Local seismic response studies in the north-western portion of the August 24th, 2016 Mw 6.0 earthquake affected area. The case of Visso village (Central Apennines).

In this work, we investigate the possible causes of the differential damaging observed in Visso village (Central Apennines, about 28 km north from the August 24th, 2016 Mw 6.0 earthquake epicenter). Following insights from the available geological cartography at 1:10.000 scale, a preliminary geophysical survey has been performed in the damaged area in order to constrain geometries and extent of the subsoil lithotypes. Then, these results have been used to retrieve a Vs profile close to the most heavily damaged buildings. This latter has been used as input for a numerical analysis aimed at deriving the motion at the ground level in the study area. In particular, a linear equivalent simulation has been performed by means of EERA code and the waveform has been obtained convolving the time history recorded during the August 24th, 2016 mainshock at Spoleto Monteluco (SPM) site. Our preliminary results indicate a possible correlation of damaging to the thickness and shape of the geological units. Nevertheless, further analyses are necessary to highlight any 2D basin and / non- linear soil behaviour effects in order to compare them to the intrinsic buildings vulnerability, according to the EMS98 guidelines

M.Etna: crisi sismica del 19/06/88. Detezione e localizzazione mediante rete sismica digitale

In the tex

Sulle tracce del terremoto del 20 febbraio 1743 nei comuni danneggiati del Salento (Puglia meridionale, Italia)

L’area del Salento (Puglia meridionale) è considerata l’avampaese stabile della catena appenninica (Cinque et al., 1993). La sismicità strumentale, registrata dagli anni Settanta a oggi, è scarsa e di bassa energia, prevalentemente concentrata ad ovest della penisola salentina e nel canale d’Otranto, dove il massimo evento registrato è stato quello del 20 ottobre del 1974 di Mw = 5.0 (CPTI11, 2011) (Fig.1). I terremoti storici più forti degli ultimi 1.000 anni, riportati dai cataloghi disponibili in letteratura, sono stati quelli del 10 settembre 1087 di Bari (Imax = 6-7), (CPTI11, 2011), del 20 febbraio 1743 del basso Ionio (Imax=IX), (CFTIMED04, 2007; CPTI11, 2011) e del 26 ottobre 1826 di Manduria (Imax = 6-7, CPTI11, 2011). Tra questi l’evento a maggiore energia è stato il terremoto del 1743, che ha colpito la Puglia e le coste occidentali della Grecia, ma è stato avvertito anche nelle regioni dell’Italia meridionale e in alcune località dell’Italia Centrale e Settentrionale, fino a Trento e a Udine, e finanche nell’isola di Malta. É stato un evento sismico complesso, percepito come una sequenza di tre violente scosse, prodotte probabilmente dall’attivazione di diversi segmenti di faglia (CFTIMED04, 2007). Sono state formulate due ipotesi di localizzazione di questo evento: secondo la prima, l’epicentro è riportato a mare, a est di S. Maria di Leuca, ipotesi avvalorata anche dalla distribuzione dei depositi da tsunami, attribuiti a questo terremoto, lungo le coste adriatiche meridionali del Salento (Torre Sasso e Torre S. Emiliano) (Mastronuzzi et al., 2007) fino a Brindisi; per la seconda, come revisionato nel catalogo CFTIMED04 (2007), l’epicentro è riportato a terra, tra Nardò e Galatina. In Italia i danni maggiori si sono registrati in Salento, nelle cittadine di Nardò, in provincia di Lecce, e Francavilla Fontana, in provincia di Brindisi; in Grecia a Levkas e nelle isole Ionie. I morti furono circa 180, 150 nella sola Nardò. L’evento è descritto in alcune centinaia di documenti storici, da cui si evince che furono oltre 86 le località interessate. Lo studio degli effetti prodotti ha permesso di attribuire all’evento una intensità massima di Imax = 9 (per Nardò e per Levkas) e Me = 6.9 (CFTIMED04, 2007). Nonostante ci siano stati danni notevoli in tutto il Salento, la mappa di pericolosità sismica di riferimento per il territorio nazionale (MPSO4 - Ordinanza PCM 3519/2006) attribuisce bassi valori di pericolosità nell’area del Salento e alti valori nell’area a mare, nel canale di Otranto. Questo lavoro si propone di andare alla scoperta delle evidenze architettoniche distrutte e ricostruite in seguito all’evento, con l’obiettivo di creare un itinerario geoturistico sulle “tracce” di questo terremoto nel tessuto urbano delle città salentine coinvolte

Progetto per il potenziamento della Rete Sismica Mobile dell'Osservatorio Vesuviano

Not presen

Vesuvio: Rete Sismica Digitale

In the tex

Multiparametric data analysis for seismic sources identification in the Campania re-gion: merge of seismological, structural and gravimetric data.

