Concurrent deformation processes in the Matese massif area (Central-Southern Apennines, Italy)

We investigated the interseismic GPS velocity field across the transition zone between Central and Southern Apennine comprising the Meta–Mainarde-Venafro and Alto Molise–Sannio-Matese mounts. The kinematic field obtained by combining GPS network solutions is based on data collected by the unpublished episodic campaigns carried out on Southern Apennine Geodetic network (SAGNet from 2000 to 2013), IGM95 network (Giuliani et al., 2009 from 1994 to 2007) and continuous GPS stations. The data collected after the 29 December 2013 earthquake (Mw 5.0) until early 2014 allowed estimating displacements at 15 SAGNet stations. The extension rate computed across the Matese massif along an anti-Apennine profile is 2.0±0.2 mm/yr. The interseismic velocities projected along the profile show that the maximum extension does not follow the topographic high of the Apennines but is shifted toward the eastern outer belt. No significant GPS deformation corresponding to inner faults systems of the Matese massif is detected. Taking into account our results and other geophysical data, we propose a conceptual model, which identifies the 2013–2014 seismic sequence as not due to an extensional deformation style usual along the Apennine chain. In fact, we have measured too large “coseismic” displacements, that could be explained as the result of tectonic regional stress, CO2-rich fluid migration and elastic loading of water in the karst Matese massif. We recognized a tensile source as model of dislocation of 2013–2014 earthquakes. It represents a simplification of a main fault system and fracture zone affecting the Matese massif. The dislocation along NE-dipping North Matese Fault System (NMFS) could be the driving mechanism of the recent seismic sequences. Moreover, to the first time the SAGnet GPS data collected from 1994 to 2014, are share and available to the scientific community in the open access data archive.INGV and DPCS1-C1 - 2012-2021.Published2282342T. Deformazione crostale attivaJCR Journa

Indagini gravimetriche e gps in Italia centrale per il controllo delle aree sismogenetiche

