Seismogenic Structure Orientation and Stress Field of the Gargano Promontory (Southern Italy) From Microseismicity Analysis

Historical seismic catalogs report that the Gargano Promontory (southern Italy) was affected in the past by earthquakes with medium to high estimated magnitude. From the instrumental seismicity, it can be identified that the most energetic Apulian sequence occurred in 1995 with a main shock of MW = 5.2 followed by about 200 aftershocks with a maximum magnitude of 3.7. The most energetic earthquakes of the past are attributed to right-lateral strike-slip faults, while there is evidence that the present-day seismicity occur on thrust or thrust-strike faults. In this article, we show a detailed study on focal mechanisms and stress field obtained by micro-seismicity recorded from April 2013 until the present time in the Gargano Promontory and surrounding regions. Seismic waveforms are collected from the OTRIONS Seismic Network (OSN), from the Italian National Seismic Network (RSN), and integrated with data from the Italian National Accelerometric Network (RAN) in order to provide a robust dataset of earthquake localizations and focal mechanisms. The effect of uncertainties of the velocity model on fault plane solutions (FPS) has been also evaluated indicating the robustness of the results. The computed stress field indicates a deep compressive faulting with maximum horizontal compressive stress, SHmax, trending NW-SE. The seismicity pattern analysis indicates that the whole crust is seismically involved up to a depth of 40 km and indicates the presence of a low-angle seismogenic surface trending SW-NE and dipping SE-NW, similar to the Gargano–Dubrovnik lineament. Shallower events, along the eastern sector of the Mattinata Fault (MF), are W-E dextral strike-slip fault. Therefore, we hypothesized that the seismicity is locally facilitated by preexisting multidirectional fractures, confirmed by the heterogeneity of focal mechanisms, and explained by the different reactivation processes in opposite directions over the time, involving the Mattinata shear zon

Passive seismology and deep structure in central Italy

n the last decade temporary teleseismic transects have become a powerful tool for investigating the crustal and upper mantle structure. In order to gain a clearer picture of the lithosphere-asthenosphere structure in peninsular Italy, between 1994 and 1996, we have deployed three teleseismic transects in northern, central, and southern Apennines, in the framework of the project GeoModAp (European Community contract EV5V-CT94–0464). Some hundreds of teleseisms were recorded at each deployment which lasted between 3 and 4 months. Although many analyses are still in progress, the availability of this high quality data allowed us to refine tomographic images of the lithosphere-asthenosphere structure with an improved resolution in the northern and central Apennines, and to study the deformation of the upper mantle looking at seismic anisotropy through shear-wave splitting analysis. Also, a study of the depth and geometry of the Moho through the receiver function technique is in progress. Tomographic results from the northernmost 1994 and the central 1995 teleseismic experiments confirm that a high-velocity anomaly (HVA) does exist in the upper 200–250 km and is confined to the northern Apenninic arc. This HVA, already interpreted as a fragment of subducted lithosphere is better defined by the new temporary data, compared to previous works, based only on data from permanent stations. No clear high-velocity anomalies are detected in the upper 250 km below the central Apennines, suggesting either a slab window due to a detachment below southern peninsular Italy, or a thinner, perhaps continental slab of Adriatic lithosphere not detectable by standard tomography. We found clear evidence of seismic anisotropy in the uppermost mantle, related to the main tectonic processes which affected the studied regions, either NE–SW compressional deformation of the lithosphere beneath the mountain belt, or arc-parallel asthenospheric flow (both giving NW–SE fast polarization direction), and successive extensional deformation ( E–W trending) in the back-arc basin of northern Tyrrhenian and Tuscany. Preliminary results of receiver function studies in the northern Apennines show that the Moho depth is well defined in the Tyrrhenian and Adriatic regions while its geometry underneath the mountain belt is not yet well constrained, due to the observed high complexity.Published479-4934T. Sismicità dell'ItaliaJCR Journa

Pattern of seismicity in the Lucanian Apennines and foredeep (Southern Italy) from recording by SAPTEX temporary array

The deployment of a temporary seismic network in Southern Italy during 2001-2004 (the SAPTEX array, Southern APennine Tomography EXperiment) allowed us to relocate the hypocenters of Southern Apennines earthquakes with low uncertainty among the location parameters. The best array distribution of the SAPTEX network for the analysis of seismicity in the Lucanian Apennines and foredeep was reached in the first two years of recording. The SAPTEX data were merged with those of the Italian National Seismic Network (RSNC) operated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). For the hypocenters computation of events in the upper Agri Valley we also included P- and S- waves arrivals from the local Eni-Agip network. The seismicity for the Lucanian Apennines and foredeep in the analyzed period has magnitudes ranging from 2.0 to 4.1. A major finding is the identification of two different crustal domains: the westernmost characterizing the chain, mostly with shallow earthquakes (within about 20 km of depth), and the easternmost one belonging to the outer margin of the chain and to the foredeep, with deeper seismicity (mostly between 20-40 km of depth). Thirty fault-plane solutions were computed and used for stress inversion; most of them are related to earthquakes within the chain sector and indicate a generalized NE-SW extension. Moreover, the dense network allowed us to improve the location of events relative to two low magnitude sequences which occurred in the study period

