Investigation of the active Celano-L'Aquila fault system, Abruzzi (central Apennines, Italy) with combined ground-penetrating radar and palaeoseismic trenching

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Tephrochronology in faulted Middle Pleistocene tephra layer in the Val d’Agri area (Southern Italy)

The High Agri River Valley is a Quaternary Basin located along the hinge of the Southern Apennines fold-andthrust belt. The inner margin of the orogen has been affected by intense transtensional and normal faulting, which accompanied vigorous volcanism during the Quaternary. Marker tephra layers are distributed across the whole of Southern Italy and provide a powerful tool to constrain both the size of eruptions and the regional activity of extensional faults controlling basin evolution. Paleoseismological trenching within the Monti della Maddalena range, that borders the Agri River Valley to the south-west, has exposed a faulted stratigraphic sequence and recovered a 10 cm thick tephra layer involved in deformation. This is the first tephra horizon recognized in the high Agri Valley, which, based on the stratigraphic study of the trench, lies in a primary position. 40Ar/39Ar dating constrain its age to 266 ka and provide an important marker for the Middle Pleistocene tephrochronology of the region. Together with dating, geochemical analysis suggests a possible volcanic source in the Campanian region

Detecting young, slow‐slipping active faults by geologic and multidisciplinary high‐resolution geophysical investigations: A case study from the Apennine seismic belt, Italy.

The Southern Apennines range of Italy presents significant challenges for active fault detection due to the complex structural setting inherited from previous contractional tectonics, coupled to very recent (Middle Pleistocene) onset and slow slip rates of active normal faults. As shown by the Irpinia Fault, source of a M6.9 earthquake in 1980, major faults might have small cumulative deformation and subtle geomorphic expression. A multidisciplinary study including morphological-tectonic, paleoseismological, and geophysical investigations has been carried out across the extensional Monte Aquila Fault, a poorly known structure that, similarly to the Irpinia Fault, runs across a ridge and is weakly expressed at the surface by small scarps/warps. The joint application of shallow reflection profiling, seismic and electrical resistivity tomography, and physical logging of cored sediments has proved crucial for proper fault detection because performance of each technique was markedly different and very dependent on local geologic conditions. Geophysical data clearly (1) image a fault zone beneath suspected warps, (2) constrain the cumulative vertical slip to only 25–30 m, (3) delineate colluvial packages suggesting coseismic surface faulting episodes. Paleoseismological investigations document at least three deformation events during the very Late Pleistocene (<20 ka) and Holocene. The clue to surface-rupturing episodes, together with the fault dimension inferred by geological mapping and microseismicity distribution, suggest a seismogenic potential of M6.3. Our study provides the second documentation of a major active fault in southern Italy that, as the Irpinia Fault, does not bound a large intermontane basin, but it is nested within the mountain range, weakly modifying the landscape. This demonstrates that standard geomorphological approaches are insufficient to define a proper framework of active faults in this region. More in general, our applications have wide methodological implications for shallow imaging in complex terrains because they clearly illustrate the benefits of combining electrical resistivity and seismic techniques. The proposed multidisciplinary methodology can be effective in regions characterized by young and/or slow slipping active faults.PublishedB113073.2. Tettonica attivaJCR Journalpartially_ope

SCIENZAPERTA: EARTH SCIENCE FOR EVERYONE... FINALLY IN MILAN!

ScienzAperta is an outreach science venue that the Istituto Nazionale di Geofisica e Vulcanologia started in 2011 as the spring of science: the doors of the headquarters of science were finally opened to public. A number of events, conferences, seminars, guided tours through the Institute and its laboratories are every year offered to general public. The venue is held in most of the cities where the Institute is located, priority to high seismic and/or volcanic risk regions. On May 2014 we held ScienzAperta for the first time in Milano and open up the doors to schools specifically dealing mostly with seismic hazard in a region where general public not necessarily think it might We offered students conferences, seminars and educational activities to highlight the fun of science and jet raise awareness on proper behaviours in case of earthquake shaking. We asked students and teachers, from elementary to high schools, to fill in a questionnaire that we use to evaluate the appreciation the venue had. One hundred years after Giuseppe Mercalli’s death we could not forget to celebrate his science the city where he was born.UnpublishedMilano3T. Pericolosità sismica e contributo alla definizione del rischiorestricte

Evidence for surface rupture associated with the Mw 6.3 L’Aquila earthquake sequence of April 2009 (central Italy)

