bluuebunny/crossref_metadata_2025 huggingface dataset:
The science of rumors
Authors: Massimo Crescimbene  , Federica La Longa  , Tiziana Lanza
Published: June 2021

This study takes a soft scientific cut to talks about rumors, hoaxes and urban legends. Social psychology, more elegantly, uses the latin word rumor (rumour in British English), which means sound, voice, or gossip. In social, economical, political, cultural and scientific communication, rumors indicate news that is presumed true, that circulates without being confirmed or made evident. The scientific history of rumors is briefly described starting from the period of ancient Rome, throughout the Second World War and the Internet era, up to today. We will try to answer some questions that can be useful to scientists today. What are rumors? How are they born? How do they spread? By which laws are they regulated? How do we need to fight them? A final question regards the collocation of rumors into modern science. Science today is divided into ‘hard’ and ‘soft’ science (the latter of which generally lacks a basic mathematical structure); these terms, respectively, indicate the natural sciences, which investigate Nature, and the social/human sciences, which investigate man in all his facets. Maybe rumors can be thought of as a bridge suspended between two banks: those of ‘scientific truth’ and ‘human truth’.
Stability analysis of slip of a one-body spring-slider model in the presence of thermal pressurization
Authors: Jeen-Hwa Wang
Published: June 2021

This study is focused on stability of slip in a one-body spring-slider system, with stiffness k of the slider, in the presence of thermal pressurizationfor two end-member models of thermal pressurization, i.e., the adiabatic-undrained- deformation (AUD) model and slip-on-a-plane (SOP) model. Analytic studies based on the functions of frictional stress, tf, versus slip, d, of the two models show that kcr=|dtf/dd| at d=0 is the critical stiffness of the system. kcr is a finite positive value for the AUD model and infinity for the SOP model. Slip is stable when k>kcr and unstable when k<kcr. Analytic stability conditions of slip from the equations of motions of a one-body spring-slider model with the tf–d function of the ADU model are also those from |dtf/dd| at d=0. Under ADU thermal pressurization, modeled final slip and maximum velocity for k=5 to 31 MPa/m, with kcr=30 MPa/m, both decrease with increasing k. The motions become very weak when k≥kcr, thus being unable to result in unstable motions. The phase portraits of v versus d for k<30 MPa/m show the existence of a non-zero unstable fixed point.
What can we learn from the January 2012 northern Italy earthquakes?
Authors: Marco Massa  , Gabriele Ameri  , Sara Lovati  , Rodolfo Puglia  , Gianlorenzo Franceschina  , Francesca Pacor  , Lucia Luzi  , Paolo Augliera
Published: June 2021

This note focuses on the ground motion recorded during the recent moderate earthquakes that occurred in the central part of northern Italy (Panel 1), a region that is characterized by low seismicity. For this area, the Italian seismic hazard map [Stucchi et al. 2011] assigns a maximum horizontal acceleration (rock site) of up to 0.2 g (10% probability of being exceeded in 50 yr). In the last 4 yr, this region has been struck by 9 earthquakes in the magnitude range 4 ≤Mw ≤ 5.0, with the three largest located in the Northern Apennines (the Mw 4.9 and 5.0 Parma events, in December 2008 and January 2012) and on the Po Plain (the Mw 4.9 Reggio Emila event, in January 2012). We have analyzed the strong-motion data (distance <300 km) from these events as recorded by stations belonging to the Istituto Nazionale di Geofisica e Vulcanologia (RAIS, http://rais.mi.ingv.it; RSNC, http://iside.rm.ingv.it) and the Department of Civil Protection (RAN, www.protezionecivile.it; http://itaca.mi.ingv.it). […]
DENSITÀ ELETTRONICA IN UNA IONOSFERA NON ISOTERMA
Authors: F. MARIANI
Published: June 2021

Nella presente nota, studiamo (paragr. 1 e 2), quale completamento
della teoria della fotoionizzazione in atmosfera non isoterma, considerata
in altra nota (M che qui indicheremo con la sigla M, l'effetto
della curvatura terrestre sulla intensità di ionizzazione (e quindi sulla
densità elettronica) nei due casi in cui il gradiente verticale di temperatura
sia costante in tutto l'intervallo di quote considerato (caso
questo studiato da Gledhill e Szendrei (2 ) solo in condizioni stazionarie
e trascurando l'effetto della curvatura terrestre) e in quello in
cui il gradiente ha un valore costante e positivo con la quota fino a
una quota c e valore zero per quote superiori. Deduciamo inoltre
(paragr. 3) delle espressioni approssimate per la densità elettronica stabilendone
i limiti di validità e di applicabilità alla interpretazione dei
dati sperimentali; stabiliamo infine (paragr. 4) una relazione di validità
generale, nel caso stazionario e per un generico andamento della
temperatura con la quota, tra densità elettronica, coefficiente di ricombinazione
generalizzato, densità di materia e coefficiente di assorbimento
della radiazione monocromatica ionizzante
The Mallet Project: from an earthquake laboratory to laboratories on the territory
Authors: Graziano Ferrari
Published: June 2021

