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BackgroundThe worldwide inequitable access to vaccination claims for a re-assessment of policies that could minimize the COVID-19 burden in low-income countries. An illustrative example is what occurred in Ethiopia, where nine months after the launch of the national vaccination program in March 2021, only 3% of the population received two doses of COVID-19 vaccine. In the meantime, a new wave of cases caused by the emergence of Delta variant of SARS-CoV-2 was observed between July and November 2021.MethodsWe used a SARS-CoV-2 transmission model to estimate the level of immunity accrued before the launch of vaccination in the Southwest Shewa Zone (SWSZ) and to evaluate the impact of alternative age priority vaccination targets in a context of limited vaccine supply. The model was informed with available epidemiological evidence and detailed contact data collected across different socio-demographic settings.ResultsWe found that, during the first year of the pandemic, 46.1-58.7% of SARS-CoV-2 infections and 24.9-48% of critical cases occurred in SWSZ were likely associated with infectors under 30 years of age. During the Delta wave, the contribution of this age group in causing critical cases was estimated to increase to 66.7-70.6%. However, our findings suggest that, when considering the vaccine product available at the time (ChAdOx1 nCoV-19; 65% efficacy against infection after 2 doses), prioritizing the elderly for vaccination remained the best strategy to minimize the disease burden caused by Delta, irrespectively to the number of available doses. Vaccination of all individuals aged 50□years or older would have averted 40 (95%CI: 18-60), 90 (95%CI: 61-111), and 62 (95%CI: 21-108) critical cases per 100,000 residents in urban, rural, and remote areas, respectively. Vaccination of all individuals aged 30□years or more would have averted an average of 86-152 critical cases per 100,000 individuals, depending on the setting considered.ConclusionsDespite infections among children and young adults likely caused 70% of critical cases during the Delta wave in SWSZ, most vulnerable ages should remain a key priority target for vaccination against COVID-19.

Background and Importance:The dispatch of Advanced Life Support (ALS) teams in Emergency Medical Services (EMS) is still a hardly studied aspect of prehospital emergency logistics. In 2015, the dispatch algorithm of Emilia Est Emergency Operation Centre (EE-EOC) was implemented and the dispatch of ALS teams was changed from primary to secondary based on triage of dispatched vehicles for high-priority interventions when teams with Immediate Life Support (ILS) skills were dispatched.Objectives:This study aimed to evaluate the effects on the appropriateness of ALS teams’ intervention and their employment time, and to compare sensitivity and specificity of the algorithm implementation.Design:This was a retrospective before-after observational study.Settings and Participants:Primary dispatches managed by EE-EOC involving ambulances and/or ALS teams were included. Two groups were created on the basis of the years of intervention (2013-2014 versus 2017-2018).Intervention:A switch from primary to secondary dispatch of ALS teams in case of high-priority dispatches managed by ILS teams was implemented.Outcomes:Appropriateness of ALS team intervention, total task time of ALS vehicles, and sensitivity and specificity of the algorithm were reviewed.Results:The study included 242,501 emergency calls that generated 56,567 red code dispatches. The new algorithm significantly increased global sensitivity and specificity of the system in terms of recognition of potential need of ALS intervention and the specificity of primary ALS dispatch. The appropriateness of ALS intervention was significantly increased; total tasking time per day for ALS and the number of critical dispatches without ALS available were reduced.Conclusion:The revision of the dispatch criteria and the extension of the two-tiered dispatch for ALS teams significantly increased the appropriateness of ALS intervention and reduced both the global tasking time and the number of high-priority dispatches without ALS teams available.

In this work we examine the seismicity of Montefeltro, a historical region of central Italy located between the northern Apennines and the Republic of San Marino towards the northern Adriatic coast...

The Zagros thrust belt formed due to the convergence between the Arabian and Eurasian plates during the closure of the Neo-Tethys Ocean. GPS measurements show that the northward relative motion of ...

To unravel how and where coseismic and interseismic deformation impacts the spatial and temporal patterns of rock uplift of the Lurestan sector of the Zagros Mountains, we performed an investigation of the large‐scale features of topography and river network coupled with 2‐D finite element modeling. Geomorphological analysis and constraints from parameters such as elevation, local relief, normalized channel steepness index (ksn), river longitudinal profiles, and transformed river profiles (chi plots) were used to unravel the time‐space distribution of vertical motions. Whereas the much longer timescale over which topography grows and/or rivers respond to tectonic or climatic perturbations with respect to even multiple seismic cycles, the outputs of the finite element model yield fundamental information on the source of the late part of the spatiotemporal evolution of surface uplift recorded by the geomorphology. Model outputs shed new light into the processes controlling relief evolution in an actively growing mountain belt underlain by a major blind thrust. The outputs illustrate how coseismic slip controls localized uplift of a prominent topographic feature—the Mountain Front Flexure—located above the main upper crustal ramp of the principal basement thrust fault of the region, while continuous displacement along the deeper, aseismic portion of the same basement fault controls generalized uplift of the whole crustal block located farther to the NE, in the interior of the orogen.

