recorded ground motion with seismic hazard estimates and design spectra. All of the comparisons presented in this study are for the horizontal components only, as the Italian hazard model did not perform any estimates for the vertical component. […]
The 2012 Pianura Padana Emiliana seimic sequence: locations, moment tensors and magnitudes
Authors: Laura Scognamiglio  , Lucia Margheriti  , Francesco Mariano Mele  , Elisa Tinti  , Andrea Bono  , Pasquale De Gori  , Valentino Lauciani  , Francesco Pio Lucente  , Alfonso Giovanni Mandiello  , Carlo Marcocci  , Salvatore Mazza  , Stefano Pintore  , Matteo Quintiliani
Published: June 2021

On May 20, 2012 (02:03:53 UTC), an Mw 5.86 (Ml 5.9) earthquake struck the Pianura Padana Emiliana region (northern Italy), causing five deaths and damage to several villages and to the towns of Ferrara and Modena. The mainshock was preceded, three hours earlier, by a Mw 3.98 (Ml 4.1) foreshock, which almost co-located with the main event. After the main event, the seismic sequence included six earthquakes with magnitudes >5.0. The biggest aftershock was located about 12 km west of the first mainshock, and was a Mw 5.66 (Ml 5.8) earthquake that occurred on May 29, 2012 (07:00:03 UTC); this can be considered as a second mainshock. After this event, the official death toll of the seismic sequence was 17 people. Moreover, there had been severe damage to the economy of the region and there were 13,000 homeless. [...]

 

 

 

 
Daily earthquake forecasts during the May-June 2012 Emilia earthquake sequence (northern Italy)
Authors: Warner Marzocchi  , Maura Murru  , Anna Maria Lombardi  , Giuseppe Falcone  , Rodolfo Console
Published: June 2021

On May 20, 2012, at 02:03 UTC, a magnitude Ml 5.9 earthquake hit part of the Po Plain area (latitude, 44.89 ˚N; longitude, 11.23 ˚E) close to the village of Finale-Emilia in the Emilia-Romagna region (northern Italy). This caused a number of human losses and significant economic damage to buildings, and to local farms and industry. This earthquake was preceded by an increase in the seismicity the day before, with the largest shock of Ml 4.1 at 23:13 UTC (latitude, 44.90 ˚N; longitude, 11.26 ˚E). It was then followed by six other Ml 5.0 or greater events in the following weeks. The largest of these six earthquakes occurred on May 29, 2012, at 07:00 UTC (Ml 5.8), and was located 12 km southwest of the May 20, 2012, main event (latitude, 44.85 ˚N; longitude, 11.09 ˚E), resulting in the collapse of many buildings that had already been weakened, a greater number of victims, and most of the economic damage (see Figure 1). This sequence took place in one of the Italian regions that is considered to be at small-to-moderate seismic hazard [Gruppo di Lavoro MPS 2004]. Earthquakes of the M6 class have occurred in the past in this zone [Gruppo di Lavoro CPTI 2004], but with a much smaller time frequency with respect to the most seismically hazardous parts of Italy. […]
The May-June 2012 Ferrara Arc earthquakes (northern Italy): structural control of the spatial evolution of the seismic sequence and of the surface pattern of coseismic fractures
Authors: Giusy Lavecchia  , Rita de Nardis  , Daniele Cirillo  , Francesco Brozzetti  , Paolo Boncio
Published: June 2021

The Ferrara 2012 seismic sequence was characterized by two main compressional events, which occurred on May 20 and 29, 2012, with Mw 6.1 and Mw 6.0, respectively (quick Regional Centroid Moment Tensor [RCMT] at http://autorcmt.bo.ingv.it/quicks.html). These events were followed by five events with Mw >5.0 (two on May 20 and three on May 29, 2012) and by hundreds of events of lower magnitudes distributed along a WNW-ESE-elongated area of ca. 500 km2 (ISIDe database at http://iside.rm.ingv.it/ iside/standard/index.jsp.). The ongoing activity of the northward-verging fold-and-thrust structures of the Ferrara-Romagna Arc (Figure 1A) and the eastward-verging Coastal Adriatic Arc (referred to as the Outer Thrust System [OTS] in Lavecchia et al. 2003) has been a debated topic in the Italian literature. […]
Characterization of GPS total electron content (GPS-TEC) in Antarctica from 2004 to 2011
Authors: Emília Correia  , Amanda Junqueira Paz  , Mauricio A. Gende
Published: June 2021