On December 16, 1857, an earthquake wreaked havoc across a huge area of the regions of Basilicata and Campania (Val d’Agri and Vallo di Diano). More than 180 villages in an area of over 20,000 km2 suffered very severe damage. More than 6,000 houses collapsed or became uninhabitable, and 19,000 people were killed. In the months of February and March 1858, the Irish engineer Robert Mallet undertook a mission to study the earthquake with a grant from the Royal Society of London. In 1862, he published his extraordinary study diary, in which the technical and scientific observations mingled with descriptive and literary details. This represents, from different angles, a unique ‘observatory’ over the landscape and the social, economic and cultural aspects of Val d’Agri and Vallo di Diano. In 2003, the Provinces of Salerno and Potenza started up a joint venture with the Storia Geofisica Ambiente of Bologna and with the scientific partnership of the Istituto Nazionale di Geofisica e Vulcanologia, with a view to setting up provincial laboratories dedicated to environmental education, and named after Robert Mallet. The Mallet Project proceeded up to 2009 on three agreements. Within the framework of the idea of a ‘Mallet Laboratories’ Project, there has been the opportunity to set up a network of study centers in the territories of these two provinces (Salerno and Potenza), which can promote research with great national and international breadth, starting with the world of schools and local communities. The study entitled Viaggio nelle aree del terremoto del 16 dicembre 1857 was published through the period from 2004 to 2009.
SUGLI ERRORI PROGRESSIVI DELLE LETTURE DI UN GRAVIMETRO
Authors: ARMANDO NORINELLI
Published: June 2021

L'Istituto (li Geodesia e Geofisica dell'Università di Padova lia in
uso, quale cortese prestito della Società Montecatini, il gravimetro
Western G4 A, N. I l di matricola. Tale gravimetro servì a terminare
un rilievo gravimetrico dettagliato dell'area eruttiva euganeo-bericolessinea
e serve attualmente a completare quello a larghe maglie (1 stazione
ogni 100 km2) della regione assegnata per tale scopo all'Istituto
dalla Commissione Geodetica Italiana.
Poiché la Casa costruttrice del gravimetro ha fornito per esso
due costanti di scala: —0,08515 per le dieci rivoluzioni più hasse del
tamburo e —0,08575 per le rimanenti, mi accinsi, con l'approvazione
del prof. Silva, ad esaminare più a fondo la variazione della costante di
scala determinando gli errori progressivi delle letture. Non ci si riferisce
([iti agli errori progressivi propri della vite, perché assieme alla
non costanza del passo di essa può associarsi fra l'altro una non rigogosa
proporzionalità tra l'allungamento della molla di misura e la
variazione della sua reazione elastica, il che conduce ad una non rigorosa
proporzionalità tra le variazioni di lettura al tamburo, che sono
proporzionali all'allungamento, e le variazioni di gravità, alle quali è
proporzionale la variazione della reazione elastica al momento della
lettura. In tale ipotesi il valore della costante di scala dovrebbe variare
in modo uniforme con le letture.
sismicita dell'iran
Authors: f. Peronacci
Published: June 2021

Le caratteristiche sismiche di una regionevengono in genere compendiate dallaconoscenza di quattro dati fondamentali:intensità delle scosse, frequenza, coordinateipocentrah, natura fisica della scossa all'ipocentro.Ora mentre por quanto riguardagh ultimi tre elementi non vi è incertezza,dato che essi possono solo ricavarsidalle osservazioni microsismiche fornite dalmateriale di registrazione, e quindi legatesolo al fatto che nella regione esista un numerosufficiente di osservatori, per quantoriguarda l'intensità, i criteri valutativi possonoessere i più disparati e a nostro avvisonessuno soddisfacente da tutti i punti divista.
SU ALCUNE ANOMALIE DELLA FREQUENZA CRITICA IONOSFERICA DURANTE UN'ECLISSE DI SOLE
Authors: GUGLIELMO ZANOTELLI
Published: June 2021

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TEORIA PER LA DETERMINAZIONE DEL CONTENUTO RADIOATTIVO DEI MINERALI II
Authors: DONATO PALUMBO
Published: June 2021

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MISURA DELLA RADIOATTIVITÀ ATMOSFERICA CON EMULSIONI NUCLEARI
Authors: E. MORASCHINELLI
Published: June 2021

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Rock-falls and liquefaction related phenomena triggered by the June 8, 2008, Mw=6.4 earthquake in NW Peloponnesus, Greece
Authors: Spyros Pavlides  , George Papathanassiou  , Sotiris Valkaniotis  , Alexis Chatzipetros  , Sotiris Sboras  , Riccardo Caputo
Published: June 2021

A strong earthquake (Mw=6.4) occurred in NW Peloponnesus, Greece, on June 8, 2008. The focal mechanism shows a transcurrent kinematics, and based on aftershocks distribution the causative fault is a dextral strike-slip NNE-SSW trending structure. The shock generated severe secondary environmental effects like rock-falls and liquefaction phenomena inducing structural damages and ground failures mainly along the fault strike. Evidence of liquefaction was observed in the area of Kato Achaia and Roupakia villages, while rock-falls were triggered mainly close to the epicentre at the foothills of the Skolis Mountain. Based on a quantitative methodological approach, the ground deformation and failures generated by the event have been investigated. In particular, based on an immediate post-event survey, we mapped in detail the distribution of the earthquake-induced ground failures, defining the areas prone to liquefaction and their associated potential. Moreover, a rock-fall hazard zonation in the area of Skolis Mountain has been developed based on the shadow angle approach, confirming the validity of the safety run-out distance models.
Su alcune disposizioni elettrodiche interessanti processi elettrocinetici in terreni saturi d'acqua
Authors: A. CREA
Published: June 2021

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TECNICA DI PRELEVAMENTO E PURIFICAZIONE DEI GAS NATURALI E VULCANICI
Authors: M. SANTANGELO
Published: June 2021

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IL CALCOLO DELLE SUPERFICI RIFLETTENTI NEI RILIEVI SISMICI A RIFLESSIONE
Authors: CAMILLO CONTINI
Published: June 2021

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ULTERIORE STUDIO SULLE OSCILLAZIONI LIBERE DEL LAGO DI SCANNO
Authors: P. CALOI  , D. DI FILIPPO  , M. C. SPADEA
Published: June 2021

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DER UNTERGRUND DER KONTINENTE UND OZEANE NACH GEOPHYSIKALISCHEN UNTERSUCHUNGEN
Authors: LUDGER MINTROP
Published: June 2021