The 2018 Gulf of Alaska earthquake (Mw 7.9) occurred in a region of the Pacific plate southwest of the Alaskan subduction zone. The earthquake was a strike-slip event, with the hypocenter located at a depth of about 25 km and a seismic moment equal to 0.96 × 1021 Nm. Two observed moment rates have been obtained by the Geoscope Observatory, France, and by the United States Geological Survey (USGS). Both of them can be interpreted as due to the failure of two asperities on the fault surface. We consider a discrete fault model, with two asperities of different areas and strengths, and show that the observed moment rates can be reproduced by appropriate values of the model parameters, as inferred from the available data. A good fit to the observed moment rates is obtained by a sequence of three dynamic modes of the system, including a phase of simultaneous slip of the asperities. The two moment rates are however characterized by different initial conditions, in terms of different initial shear stress distributions on the fault. Shear stresses on the asperities are calculated as functions of time during the event and show a similar evolution in the two cases, but with different final values. The model results show that the presence of simultaneous asperity motion can significantly increase the seismic moment of a large earthquake.

Using an analytical methodology taking into account heat flow density data, frictional heating, temperature variations due to the re-equilibrated conductive state after thrusting and geological constrains, we calculated surface heat flow, geotherms and isotherms along a balanced and restored regional geological cross-section. Our results highlight the impact of frictional heating produced by thrusts on the thermal structure of the study area, leading to a raising of the isotherms both in the inner Albanides to the E and in the Adriatic sector offshore. Minimum values of Qs in the surroundings of Tirana and the reconstructed 2D thermal structure suggest less favorable conditions for exploitation of geothermal energy, besides the direct use (Borehole Heat Exchanger-Geothermal Heat Pump systems). Nevertheless, the occurrence of the “Kruja geothermal zone”, partially overlapping this area and including hot spring manifestations, emphasize the structural control in driving hot fluids to the surface with respect to the regional thermal structure.

A geothermal model for the area of the Val d’Agri oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derivedconstraints - thrust depth, timing of thrusting, slip rate - obtained by the integration of surface and subsurface datasets. The results of this work, representing a first attempt to reconstruct a geothermal 3D model for the Val d’Agri zone of the Basilicata region, emphasize two main regional features: (i) the isotherms relative to temperatures lower than 350 °C are roughly parallel and sub-horizontal across thewhole study area, tending to deepen just along the NE-most edge of the investigated region; (ii) the isotherms relative to temperatures greater than 350 °C tend to deepen toward the center of the valley. Therefore, while the thermal structure at mid crustal depths appears to be perturbed and roughly mirroring the surface valley, the seismogenic upper crust of the study area is characterized by an unperturbed, roughly homogeneous and regular thermal structure.

We study the effects of friction heterogeneity on the dynamics of a seismogenic fault. To this aim, we consider a fault model containing two asperities with different static frictions and a rate-dependent dynamic friction. We consider the seismic events produced by the consecutive failure of the two asperities and study their properties as functions of the ratio between static frictions. In particular, we calculate the moment rate, the stress evolution during fault slip, the average stress drop, the partitioning of energy release, the seismic energy, the far-field waveforms and the spectrum of seismic waves. These quantities depend to various extent on the friction distribution on the fault. In particular, the stress distribution on the fault is always strongly heterogeneous at the beginning of the seismic event. Seismic energy and frictional heat decrease with increasing friction heterogeneity, while seismic efficiency is constant. We obtain an equation relating seismic efficiency to the parameters of the friction law, showing that the efficiency is maximum for smaller values of dynamic friction. The seismic spectrum depends on the friction distribution as to the positions and the values of the minima. However, under the model assumption that the slip durations are the same for both asperities, the corner frequency is independent of the friction distribution, but it depends on the friction law and on the coupling between asperities. The model provides a relation between the total radiated energy and the seismic moment that is consistent with the empirical relation between the two quantities. The fault model with one asperity is also considered as a particular case. The model is applied to the 1965 Rat Islands (Alaska) earthquake and shows the role of fault heterogeneity in controlling the spatial distribution of stress drop as well as the time dependence and the final amount of radiated energy.

