An inventory of river anomalies in the Po Plain, Northern Italy: evidence for active blind thrust faulting

The Po Plain is a low-relief area characterised by active shortening accommodated by blind thrust faulting. In this almost flat region depositional rates are similar to tectonic rates and deformation is seldom expressed by noticeable surface anticlines. We adopted a geomorphological approach based on the detailed analysis of the drainage network to identify the location of active thrust faults. A total of 36 anomalies represented by sudden river diversions and shifts in channel pattern were accurately mapped. After comparison with the location of subsurface buried anticlines and of historical seismicity, these anomalies could be related to a tectonic origin and included in a database. Their distribution highlights the activity of the buried outer thrust fronts of both the Southern Alps and the Northern Apennines. Among all the anomalies, we identified one related to the seismogenic source responsible for the 12 May 1802 earthquake (Me 5.7), which struck the Oglio River Valley near Soncino (Cremona). We propose that this earthquake was generated by an east-west trending, north-dipping, blind thrust fault that roots into the Alpine system. If this inference is correct, other faults along the Southern Alpine margin are potentially seismogenic

Morphometric analysis in the offshore of the southern Taranto Gulf: unveiling the structures controlling the Late Pleistocene-Holocene bathymetric evolution

The present study is focused on a morphometric analysis of high resolution multibeam data (10m, 5m and, locally, 2m resolution), that were acquired during the oceanographic TEATIOCA 2011 campaign along a sector of the Ionian margin of northern Calabria. The integration of morphometric analysis with sparker and chirp data allowed to unveil basic but robust information about: 1. hierarchy of the fault systems controlling the bathymetric evolution; 2. the interplay between tectonic and erosional processes in sea-floor modeling; 3. uplift rates; 4. tilting processes

The effects of pre-existing discontinuities on the surface expression of normal faults: insights from wet-clay analogue modeling

We use wet-clay analogue models to investigate how pre-existing discontinuities (i.e. structures inherited from previous tectonic phases) affect the evolution of a normal fault at the Earth\u2019s surface. To this end we first perform a series of three reference experiments driven by a 45\ub0 dipping master fault unaffected by pre-existing discontinuities to generate a mechanically isotropic learning set of models. We then replicate the xperiment six times introducing a 60\ub0-dipping precut in the clay cake, each time with a different attitude and orientation with respect to an initially-blind, 45\ub0-dipping, master normal fault. In all experiments the precut intersects the vertical projection of the master fault halfway between the center and the right-hand lateral tip. All other conditions are identical for all seven models. By comparing the results obtained from the mechanically isotropic experiments with results from experiments with precuts we find that the surface evolution of the normal fault varies depending on the precut orientation. In most cases the parameters of newly-forming faults are strongly influenced. The largest influence is exerted by synthetic and antithetic discontinuities trending respectively at 30\ub0 and 45\ub0 from the strike of the master fault, whereas a synthetic discontinuity at 60\ub0 and an antithetic discontinuity at 30\ub0 show moderate influence. Little influence is exerted by a synthetic discontinuity at 45\ub0 and an antithetic discontinuity at 60\ub0 from the strike of the master fault. We provide a ranking chart to assess fault-to-discontinuity interactions with respect to essential surface fault descriptors, such as segmentation, vertical-displacement profile, maximum displacement, and length, often used as proxies to infer fault properties at depth. Considering a single descriptor, the amount of deviation induced by different precuts varies from case to case in a rather unpredictable fashion. Multiple observables should be taken into consideration when analyzing normal faults evolving next to pre-existing discontinuities

Seismic waves and acoustic waves: from earthquake to music

INGV is currently the largest European scientific institution dealing with Earth Sciences research and real-time surveillance, early warning, and forecast activities in geophysics and volcanology. The Laboratorio Didattica e Divulgazione Scientifica of INGV organizes every year rich educational and outreach activities with schools of different levels and with general public to convey scientific knowledge and to promote research on science and nature, focusing on volcanic and seismic hazard. The activities encompass a wide variety of formats, such as the opening of our labs to schools for guided visits, contributing to national (e.g., the Italian “Week of the Scientific Culture”, launched by the Ministry of Education and Research) and international (e.g., the European “Night of the Researchers”) events, editing educational videos, creating multimedia tools also available on the Web. Moreover, we contribute to expositions and science festivals organizing exhibitions with experiments, models, and exhibits designed to teaching and learning geophysics. Finally, we offer guided visits to the control rooms run by our Institute, which ensures the round-the-clock volcanic and seismic surveillance of the whole Italian territory. During the Week of the Scientific Culture and the Night of the Researchers we opened our Institute to the general public, in order to show our laboratories, to talk about new researches on Earth Sciences and to explain the volcanic and seismic risk and the related surveillance activities. These initiatives are widely appreciated by the community and we organized special events with the aim to inspire curiosity toward scientific research, and to facilitate the approach of the general public to science and nature. The special event of the 2010 programmes was a scientific-musical format: Seismic waves and acoustic waves, from earthquake to music. The aim of this project was to involve the public in scientific events offering happening where the scientific language is mediate through the language of the music. In this way, scientific phenomenon are brought in using emotion, making easier the understanding of the scientific themes. The format started with short lectures on earthquake and seismic wave propagation to move on the comparison between the seismic waves and the acoustic waves. We used seismograms, acoustic instruments, the voice, and the Earth sounds to explain the relation between earthquake waves and music. The scientific talks were organized to create a trail that, through emotion and curiosity, guides the public to the discovery and comprehension of the scientific phenomenon. The final part of the event was devoted to classical/jazz/blues live concerts performed by groups and ensembles, some of them arranged by INGV researchers. As a general result, thanks to this project we joined science and community, merging the INGV mission with the public expectation. This scientific-musical format represented an experimental outreach project, new, stimulating, and appreciated by the audience that can be used as good practice of scientific divulgation