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PROPAGAZIONE DELLA MAREA NELLA LAGUNA DI VENEZIA
Authors: SILVIO POLLI
Published: June 2021

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DAS VERHALTEN VON BLATTFEDERSEISMOGRAPHEN BEI FREIER UND ERZWUNGENER SCHWINGUNG
Authors: VON O. FORTSCH
Published: June 2021

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CRITERI E PROBLEMI COSTRUTTIVI DI STRUMENTI PER MISURE DI RESISTIVITÀ
Authors: LUIGI SOLAINI
Published: June 2021

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CONTRIBUTO AL CALCOLO DELL'ASSORBIMENTO NELLA PROPAGAZIONE IONOSFERICA DELLE ONDE CORTE
Authors: A. BOLLE  , P. DOMINICI
Published: June 2021

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MISURA DEI LENTI MOVIMENTI VERTICALI DELLA SUPERFICIE TERRESTRE
Authors: SILVIO POLLI
Published: June 2021

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UNA SOLUZIONE DEL PROBLEMA DELLE REGISTRAZIONI MECCANICHE
Authors: E. MEDI
Published: June 2021

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GLI ATTUALI MOVIMENTI VERTICALI DELLE COSTE CONTINENTALI
Authors: SILVIO POLLI
Published: June 2021

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Su un indice di rendimento in Meteorologia Agraria
Authors: E. Rosini
Published: June 2021

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Numeri caratteristici dei flocculi d'idrogeno e di calcio e dei filamenti d'idrogeno per l'anno 1956
Authors: G. Godoli  , M. P. Strocchi
Published: June 2021

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POLARISATION OF THE S - PHASE OF SEISMOGRAMS
Authors: R. STONELEY
Published: June 2021

In earthquakes recorded at moderate distances it lias been ohservedthat S phase appears first as SII, folloived some 10 to 14 seconds laterby SV. The object of tliis paper is to try to decide ichether doublérefraction is likely to be the explanation of tliis jìlwnomenon.A simpie model to consider ivould be a « transversely isotropie »material, symmetrical about the radiai direction. Formulae for thevelocities of SII and SV waves are available; tliese velocities dependon the angle that the ray makes ivi t li the norma!. It is unlikely thatthe Eartli could be as markedly anisotropie as the minerai beryl, whichis transversely isotropie; aceordingly, this material, of ivhich the fi veclastic constants are knoivn is taken as an extreme example, andthe velocities of SH and SV for different angles of incidence are« scaled down » so as to match the velocity of distortional ivaves ingranite. It is then possible to calcitiate the difference in the timo takenby ivaves from one point of the surface of the Earth to anotlier pointon the surface according as the S wave in the surface layer is of SHor SV type.
UNTERSUCIIUNGEN UEBER MIKROSEISMIK IN DEUTSCHEAND WAEHREND DES ZWEITEN WELTKRIEGES
Authors: E. Hardtvig
Published: June 2021

Ini Laufe des Jahres 1942 wurde vom damaligen DeutschenWetterdienst der Beschluss gefasst, den Zusammenhang zwisclienMikroseismik und Wetterlage genau untersuchen zu tasseti. Zweckder Untersuchungen solite sein, herauszufinden, oh die durch die M.S.gegebenen Dateti f i i r die Erkennung der Grosswetterlage geeignet undeventuell fiir die Prognose verwertbar seien. Mit der Oberleitungwurde Prof. Angenheister in Gottingen, betraut.
OSCILLAZIONI LIBERE DEL LAGO DI LEVICO
Authors: P. CALOI
Published: June 2021

In questa prima parte del lavoro dedicato allo studio delle oscillazionilibere del lago di Levico, vengono riassunti i risultati dell'applicazionedi tre distinti metodi analitici alla determinazione deiperiodi, dei nodi e dell'andamento delle ampiezze, relativi alle primetre sesse del lago. I risultati sono in buon accordo tra loro.Ci riserviamo di completare lo studio non appena avremo ottenutouna opportuna serie di registrazioni limnografiche.
Su una costante isoterma dei gas
Authors: G. Paoluzzi
Published: June 2021

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RILIEVO SPERIMENTALE GRAVIMETRICO-MAGNETICO NELL' AVAMPAESE DEI COLLI EUGANEI
Authors: c. morelli
Published: June 2021

Proseguendo le ricerche sperimentali in preparazione di un rilievogeofisico sistematico attorno ai Colli Euganei, in corrispondenzadelle stazioni eòtvóssiane e gravimetriche eseguite nella zona fra Battaglia,Pontelongo e Ponte S. Nicolò è stata eseguita con variometrimagnetici una rete di 51 stazioni nella componente verticale ed orizzontale.Le anomalie magnetiche, specie quelle nella Z, confermanoed integrano le anomalie gravimetriche, dimostrando così la connessionefisica dei due fenomeni e fornendo elementi utili per l'individilazionedella topografia sotterranea.
SULLA STRUTTURA DELLA CROSTA TERRESTRE NEL MEDITERRANEO CENTRO-OCCIDENTALE E NELL'ADRIATICO
Authors: P. E. Valle
Published: June 2021

Mediante una misura della velocità media di gruppo delle onde Lrelativa al periodo di 20s, si pone in evidenza il fatto che tale velocitàè notevolmente più elevata nel Mediterraneo centro-occidentale chenell'Europa, mentre nel Mare Adriatico diminuisce leggermente. Untentativo di prospezione profonda nel Mediterraneo centro-occidentalee nell'Adriatico, mostra il notevole assottigliamento, rispetto all'Europa,dello spessore medio del primo strato della crosta terrestre.
SULL'ORIGINE DEL ROMBO DEL TUONO
Authors: g. zanotelli
Published: June 2021

Si interpretano le cause fisiche di due fra le più singolari caratteristichedel rombo del tuono, e cioè la sua lunga persistenza ed iltimbro eminentemente ricco di suoni bassi. Per quanto altri autoriavessero in passato localizzato l'origine di questi fatti in svariate edoccasionali circostanze di ambiente, si è potuto dimostrare teoricamentenel presente lavoro come gli ammassi di goccioline di acqua checostituiscono le formazioni nuvolose esercitino una riflessione selettivasulle onde sonore incidenti: precisamente tale riflessione avviene inmisura apprezzabile solo per le componenti della perturbazione sonora,originata dallo scoppio del fulmine, di frequenza inferiore acerte due frequenze di taglio, proprie, l'ima del fenomeno di alternacondensazione ed evaporazione delle goccioline sotto l'azione delle variazionidi pressione sonora, e l'altra del parziale trascinamento dellegoccioline stesse nel moto dell'onda sonora per effetto della viscositàdell'aria. In base a questi risultati e tenuta anche presente la eventualitàdi più riflessioni successive si giustifica come, a causa dellabassa velocità del suono nell'atmosfera e della relativamente grandedistanza delle nubi, il rumore del tuono possa persistere a lungo; sipuò inoltre prevedere che il timbro sonoro debba farsi sempre piùcupo, via via che il rimbombo si prolunga.
TARATURA DI DUE GRAVIMETRI WORDEN E COLLEGAMENTI EUROPEI
Authors: c. morelli
Published: June 2021

Per i due gravimetri Worden n. 50 e re. 52 la determinazione dellacostante di scala è stata effettuata per confronto con 18 stazionipendolari tedesche, entro un campo di 1500 mgal (da 980,00 a 981,50:praticamente corrispondente all' Europa centro-meridionale). È risulta52 4 CAbLO MORELLIto che le costanti fornite dalla Casa costruttrice avevano un errore dicirca il 2%c. Le nuove costanti risultano lineari, nel campo considerato,con un errore del 0,35%«. Ciò consente di utilizzare con vantaggio igravimetri in questione, sempre nel campo di taratura e con opportunicriteri d'impiego, in sostituzione dei pendoli, con un errore medio« reale » inferiore al 0,5%o. Se ne è fatto impiego per collegare, indirettamente,con Potsdam le stazioni nazionali di riferimento di Uccie(981,132.0 ± 0.2), Parigi (980,943.8 ± 0 . 3 ) , De Bilt (980,268.8 ±0,3),{Copenhagen (981,557.5 ± 0.4), e Padova (980,658.6 ± 0.4), nonché lemisure assolute di Teddington (981,196.3 ± 0.2), Monaco (980,733.0 ±+ 0.4), Braunschweig (981,265.5 ± 0 . 1 ) e Roma (980,361.6 ±0.4). Lacorrezione provvisoria all'attuale « sistema di Potsdam » viene così confermatain — 13.9 ± 3.5 mgal.
SULL'ORIGINE DEI MICROSISMI CON PARTICOLARE RIGUARDO ALL'ALTO ADRIATICO (*)
Authors: P. CALOI
Published: June 2021

Già dal 1936 avevo provato che, nel transito dei cicloni sull'altoAdriatico, le rapide variazioni di pressione collegate a detti cicloni e,specialmente, alla fase positiva montante degli stessi, davano originealla formazione di microsismi, tanto più sensibili quanto più prossimaalla velocità delle onde libere del mare sottostante è la velocitàdei disturbi microbarici.L'ampiezza dei microsismi diventa particolarmente notevole quando,sul golfo di Trieste in direzione del suo asse e in senso contrarioa quello secondo cui crescono le distanze dalla sua base, transitanorapide variazioni della pressione, collegate oppure no a nuclei ciclonici,con velocità paragonabili a quella delle onde libere del mare.L'effetto è massimo per nuclei a tendenza positiva, collegati a cicloniin transito.
UBER SEICHES IN MEERESBUCHTEN UND DIE FRAGE DER MUNDUNGSKORREKTUR
Authors: GERHARD NEUMANN
Published: June 2021

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IL CICLO CLIMATICO DI 8 ANNI E SUA REALTA' FISICA
Authors: SILVIO POLLI
Published: June 2021

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SULLA NATURA FISICA DEI MICROSISMI
Authors: G. D'HENRY
Published: June 2021

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SUL DECADIMENTO DEL K40
Authors: C. FESTA  , M. SANTANGELO
Published: June 2021

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RILIEVO MAGNETICO REGIONALE NELLE MARCHE PER LA ISTITUZIONE DI UN OSSERVATORIO MAGNETICO CENTRALE
Authors: M. GIORGI  , E. MEDI  , C. MORELLI
Published: June 2021

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DUE CARATTERISTICI TIPI DI MICROSISMI
Authors: PIETRO CALOI
Published: June 2021

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MATHEMATISCHE PROBLEME DER GEOPHYSIK
Authors: ERWIN HARDTWIG
Published: June 2021

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LA DISTRIBUZIONE SPETTRALE DELLA POLARIZZAZIONE DELLA LUCE DEL CIELO
Authors: RENATO Cialdea
Published: June 2021

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PENETRAZIONE DELLE RADIAZIONI LUMINOSE NEL GHIACCIO E NELLA NEVE
Authors: SILVIO POLLI
Published: June 2021

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DETERMINAZIONE DEL VALORE MEDIO DELLO SPESSORE DELLO STRATO DI GRANITO PER I TRAGITTI TURKESTAN-EUROPA
Authors: FRANCESCO PERONACI
Published: June 2021

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Aerial inventory of surficial geological effects induced by the recent Emilia earthquake (Italy): preliminary report
Authors: Giovanni Bertolini  , Chiara Fioroni
Published: June 2021