Esiste un ampio dibattito sia sulla struttura profonda dell'Appennino meridionale, sia sulla geometria e cinematica dei sistemi di faglia che controllano la deformazione attiva e la sismicit�. Il prisma d�accrezione degli Appennini forma un elemento alloctono sovrapposto sugli strati carbonatici dell'avampaese, continui con quelli esposti nel promontorio Apulo a NE. La porzione tettonicamente sepolta della Piattaforma Apula � stata coinvolta nelle fasi finali del raccorciamento, generando ampie pieghe associate a faglie inverse. Tali pieghe ad elevata lunghezza d'onda formano le trappole per gli idrocarburi che caratterizzato gli importanti giacimenti petroliferi nell'Italia meridionale. Recenti studi geofisici hanno evidenziato che il basamento � coinvolto nella deformazione associata al raccorciamento crostale, mentre l'interpretazione di profili sismici ad alta risoluzione e il bilanciamento di sezioni geologiche favoriscono modelli di inversione tettonica con riattivazione delle preesistenti faglie normali (principalmente Permo-Triassiche) presenti nel basamento. La zona di m�lange interposta tra i carbonati della Piattaforma Apula sepolta e le unit� alloctone di superficie gioca un ruolo rilevante nella evoluzione tettonica dell�orogene. Tale zona di m�lange rappresenta, infatti, un efficiente livello di scollamento tra i livelli strutturali superficiali e quelli profondi. Mentre questi ultimi sono dominati dalle principali faglie radicate in profondit�, le unit� superficiali sono dissecate da numerose strutture fragili che si sono formate in diverse fasi durante l'evoluzione tettonica degli Appennini. D'altra parte, le principali strutture fragili presenti nei carbonati sepolti della Piattaforma Apula e nel sottostante basamento rappresentano importanti zone di faglia che hanno accumulato notevoli rigetti in tempi geologici, costituendo pertanto strutture sismogenetiche in grado di enucleare grandi terremoti in caso di loro riattivazione all�interno del campo di stress attuale. L�analisi e la modellazione numerica di tali strutture e degli associati stress e strain rates richiedono una definizione soddisfacente della struttura termica della crosta. In questo studio ci si propone di realizzare un modello termico lungo un transetto dall�alta Val d�Agri (Basilicata) a Bari (Puglia), basandoci sulle attuali conoscenze tettono-stratigrafiche della zona in esame. Gli effetti termici sono analizzati utilizzando la soluzione proposta da Dragoni et al. (1996), per la Piattaforma Apula, e da Molnar et al. (1983), per il bacino del fiume Agri. La geoterma per la zona della Valle del Sauro e quella per la zona della Val d�Agri sono state ottenute per mezzo di una procedura analitica che tiene conto delle strutture della Piattaforma Apula sepolta, che costituisce il reservoir degli idrocarburi del giacimento di Tempa Rossa. Viene evidenziato come il coinvolgimento del basamento nei processi di raccorciamento tettonico determina la necessit� di utilizzare diverse procedure analitiche per la limitrofa area dell�Alta Val d�Agri, nel cui sottosuolo un�importante faglia inversa si approfondisce verso SW con una rampa che coinvolge il basamento sottostante i carbonati che costituiscono il reservoir degli idrocarburi del giacimento di Monte Alpi. I risultati ottenuti in questo studio permettono in ogni caso di ottenere una soddisfacente descrizione della struttura termica dell�Appennino meridionale dall�avampaese apulo sino alla zona assiale della catena.

The Zagros thrust belt is a large orogenic zone located along the southwest region of Iran. To obtain a better knowledge of this important mountain chain, we elaborated the first 3-D model reproducing the thermal structure of its northwestern part, i.e., the Lurestan arc. This study is based on a 3-D structural model obtained using published geological sections and available information on the depth of the Moho discontinuity. The analytical calculation procedure took into account the temperature variation due to: (1) The re-equilibrated conductive state after thrusting, (2) frictional heating, (3) heat flow density data, and (4) a series of geologically derived constraints. Both geotherms and isotherms were obtained using this analytical methodology. The results pointed out the fundamental control exerted by the main basement fault of the region, i.e., the Main Frontal Thrust (MFT), in governing the thermal structure of the crust, the main parameter being represented by the amount of basement thickening produced by thrusting. This is manifested by more densely spaced isotherms moving from the southwestern foreland toward the inner parts of orogen, as well as in a lateral variation related with an along-strike change from a moderately dipping crustal ramp of the MFT to the NW to a gently dipping crustal ramp to the SE. The complex structural architecture, largely associated with late-stage (Pliocene) thick-skinned thrusting, results in a zone of relatively high geothermal gradient in the easternmost part of the study area. Our thermal model of a large crustal volume, besides providing new insights into the geodynamic processes affecting a major salient of the Zagros thrust belt, may have important implications for seismotectonic analysis in an area recently affected by a Mw = 7.3 earthquake, as well as for geothermal/hydrocarbon exploration in the highly perspective Lurestan region.

Ultrasound imaging remains out of reach for most pregnant women in developing countries because it requires a trained sonographer to acquire and interpret the images. We address this problem by presenting a system that can automatically estimate the fetal head circumference (HC) from data obtained with use of the obstetric sweep protocol (OSP). The OSP consists of multiple pre-defined sweeps with the ultrasound transducer over the abdomen of the pregnant woman. The OSP can be taught within a day to any health care worker without prior knowledge of ultrasound. An experienced sonographer acquired both the standard plane-to obtain the reference HC-and the OSP from 183 pregnant women in St. Luke's Hospital, Wolisso, Ethiopia. The OSP data, which will most likely not contain the standard plane, was used to automatically estimate HC using two fully convolutional neural networks. First, a VGG-Net-inspired network was trained to automatically detect the frames that contained the fetal head. Second, a U-net-inspired network was trained to automatically measure the HC for all frames in which the first network detected a fetal head. The HC was estimated from these frame measurements, and the curve of Hadlock was used to determine gestational age (GA). The results indicated that most automatically estimated GAs fell within the P2.5-P97.5 interval of the Hadlock curve compared with the GAs obtained from the reference HC, so it is possible to automatically estimate GA from OSP data. Our method therefore has potential application for providing maternal care in resource-constrained countries.