The vertical total electron content (VTEC) obtained from 2004 to 2011 at Comandante Ferraz Brazilian Antarctic Station (62.1°S, 58.4°W) is analyzed to study the mean diurnal, seasonal and annual variations. The maximum daytime VTEC had an annual variation that decreased from 2004 to 2008, and then starting to increase in 2009, which followed the variation of the solar activity. The daily VTEC shows good linear correlation with solar radiation intensity, which is also dependent on the solar zenithal angle. The mean diurnal VTEC shows a semiannual variation, with larger peaks in equinoxes for all years; no winter anomaly was observed, and in summer, there was no clear diurnal variation. The semiannual variation of the VTEC is also modulated by solar activity, with larger VTEC peaks when the solar activity was higher.
Preface
Authors: Marco Anzidei  , Alessandra Maramai  , Paola Montone
Published: June 2021

The seismic sequence that struck Emilia area (northern Italy) on May-June 2012 represented an important case study for scientists involved in the Earth sciences. Multidisciplinary and multiparametric datasets were collected from the beginning of the seismic sequence. Geological, geochemical and geophysical data were rapidly analyzed, to identify the seismogenic structures, to define the level of damage, and to study the effects on the environment, with the ultimate goal being to better understand earthquakes and to provide new knowledge for civil protection applications. [...]
Magnetic storm effect on the occurrence of ionospheric irregularities at an equatorial station in the African sector
Authors: Olushola Abel Oladipo  , Torben Schüler
Published: June 2021

Large-scale ionospheric irregularities usually measured by GPS TEC fluctuation indices are regular occurrence at the equatorial region shortly after sunset around solar maximum. Magnetic storm can trigger or inhibit the generation of these irregularities depending on the local time the main phase of a particular storm occurs. We studied the effect of nine (9) distinct storms on the occurrence of ionospheric irregularities at Fraceville in Gabon (Lat = −1.63˚, Long = 13.55˚, dip lat. = −15.94˚), an equatorial station in the African sector. These storms occurred between November 2001 and September 2002. We used TEC fluctuation indices (i.e. ROTI and ROTIAVE) estimated from 30 s interval Rinex data and also we used the storm indices (i.e. Dst, dDst/dt, and IMF BZ) to predict the likely effect of each storm on the irregularities occurrence at this station. The results obtained showed that most of the storms studied inhibited ionospheric irregularities. Only one out of all the storms studied (i.e. September 4, 2002 storms with the main phase on the night of September 7-8) triggered post-midnight ionospheric irregularities. There are two of the storms during which ionospheric irregularities were observed. However, these may not be solely attributed to the storms event because the level of irregularities observed during these two storms is comparable to that observed during previous days before the storms. For this station and for the storms investigated, it seems like a little modification to the use of Aarons categories in terms of the local time the maximum negative Dst occurs could lead to a better prediction. However, it would require investigating many storms during different level of solar activities and at different latitudes to generalize this modification.
Geomorphic evidence of recent activity along the Vodice thrust fault in the Ljubljana Basin (Slovenia) – a preliminary study
Authors: Petra Jamšek Rupnik  , Lucilla Benedetti  , Frank Preusser  , Miloš Bavec  , Marko Vrabec
Published: June 2021

We investigated two prominent, ~E-W trending scarps in Quaternary sediments, located close to the town of Vodice in the Ljubljana Basin (central Slovenia). By using detailed geomorphological analysis of the scarps, field surveying, and structural observations of deformed Quaternary sediments, we conclude that the scarps are the surface expression of a N-dipping thrust fault that has been active during the Quaternary. From Optically Stimulated Luminescence and Infrared Stimulated Luminescence dating of deformed Quaternary sediments we estimate a slip rate of 0.1 to 0.3 mm a-1 in the last 133 ka. Using the published empirical fault-scaling relationships, we estimate that an earthquake of magnitude 5.9 to 6.5 may be expected on the Vodice thrust fault. The fault may, therefore, present a major seismic hazard for the densely populated and urbanised region of central Slovenia.
The active tectonic landscape of Lake Ohrid (FYR of Macedonia/Albania)
Authors: Nadine Hoffmann
Published: June 2021