The INGV science theatre experiences

Since September 2008, the Istituto Nazionale di Geofisca e Vulcanologia in Rome has started to experiment science theatre as an innovative tool to promote seismic risk awareness and earth education. Up to now two projects have been implemented within the Laboratorio di Didattica e Divulgazione Scientifica. The first one, more traditional, involving pupils of the primary school was devoted to promote seismic risk and earthquake education among children aged 6-10. The Sicilian “Colapesce” tale was rewritten and readapted to commemorate the 100 years from 1908 Messina Earthquake, to be performed in a school theatre by pupils (II and IV classes Scuola Primaria Federico Di Donato, Rome). It was as well an experiment of science without frontiers for the presence of schoolmates from different countries (Asia, Africa, South America, East Europe and Italy). The second was a pilot-project developed in collaboration with Ente Parco dei Castelli Romani and concerning the possibility to establish in the future an Ecomuseum in one of the Lazio Region areas rich of natural landscapes and history. The students of two classrooms of the Mancinelli and Falconi Institute in Velletri (III Classical Lyceum and III Socio-Pedagogical Lyceum ), aged 16, chose an itinerary in the volcanic-origin area around the Nemi Lake to be developed in three items: the Roman Ships Museum; The lake itself; and the Diana Nemorensis Temple’s ruins. The final goal was interpreting the territory with the help of scenic actions. It was a sort of opened-air theatre where history, legends and their historical figures - mainly Caligula and the Goddess Diana - described the area from the different points of view: geological, historical, naturalistic and even gastronomic. Both the projects have been evaluated, but in the second case, one of the two classrooms, being a Socio-Pedagogical Lyceum, was involved in the evaluation process under the supervision of Ingv Didactic Lab. Results from both projects, and a comparison between the two will be shown

An Ecomuseum Experience In The Castelli Romani Area for Didactic Purposes

Among the different methodologies to educate people to the planet sustainability, the Ecomuseum is one of the most innovative and advanced. It offers the opportunity of using different didactic modules such as drama and museography in order to obtain the full involvement of the people to be educated. In the Ecomuseum, visitors are not just the observers but also interactors and in a wide perspective even the watchmen of the territory where they live. In Italy already exist eighty Ecomuseums, two already established in the Lazio Region. One of those, the one in the Agro-pontino area, is already operating at a large scale and in a European contest with great results. Following the same path, the Istituto Nazionale di Geofisica e Vulcanologia in Rome chose an area, the Albani Hills, to implement a pilot-project for the establishment of an Ecomuseum in one of the Lazio Region areas rich of natural landscapes and history. In collaboration with the Ente Parco dei Castelli Romani a program for Lyceum students was implemented during a year (2009-2010). The students of two classrooms of the Mancinelli and Falconi Institute in Velletri (III Classical Lyceum and III Socio-Pedagogical Lyceum ), aged 16, chose an itinerary in the volcanic-origin area around the Nemi Lake to be developed in three items: the Roman Ships Museum; The lake itself; and the Diana Nemorensis Temple’s ruins. The final goal was interpreting the territory with the help of scenic actions. It was a sort of opened-air theatre where history, legends and their historical figures - mainly Caligula and the Goddess Diana - described the area from the different points of view: geological, historical, naturalistic and even gastronomic. The project evaluation was assigned to a Socio-Pedagogical Lyceum, under the supervision of INGV Didactic Lab. Results are encouraging even if innovative way to gain students enthusiasm should be thought since only a small group of students participated actively to the project. For future experiences it is important to succeed in involving as many teachers as possible to have more hours at disposal to be dedicated also to the dramatization

GINGER

In this paper, we outline the scientific objectives, the experimental layout, and the collaborations envisaged for the GINGER (Gyroscopes IN GEneral Relativity) project. The GINGER project brings together different scientific disciplines aiming at building an array of Ring Laser Gyroscopes (RLGs), exploiting the Sagnac effect, to measure continuously, with sensitivity better than picorad/ s, large bandwidth (ca. 1 kHz), and high dynamic range, the absolute angular rotation rate of the Earth. In the paper, we address the feasibility of the apparatus with respect to the ambitious specifications above, as well as prove how such an apparatus, which will be able to detect strong Earthquakes, very weak geodetic signals, as well as general relativity effects like Lense-Thirring and De Sitter, will help scientific advancements in Theoretical Physics, Geophysics, and Geodesy, among other scientific fields.Comment: 21 pages, 9 figure

Bollettino Sismico Italiano: Analisys of Early Aftershocks of the 2016 MW 6.0 Amatrice, MW 5.9 Visso and MW 6.5 Norcia earthquakes in Central Italy