An earthquake of Mw = 6.3 struck L Aquila town (central Italy) on 6 April 2009 rupturing an ~18-km-long SW-dipping normal fault. The aftershock area extended for a length of more than 35 km and included major aftershocks on 7 and 9 April and thousands of minor events. Surface faulting occurred along the SW-dipping Paganica fault with a continuous extent of ~2.5 km. Ruptures consist of open cracks and vertical dislocations or warps (0.1m maximum throw) with an orientation of N130°–140°. Small triggered slip and shaking effects also took place along nearby synthetic and antithetic normal faults. The observed limited extent and small surface displacement of the Paganica ruptures with respect to the height of the fault scarps and vertical throws of palaeo-earthquakes along faults in the area put the faulting associated with the L' Aquila earthquake in perspective with respect to the maximum expected magnitude and the regional seismic hazard.Published43-513.2. Tettonica attivaJCR Journalreserve

Evidence for surface rupture associated with the Mw 6.3 L’Aquila earthquake sequence of April 2009 (central Italy)

An earthquake of Mw=6.3 struck L’Aquila town (central Italy) on April 6, 2009 rupturing an approximately 18 km long SW-dipping normal fault. The aftershock area extended for a length of more than 35 km and included major aftershocks on April 7 and 9, and thousands of minor events. Surface faulting occurred along the SW-dipping Paganica fault with a continuous extent of ~2.5 km. Ruptures consist of open cracks and vertical dislocations or warps (0.1 maximum throw) with an orientation of N130°-N140°. Small triggered slip and shaking effects also took place along nearby synthetic and antithetic normal faults. The observed limited extent, and small surface displacement, of the Paganica ruptures with respect to the height of the fault scarps and vertical throws of paleoearthquakes along faults in the area, puts the faulting associated with the L’Aquila earthquake in perspective with respect to the maximum expected magnitude, and the regional seismic hazard

Evidence for surface rupture associated with the Mw 6.3 L’Aquila earthquake sequence of April 2009 (central Italy)

An earthquake of Mw = 6.3 struck L Aquila town (central Italy) on 6 April 2009 rupturing an ~18-km-long SW-dipping normal fault. The aftershock area extended for a length of more than 35 km and included major aftershocks on 7 and 9 April and thousands of minor events. Surface faulting occurred along the SW-dipping Paganica fault with a continuous extent of ~2.5 km. Ruptures consist of open cracks and vertical dislocations or warps (0.1m maximum throw) with an orientation of N130°–140°. Small triggered slip and shaking effects also took place along nearby synthetic and antithetic normal faults. The observed limited extent and small surface displacement of the Paganica ruptures with respect to the height of the fault scarps and vertical throws of palaeo-earthquakes along faults in the area put the faulting associated with the L' Aquila earthquake in perspective with respect to the maximum expected magnitude and the regional seismic hazard

Rilievi geologici nell’area epicentrale della sequenza sismica dell’Aquilano del 6 aprile 2009

Il 6 Aprile 2009 un terremoto di Ml=5.8 (Mw=6.2) ha colpito L’Aquila e la media valle dell’Aterno in Abruzzo. In questo lavoro presentiamo in maniera sintetica i rilievi geologici effettuati in campagna dal gruppo di lavoro EmerGeo a seguito della sequenza sismica aquilana. Le attività di rilevamento condotte sono consistite principalmente nella verifica, definizione e caratterizzazione delle deformazioni cosismiche superficiali osservate lungo le strutture tettoniche note in letteratura; sono stati inoltre rilevati e riportati altri effetti cosismici locali (fratture su asfalto, frane e scivolamenti) non direttamente collegati alla presenza di strutture tettoniche. In totale sono stati rilevati oltre 300 punti di osservazione su una porzione di territorio estesa circa 900 km2. L’analisi preliminare dei rilievi effettuati indica che le rotture osservate lungo la faglia di Paganica, per la continuità e le caratteristiche, rappresentano l’espressione superficiale della faglia responsabile dell’evento del 6 aprile 2009, e che le rotture lungo le faglie di Bazzano e di Monticchio-Fossa possono rappresentare l’espressione in superficie di una struttura antitetica riattivata durante l’evento

Investigating seismogenic faults in Central and Southern Apennines (Italy): modeling of fault-related landscape features

The direct identification of seismogenic structures in Southern Italy is often a difficult task, since finding seismogenic faults with clear surface expression associated is unlikely, even if they are the source of large magnitude earthquakes. A possible way to solve this problem is the investigation of a series of features of the surface landscape that could be attributed to repeated movements along a fault. In this paper we investigated the drainage, ancient coastlines, marine terraces and recent deposits of three different active tectonic basins in central and Southern Italy. The combination of the modeling of these fault-related landscape features with historical and seismological data better constrained the geometry of the seismogenic faults responsible for three large magnitude historical events in the studied areas. The results show that in this section of the peninsula seismogenesis is often connected with blind almost pure dip-slip normal faults; the long-term activity of these faults produces intermontane basins or coastal plains that are sinking relative to the surrounding areas; the application of this methodology emphasises the importance of geological and geomorphological studies for the recognition of seismogenic faults and for a complete assessment of the seismic hazard in Italy