As a consequence of the two main shocks that recently struck the central alluvial Po Plain (May 20, 2012, Ml 5.9, and May 29, 2012, Ml 5.8), a great number of surficial geologic disturbances appeared over a wide area (ca. 500 km2), which extended up to 20 km from the epicenters. The affected area includes Mirabello, San Carlo, Sant'Agostino (Province of Ferrara), San Felice, Cavezzo, Concordia (Modena), Moglia and Quistello (Mantova). Most of the surficial effects that were observed during this study were clearly induced (directly or indirectly) by sand liquefaction phenomena, such as sand volcanoes, burst of water and sand from domestic wells, tension cracks, lateral spreading and associated deformation, graben-like fracturing, and sink-holes. Other effects can probably be ascribed simply to the shaking of the ground (e.g., small collapses of irrigation canal walls). Lastly, there were also some features of dubious origin, such as two 'yellow crop spots' that are cited here with reservations. All of these data were surveyed by means of a small airplane that was especially adapted for this purpose. The aim of this study was to furnish a wide-ranging image of the surface deformation over the whole area impacted by these recent earthquakes, as an instrument towards more exhaustive research, both at the scientific and technical levels (e.g., seismic microzonation). […]
The survey and mapping of sand-boil landforms related to the Emilia 2012 earthquakes: preliminary results
Authors: Andrea Ninfo  , Davide Zizioli  , Caludia Meisina  , Doriano Castaldini  , Francesco Zucca  , Lucia Luzi  , Mattia De Amicis
Published: June 2021

Sand boils, which are also known as sand blows or sand volcanoes, are among the most common superficial effects induced by high-magnitude earthquakes. These generally occur in or close to alluvial plains when a strong earthquake (M >5) strikes on a lens of saturated and unconsolidated sand deposits that are constrained between silt-clay layers [Ambraseys 1988, Carter and Seed 1988, Galli 2000, Tuttle 2001, Obermeier et al. 2005], where the sediments are converted into a fluid suspension. The liquefaction phenomena requires the presence of saturated and uncompacted sand, and a groundwater table near the ground surface. This geological–geomorphological setting is common and widespread for the Po Plain (Italy) [Castiglioni et al. 1997]. The Po Plain (ca. 46,000 km2) represents 15% of the Italian territory. It hosts a population of about 20 million people (mean density of 450 people/km2) and many infrastructures. Thus, the Po Plain is an area of high vulnerability when considering the liquefaction potential in the case of a strong earthquake. Despite the potential, such phenomena are rarely observed in northern Italy [Cavallin et al. 1977, Galli 2000], because strong earthquakes are not frequent in this region; e.g., historical data report soil liquefaction near Ferrara in 1570 (M 5.3) and in Argenta 1624 (M 5.5) [Prestininzi and Romeo 2000, Galli 2000]. In the Emilia quakes of May 20 and 29, 2012, the most widespread coseismic effects were soil liquefaction and ground cracks, which occurred over wide areas in the Provinces of Modena, Ferrara, Bologna, Reggio Emilia and Mantova (Figure 1). […]
Combination of coseismic displacement fields: a geodetic perspective
Authors: Roberto Devoti
Published: June 2021

This study provides the mathematical framework for the rigorous combination of coseismic offsets observed by a global positioning system (GPS) network and investigates the results obtained on the occasion of the recent Emilia earthquakes (Italy). This seismic sequence that affected northern Italy from May 20, 2012, allowed two offset fields to be computed, one with reference to the mainshock (M 5.9, followed by two other M 5.1 events on the same day), and a second with reference to the replicas that occurred on May 29, 2012 (M 5.8, M 5.3 and M 5.2; ISIDe data archive, http://iside.rm.ingv.it). The final displacement field is basically the result of a comparison and validation process with repeated feedback between the different analysis groups at the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology) that was established to obtain prompt coseismic displacement solutions, as precise as possible, and in the first days after an event. This is important for early seismic-source evaluation as it represents the most complete and validated dataset at the very early stage of a seismic crisis, and it is also extremely useful in reducing random and systematic errors in the estimated parameters. This study is the result of a cooperative effort that involved different research groups at INGV, with the sharing of all of the collected GPS data. The intention was to compare these results and thus reducing sources of error associated with individual processing strategies, to allow the final combination of the different displacement fields into a single consensus solution. The process assessed the robustness of each single GPS result, thus minimizing erroneous interpretations of individual solutions. […]
Searching for the effects of the May-June 2012 Emilia seismic sequence (northern Italy): medium-depth deformation structures at the periphery of the epicentral area
Authors: Lisa Borgatti  , Antonio Edoardo Bracci  , Stefano Cremonini  , Giovanni Martinelli
Published: June 2021

In 2012, a seismic sequence occurred in the lowlands of the Emilia-Romagna Region (northern Italy), between the borders of the Modena, Ferrara and Bologna Provinces. It consisted of seven mainshocks (5.9 > Ml > 5) that were recorded between May 20 and 29, 2012 [INGV 2012a] and 2,200 minor earthquakes [INGV 2012b]. An interferometric analysis [Bignami et al. 2012, Salvi et al. 2012, this volume] highlighted three main deformation areas, each of which was 12 km wide (from S to N) and 10 km to 20 km long in an ESE-WNW to E-W direction, thus affecting an area of about 600 km2 (Figure 1). Field and aerial geological surveys recorded numerous surficial effects, such as: (i) sediment liquefaction [Crespellani et al. 2012]; (ii) localized ground fissures resembling surficial faulting [Fioravante and Giretti 2012] (Figure 2); (iii) groundwater levels rising up to 400 cm above the local ground level in phreatic wells during the mainshocks (lower values were observed in confined aquifers); and (iv) dormancy of previously known sinkholes [Borgatti et al. 2010, Cremonini 2010a, and references therein]. Some of the observed surface phenomena were previously recorded as coseismic effects during the earthquakes of Ferrara (1570) and Argenta (1624) [Boschi et al. 1995, Galli 2000], together with the early rising of the water level of the Po River in the Stellata section. […]
Liquefaction phenomena along the paleo-Reno River caused by the May 20, 2012, Emilia (northern Italy) earthquake
Authors: Giorgos Papathanassiou  , Riccardo Caputo  , Dimitra Rapti-Caputo
Published: June 2021

On the May 20, 2012 (04:03:52 local time; 02:03:52 UTC), a moderate earthquake (Ml 5.9) [Scognamiglio et al. 2012, this volume] with a focal mechanism showing E-W-trending, S-dipping, reverse-faulting occurred in the eastern sector of the alluvial plain of the Po River, close to the border between the Regions of Emilia-Romagna and Lombardia (northern Italy). The tectonic structure is completely blind, but it was well known from a dense grid of seismic profiles for hydrocarbon explorations [e.g., Pieri and Groppi 1981, Toscani et al. 2009]. The earthquake triggered extensive liquefaction-induced ground effects at the surface, and caused severe structural damage to nonreinforced masonry and precast industrial buildings within the broader epicentral area. The hypocenter was at 44.89 ˚N, 11.23 ˚E, at a depth of 6.3 km [Scognamiglio et al. 2012], while the maximum acceleration was recorded in Mirandola, with peak ground acceleration 310 cm/s2 and 264 cm/s2 along the vertical and horizontal components, respectively [Bozzoni et al. 2012, this volume]. In this report, we focus on a zone including the Sant'A-gostino, San Carlo and Mirabello villages (west Ferrara Province), which were built along an abandoned reach of the Reno River and where liquefaction phenomena were particularly diffuse, with very intense local effects. […]
Electrical resistivity tomography investigation of coseismic liquefaction and fracturing at San Carlo, Ferrara Province, Italy
Authors: Nasser Abu Zeid  , Samuel Bignardi  , Riccardo Caputo  , Giovanni Santarato  , Marco Stefani
Published: June 2021

Massive surface fracturing and sand ejection took place during the main shock of the May 20, 2012, earthquake (Ml = 5.9) in the Emilia-Romagna region, northern Italy. These phenomena were induced by the liquefaction of water-saturated sand layers, and they damaged several buildings, as well as many roads and sidewalks. They were clustered between the villages of Sant'Agostino and Vigarano Mainarda, located along a paleo-reach of the Reno River [Papathanassiou et al. 2012, this volume]. The subsurface surrounding two major (several decameters long) ground ruptures was investigated using electrical resistivity tomographies (ERT), as resistivity is strongly affected by the chemico-physical conditions of loose sediments. Italian regulations require the Municipalities within seismically active areas to develop maps of the potential liquefaction risk. Not all of the territories that are under this kind of risk have been investigated to date. A strong effort to improve this knowledge is therefore needed. Noninvasive geophysical methods can help to fill this gap, as high-resolution techniques are available with good result-to-cost ratios. Among the available methodologies, the most suitable are the methods based on electrical resistivity and permittivity, as they are highly sensitive to the presence of underground water. The ERT method has been carried out successfully across active faults, providing crucial paleoseismological information [Caputo et al. 2003, 2007]. […]
Rapid response to the earthquake emergency of May 2012 in the Po Plain, northern Italy
Authors: Milena Moretti  , et al.
Published: June 2021

Rapid-response seismic networks are an important element in the response to seismic crises. They temporarily improve the detection performance of permanent monitoring systems during seismic sequences. The improvement in earthquake detection and location capabilities can be important for decision makers to assess the current situation, and can provide invaluable data for scientific studies related to hazard, tectonics and earthquake physics. Aftershocks and the clustering of the locations of seismic events help to characterize the dimensions of the causative fault. Knowing the number, size and timing of the aftershocks or the clustering seismic events can help in the foreseeing of the characteristics of future seismic sequences in the same tectonic environment. Instrumental rapid response requires a high degree of preparedness. A mission in response to a magnitude (Ml) 6 event with a rupture length of a few tens of kilometers might involve the deployment within hours to days of 30-50 seismic stations in the middle of a disaster area of some hundreds of square kilometers, and the installation of an operational center to help in the logistics and communications. When an earthquake strikes in a populated area, which is almost always the case in Italy, driving the relevant seismic response is more difficult. […]
Coseismic deformation pattern of the Emilia 2012 seismic sequence imaged by Radarsat-1 interferometry
Authors: Christian Bignami  , Pierfrancesco Burrato  , Valentina Cannelli  , Marco Chini  , Emanuela Falcucci  , Alessandro Ferretti  , Stefano Gori  , Christodoulos Kyriakopoulos  , Daniele Melini  , Marco Moro  , Fabrizio Novali  , Michele Saroli  , Salvatore Stramondo  , Gianluca Valensise  , Paola Vannoli
Published: June 2021

On May 20 and 29, 2012, two earthquakes of magnitudes 5.9 and 5.8 (Mw), respectively, and their aftershock sequences hit the central Po Plain (Italy), about 40 km north of Bologna. More than 2,000 sizable aftershocks were recorded by the Isti-tuto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology) National Seismic Network (http://iside.rm.ingv.it/). The sequence was generated by pure compressional faulting over blind thrusts of the western Ferrara Arc, and it involved a 50-km-long stretch of this buried outer front of the northern Apennines. The focal mechanisms of the larger shocks agree with available structural data and with present-day tectonic stress indicators, which show locally a maximum horizontal stress oriented ca. N-S; i.e. oriented perpendicular to the main structural trends. Most of the sequence occurred between 1 km and 12 km in depth, above the local basal detachment of the outer thrust fronts of the northern Apennines. We measured the surface displacement patterns associated with the mainshocks and some of the larger aftershocks (some of which had Mw >5.0) by applying the Interferometric Synthetic Aperture Radar (InSAR) technique to a pair of C-Band Radarsat-1 images. We then used the coseismic motions detected over the epicentral region as input information, to obtain the best-fit model fault for the two largest shocks. […]
The MCS macroseismic survey of the Emilia 2012 earthquakes
Authors: Paolo Galli  , Sergio Castenetto  , Edoardo Peronace
Published: June 2021