The study area at the Lake Ohrid Basin is located on 693 m a.s.l. at the south-western border of the Former Yugoslavian Republic of Macedonia with Albania. It is a suitable location for neotectonic studies. It exhibits a large variety of morphological expressions associated with the seismic activity of the region. Linear bedrock fault scarps give the relief on both sides of the lake a staircase-like appearance; other features are wine-glass shaped valleys and triangular facets. These often short living features are used to identify active faults and to parameterise palaeoearthquakes (slip rates, subsidence and erosion). According to the results of fault scarp profiling a halfgraben shape of the basin is proposed with the west coast being dominated by mass wasting processes most likely triggered by seismic events.
Demagnetization Analysis in Excel (DAIE). An open source workbook in Excel for viewing and analyzing demagnetization data from paleomagnetic discrete samples and u-channels
Authors: Leonardo Sagnotti
Published: June 2021

The Demagnetization Analysis in Excel (DAIE) software is a single Microsoft Excel file designed for viewing and analyzing stepwise demagnetization data of both discrete and u-channel samples in paleomagnetic studies. DAIE is an Excel workbook and has an open modular structure organized in 10 worksheets. It is designed for an easy use and an interactive operability; all the commands and choices can be entered by sliding menus associated to single cells. The standard demagnetization diagrams and various parameters of common use are shown on the same worksheet including selectable parameters and user's choices. The remanence characteristic components may be computed by principal component analysis (PCA) on a selected interval of demagnetization steps. Saving of the PCA data can be done both sample by sample, or in automatic by applying the selected choices to all the samples included in the file. The whole workbook is free both for use and editing and it is available for download on a dedicated website.
Mathematical analogies in physics. Thin-layer wave theory
Authors: José M. Carcione  , Vivian Grünhut  , Ana Osella
Published: June 2021

Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law). In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies) between material properties and field variables. For instance, the wave equation and the related mathematical developments can be used to describe anelastic and electromagnetic wave propagation, and are extensively used in quantum mechanics. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission) problem of a thin layer embedded between dissimilar media, considering the presence of anisotropy and attenuation/viscosity in the viscoelastic case, conductivity in the electromagnetic case and a potential barrier in quantum physics (the tunnel effect). The analogy is mainly illustrated with geophysical examples of propagation of S (shear), P (compressional), TM (transverse-magnetic) and TE (transverse-electric) waves. The tunnel effect is obtained as a special case of viscoelastic waves at normal incidence.
Validation of the IASI operational CH4 and N2O products using ground-based Fourier Transform Spectrometer: preliminary results at the Izaña Observatory (28ºN, 17ºW)
Authors: Omaira García  , Matthias Schneider  , Frank Hase  , Thomas Blumenstock  , Andreas Wiegele  , Eliezer Sepúlveda  , Angel Gómez-Peláez
Published: June 2021

Within the project VALIASI (VALidation of IASI level 2 products) the validation of the IASI operational atmospheric trace gas products (total column amounts of H2O, O3, CH4, N2O, CO2 and CO as well H2O and O3 profiles) will be carried out. Ground-based FTS (Fourier Transform Spectrometer) trace gas measurements made in the framework of NDACC (Network for the Detection of Atmospheric Composition Change) serve as the validation reference. In this work, we will present the validation methodology developed for this project and show the first intercomparison results obtained for the Izaña Atmospheric Observatory between 2008 and 2012. As example, we will focus on two of the most important greenhouse gases, CH4 and N2O.
Long-term intercomparison of MIPAS additional species ClONO2, N2O5, CFC-11, and CFC-12 with MIPAS-B measurements
Authors: Gerald Wetzel  , Hermann Oelhaf  , Felix Friedl-Vallon  , Anne Kleinert  , Guido Maucher  , Hans Nordmeyer  , Johannes Orphal
Published: June 2021