Active deformation evidence in the offshore of western Calabria (southern Tyrrhenian Sea) from ultra-resolution multichannel seismic reflection data: results from the Gulf of Sant'Eufemia

An ultra-resolution, multichannel seismic reflection data set was collected during an oceanographic cruise organised in the frame of the “Earthquake Potential of Active Faults using offshore Geological and Morphological Indicators” (EPAF) project, which was founded by the Scientific and Technological Cooperation (Scientific Track 2017) between the Italian Ministry of Foreign Affairs and International Cooperation and the Ministry of Science, Technology and Space of the State of Israel. The data acquisition approach was based on innovative technologies for the offshore imaging of stratigraphy and structures along continental margins with a horizontal and vertical resolution at decimetric scale. In this work, we present the methodology used for the 2D HR-seismic reflection data acquisition and the preliminary interpretation of the data set. The 2D seismic data were acquired onboard the R/V Atlante by using an innovative data acquisition equipment composed by a dual-sources Sparker system and one HR 48-channel, slant streamers, with group spacing variable from 1 to 2 meters, at 10 kHz sampling rate. An innovative navigation system was used to perform all necessary computations to determining real-time positions of sources and receivers. The resolution of the seismic profiles obtained from this experiment is remarkable high respect to previously acquired seismic data for both scientific and industrial purposes. In addition to the seismic imaging, gravity core data were also collected for sedimentological analysis and to give a chronological constraint using radiocarbon datings to the shallower reflectors. The investigated area is located in the western offshore sector of the Calabrian Arc (southern Tyrrhenian Sea) where previous research works, based on multichannel seismic profiles coupled with Chirp profiles, have documented the presence of an active fault system. One of the identified faults was tentatively considered as the source of the Mw 7, 8 September 1905 seismic event that hit with highest macroseismic intensities the western part of central Calabria, and was followed by a tsunami that inundated the coastline between Capo Vaticano and the Angitola plain. On this basis, the earthquake was considered to have a source at sea, but so far, the location, geometry and kinematics of the causative fault are still poorly understood. In this study we provide preliminary results of the most technologically advanced ultra-high-resolution geophysical method used to reveal the 3D faulting pattern, the late Quaternary slip rate and the earthquake potential of the marine fault system located close to the densely populated west coast of Calabria

Geometry and modeling of an active offshore thrust-related fold system: the Amendolara Ridge, Ionian Sea, southern Italy

On the Ionian Sea coast of southern Italy, spanning the transition from the Calabrian Arc to the Apennines, NE-directed motion of the thin-skinned frontal thrust belt of the Apennines toward the Apulian foreland reportedly ceased during the Early-Middle Pleistocene. The submarine extension of the frontal thrust belt is represented by the Amendolara ridge, which stretches for over 80 km to the SE beneath the Taranto Gulf. High-resolution marine geophysical data collected on the Amendolara ridge during the TEATIOCA_2011 cruise provided unequivocal constraints to assert active fault-related fold growth. Single-channel seismic (sparker) and acoustic CHIRP profiles, corroborated by multibeam mapping and shallow coring, form the novel dataset to constrain the near-bottom evolution. The new data were benchmarked to the crustal geometry by means of interpretation of existing multichannel seismic profiles

Identification of tsunami deposits and liquefaction features in the Gargano area (Italy): paleoseismological implication

The Gargano region (Southeastern Italy) was hit by a M = 6.8 earthquake and inundated by a subsequent tsunami in 1627. To better define the hazard in the region, we searched for evidence of this and prior earthquakes in the geologic record. We identified potential earthquake-related liquefaction features and tsunami deposits in the stratigraphic sequences of the marsh areas both north and south of the Gargano promontory. We recognized clear liquefaction features and possible tsunamigenic sands that can be related to the 1627 seismic event in irrigation ditch exposures and gouge cores along the Northern Gargano coast. In total, six potential tsunami sand deposits have been recognized in two areas located close to the northern and southern coasts of the Gargano promontory. However, ambiguous evidence comes from the paleontological analysis of these sands. Although fragments of marine shells have been found in the coarser portion of the sand samples, foraminifera and ostracods assemblages are typical of brackish water condition. Radiocarbon dating of three of these deposits from the Northern Gargano coast, near the town of Lesina, suggests an average recurrence interval of 1700 years for tsunami events in this area. Assuming that all the paleotsunamis are related to the same seismogenic source responsible for the 1627 earthquake, this average recurrence interval may be typical for that source. Radiocarbon dating of three sand layers observed on the southern coast, close to the city of Manfredonia, suggests that the average recurrence time for violent sea inundation there is about 1200 years

Database of Individual Seismogenic Sources (DISS), Version 3.2.1: A compilation of potential sources for earthquakes larger than M 5.5 in Italy and surrounding areas

Istituto Nazionale di Geofisica e VulcanologiaPublished2T. Deformazione crostale attiva3T. Sorgente sismica4T. Sismicità dell'Italia5T. Sismologia, geofisica e geologia per l'ingegneria sismica6T. Studi di pericolosità sismica e da maremoto4IT. Banche dat

Geophysics for Kids: The Experience of the Istituto Nazionale di Geofisica e Vulcanologia (Italy)

Paper describing the outreach activities at INGV.Published529-5352TM. Divulgazione ScientificaJCR Journa