L’attività presentata è parte del Progetto dal titolo “Feasibility of an absolute gravity network in central Italy: toward a multi-disciplinary approach to natural risk assessment”, finanziato dall’Istituto Nazionale di Geofisica e Vulcanologia (INGV) nell’ambito dei Progetti di Ricerca Libera finalizzati allo studio e al monitoraggio dei rischi naturali dell’Italia Centrale. Lo scopo del progetto è la realizzazione di una rete gravimetrica, assoluta e relativa, e di stazioni GPS a larga scala in Italia Centrale, nelle aree interessate dalla più recente attività sismica, e di gettare le basi per un approccio multidisciplinare alla valutazione del rischio naturale. La fattibilità del progetto è stata possibile per la disponibilità presso l’INGV di due gravimetri assoluti, uno da laboratorio (Micro-g LaCoste FG5#238) e uno da campagna (Micro-g LaCoste A10#39). La finalità principale del progetto è quella di rilevare, mediante l’occupazione di siti già esistenti sul territorio e misurati in passato, eventuali variazioni della gravità e di deformazioni del suolo occorse su lungo periodo. Dopo una ricerca sull’esistenza di vertici gravimetrici e GPS nel territorio, di interesse per il progetto, e a seguito di sopralluogo, sono stati selezionati 5 siti distribuiti tra Lazio e Abruzzo, come illustrato nella Fig.1. Figura 1: Distribuzione delle stazioni selezionate per misure gravimetriche e GPS in Centro Italia. Due vertici di misure relative (Terni e Popoli), appartenenti alla rete del rilievo gravimetrico condotto dall’ING nel 1954 (Morelli, 1955), sono stati collegati a due stazioni assolute instituite nell’ambito del presente progetto nella stessa area; la stazione assoluta di Sant’Angelo Romano è stata istituita nel 2005 nell’ambito di un Progetto di Ricerca INGV-DPC sui Colli Albani (Berrino et al., 2006; Riguzzi et al., 2007; D’Agostino et al., 2008); un sito per misure relative presso i laboratori superficiali dei Laboratori Nazionali del Gran Sasso (LNGS) istituito nel 2010 nel corso di indagini svolte a seguito dell’evento sismico del 2009 e quando fu contemporaneamente realizzata anche una stazione assoluta nel centro della città di L’Aquila (Berrino et al., 2010); la stazione assoluta all’Aquila presso l’Università di Coppito è stata istituita nel corso del presente progetto in sostituzione di quella realizzata nel 2010 attualmente non occupabile. La prima campagna di misure è stata effettuata nella seconda metà di giugno 2018 durante la quale sono state effettuate: a) misure assolute dell’accelerazione di gravità, con il solo gravimetro FG5#238 per indisponibilità dell’A10#39; b) misure gravimetriche relative per i collegamenti tra i vari vertici assoluti e le rispettive stazioni satelliti relative, e per la misura del locale gradiente verticale della gravità nelle stazioni assolute; c) misure GPS e topografiche classiche per il posizionamento dei siti di misura e il riporto della quota, anche da capisaldi altimetrici dell’IGMI dove esistenti. Una seconda campagna di misura è stata svolta tra la fine di settembre e gli inizi di ottobre 2018 durante la quale sono state effettuate solo misure assolute di gravità, ma con entrambi i gravimetri disponibili, e ulteriori misure GPS e topografiche classiche. Nel corso della seconda campagna, data la possibilità dell’utilizzo del gravimetro assoluto da campagna, è stata anche effettuata la misura assoluta sul sito relativo dei LNGS superficiali. L’utilizzo congiunto dei due gravimetri permette la loro inter-comparazione, utile allo scopo di poter effettuare le misure assolute anche separatamente in qualsiasi altra eventuale occasione che comporta l’utilizzo di più strumenti. Il gravimetro FG5#238 è stato già più volte inter-comparato con il gravimetro di riferimento italiano (Jiang et al., 2012; Greco et al., 2015; Pálinkáš et al., 2017), che è il gravimetro Standar Primario IMGC-02 realizzato presso l’Istituto Nazionale per la Ricerca Metrologica (INRiM) di Torino; mentre per l’A10 è in fase di attuazione l’inter-comparazione direttamente presso i Laboratori dell’INRiM. L’inter-comparazione tra strumenti è, come ben noto, fondamentale per l’omogeneizzazione dei dati, e la procedura seguita rientra nelle indicazioni date nel 2014 dalla Consultive Committee for Mass and related quantities (CCM) della International Association of Geodesy (IAG) (CCM-IAG Strategy for Metrology in Absolute Gravimetry). Alcune delle stazioni assolute misurate nel presente progetto faranno parte della Rete Gravimetrica Italiana di Riferimento “G0”, che è in fase di progettazione e che sarà costituita da sole stazioni assolute della gravità opportunamente misurate e/o rimisurate. Sebbene i dati raccolti siano ancora in corso di analisi, i risultati ottenuti hanno permesso di evidenziare le variazioni di gravità e di quota occorse ai singoli vertici, sia con riferimento al periodo relativo all’istituzione di ciascun vertice (relativo o assoluto) che tra le due campagne; e in particolare, dall’analisi congiunta dei dati gravimetrici assoluti e relativi, è stato possibile confermare il bias di circa -14 mGal alla stazione di Potsdam, utilizzata come riferimento nella maggior parte dei rilievi gravimetrici condotti in Italia sin dagli anni ’50. Saranno presentati, discussi e analizzati i risultati preliminari ottenuti dalle indagini effettuate.PublishedBologna, Palazzo della Regione2T. Deformazione crostale attiv

High-rate (1 Hz to 20 Hz) GPS coseismic dynamic displacements carried out during the Emilia 2012 seismic sequence

In May-July 2012, Emilia Romagna (northern Italy) was struck by a significant seismic sequence, which was characterized by two moderate-magnitude earthquakes: a Ml 5.9 event on May 20, 2012, at 02:03:53 UTC, and a Ml 5.8 event on May 29, 2012, at 07:00:03 UTC, about 12 km to the west of the first mainshock. The earthquake sequence produced a total of 20 casualties and severe and widespread damage, mainly to historical and commercial buildings. A detailed description of the seismic sequence can be found in Sco-gnamiglio et al. [2012, this volume]. The largest of the earthquake static displacements were recorded by tens of continuous global positioning system (cGPS) stations, as described in Serpelloni et al. [2012, this volume]. Most of these stations were operating with a sampling frequency of 1 Hz, and they belonged to scientific or commercial networks: RING (http://ring.gm.ingv.it); ITALPOS (http://smartnet.leica-geosystems.it); GeoTop (http://www.netgeo.it); Fondazione Geometri Emilia Romagna (http://www.gpsemiliaromagna.it; Lombardia [http://www.gpslombardia.it); and Veneto (http://147.162.229.63). Some hours after the first mainshock, the sampling frequency of the near-field RING stations (SBPO and MODE) were switched to 20 Hz, thus recording the coseismic displacements produced by the May 29, 2012, earthquake at higher frequency. This sampling frequency was previously used for the detection of coseismic dynamic displacements only for the Mw 9 Tohoku-Oki 2011 event [Colosimo et al. 2011b]. Thus, the 20-Hz-sampling displacements for the Tohoku-Oki 2011 earthquake and the May 29, 2012, Emilia event might represent important recordings to investigate coseismic contributions at frequencies higher than 1 Hz with GPS. In the present study, after the description of the high-rate GPS (HRGPS) data analysis, we will show and compare the preliminary results. Then, for the two mainshocks, we will compare the displacements recorded by the HRGPS (1 Hz up to 20 Hz) and the strong-motion time histories (100 Hz) at MODE, where the different instruments were approximately co-located (Figure 1, inset, relative distance of ca. 90 m). […