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the environmental satellite ENVISAT is a limb-viewing Fourier-transform emission spectrometer working in the mid-infrared spectral region between 685 cm-1 and 2410 cm-1 [...]
Analysis of new species retrieved from MIPAS
Authors: Shaomin Cai  , Anu Dudhia
Published: June 2021

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument which operated on the Envisat satellite from 2002-2012 is a Fourier transform spectrometer for the measurement of high-resolution gaseous emission spectra at the Earth's limb. It operates in the near- to mid-infrared, where many of the main atmospheric trace gases have important emission features. The initial operational products were profiles of Temperature, H2O, O3, CH4, N2O, HNO3, and NO2, and this list was recently extended to include N2O5, ClONO2, CFC-11 and CFC-12. Here we present preliminary results of retrievals of the third set of species under consideration for inclusion in the operational processor: HCN, CF4, HCFC-22, COF2 and CCl4.
Disaggregation of probabilistic ground motions in two cities of Western Iran, Kermanshah and Sanandaj
Authors: Elham Shabani  , Noorbakhsh Mirzaei  , Mehrdad Pakzad
Published: June 2021

This article presents the results of disaggregation of ground motion hazard obtained for two of Iran’s urban centers, Kermanshah and Sanandaj. Disaggregation of peak ground acceleration (PGA) and spectral acceleration hazard corresponding to mean return periods of 475 and 50 years is performed. 12 area seismic sources in the study region as well as 15 area seismic sources in a 150-km distance from the region are delineated. The scenario earthquakes are characterized by bins of magnitude, M, source-to-site distance, R, and number of standard deviations, ε, that the ground-motion parameter is away from its median value for that M-R pair as estimated by a prediction equation. In most cases, the sources closer to the site dominate. Larger, more distant earthquakes contribute more significantly to hazard for longer periods than for shorter periods. Disaggregation plots can provide useful information on the distance and magnitude of predominant sources, which can be used to generate scenario earthquakes and select corresponding time histories for seismic design.
Ionospheric precursors to scintillation activity
Authors: Paul S.J. Spencer
Published: June 2021

Ionospheric scintillation is the rapid fluctuation of both phase and amplitude of trans-ionospheric radio waves due to small scale electron density irregularities in the ionosphere. Prediction of the occurrence of scintillation at L band frequencies is needed to mitigate the disruption of space-based communication and navigation systems. The purpose of this paper is to present a method of using tomographic inversions of the ionospheric electron density obtained from ground-based GPS data to infer the location and strength of the post-sunset plasma drift vortex. This vortex is related to the pre-reversal enhancement in the eastwards electric field which has been correlated to the subsequent occurrence of scintillation.
Determining precipitable water in the atmosphere of Iran based on GPS zenith tropospheric delays
Authors: Elaheh Sadeghi  , Masoud Mashhadi-Hossainali  , Hossein Etemadfard
Published: June 2021

Precipitable water (PW) is considered as one of the most important weather parameters in meteorology. Moreover, moisture affects the propagation of the Global Positioning System’s (GPS) signals. Using four different models, the current paper tries to identify the best relationship between the atmospheric error known as zenith wet delay (ZWD) and PW. For that matter, based on 54,330 radiosonde profiles from 11 stations, two different models i.e. linear and quadratic have been derived for Iran. For analyzing the accuracy of these models, ZWDs of three permanent GPS stations located in the cities of Tehran, Ahvaz and Tabriz have been used. Applying the aforementioned models as well as those already developed for Europe and the U.S., PWs are derived at the position of these stations in Iran. Further, in this research, root mean square error (RMSE) and bias are the measures for selecting the optimal model. Here, the bias and the RMSE (between GPS and radiosonde derived PWs) for the proposed linear model for Iran is 1.44 mm and 4.42 mm, and for quadratic model 2.18 mm and 4.74 mm respectively while, the bias and the RMSE for Bevis’ linear model is 2.63 mm and 4.98 mm and for Emardson and Derk’s quadratic models are 2.80 mm and 5.08 mm respectively. As such, it is observed that the bias of the proposed linear model for Iran is 1.19 mm and 1.36 mm less than the Bevis’ and Emardson and Derk’s models. In addition, the RMSE of the proposed linear model is 0.56 and 0.66 mm less than the RMSE of the later ones. This emphasizes that the estimation of the model coefficients must be based on regional meteorological measurements.
Flood hazard of the Somma-Vesuvius region based on historical (19-20th century) and geomorphological data
Authors: Giuliana Alessio  , Melania De Falco  , Giuseppe Di Crescenzo  , Rosa Nappi  , Antonio Santo
Published: June 2021