Most of the inhabitants of northern Italy were woken up during the night of May 20, 2012, by the Mw 6.1 earthquake [QRCMT 2012] that occurred in the eastern Po Plain. The mainshock was preceded a few hours before by a Mw 4.3 shock, and it was followed by a dozen Ml >4 aftershocks in May and June, amongst which 11 had Ml ≥4.5. On May 29, 2012, a second Mw 6.0 mainshock struck roughly the same area [QRCMT 2012], which resulted in further victims, most of whom were caught under the collapse of industrial warehouses. Such earthquakes are an unexpected event in this region, as testified by the lack of local epicenters in the Italian seismic catalog [Rovida et al. 2011: CPTI11 from now] and by the consequent low level of the local seismic classification (seismic zone 3) [DPC 2012]. Apart from the warehouses and hundreds of old, crumbling farmsteads, severe damage was focused on ancient, tall buildings, such as churches, bell towers, castles, towers and palaces. Residential buildings generally suffered only light and/or moderate effects, apart from some exceptional cases. Using the Mercalli–Cancani–Sieberg (MCS) scale [Sieberg 1930], we began a macroseismic survey in the early morning of May 20, 2012, that ultimately included visits to almost 200 localities, 52 of which were carried out before the second mainshock. […]
The Ferrara thrust earthquakes of May-June 2012: preliminary site response analysis at the sites of the OGS temporary network
Authors: Enrico Priolo  , Marco Romanelli  , Carla Barnaba  , Marco Mucciarelli  , Giovanna Laurenzano  , Lorella Dall'Olio  , Nasser Abu Zeid  , Riccardo Caputo  , Giovanni Santarato  , Luigi Vignola  , Carmine Lizza  , Paolo Di Bartolomeo
Published: June 2021

Following the Ml 5.9 earthquake that struck the Emilia area in northern Italy on May 20, 2012, at 02:03:53 UTC, and in co-operation with the personnel of the Municipality of Ferrara and the University of Ferrara, a team of seismologists of the Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS; National Institute of Oceanography and Experimental Geophysics) deployed a temporary seismographic network. This consisted of eight portable seismological stations, to record the local earthquakes that occurred during the seismic sequence. The OGS intervention was integrated into the broader action of the emergency response to the earthquake sequence, which was promoted by the National Department of Civil Protection and the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology) [Moretti et al. 2012, this volume]. The aim of the OGS intervention was on the one hand to extend the seismic monitoring area towards the East, to include Ferrara and its surroundings, to be ready in case of migration of the seismicity in that direction, and on the other hand to evaluate the seismic response at the instrumented sites. Some days later, another team of researchers coordinated by the University of Potenza carried out some investigations at a number of sites, and in particular at three of the sites instrumented by the OGS temporary network. […]

 
The new CAS-DIS digital ionosonde
Authors: Wang Shun  , Chen Ziwei  , Zhang Feng  , Fang Guangyou
Published: June 2021

A high quality digital ionosonde called the Chinese Academy of Sciences digital ionosonde (CAS-DIS) has been developed for investigations of the ionosphere. Two important features are used for the CAS-DIS; first, the technique of analog down-conversion has been replaced by the new approach of digital down-conversion technology. Secondly, to solve the problem of large instantaneous receiving bandwidth in digital receivers, an analog narrowband tracking filter is used for the CAS-DIS. The center frequency of the filter tracks the carrier frequency transmitted in real-time, to ensure that the frequency components are filtered out of the effective bandwidth. This report describes the system architecture of the CAS-DIS, its main features, and its test results for ionosphere detection.

 
Neural network approach to the prediction of seismic events based on low-frequency signal monitoring of the Kuril-Kamchatka and Japanese regions
Authors: Irina Popova  , Alexander Rozhnoi  , Maria Solovieva  , Boris Levin  , Masashi Hayakawa  , Yasuhide Hobara  , Pier Francesco Biagi  , Konrad Schwingenschuh
Published: June 2021

Very-low-frequency/ low-frequency (VLF/LF) sub-ionospheric radiowave monitoring has been widely used in recent years to analyze earthquake preparatory processes. The connection between earthquakes with M ≥5.5 and nighttime disturbances of signal amplitude and phase has been established. Thus, it is possible to use nighttime anomalies of VLF/LF signals as earthquake precursors. Here, we propose a method for estimation of the VLF/LF signal sensitivity to seismic processes using a neural network approach. We apply the error back-propagation technique based on a three-level perceptron to predict a seismic event. The back-propagation technique involves two main stages to solve the problem; namely, network training, and recognition (the prediction itself). To train a neural network, we first create a so-called ‘training set’. The ‘teacher’ specifies the correspondence between the chosen input and the output data. In the present case, a representative database includes both the LF data received over three years of monitoring at the station in Petropavlovsk-Kamchatsky (2005-2007), and the seismicity parameters of the Kuril-Kamchatka and Japanese regions. At the first stage, the neural network established the relationship between the characteristic features of the LF signal (the mean and dispersion of a phase and an amplitude at nighttime for a few days before a seismic event) and the corresponding level of correlation with a seismic event, or the absence of a seismic event. For the second stage, the trained neural network was applied to predict seismic events from the LF data using twelve time intervals in 2004, 2005, 2006 and 2007. The results of the prediction are discussed.
Geodetic evidence for passive control of a major Miocene tectonic boundary on the contemporary deformation field of Athens (Greece)
Authors: Michael Foumelis  , Ioannis Fountoulis  , Ioannis D. Papanikolaou  , Dimitrios Papanikolaou
Published: June 2021