Accurate Monte Carlo modeling of cyclotrons for optimization of shielding and activation calculations in the biomedical field

Biomedical cyclotrons for production of Positron Emission Tomography (PET) radionuclides and radiotherapy with hadrons or ions are widely diffused and established in hospitals as well as in industrial facilities and research sites. Guidelines for site planning and installation, as well as for radiation protection assessment, are given in a number of international documents; however, these well-established guides typically offer analytic methods of calculation of both shielding and materials activation, in approximate or idealized geometry set up. The availability of Monte Carlo codes with accurate and up-to-date libraries for transport and interactions of neutrons and charged particles at energies below 250MeV, together with the continuously increasing power of nowadays computers, makes systematic use of simulations with realistic geometries possible, yielding equipment and site specific evaluation of the source terms, shielding requirements and all quantities relevant to radiation protection. In this work, the well-known Monte Carlo code FLUKA was used to simulate two representative models of cyclotron for PET radionuclides production, including their targetry; and one type of proton therapy cyclotron including the energy selection system. Simulations yield estimates of various quantities of radiological interest, including the effective dose distribution around the equipment, the effective number of neutron produced per incident proton and the activation of target materials, the structure of the cyclotron, the energy degrader, the vault walls and the soil. The model was validated against experimental measurements and comparison with well-established reference data. Neutron ambient dose equivalent H*(10) was measured around a GE PETtrace cyclotron: an average ratio between experimental measurement and simulations of 0.99\ub10.07 was found. Saturation yield of 18F, produced by the well-known 18O(p,n)18F reaction, was calculated and compared with the IAEA recommended value: a ratio simulation to IAEA of 1.01\ub10.10 was found

Sannio-Matese Mounts (Southern Italy) deformation field from GPS Data (2002-2014)

A ML=4.9 earthquake occurred in the Sannio-Matese area at 18:08 on December 29 2013. The epicenter was located in the “Monti del Matese seismic district”. The epicentral area lies between the small towns of San Gregorio Matese, Cusano Mutri, Gioia Sannitica, Piedimonte Matese, San Potito Sannita in the Caserta province in an area with an high seismic Hazard. The area was struck by large and destructive earthquakes in the past (1456, 1688, 1702, 1732, 1805,1962) with maximum magnitude up to 7.2. Past and recent seismicity of the area is generally characterized by both single events and low energy seismic sequences (1885, 1903, 1905, 1990, 1992, 1997). The last sequence occurred on 1997 with the largest event (MD = 4.1, 19 March) occurred at the border between the Benevento and Campobasso provinces followed by an intense activity ended only in September of the same year. The epicentral distribution of the 1997 low energy (M ≤ 4.0) seismic sequence is mainly NE-SW oriented suggesting the activation of anti-Apennine faults. The December 29 2013 seismic event, is located very close to the 1688 earthquake area. Still open debate is the association of the main event of the sequence and its aftershocks with the seismogenic structures present in the area. The SAGNET (Southern Apennine Geodetic NETwork) is the Non-permanent GPS network covering the area between the Matese Mounts and the Mainarde–Meta Mountains and consists of 40 3D GPS vertices. GPS dataset consists of data recorded at non-permanent stations in the time spam 2002-2014 and at the Continuous GPS stations (CGPS) of the RING network (managed of INGV) located in the central and southern Apennines regions. We have calculated the GPS velocity field with permanent and non-permanent stations (with time series of at least 3 surveys). The horizontal velocity field, expressed with respect to a fixed Eurasian plate, shows a good coherence between the velocities field estimated from the SAGNET and CGPS. In this paper we have evaluated the strain rate in the Sannio-Matese area. Before the earthquake, GPS data analysis showed a decrease in the velocity in the southern sector of Matese Massif (where the December 29 2013 earthquake epicenter will be localized) with respect to the surrounding areas which is also evident from the lower values of the strain rate ranging between 15÷20 *10-9 yr-1. Lower GPS Strain rate has been recognized at the end of seismic cycle and appear as a useful tool to point out hazardous seismic areas as already highlighted in the 2009 L'Aquila and in the 2012 Emilia earthquakes