This paper presents a preliminary susceptibility map of the flood hazard for the Somma-Vesuvius volcanic district, worked out by means of multi-disciplinary historical, geological, geomorphological and rainfall data processing. It is well known that the Somma-Vesuvius volcano, due to its explosive volcanism and the dense urbanization of the surrounding area, with a population exceeding 650,000 is one of the most dangerous active volcanoes of the world. Although this area has been extensively studied from the volcanological point of view with regards to its volcanic hazard, there are currently not many detailed studies about its flood hazard factors, despite the fact that, in the last century, many intense rainfall events in this area have produced several floods that invaded the surrounding plains affecting towns and roads, and causing much damages and loss of lives. Accordingly, in this paper high-resolution DEM (5×5 m pixel) and detailed geomorphological maps of the whole area have been analyzed and processed in GIS environment, carrying out a comparative study of the present-day morphology and the morphology of the 1900’s volcanic edifice, including changes of infrastructures and buildings throughout the last century. These results, together with historical chronicles data and the rainfall accurate data for all flood events, have been processed in this paper for highlighting the drainage basins areas of Somma-Vesuvius where the flood phenomena could be more probable in the future, working out a preliminary zoning map, also suggesting in which sectors interventions useful for mitigation of flood risk should be implemented.
Analytical models of volcanic ellipsoidal expansion sources
Authors: Antonella Amoruso  , Luca Crescentini
Published: June 2021

Modeling non-double-couple earthquakes and surficial deformation in volcanic and geothermal areas usually involves expansion sources. Given an ensemble of ellipsoidal or tensile expansion sources and double-couple ones, it is straightforward to obtain the equivalent single moment tensor under the far-field approximation. On the contrary, the moment tensor interpretation is by no means unique or unambiguous. If the far-field approximation is unsatisfied, the single moment tensor representation is inappropriate. Here we focus on the volume change estimate in the case of single sources, in particular finite pressurized ellipsoidal sources, presenting the expressions for the computation of the volume change and surficial displacement in a closed analytical form. We discuss the implications of different domains of the moment-tensor eigenvalue ratios in terms of volume change computation. We also discuss how the volume change of each source can be obtained from the isotropic component of the total moment tensor, in few cases of coupled sources where the total volume change is null. The new expressions for the computation of the volume change and surficial displacement in case of finite pressurized ellipsoidal sources should make their use easier with respect to the already published formulations.
Seismic activity and thermal regime of low temperature fumaroles at Mt. Vesuvius in 2004-2011: distinguishing among seismic, volcanic and hydrological signals
Authors: Paola Cusano  , Simona Petrosino  , Paolo Madonia  , Cinzia Federico
Published: June 2021