The Campania region is one of the Italian most active areas from a geodynamic point of view since it is characterized by occurrence of intense and widely spread seismic activity. The seismicity of the area is concentrated mainly along the Southern Apennines chain, as well as beneath the Campanian volcanic areas (Vesuvio, Campi Flegrei, Ischia) and is also originated by seismic sources buried in the Campanian Plain and offshore the Thyrrenian sea. The aim of this paper is an attempt to better constrain the main active, outcropping and buried fault systems of the Campanian area through the correlation between seismicity, tectonic structures (from geological data and image analysis) and gravimetric data. The main seismogenetic sources of the Campanian Apennines, responsible for the destructive historical events of 1456, 1688, 1694, 1702, 1732, 1930, 1962 and 1980 (Io = X-XI MCS), activated mainly along NW–SE faults (CPTI, 2004; DISS, 2010) with hypocenters concentrated within the upper 20 km of the crust. The available focal mechanisms of the larger events show normal solutions consistent with NE–SW extension (Pondrelli et al., 2007). The Plio-Pleistocene Campanian Plain is a structural depression located between the eastern side of the Tyrrhenian Sea and the Southern Apennines chain. The stress field acting in the Campanian Plain is strongly debated. Structural observations on the faults of the Plain suggest prevalent normal motion for the NW–SE and the NE–SW trending faults, and minor oblique motion, consistent with deformation style of the Southern Apennines. The Plain is characterized by seismicity of energy lower than the seismic activity of the Southern Apennines chain mainly occurring along its margins. Minor seismicity spreads out inside the Plain. In this paper, seismic, geologic and gravimetric data have been analysed in GIS environment. In particular, the seismological data used in this study are relative both to the historical and recent seismic activity, collected by the following Catalogues: CPTI04 Catalogue of Parametric Italian Earthquakes, 2004 (217 b.C to 2002); CSI Catalogue of Instrumental Italian Earthquakes (1981-2002); CNT Seismic Bulletin of Istituto Nazionale di Geofisica e Vulcanologia (2003-2008); Data Base of Seismic Laboratory of Osservatorio Vesuviano (Istituto Nazionale di Geofisica e Vulcanologia) (2000-2009); SisCam Catalogue (Seismotectonic Information System of the Campanian Region) (1980-2000). Seismic data have been merged in a new seismic database. Moreover, new precise locations of a set of seismic events relative to the Campanian Plain have been processed. Some clusters of epicentres have been identified confirming the existence of active buried fault systems inside the Plain. The Geological Dataset has been implemented by merging all outcropping and buried faults extracted from the available geological and geophysical papers and maps (Bigi et al., 1983; Ambrosetti et al. 1986; Bonardi et al.,1988; Orsi et al. 1996; Milia A. e Torrente M.M.,1999; Cinque et al. 2000; Bruno et al. 2003). A multiscale analysis of the gravity and magnetic fields of the Southern Italy has been performed by Fedi et al, 2005. Multiscale Derivative Analysis (MDA) provided an almost complete representation of the structural framework of Southern Italy at three different scales. Most of the known geological elements of the Apennine system are clearly shown at intermediate and short scales, together with several trends indicating the location of buried structures. The main results of the combined analysis of seismic epicentres, faults and gravity data, indicate a strong correlation between seismicity and MDA lineaments from gravity data. Moreover, tectonic structures without correlated seismic activity and spread seismicity, apparently not linked with already known faults (buried faults?) have been identified

STUDIO DELLA STRUTTURA CROSTALE NELLE AREE VULCANICHE DEL VESUVIO E DEI CAMPI FLEGREI

Alla fine degli anni '80 furono effettuate numerose indagini DSS e WARR nell'area campana con l'obiettivo di investigarne la struttura crostale, in particolare quella dell'area vulcanica costiera, impostata nella zona di transizione tra il bacino tirrenico e la catena appenninica. Le geometrie punto di scoppio - punti di registrazione, lineari e a offset costante, furono scelte per ottenere informazioni sulla distribuzione delle velocità sismiche e sulla geometria delle principali discontinuità crostali. In questo lavoro presentiamo i risultati della modellazione dinamica (gaussian-bean dynamic ray-tracing) dei profili PP (Tirreno-Campi Flegrei), PV (Tirreno-Vesuvio), PB (Capri-Penisola Sorrentina) e V3 (Penisola Sorrentina-Vesuvio)e del profilo a offset costante Fan C-B

A geology-based 3D velocity model of the Amatrice Basin (Central Italy)

In this paper we present a new methodological approach which integrates geological and geophysical data into a 3D modelling process to be mainly employed in seismic hazard assessment studies of earthquake-prone areas around the world, as well as in applications for land use and urban planning. As a case study, the reconstruction of a geology-based 3D velocity model of the uppermost hundreds of metres of the Amatrice high-seismic-hazard area is described. The model was constructed using geological (e.g., maps, cross-sections and core-wells) and geophysical (e.g., down-hole, MASW, refraction, and seismic noise measurements) data, which were georeferenced and uploaded into 3D geological modelling software, where faults, stratigraphic boundaries, and geophysical attributes were digitised, checked, hierarchised, and modelled. The performed 3D geological model was parameterised with Vs and Vp velocities and, finally, the environmental noise (i.e., horizontal-to-vertical spectral ratio analysis, HVSR) recorded at some seismic stations was compared with the seismic responses modelled at some nearby control points. In the study area, the proposed geology-based 3D velocity model represents both a new potential geophysical prediction tool for areas devoid of geophysical measurements (i.e. HVSR curves) and a potential input-model for future ground-motion and seismic-wave-propagation simulations aimed at a more precise local seismic response assessment and, consequently, at the development of more realistic seismic hazard scenarios. The model here presented constitutes a first version of the 3D geological-geophysical model for the studied area, which will be improved with new data and more advanced algorithms available in the future