A GPS-derived velocity field is presented from a dense geodetic network (~5km distance between stations) established in the broader area of Athens. It shows significant local variations of strain rates across a major inactive tectonic boundary separating metamorphic and non-metamorphic geotectonic units. The southeastern part of Athens plain displays negligible deformation rates, whereas towards the northwestern part higher strain rates are observed, indicating the control of the inactive tectonic boundary on the contemporary deformation field of the region. These findings are in agreement with previous geological observations, however, due to the dense local GPS network it was fatherly possible to localize and quantify the effect of such a major inherited tectonic feature on the deformation pattern of the area.
Measuring GNSS ionospheric total electron content at Concordia, and application to L-band radiometers
Authors: Vincenzo Romano  , Giovanni Macelloni  , Luca Spogli  , Marco Brogioni  , Giuditta Marinaro  , Cathryn N. Mitchell
Published: June 2021

In the framework of the project BIS - Bipolar Ionospheric Scintillation and Total Electron Content Monitoring, the ISACCO-DMC0 and ISACCO-DMC1 permanent monitoring stations were installed in 2008. The principal scope of the stations is to measure the ionospheric total electron content (TEC) and to monitor the ionospheric scintillations, using high-sampling-frequency global positioning system (GPS) ionospheric scintillation and TEC monitor (GISTM) receivers. The disturbances that the ionosphere can induce on the electromagnetic signals emitted by the Global Navigation Satellite System constellations are due to the presence of electron density anomalies in the ionosphere, which are particularly frequent at high latitudes, where the upper atmosphere is highly sensitive to perturbations coming from outer space. With the development of present and future low-frequency space-borne microwave missions (e.g., Soil Moisture and Ocean Salinity [SMOS], Aquarius, and Soil Moisture Active Passive missions), there is an increasing need to estimate the effects of the ionosphere on the propagation of electromagnetic waves that affects satellite measurements. As an example, how the TEC data collected at Concordia station are useful for the calibration of the European Space Agency SMOS data within the framework of an experiment promoted by the European Space Agency (known as DOMEX) will be discussed. The present report shows the ability of the GISTM station to monitor ionospheric scintillation and TEC, which indicates that only the use of continuous GPS measurements can provide accurate information on TEC variability, which is necessary for continuous calibration of satellite data.
VLF-EM and VES: an application to groundwater exploration in a Precambrian basement terrain SW Nigeria
Authors: Adebowale Obasanmi Adelusi  , Michael A. Ayuk  , John Stephen Kayode
Published: June 2021

In a hard rock environment with surface or near surface expression of outcrops, the use of VES only becomes difficult due to its associated problems and limitations. However, the use of VLF-EM becomes imperative in mapping basement structures relevant to groundwater development. A total of 2100 VLF-EM data plus selected VES points were covered over 7 traverses with length varying from 3000 to 4500 m. The VLF-EM result mapped basement structures relevant in groundwater development. This is further studied using VES. Results of the investigation indicate that a HKH sounding curve is obtained with a maximum of five subsurface layers comprising: the top soil, clay/sandy clay unit, the fresh basement, fractured basement and the basement bedrock. The fractured basement layer constitutes the main aquifer unit with thickness of 20-25 m. The layer resistivity and thickness ranges are 60-100 ohm-m; 40-80 ohm-m, 1600-2100 ohm-m, 250-420 ohm-m, and 2200-7500 ohm-m; and 0.3-1.2 m, 1.9-2.5 m, 16.5-22.5 m and 22-30 m for the five layers respectively. The geoelectric results compared favorably well with drilling information to above 90%. The yield of the well is 2 L/s with good recharge capability.
Development of a new seismic-data acquisition station based on system-on-a-programmable-chip technology
Authors: Zhang Qi-sheng  , Deng Ming  , Guo Jian  , Luo Wei-bing  , Wang Qi  , Feng Yong-qiang
Published: June 2021

There has been considerable development of seismic detectors over the last 80 years. However, there is still a need to further develop new earthquake exploration and data acquisition systems with high precision. In particular, for China to keep up with the latest technology of these systems, it is important to be involved in the research and development, instead of importing systems that soon fall behind the latest technology. In this study, the features of system-on-a-programmable-chip (SoPC) technology are analyzed and used to design a new digital seismic-data acquisition station. The hardware circuit of the station was developed, and the analog board and the main control data-transmission board were designed according to the needs of digital seismic-data acquisition stations. High-definition analog-to-digital converter sequential digital filter technology of the station (cascade integrator comb filter, finite impulse response digital filter) were incorporated to provide advantages to the acquisition station, such as high definition, large dynamic scope, and low noise. A specific data-transmission protocol was designed for the station, which ensured a transmission speed of 16 Mbps along a 55-m wire with low power consumption. Synchronic acquisition was researched and developed, so as to achieve accuracy better than 200 ns. The key technologies were integrated into the SoPC of the main control data-transmission board, so as to ensure high-resolution acquisition of the station, while improving the accuracy of the synchronic acquisition and data-transmission speed, lowering the power consumption, and preparing for the follow-up efforts to tape out.
MIPAS Level 2 Processor Prototype: from validation to operation
Authors: Marc Bernau  , Heidrun Weber  , Michael Schmitt  , Sven Bartha  , Roland Gessner
Published: June 2021

In the research field of atmospheric chemistry a central question for acquired data sets is about validation. Have the data been validated to be useful for science? Has the data set been compared to other data sets? If deviations occur, which cause could be identified? Ultimately, two causes are possible when the same scene is observed: either the acquired raw data set is erroneous (hardware problem) or the data processing infers erroneous information (software problem). In order to make sure that the software works as expected, software validation plays a key role in the overall data set validation campaigns. This paper deals with operational software validation, which is an important component of the entire scientific validation chain. [...]
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Authors: AePIC CILEA
Published: June 2021

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