Seismological, soil temperature and hydrological data from Mt. Vesuvius are collected to characterize the present-day activity of the volcanic/hydrothermal system and to detect possible unrest-related phenomena. We present patterns of seismicity and soil temperature in the crater area during the period February 2004-December 2011. The temporal distribution of number and depth of Volcano-Tectonic earthquakes and the energy release are considered. Hourly data of soil temperature have been acquired since January 2004 in different locations along the rim and within the crater. The observed changes of temperature are studied to establish a temporal-based correlation with the volcanic activity and/or with external forcing, as variations of the regional and local stress field acting on the volcano or meteorological phenomena. The comparison between seismic activity and temperature data highlights significant variations possibly related to changes in fluid circulation in the hydrothermal system of the volcano. The common continuous observations start just before a very shallow earthquake occurred in August 2005, which was preceded by a thermal anomaly. This coincidence has been interpreted as related to fluid-driven rock fracturing, as observed in other volcanoes. For the successive temporal patterns, the seismicity rate and energy release are characterized by slight variations accompanied by changes in temperature. This evidence of reactivity of the fumarole thermal field to seismic strain can be used to discriminate between tectonic and volcanic signals at Mt. Vesuvius.
Inside Mt. Vesuvius: a new method to look at the seismic (velocity and attenuation) tomographic imaging
Authors: Edoardo Del Pezzo  , Francesca Bianco
Published: June 2021

New velocity and attenuation images of the geological structures below Mt. Vesuvius have been obtained using the programming facilities as well as the enhanced graphical power of Mathematica8TM. The velocity and attenuation space distributions, already calculated inverting respectively P-wave travel times and amplitude spectra of local VT quakes, are first optimally interpolated and then graphically represented in a new Mathematica8TM code notebook (a powerful computational document with more facilities than a simple code) developed by the present authors. The notebook aims at interactively and friendly representing 3D volume distributions of velocity and attenuation parameters. The user can easily obtain vertical sections (N-S, E-W, NE-SW and NW-SE oriented) and define color scales to represent velocity or attenuation variations or prefer iso-surface plots to represent the pattern of peculiar geological structures. The use of dynamic graphical representation, allowing the sliding of any (horizontal and/or vertical) slice through the volume under study, gives an unusual and powerful vision of any small velocity or attenuation anomaly. The (open source) code, coupled with the friendly use of internal routines of Mathematica, allows to adapt the graphical representation to any user necessity. The method appears to be particularly adapt to represent attenuation images, where the space variations of the parameters are strong with respect to their average. The 3-D plots of the interpolated velocity and attenuation fields enhance the image of Mt. Vesuvius structure, evidencing low-velocity associated with high attenuation anomalies which appeared unfocused in the plots reported by Scarpa et al. [2002] and De Siena et al. [2009].
Wavefront distortion across Mt. Vesuvius observed by a seismic array
Authors: Danilo Galluzzo  , Mario La Rocca
Published: June 2021

Local and regional earthquakes recorded at Mt. Vesuvius in 1997 and 1998 by a temporary seismic array have been analyzed with array methods to estimate slowness and backazimuth of correlated phases. The backazimuth observed for the direct P-wave has been compared with the expected direction, and results show surprising large differences in most of the cases. Since the observed difference is not systematic but depends on the epicenter backazimuth, we ascribe it to a wavefront distortion produced by the propagation through a non-homogenous velocity structure. To check this hypothesis we computed synthetic wavefront propagation in two different velocity models by applying a finite-difference method. The first model was homogeneous, while the second one was heterogeneous, with 2D symmetry in the horizontal plane given by a positive velocity anomaly centered at the volcano crater. We observe that the heterogeneous model gives results in good qualitative agreement with the observations. Such model is supported by the results of tomographic studies carried out for Mt. Vesuvius.
Level of carbon dioxide diffuse degassing from the ground of Vesuvio: comparison between extensive surveys and inferences on the gas source
Authors: Domenico Granieri  , Maria Luisa Carapezza  , Rosario Avino  , Stefano Caliro  , Carlo Cardellini  , Giovanni Chiodini  , Marco Donnini  , Carmine Minopoli  , Massimo Ranaldi  , Tullio Ricci  , Luca Tarchini
Published: June 2021