Cahuachi, located on the coastal desert of Southern Peru (Nasca Province), represented the main ceremonial centre of the Nasca culture. An hypothesis of destruction of the site related to catastrophic floods (the youngest around the 10th century AD), due to El Niño-Southern Oscillation (ENSO) was proposed by Grodzicki (1990) three decades ago. This paradigm finally led to believe that Cahuachi was covered by huge catastrophic floods accumulating conglomerates up to the top of the highest buildings. By contrast, Orefici (2016) emphasizes progressive abandonment of large areas of the ceremonial site probably due to several environmental stress such as the occurrence of huaycos (i.e. moderate non-catastrophic debris flows) and earthquakes. In order to investigate the origin of the conglomerates at Cahuachi, a stratigraphic succession outcropping on the bedrock of the "Pirámide Sur" was studied by means of mineralogical, petrographic and sedimentological approaches. In addition, a comprehensive overview of the paleoclimatic data from the literature concerning southern Peru (coast vs. Andean Cordillera), such as ENSO cycles, SOI (Southern Oscillation Index) and oxygen isotopes contributed to unravel the cause/s of the Nasca culture decline and demise. The investigated stratigraphic succession consists of mudstones, siltstones, sandstones and conglomerates, all sharing similar silty-clayey components (powder XRD data). Conglomerates, likely resulting from progradation of alluvial fan systems, have the same lithotypes of pebbles (mainly granitoids/diorites, lavas of andesite/dacite/rhyolite compositions, vitrophyric pyroclasts, arenites/quarzarenites). In addition, the conglomerates occurring at the top of the section unequivocally underlie the ceremonial buildings. Along the stratigraphic succession a clear volcaniclastic silty layer (CH3) was also found, just above the two conglomerates at the bottom (CH1-CH2) of the stratigraphic sequence. This volcaniclastic level could also represent a tephrostratigraphic regional marker. Independent paleoclimatic data indicate, around 700 AD, an increase of temperature, driven by the intensification of the ENSO events. At high altitudes strong ENSO implies an increase of precipitation (mainly snow) as confirmed by the SOI. This increase in temperature correspond to dry condition in the lowlands of Southern Peru, where a period of aridity started after 250 AD, culminating after 650 AD, which is also confirmed by an increase of river incision (Eitel et al., 2005). Among the conglomerates of the investigated stratigraphic succession, mineralogical and petrographic studies of the samples do not point out differences in components (i.e. lithology of the pebbles and composition of the fine fraction of the whole samples). This surveyed stratigraphic section well correlates with the Upper Pliocene-Lower Pleistocene "Changuillo Formation" (Montoya et al., 1994). The conglomerate deposits at the top of the section could be also interpreted as a lateral facies of the base of the "Canete Formation" and unequivocally underlie the ceremonial buildings (Delle Rose, 2016). This finding is at odd with the late Holocene age proposed by Grodzicki (1990) for this succession. We suggest that, rather than the mere effect of ENSO-related catastrophic floods, the decline of Cahuachi was related to the increase of aridity and, possibly, other natural disaster events such as earthquakes. A progressive weakness of the resiliency of the Cahuachi population, coupled with possible changes in social acceptance of the environmental stress as motivated by the religious hierarchy, could have played a major role in the decline and demise of the Nasca Culture. References Delle Rose M. 2016. The Geology of Cahuachi (Chapter 3). In: R. Lasaponara, N. Masini, G. Orefici (Eds.) The Ancient Nasca World, Springer, 47-64. Eitel B., Hecht S., Mächtle B., Schukraft G., Kadereit A., Wagner G. A., Kromer B., Unkel I., Reindel M. (2005). Geoarchaeological evidence from desert loess in the Nazca-Palpa region, southern Peru: palaeoenvironmental changes and their impact on pre-Columbian cultures, Archaeometry, 47, 137-158. Grodzicki J. 1990. Las catastrofes ecologicas en la pampa de Nazca en fines del Holoceno y el fenomeno El Niño. In: El fenomeno El Niño a traves de las fuentes arqueologicas y geologicas. MAA, Actas de la Conferencia en Varsavia, 66-101. Masini N., Lasaponara R., Rizzo E., Orefici G. 2012 . Integrated Remote Sensing Approach in Cahuachi (Peru): Studies and Results of the ITACA Mission (2007-2010). In: R. Lasaponara and N. Masini (eds.), Satellite Remote Sensing: A New Tool for Archaeology, Remote Sensing and Digital Image Processing 16, Springer Science+Business Media B.V., 307-344. Montoya M., García W., Caldas J. 1994. Geología de los cuadrángulos de Lomitas, Palpa, Nasca y Puquio. Volume 53, Boletín INGEMMET. Orefici G. 2016. The Decline of Cahuachi and the end of the Nasca Theocracy (Chapter 19). In: R. Lasaponara, N. Masini, G. Orefici (Eds.) The Ancient Nasca World, Springer, 449-468.