Coseismic displacement waveforms for the 2016 August 24 Mw 6.0 Amatrice earthquake (central Italy) carried out from High-Rate GPS data

We used High-Rate sampling Global Positioning System (HRGPS) data from 52 permanent stations to retrieve the coseismic dynamic displacements related to the 2016 August 24 Mw 6.0 Amatrice earthquake. The HRGPS position time series (named hereinafter "GPSgrams") were obtained with two different analysis strategies of the raw GPS measurements (Precise Point Positioning [PPP] and Double-Difference [DD] positioning approaches using the Gipsy-Oasis II and the TRACK (GAMIT/GLOBK) software, respectively). These GPSgrams show RMS accuracies mostly within 0.3 cm and, for each site, an agreement within 0.5 cm between the two solutions. By using cross-correlation technique, the GPSgrams are also compared to the doubly-integrated strong motion data at sites where the different instrumentations are co-located in order to recognize in the GPSgrams the seismic waves movements. The high values (mostly greater than 0.6) of the cross-correlation functions between these differently-generated waveforms (GPSgrams and the SM displacement time-histories) at the co-located sites confirm the ability of GPS in providing reliable waveforms for seismological applications

GPS observations of coseismic deformation following the 2016, August 24, Mw 6 Amatrice earthquake (central Italy): data, analysis and preliminary fault model

We used continuous Global Positioning System (GPS) measurements to infer the fault geometry and the amount of coseismic slip associated to the August 24, 2016 Mw 6 Amatrice earthquake. We realized a three dimensional coseismic displacement field by combining different geodetic solutions generated by three independent analyses of the raw GPS observations. The coseismic deformation field described in this work aims at representing a consensus solution that minimizes the systematic biases potentially present in the individual geodetic solutions. Because of the limited number of stations available we modeled the measured coseismic displacements using a uniform slip model, deriving the geometry and kinematics of the causative fault, finding good agreement between our geodetically derived fault plane and other seismological and geological observations.

GPS observations of coseismic deformation following the May 20 and 29, 2012, Emilia seismic events (northern Italy): data, analysis and preliminary models

In May-July 2012, a seismic sequence struck a broad area of the Po Plain Region in northern Italy. The sequence included two Ml >5.5 mainshocks. The first one (Ml 5.9) occurred near the city of Finale Emilia (ca. 30 km west of Ferrara) on May 20 at 02:03:53 (UTC), and the second (Ml 5.8) occurred on May 29 at 7:00:03 (UTC), about 12 km southwest of the May 20 mainshock (Figure 1), near the city of Mirandola. The seismic sequence involved an area that extended in an E-W direction for more than 50 km, and included seven Ml ≥5.0 events and more than 2,300 Ml >1.5 events (http://iside.rm.ingv.it). The focal mechanisms of the main events [Pondrelli et al. 2012, Scognamiglio et al. 2012, this volume] consistently showed compressional kinematics with E-W oriented reverse nodal planes. This sector of the Po Plain is known as a region characterized by slow deformation rates due to the northwards motion of the northern Apennines fold-and-thrust belt, which is buried beneath the sedimentary cover of the Po Plain [Picotti and Pazzaglia 2008, Toscani et al. 2009]. Early global positioning system (GPS) measurements [Serpelloni et al. 2006] and the most recent updates [Devoti et al. 2011, Bennett et al. 2012] recognized that less than 2 mm/yr of SW-NE shortening are accommodated across this sector of the Po Plain, in agreement with other present-day stress indicators [Montone et al. 2012] and known active faults [Basili et al. 2008]. In the present study, we describe the GPS data used to study the coseismic deformation related to the May 20 and 29 mainshocks, and provide preliminary models of the two seismic sources, as inverted from consensus GPS coseismic deformation fields. […