An extensive campaign of diffuse CO2 soil flux was carried out at the cone of Vesuvio in October 2006 with two main objectives: 1) to provide an estimation of CO2 diffusely discharged through the soils in the summit area and 2) to evidence those sectors of the volcano where structural and morphological conditions could favour the gas output. The survey consisted of 502 measurements of soil CO2 flux homogenously distributed over an area of about 1.8 km2. Results of this survey were compared with those obtained during a similar campaign carried out by Frondini et al. in 2000, from which we have taken and reinterpreted a subset of data belonging to the common investigated area. Graphical statistical analysis showed three overlapping populations in both surveys, evidencing the contribution of three different sources feeding the soil CO2 degassing process. The overall CO2 emission pattern of 2006 is coherent with that observed in 2000 and suggests that a value between 120 and 140 t/day of CO2 is representative of the total CO2 discharged by diffuse degassing from the summit area of Vesuvio. The preferential exhaling area lies in the inner crater, whose contribution resulted in 45.3% of the total CO2 emission in 2006 (with 62.8 t/day) and in 57.4% (with 70.3 t/day) in 2000, although its extension is only 13% of the investigated area. This highly emissive area correlated closely with the structural discontinuities of Vesuvio cone, mainly suggesting that the NW-SE trending tectonic line is actually an active fault leaking deep gas to the bottom of the crater. The drainage action of the fault could be enhanced by the “aspiration” effect of the volcanic conduit.
19 years of tilt data on Mt. Vesuvius: state of the art and future perspectives
Authors: Ciro Ricco  , Ida Aquino  , Sven Ettore P. Borgstrom  , Carlo Del Gaudio
Published: June 2021

Mt. Vesuvius, located along the SW border of the Campania Plane graben, is one of the most studied volcanoes worldwide, from both the volcanological and the geophysical, geochemical and geodetic point of view. In order to better understand its dynamics, the deformation of the volcano has been already studied since the early ’70s by setting up levelling lines and, since a few years later, through trilateration networks, whereas ground tilt monitoring started in 1993. Tilt variations were recorded by an automatic surface station set up at the Osservatorio Vesuviano (O.V.) bunker (OVO) and data recorded were transmitted to the O.V. Surveillance Centre in Naples. Afterwards, in 1996 two more identical stations were set up close to Torre del Greco (CMD), and close to Trecase (TRC). In 2002 the data acquisition system was replaced, while at the end of 2011 a Lily borehole sensor was set up at 26 m depth, replacing the old TRC tilt station. The paper describes in details the tilt network of Mt. Vesuvius, its development over time and the data processing procedure; moreover, the ground deformation pattern is discussed, as inferred from the study of 19 years of data and its change during the seismic crises of 1995-1996 and 1999-2000. From the information obtained from the tiltmetric monitoring, a complex deformation pattern can be deduced, strongly dependent on the position of the sites in which the sensors were set up with respect to the morphology of the volcanic edifice and its structural outlines. If we consider the signals as they were recorded, although previously corrected for the influences of the thermo-elastic strain on the sensors, the tilting occurs mainly in the SW direction with rates of about 11 µradians/year on both the western and eastern flanks and of about 13 µradians/year on the southern one. Because tilt vectors point in the long term outward from the summit and towards the subsiding area, this supports the hypothesis of a southern areas subsidence, according with a spreading effect of Vesuvius, taking into account geological, structural, geophysical and geodetical (optical levelling, InSAR) data. The SW tilting occurs therefore irregularly and shows some seasonalities, consistent with the solar thermal radiation whose removal by statistical procedure outlines a different but equally interesting deformation field as it shows interruptions with changes in both trend and amplitude during two periods of strong seismic activity that affected Mt. Vesuvius in the periods 1995-1996 and late 1999-2000, marked by an average rate of energy release of at least one order of magnitude greater than the previous and following periods. Another change in intensity and direction of the deformation detected by tiltmeters since 2000, connected with the variations of the phase shift between the tilt components and the temperature recorded, compared to previous years, occurs during a strong decrease of the energy released by Vesuvius earthquakes.
Somma Vesuvius volcano: ground deformations from CGPS observations (2001-2012)
Authors: Umberto Tammaro  , Prospero De Martino  , Francesco Obrizzo  , Giuseppe Brandi  , Andrea D’Alessandro  , Mario Dolce  , Santa Malaspina  , Claudio Serio  , Folco Pingue
Published: June 2021

This paper is a contribution to the evaluation of ground deformations at Somma-Vesuvius volcano by means GPS measurements from 2001 to 2012. In this study we use a dataset from nine continuous GPS stations of the Neapolitan Volcanoes Continuous GPS network (NeVoCGPS), which covers the Neapolitan volcanic area, and is operated by the Istituto Nazionale di Geofisica e Vulcanologia. The GPS data processing is performed by the Bernese software v. 5.0. The results of the data processing show that the dynamics of the Somma-Vesuvio volcano, between 2001 and 2012, is characterized by a general subsidence, with maximum values on the Gran Cono at BKNO (−11.7 ± 0.65 mm/year) and BKE1 (−4.92 ± 0.36 mm/year) stations. The subsidence decrease from the crater down to the coast and the horizontal displacements are concentrated in Gran Cono area, the youngest part of the volcano. The parameters of the principal strain components indicate that Somma-Vesuvius is affected by a predominant contraction phase, which is concentrated in the areas with the greatest altitudes.
A numerical study of the windstorm Klaus: sensitivity to sea surface temperature
Authors: Nazario Tartaglione  , Rodrigo Caballero
Published: June 2021

This article investigates the role of sea surface temperature (SST) as well as the effects of evaporation and moisture convergence on the evolution of cyclone Klaus, which occurred on January 23 and 24, 2009. To elucidate the role of sea surface temperature (SST) and air–sea fluxes in the dynamics of the cyclone, ten hydrostatic mesoscale simulations were performed by Bologna Limited Area Model (BOLAM). The first one was a control experiment with European Centre for Medium-Range Weather Forecasts (ECMWF) SST analysis. The nine following simulations are sensitivity experiments where the SST are obtained by adding a constant value by 1 to 9 K to the ECMWF field. Results show that a warmer sea increases the surface latent heat fluxes and the moisture convergence, favoring the development of convection in the storm. Convection is affected immediately by the increased SST. Later on, drop of mean sea level pressure (MSLP) occurs together with increasing of surface winds. The cyclone trajectory is not sensitive to change in SST differently from MSLP and convective precipitation.
The characterization of diffusion tensor for mid-latitude ionospheric plasma
Authors: Selcuk Sagir  , Ali Yesil  , Gulay Sanac  , Ibrahim Unal
Published: June 2021

In this study, the relationship between diffusion and the electrical conductivity tensor is investigated by using the real geometry of the Earth’s magnetic field in the Northern Hemisphere for mid-latitudes. This relationship is derived from equation. Only in the elements of the diagonal of the tensor is an equal relationship found between the electrical conductivity called the longitudinal conductivity and the diffusion coefficient. The diagonal elements are equal to each other and do not depend on the Earth’s magnetic field; however, the other elements of the tensor strongly depend on the Earth’s magnetic field and they have characteristic of Bohm diffusion became a semi-empirical model (DB= (1/16)kT/eB) but they do not depend on the electrical conductivity or the classical diffusion coefficient.
The effect of the stratospheric QBO on the neutral density of the D region
Authors: Selçuk Sağır  , Ramazan Atıcı  , Osman Özcan  , Nurullah Yüksel
Published: June 2021

A multiple regression model, which defines relationship between two variables, is used to perform a statistical analysis of the relationship between the stratospheric QBO and the neutral density of the D region (NnD) at altitudes of 75 km and 90 km for Singapore station. While performing the analysis, the solar maxima and solar minima epochs of the sun for 21st, 22nd and 23rd solar cycles (SCs) are taken into account. Before applying the model for the statistical analysis of the relationship, the stationary of the variables is investigated by using the unit root test. The relationship between the variables is also investigated by using the co-integration test. The relationship between NnD measured at 75 km altitude and QBO obtained at altitude of 10 hPa is observed that it is positive for solar maximum epoch at 21st and 23rd SCs and for solar minimum epoch at 21st SC and is negative at the other epochs. The relationship between NnD measured at 90 km altitude and QBO is observed to be negative at both the solar maxima expect for solar maximum of 23rd SC and the solar minima epochs. The relationship between variables is positive for both phases (east and west) of QBO. Thus, QBO leads to a statistical change in the NnD. It may also give rise to changes on the ion chemistry of the D region.