We study the dynamics of a fault containing two asperities having different strengths and subject to a constant strain rate. The fault is modeled by a discrete dynamical system with two degrees of freedom that are the slip deficits of the asperities. The radiation of elastic waves during the slipping modes is taken into account by introducing a term proportional to slip rate in the equations of motion. We give a complete analytical solution of the four dynamic modes of the system. Any seismic event can be expressed as a sequence of modes, for which the moment rate, the spectrum and the total seismic moment can be calculated. We consider the energy budget of the event and calculate the seismic efficiency. The presence of radiation may remarkably change the evolution of the system from a given state, since it moves the boundaries between the different subsets of the sticking region. In addition, the slip amplitude in a seismic event is smaller, while the slip duration is longer in the presence of radiation. The shape of the moment rate function depends on the seismic efficiency and the seismic moment decreases with increasing efficiency, at constant radiated energy. As an application of the model, we consider the 1964 Great Alaska earthquake and calculate the mode durations, the slip distribution, the moment rate function and the seismic moment of the earthquake, obtaining values that are consistent with observations.

The Val d'Agri area provides the opportunity to analyse active structures in a seismic region for which a large amount of subsurface data is available. This area, which was struck in 1857 by one of the most destructive earthquakes in Italy (MW = 7.03), represents a unique natural laboratory to gain new insights into geometry, modes and rates of faulting controlling crustal deformation in an actively extending orogen. In this study, a crustal geological section through the southern Apennines is discretized into a finite element model (FEM). We present a 2D elastoplastic FEM that reproduces stress perturbations and strain field around the Val d'Agri active fault system. The influence of fault strand activity on interseismic crustal deformation is tested by a series of computer models, whose predictions are compared with the horizontal velocity components of continuous GPS sites in the region and with stress directions and geological data. The best fit with available geological and geophysical constraints is obtained with a 300 km long, 29 km deep model formed by a multilayer including three components having different rheological characteristics and including several shallow, locked fault segments, which branch into a freely slipping major basement fault at depth. Finite element modelling provides new insights into the controversial and widely debated active tectonic setting of the study area, pointing out the fundamental role played by a structural reactivation process involving inherited, long-lived, mature fault systems at depth. Our FEM, reconciling apparently contrasting geological and geophysical constraints from the study area, points to maximum stress build up and strain accumulation at a depth of 15 ± 5 km. Such a depth range is suggested as the most likely one for the nucleation of large events such as the 1857 Val d'Agri earthquake.

Worldwide, 99% of all maternal deaths occur in low-resource countries. Ultrasound imaging can be used to detect maternal risk factors, but requires a well-trained sonographer to obtain the biometric parameters of the fetus. One of the most important biometric parameters is the fetal Head Circumference (HC). The HC can be used to estimate the Gestational Age (GA) and assess the growth of the fetus. In this paper we propose a method to estimate the fetal HC with the use of the Obstetric Sweep Protocol (OSP). With the OSP the abdomen of pregnant women is imaged with the use of sweeps. These sweeps can be taught to somebody without any prior knowledge of ultrasound within a day. Both the OSP and the standard two-dimensional ultrasound image for HC assessment were acquired by an experienced gynecologist from fifty pregnant women in St. Luke’s Hospital in Wolisso, Ethiopia. The reference HC from the standard two-dimensional ultrasound image was compared to both the manually measured HC and the automatically measured HC from the OSP data. The median difference between the estimated GA from the manual measured HC using the OSP and the reference standard was -1.1 days (Median Absolute Deviation (MAD) 7.7 days). The median difference between the estimated GA from the automatically measured HC using the OSP and the reference standard was -6.2 days (MAD 8.6 days). Therefore, it can be concluded that it is possible to estimate the fetal GA with simple obstetric sweeps with a deviation of only one week.

Ultrasound imaging can be used to detect maternal risk factors, but it remains out of reach for most pregnant women in developing countries because there is a severe shortage of well-trained sonographers. In this paper we show the potential of combining the obstetric sweep protocol (OSP) with image analysis to automatically obtain information about the fetus. The OSP can be taught to any health care worker without any prior knowledge of ultrasound within a day, obviating the need for a well-trained sonographer to acquire the ultrasound images. The OSP was acquired from 317 pregnant women using a low-cost ultrasound device in St. Luke’s Hospital in Wolisso, Ethiopia. A deep learning network was used to automatically detect the fetal head in the OSP data. The fetal head detection was used to detect twins, determine fetal presentation and estimate gestational age without the need of a well-trained sonographer.

A geothermal model for the area of the Basilicata oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derived constraints – thrust depth, timing of thrusting, slip rate – obtained by the integration of surface and subsurface datasets. For the top 5 km of the crust, the resulting geothermal curve shows a remarkably good fit with temperatures recorded from deep oil wells. The new geotherm provides a fundamental constraint for rheological and stress accumulation modelling in the seismically active study area. Furthermore, the analytical solution provided in this study may be used as a basis to calculate the relevant geotherm for further areas and/or tectonic settings.

A fault made of two coplanar asperities subject to a constant strain rate is considered. The fault is modelled as a discrete dynamical system made of two blocks coupled by a spring and pulled at constant velocity on a rough plane. Such a system exhibits a variety of slipping modes, including the slip of single asperities and the simultaneous slip of both asperities. The associated source function can be expressed by the seismic moment rate as a function of time. The moment rate depends on the state of the system preceding the earthquake, which can be described by a single variable expressing the difference between the stresses imposed to the two asperities. We present a systematic study of the moment rate as a function of this variable and show how the moment rate changes as a function of the model parameters. The observed source function of the 2010 Maule (Chile) earthquake, that was the result of the failure of two main asperities, is interpreted in the framework of the proposed model.

The recent earthquake sequences of 2012 (northern Italy) and 2013 (Marche offshore) provided new, fundamental constraints to the active tectonic setting of the outer northern Apennines. In contrast to the Po Plain area, where the 2012 northern Italy earthquakes confirmed active frontal thrusting, the new focal mechanisms obtained in this study for the 2013 Marche offshore earthquakes indicate that only minor thrust fault reactivation occurs in the Adriatic domain, even for a theoretically favourably oriented maximum horizontal compression. Recent seismicity in this domain appears to be mainly controlled by transcurrent crustal faults dissecting the Apennine thrust belt. The along-strike stress field variation from the Po Plain to the Adriatic area has been quantitatively investigated by applying the multiple inverse method (MIM) to the analysis of the entire seismicity recorded from January 1976 to August 2014, from the top 12 km of the crust (fault plane solutions from 127 earthquakes with MW ≥ 4), allowing us to obtain a comprehensive picture of the state of stress over the outer zone of the fold and thrust belt. The present-day stress field has been defined for 39 cells of 1.5° × 1.5° surface area and 12 km depth. The obtained stress field maps point out that, although the entire outer northern Apennines belt is characterized by a sub-horizontal maximum compressive axis (σ1), the minimum compression (σ3) is sub-vertical only in the Po Plain area, becoming sub-horizontal in the Adriatic sector, thus confirming that the latter region is dominated by an active tectonic regime of strike-slip type.

Studio della composizione litologica delle rocce circostanti i Laboratori sotterranei del Gran Sasso: valutazione di peso atomico, numero atomico e densita.Al fine di ottimizzare l’analisi dei risultati di alcuni esperimenti condotti nei laboratori sotterranei del Gran Sasso, si e reso necessario valutare l'interazione con i raggi cosmici dei materiali rocciosi per definire il rapporto tra il flusso di energia incidente e il flusso di energia dei raggi cosmici rilevata. L’analisi della stratigrafia e la definizione della composizione litologica sono fondamentali al fine di ottenere peso atomico (Z), numero atomico (A) e densita (ρ) del materiale che un raggio cosmico attraversa prima di essere intercettato dai rivelatori dei laboratori sotterranei. Allo scopo, sono state studiate otto sezioni geologiche attraverso i volumi rocciosi intorno ai laboratori, tracciate come i raggi di una ruota rispetto ad un azimut. In altre parole si considera un cerchio con i Laboratori Nazionali del Gran Sasso al centro: ogni sezione e un diametro del cerchio. Queste sezioni sono distribuite in tutta la gamma degli angoli di azimut (360°), con ogni sezione alla stessa distanza angolare (22° 30') dalle altre adiacenti. Le otto sezioni hanno consentito di determinare la litologia attraversata dai raggi cosmici in funzione degli angoli di zenit e di azimut, quindi di ottenere le caratteristiche fisiche delle rocce del Gran Sasso intorno ai laboratori. Le informazioni suddette hanno inoltre permesso di calcolare la media ponderata di peso atomico, numero atomico e densita per i raggi cosmici rilevati con un angolo zenitale di 70°, 80° e 90°. In tal modo si e potuto evidenziare come le variazioni della litologia, per elevati angoli di zenit, sono in grado di determinare notevoli variazioni del peso atomico, del numero atomico e dei valori di densita e di conseguenza variazioni significative nella valutazione del flusso di energia rilevato.

The availability of a large amount of surface geological data and subsurface information gathered by the oil industry, together with seismic and geodetic data, allowed us to define and analyse the active structures in the Val d'Agri area of the southern Apennines. Taking into account that the study of interseismic deformation can be significant to identify locked fault areas that can potentially slip, in this study we present 2D elastoplastic finite-element models to reproduce interseismic characteristics of the study area. This hosts the largest Europe's onshore oil field and is characterised by an active extensional tectonic regime, as inferred from earthquake focal mechanisms and fault slip data from late Quaternary structures. Based on high-quality seismic profiles tied with deep well logs, we constructed a detailed geological section across the study area. Outcropping units are dissected by numerous brittle structures that formed at various stages during the tectonic evolutionof the Apennines, while the deep ones are dominated by deeply rooted major faults. The rheological behaviour has been constrained by the reconstruction of the thermal structure of the fold and thrustbelt, using available information from the foreland Apulian Platform and from temperature data from a series of wells. Starting from the geological model, we reproduced interseismic deformation by means of finite-element numerical modelling, varying boundary conditions and unlocking different fault segments. Our numerical models provide new insights into the controversial and widely debated active tectonic setting of the Val d'Agri area, confirming the major role played by structural inheritance and reactivation processes. In fact, recent low-magnitude seismicity tends to illuminate fault segments consisting of pre-existing reverse faults reactivated as normal faults in the present-day stress field.These long-lived, mature fault systems occurring in the buried Apulian Platform carbonates (and underlying basement) represent major brittle structures that cumulated displacements of up to a few kilometres over geologic time. As a result of their reactivation within the late Quaternaryextensional stress field, these long-lived crustal structures are capable of nucleating also moderate- to large-magnitude earthquakes. The decoupling between deep and shallow structural levels, and the different inherited structures affecting them, explain the apparent contrast between the subdued surface expression of active fault systems and the known occurrence of large magnitude seismic events in the study area, thus reconciling apparently contrasting geological and geophysical constraints.

In this study, we elaborated a 2D model that reproduces the thermal structure of the central-northern Adriatic offshore and adjacent onshore area of the Italian peninsula. Based on the crustal structure along the trace of the CROP-03 deep section, the geotherms offshore Gabicce (northern Marche region) were obtained by an analytical procedure taking into account the role of thrusting within the sedimentary cover. Basement involvement at depth beneath the neighbouring Mondaino area to the SW, where a crustal thrust ramp dips towards the hinterland, required the use of a different analytical procedure. The results obtained in this study allowed us to define a satisfactory description of the thermal state of the northern Marche coastal area and adjacent Adriatic offshore. These results, integrated with those obtained by previous studies, confirm that the isotherms of 250°C and 400°C are placed in the stable Adriatic lithosphere at depths of about 11 km and 22 km, respectively. Furthermore, the 400°C isotherm is deeper in the onshore area, reaching a depth of about 30 km in the zone comprised between Gabicce and Mondaino, whereas the 250°C isotherm deepens towards the SW along the Adriatic Sea sector, to reach a maximum depth of 13 km in coastal area, rising again at a depth of 11 km in the innermost sector of the studied section.

Since the 1980s a trend has emerged to contain the cost of space missions, which has favored trials in the construction and launch of small satellites. This effort has considerably reduced the cost of the satellites because the construction process uses both traditional components and important technological innovations. There have also been market openings for small satellites, both within the telecommunication sector and for scientific missions and those related to Earth observation. This paper contains the results of a survey of the largest manufacturers of small satellites in Europe and investigates how far (if at all) they have changed the structure of the European space industry. It finds that, through the acquisition of small satellite manufacturers, traditional large companies operating in the field of space in Europe have secured for themselves important technological innovations and market opportunities, while maintaining their oligopolistic position.

A fault with two asperities is modelled as a system made of two blocks coupled by a spring and sliding on a plane under the same values of static and dynamic friction. An analytical solution is given for the simultaneous motion of the blocks and the corresponding orbits are plotted in the phase space. It is proven that, whichever the initial state is, the long-term behaviour of the system is one of an infinite number of limit cycles, characterized by a particular pattern of forces. The region where the system is located when the blocks are stationary can be divided into narrow stripes corresponding to different orbits of the points belonging to them. This implies that the system is sensitive to perturbations and has relevant implications for a fault, which is subject to stress transfers from earthquakes generated by neighbouring faults. In this case, the fault may experience a larger earthquake, with the simultaneous failure of the two asperities, which restores a stress distribution compatible with periodic behaviour. The seismic moment associated with simultaneous asperity failure is always greater than the maximum value that can be released in a limit cycle. For strongly coupled asperities, the moment can be several times larger.

The paper reports research into the transfer of technology typically used in the construction of scientific satellites. Four case studies are analyzed to clarify some basic mechanisms of the transfer of space technology to the industrial system. The paper finds that the technologies analyzed in the construction of satellites for the most part stem from the integration of technical processes already known in various industrial sectors; the use of these processes in space involves their substantial strengthening and upgrading in terms of performance; and this upgrading permits them to return to industrial sectors that use the technological advances acquired for coping with complex problems in the space sector. This research has helped validate some of the determinants of technology transfer already noted in the literature, while increasing the number and content of these. Useful indications emerge for policy makers and agents involved in technology transfer programs.

By means of a 2D finite-element procedure, we tested how heterogeneities at the scale of seismogenic fault affect the displacement. We defined one or more slip distributions for two typical normal-faulting earthquakes in the Central Apennines, computed the displacement occurred within different structures including lateral heterogeneities, and compared the different displacement profiles to isolate the effect of the crustal structure. To understand at what magnitude the heterogeneities affect the observation significantly, we compared the predicted coseismic displacement with GPS and DInSAR data for the Colfiorito 1997 earthquake. We find that heterogeneities significantly affect the observable horizontal coseismic displacement for the larger magnitudes, whereas for smaller quakes, they affect horizontal displacement close to the fault trace only.