The Amatrice-Visso-Norcia seismic sequence is the most important of the last 30 years in Italy. The seismic sequence started on 24 August, 2016 and still is ongoing in central Apennines. At the end of February 2017 more than 57,000 events were located, 80,000 events up to the end of September 2017 (Fig. 1). The mainshocks of the sequence occurred on 24 August 2016 (Mw 6.0 and Mw 5.4), 26 October 2016 (Mw 5.4 and Mw 5.9), 30 October 2016 (Mw 6.5), 18 January 2017 (four earthquakes Mw≥ 5.0). In this seismic sequence, all the waveforms recorded by temporary stations deployed by the SISMIKO emergency group (stations T12**; Moretti et al., 2016) where available in real- time at the surveillance room of INGV. Because of the high level of seismicity and the dense seismic network installed in the region, more than 150 events per day were located at the end of February 2017; still 60 events per day were located up to the end of August 2017.The Amatrice-Visso-Norcia is the most important seismic sequence since 2015, the time when the analysis procedures of the BSI group (Bollettino Sismico Italiano) were revised (Nardi et al., 2015). BSI is now available every four months on the web: bulletins contain revised earthquakes (location and magnitude) with ML≥ 1.5, quasi-real time revision of ML≥ 3.5 earthquakes and phase arrivals from waveforms recorded on seismic stations available from the European Integrated Data Archive (EIDA), (Mazza et al., 2012). These last procedures allow the integration of signals from temporary seismic stations (Moretti et al., 2014) installed by the emergency group SISMIKO (Moretti and Sismiko working group, 2016), even when they are not in real time transmission, if they are rapidly archived in EIDA, together with real time signals from the seismic stations of the permanent INGV network. The analysis strategy of the BSI group for the Amatrice -Visso - Norcia seismic sequence (AVN.s.s in the following) was to select the earthquakes located in the box with min/max latitude: 42.2/43.2 - and min/max longitude: 12.4/14.1 to prepare a special volume of BSI on the seismic sequence.PublishedTrieste, Italy1SR. TERREMOTI - Servizi e ricerca per la Societ

Bollettino Sismico Italiano: gennaio - aprile 2015

Nel primo quadrimestre 2015 si sono verificati 5 eventi di magnitudo superiore a 4: il 23 gennaio un Mw 4.3 è stato localizzato tra le province di Bologna e Prato, seguito da una sequenza di alcune centinaia di eventi; il 6 febbraio un Mw 4.7 al largo delle Isole Eolie, ad oltre 270 km di profondità; il 28 febbraio un Mw 4.1 nella Piana del Fucino; il 15 aprile un evento di magnitudo Mw 4.3 nel Mar Tirreno, al largo della costa calabra occidentale, ad una profondità di oltre 250 km e il 24 aprile un terremoto di magnitudo ML 4.0 tra le province di Ravenna e Forlì-Cesena,seguito da una sequenza di oltre 80 repliche.Istituto Nazionale di Geofisica e Vulcanologia e Dipartimento Protezione CivilePublished4IT. Banche dat

Bollettino Sismico Italiano: maggio - agosto 2015

Nel secondo quadrimestre 2015 si sono verificati 7 eventi di magnitudo superiore a 4: il 9 maggio un evento di ML 4.5 è stato localizzato nel basso Tirreno ad una profondità di circa 217 km; l’11 maggio un terremoto di Mw 4.4 nel Mar Ionio a circa 47 km di profondità; il 29 maggio un Mw 4.2 nel Mar Adriatico di fronte a San Benedetto del Tronto; il 2 agosto un evento di magnitudo ML4.0 nel Mar Tirreno, al largo della costa calabra occidentale, ad una profondità di circa 247 km e il 3 agosto un terremoto di magnitudo ML 4.0 tra le province di Cosenza e Catanzaro a sud della Sila, seguito da una sequenza di oltre 80 repliche di piccola magnitudo. L’8 agosto 2015 si è verificato un terremoto di ML 4.1 alle Isole Eolie, ed infine il 29 agosto un evento di Mw 4.0 vicino al confine della Slovenia con il Friuli Venezia Giulia, seguito da una sequenza sismica che è continuata anche dopo il 31 agosto.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat

Bollettino Sismico Italiano: settembre - dicembre 2015

Nel terzo quadrimestre 2015 si sono verificati 5 terremoti con M>4 nel territorio Italiano. In particolare il 14 ed il 16 ottobre si sono verificati due eventi profondi del basso Tirreno il primo con M=4.2 a 300 km di profondità, il secondo con M=4.4 a circa 250 km di profondità. Due terremoti M4.2 e M4.4 sono avvenuti il 6 dicembre nel Mar Adriatico a nord delle Isole Tremiti. Associati a questi si sono verificati alcuni eventi di magnitudo sopra a 3.5: si è trattata di una vera e propria sequenza sismica durata pochi giorni. L’ultimo evento di magnitudo superiore a 4 si è verificato a NE di Palermo nel basso Tirreno il 20 dicembre con una M=4.2. E’ infine da segnalare un terremoto con M = 4.8 che si è verificato il 1 Novembre in Slovenia, al confine con la Croazia.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat