AlpArray-Italy: Site description and noise characterization

Within the framework of the European joint research initiative AlpArray (http://www.alparray.ethz.ch/), we de- ployed overall 20 seismic broad-band stations in Northern Italy and on two islands in the Tyrrhenian Sea (Capraia and Montecristo) during Fall-Winter 2015. All the stations, connected in real-time, were installed at sites selected according to the AlpArray Seismic Network plan: 16 temporary stations running for two to three years and 4 new permanent stations in sites already occupied by accelerometers of the INGV national network. Most temporary stations are equipped with REF TEK 130S digitizers and Nanometrics Trillium Compact 120s sensors (a couple have Nanometrics Trillium 120P and one Streckeisen STS2). For each site we describe the settings and discuss the noise levels, the site effects and the preliminary sensitivity analysis.PublishedVienna, Austria1T. Geodinamica e interno della Terraope

Seismic hazard for the Trans Adriatic Pipeline (TAP). Part 2: broadband scenarios at the Fier Compressor Station (Albania)

AbstractTo ensure environmental and public safety, critical facilities require rigorous seismic hazard analysis to define seismic input for their design. We consider the case of the Trans Adriatic Pipeline (TAP), which is a pipeline that transports natural gas from the Caspian Sea to southern Italy, crossing active faults and areas characterized by high seismicity levels. For this pipeline, we develop a Probabilistic Seismic Hazard Assessment (PSHA) for the broader area, and, for the selected critical sites, we perform deterministic seismic hazard assessment (DSHA), by calculating shaking scenarios that account for the physics of the source, propagation, and site effects. This paper presents a DSHA for a compressor station located at Fier, along the Albanian coastal region. Considering the location of the most hazardous faults in the study site, revealed by the PSHA disaggregation, we model the ground motion for two different scenarios to simulate the worst-case scenario for this compressor station. We compute broadband waveforms for receivers on soft soils by applying specific transfer functions estimated from the available geotechnical data for the Fier area. The simulations reproduce the variability observed in the ground motion recorded in the near-earthquake source. The vertical ground motion is strong for receivers placed above the rupture areas and should not be ignored in seismic designs; furthermore, our vertical simulations reproduce the displacement and the static offset of the ground motion highlighted in recent studies. This observation confirms the importance of the DSHA analysis in defining the expected pipeline damage functions and permanent soil deformations

Earthquake rupture forecasts for the mps19 seismic hazard model of Italy

In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone-based approaches with seismicity rates derived from earthquake catalogs are commonly used in many countries as the standard for national seismic hazard models. In Italy, a single zone-based ERF is currently the basis for the official seismic hazard model. In this contribution, we present eleven new ERFs, including five zone-based, two smoothed seismicity-based, two fault-based, and two geodetic-based, used for a new PSH model in Italy. The ERFs were tested against observed seismicity and were subject to an elicitation procedure by a panel of PSHA experts to verify the scientific robustness and consistency of the forecasts with respect to the observations. Tests and elicitation were finalized to weight the ERFs. The results show a good response to the new inputs to observed seismicity in the last few centuries. The entire approach was a first attempt to build a community-based set of ERFs for an Italian PSHA model. The project involved a large number of seismic hazard practitioners, with their knowledge and experience, and the development of different models to capture and explore a large range of epistemic uncertainties in building ERFs, and represents an important step forward for the new national seismic hazard model

From shallow to very shallow image of the highly active Kefalonia - Zakynthos fault system

4 pages, 2 figuresIn May 2022 and June 2023 two oceanographic cruises were carried out around the Ionian Islands with the aim of defining the real geometry of the strike-slip fault system of Kefalonia and of the reverse faults present south of Zakynthos. The acquired multidisciplinary and multiresolution data will also allow to understand the dynamics of the area offshore the Peoloponnese peninsula, the deformation of the surface sediments at the transition of the two systems, i.e. from reverse fault system to strike-slip fault system, and the relationship between the recorded seismicity and mapped fault activity. To date, the analysis of the processed data has allowed us to define the tectonic and morphological complexity of the fault system affecting the investigated area. [...]Thanks to the CNR for supporting the cruise with time ship, IONIANS 2022 project. Interpretation of seismic profile has been done using the Kindgom IHS Markit. Poseidon project has been supported by Eurofleet+ SEA02_13_POSEIDONPeer reviewe

Simultaneous observations of radon concentrations in soils and thermal remote sensing dynamics in a seismic active area

The paper deals with the simultaneous observation of two important environmental parameters: Land Surface Temperature (LST) and Radon (Rn) concentration. Both parameters have a consistent literature of observations in seismically active regions, especially in cases in which they are proposed as possible and reliable earthquake precursors. Till today their use is topic of discussion, explicitly related to the basic subject of the effective predictability of seismic activity. Theories also exist that link thermal infrared (TIR) emissions to Radon anomalous degassing considering its radioactive decay the cause of air ionization, water vapour condensing and release of latent heat. The simultaneous observation of two parameters was performed with two very different technologies which are best performing for each single observable: Radon is a heavy and quick to decay noble gas and can be monitored in soil, in water and in air. In this first experiment the air is inhaled by pumping from a well to notice its concentration in soil by radionuclide activity (Bq/m3); Land Surface Temperature is monitored through geostationary multispectral satellite, a technology which allow to perform a continuous and simultaneous survey of wide regions without variations of acquisition geometries and projection angles for each pixel. Geostationary thermal data have been frequently proposed to be the most useful mean to relieve thermal earthquake precursors in spite of their lower spatial resolution than those ones collected by polar satellites. The satellite thermal dynamics monitoring has been carried out by means of a recent processing technique, the Night Thermal Gradient, able to take advantage from the high time resolution of geostationary satellites and reach an important improvement in spatial resolution of maps looking at environmental thermal transients. The simultaneous observation of the two parameters was carried out along a bit more than one year but was heavily influenced by the stability of Radon sensor which went occasionally out of service. However, the first results are encouraging looking at some spikes in Rn time series that show similar timing of NTG spikes, frequently anticipating them. The comparison of the single station Rn monitoring and LST maps is especially interesting and need to be extended to more continuous data sets to confirm the presence of extended thermal anomalies at the time of a Rn spikes even in apparently absence of anomalies in the NTG time series of the only pixel containing the well of the Rn station

A radon anomaly in soil gas at Cazzaso,NE Italy, as a precursor of an ML = 5.1 earthquake

At Cazzaso (Friuli) in northeast Italy, radon (222Rn) activity concentration in soil gas in a borehole at a depth of 80 cm has been monitored continuously (at a frequency of once an hour) since May 2004, using a Barasol probe (Algade, France). In addition, environmental parameters (air and soil temperature, barometric pressure) have been recorded. The results have been evaluated and the relationship between radon levels and seismic activity is discussed. Correlation between radon concentration and barometric pressure has been observed. Preliminary results have shown a distinct radon anomaly prior to some earthquakes

The legacy of the 1976 Friuli earthquake

A brief excursus is presented on the projects funded by the Civil protection of the Friuli Venezia Giulia Region aimed at reducing Seismic risk. The project have tackled different aspect of Seismic risk reduction: the regional seismometric network can give information of earthquakes in real time, the Seismic hazard and risk map represent on guideline on how to construct new building and where to retrofit existing ones with high priority, the survey on the school buildings in the Friuli Venezia Giulia provides indication on what to do to make them safe