We develop a model of lava flow in a cylindrical tube with elliptical cross section. The lava is considered an isothermal, incompressible Newtonian fluid. We solve analytically the steady-state Navier–Stokes equation under a constant driving force, given by the component of gravity along the axis of the tube and obtain the velocity and stress field components in the fluid. The ratio between the flow rate of the elliptical tube and that of a circular tube, having the same cross sectional area, is found to be always less than 1 and to depend only on the value of eccentricity. The ratio decreases rapidly when the eccentricity becomes lower than about 0.5. The average flow velocity in a partially filled tube is calculated under the assumption of constant flow rate. In an elliptical tube, the shear traction is not uniform on the wall of the tube, but changes periodically with the position. It is maximum at the intersections with the minor axis and minimum at the intersections with the major axis, the ratio between the maximum and the minimum value being equal to the ratio between the lengths of the two axes. Assuming that the erosion rate of the wall of the tube is proportional to shear traction, we calculate the erosion of the wall as a function of time and find that its effect is such as to make the tube cross section closer to the circular shape.

Finite element modelling by means of MSC. Marc software has been used to gain new insights into the deep structure of the southern Apennines, particularly concerning the geometry and kinematics of fault systems controlling active deformation and seismicity. The Apennine accretionary wedge forms an allochthonous mass overlying foreland strata continuous with those exposed in the Apulian promontory. The tectonically buried portion of the Apulian Platform was involved in the final shortening phases, giving rise to reverse-fault- related, open, long-wavelength folds that form the hydrocarbon traps for the oil discoveries in southern Italy. Recent geophysical studies have provided evidence that deep-seated reverse faulting involves the basement, while interpretation of high-quality seismic profiles and cross-section balancing favour an inversion tectonics model involving reactivation of pre-existing (Permo-Triassic) basement normal faults, the related deformation being characterized by limited horizontal displacements. Our work suggests an important role of the mélange zone interposed between the buried Apulian Platform carbonates and the surface allochthnous units in producing effective decoupling between deep and shallow structural levels. While the former are dominated by deeply rooted major faults, surface units are dissected by numerous brittle structures that formed at various stages during Apennines evolution. As a result of late Quaternary extensional reactivation of the deep-seated major faults, the inherited fault network characterizing the shallow rigid lid (decoupled by the ductile mélange zone at its base) is reactivated in a complex fashion. This results in a highly segmented and articulated fault pattern. On the other hand, major brittle structures in the buried Apulian Platform carbonates and underlying basement represent mature fault zone that cumulated displacements of up to a few kilometres over geologic time. As such, they are capable of nucleating large earthquakes as a result of late Quaternary extensional reactivation. The role of these important discontinuities, as well as of thickness variations of different crustal layers, is emphasized by our finite element modelling, which effectively outlines stress perturbations and strain field around main active structures.

The Central Apennines, Italy, are characterized by moderate seismic activity on normal faults, oriented in directions parallel to the Apenninic chain. The subject of this study is the Umbria-Marche Apennines, a segment approximately 200-km long, where three main seismic events occurred in the last three decades. The 1979 Norcia earthquake was a Mw = 5.8 event, taking place at the south end of the considered segment. The 1984 Gubbio earthquake was a Mw = 5.6 event which took place at the north end. The 1997-1998 Colfiorito sequence constituted 8 main shocks with magnitudes Mw between 5 and 6 and epicenters located between the Gubbio and the Norcia earthquake areas. A model made of an elastic half-space is considered, in which the seismic sources are represented by rectangular dislocations which have the appropriate values of source parameters, and in which the static stress field produced by each event is calculated. The analysis of the Coulomb stress change as a function of time shows that the coseismic stress transfer and fault interaction played an important role in the region during the past three decades: 7 earthquakes of the 9 considered took place where then stress change is positive. Such an interaction has been confirmed by the analysis of the aftershocks in the Colfiorito zone post September 26, 1997: about the 61% of the aftershocks considered took place where the stress change is positive. The comparison between the Coulomb stress change due to the coseismic stress transfer and the rate of change due to the tectonic stress allows us to quantify the time advance of the earthquakes. The pattern of coseismic Coulomb stress change shows positive values in two areas that can be regarded as historical seismic gaps.

The Altotiberina low-angle normal fault in central Italy has been a focus of many recent studies. Although the existence of this fault has long been known, its seismicity and relationship to other faults are still debated. We present a 2D elastoplastic finite-element model that reproduces the interseismic deformation of the Altotiberina Fault. The model predictions are compared to observed geodetic velocities, stress orientations and geological data. The influence of the Altotiberina Fault on interseismic evolution is tested by building several models with different boundary conditions. The best model is 180 km long, 40 km deep and contains two layers with different rheological parameters, two ramps, two faults and four freely slipping segments. The main factors contributing to the large-scale interseismic deformation include basal traction, rheology and the Altotiberina Fault itself, whereas the local, small-scale variations are due to two secondary high-angle faults.