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Castello Tesino Geomagnetic Observatory 2022
No full textIstituto Nazionale di Geofisica e VulcanologiaPublishedOSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territori
Earthquake Induced Landslides (EILs) occurrence and earthquake parameters: new empirical relationships developed using the updated CFTI historical dataset
No full textThe ground shaking generated by the arrival of seismic waves released during earthquakes, besides
generating damages to the urban environment and artificial infrastructures, can trigger
widespread environmental coseismic effects, overall defined as secondary Earthquake
Environmental Effects (EEE) in the Environmental Seismic Intensity scale (ESI; Michetti et al., 2007).
These natural effects include river ponding or diversion, liquefaction, ground compaction and
failures and, among all, landslides. If, due to geological and geomorphological reasons, the area hit
by the earthquake is susceptible to their occurrence, they take place almost constantly, regardless
of the kinematic characteristics of the seismogenic sources, and affect areas of variable size
according to the earthquake magnitude. Besides potentially increasing overall earthquake damage
immediately after the mainshock, they pose long lasting secondary hazards to earthquake affected
areas (e.g. Fan et al., 2019), driving also the long-term morphological evolution of the territory
(e.g. Wang et al., 2020).
Earthquake Induced Landslides (EILs) are among the most diffused environmental hazard
connected to the earthquake activity, and especially affect recent, high relief mountain landscapes
associated to the ongoing tectonic plate dynamics. There exist in fact reciprocal feedbacks
between active tectonics, which in the long-term creates the predisposing morphological and
geological factors, and landslide activity, which works for lowering the topographic gradients.
Italy sits on the plate boundary separating the slowly converging Eurasia and Nubia plates, which in
the long run created its mostly mountain territory, and is characterized by a relatively high seismic
hazard. The combination of the relatively frequent seismic release and the locally high landslide
susceptibility (Fig. 1), makes the Italian territory especially prone to EILs occurrence. This is testified by the numerous coseismic landslide inventories compiled after recent earthquakes (e.g. Guzzetti et al., 2009).
As a first step of our workflow, we revised the database of seismic induced environmental effects
connected to the CFTI5Med historical seismic catalogue (available at
https://storing.ingv.it/cfti/cfti5/; Guidoboni et al., 2018; 2019). To achieve this goal, we collected
new data points from new historical sources, revised the EILs already included in CFTI, and finally,
in a dedicated GIS environment, we tried to locate them on topographic maps using the coeval
descriptions. In some cases, it was possible to associate the historical EILs to landslides included
and described in the Italian Landslide Inventory (IFFI database; Trigila et al., 2007). Following this,
landslides were subdivided into three classes according to their positioning precision, i.e.: Class A if
they were geographically well located using a toponymal (AI if associated to one of landslides
included in IFFI); Class B, if they were generally located in an area (BI if associated to one of
landslides included in IFFI); Class C, if not localized. The revised CFTI database includes more than
1000 historical EILs, associated to 159 individual earthquakes or seismic sequences occurred
between 117 B.C.E. and 1997 (Fig. 2). With respect to the datasets used so far for deriving
empirical relationships (e.g. Livio and Ferrario, 2019; Tanyaş et al., 2017), these figures
dramatically increase the number of available data points for the Italian territory.
As a second step, the implemented database was used to develop new empirical attenuation
relationships between the EILs density and the distance from the epicenter as a function of the
earthquake magnitude. Then, we subdivided seismic events into three magnitude classes to
account for the different extent of the maximum area affected by EILs and released energy. The
three classes are as follows: Class 1, M < 5.5; Class 2, 5.5 ≤ M < 6.5, and Class 3, M ≥ 6.5. Based on
the locations of EILs and of epicenters, we set circular search areas with a 5 km large moving
window and calculated for each area the cumulative density. We found that the cumulative density
decreases with the distance following a power law relationship, with coefficients of determination
variable between 0.95 and 0.99 according to the magnitude class, and that the maximum distance
including 95th percentile of landslides increases with increasing magnitude range. In particular, the
95th percentile distance, i.e. the distance within which 95% of EILs are expected to occur, is 42 km
for earthquakes of Class 1, 66 km for those of Class 2, and 77 km for those of Class 3.
In addition, using the shakemaps of 38 out of 159 historical earthquakes of our dataset, we
developed an empirical relationship between EILs density and PGA values. The shakemaps of
historical earthquakes were recently published by the Istituto Nazionale di Geofisica e Vulcanologia
and are available at http://shakemap.ingv.it/shake4/. EILs density was computed by classifying PGA values into classes of 0.1 g range. We used the EILs location to sample the PGA value and derive a
power law relationship showing an increasing landslide density with increasing acceleration.
As a final step, these empirical relationships were used to relate each landslide belonging to the
Italian national inventory (IFFI) to individual segments of known seismogenic sources located in the
Italian territory or in nearby countries within a maximum distance corresponding to the 95th
percentile distance calculated from the expected magnitude of the seismogenic source (Fig. 2). We
used the composite seismogenic sources of the DISS database version 3.3.0 (DISS Working Group,
2021) hypothesizing that they may trigger the EILs activation during future earthquakes and, using
a floating hypocenter approach, i.e. shifting the hypocenters along the seismogenic sources with 4
km fixed steps, built preliminary EILs scenarios for each potential hypocenter location.PublishedBolognaOST2 Deformazione e Hazard sismico e da maremot
Scattering Attenuation Images of the Control of Thrusts and Fluid Overpressure on the 2016–2017 Central Italy Seismic Sequence
No full textDeep fluid circulation likely triggered the large extensional events of the 2016–2017 Central Italy seismic sequence. Nevertheless, the connection between fault mechanisms, main crustal-scale thrusts, and the circulation and interaction of fluids with tectonic structures controlling the sequence is still debated. Here, we show that the 3D temporal and spatial mapping of peak delays, proxy of scattering attenuation, detects thrusts and sedimentary structures and their control on fluid overpressure and release. After the mainshocks, scattering attenuation drastically increases across the hanging wall of the Monti Sibillini and Acquasanta thrusts, revealing fracturing and fluid migration. Before the sequence, low-scattering volumes within Triassic formations highlight regions of fluid overpressure, which enhances rock compaction. Our results highlight the control of thrusts and paleogeography on the sequence and hint at the monitoring potential of the technique for the seismic hazard assessment of the Central Apennines and other tectonic regions.Pianeta Dinamico/2020–2022 supported by Ministero dell'Istruzione, Università e Ricerca (MIUR)Publishede2023GL103132OST3 Vicino alla fagliaJCR Journa
Analysis of Flow and Land Use on the Hydraulic Structure of Southeast Mexico City: Implications on Flood and Runoff
No full textThe southeast of Mexico City is one of the last areas of environmental importance for the
region. However, rapid urban expansion has led to a runoff increase in the presence of intense rainfall.
This situation is common to many peri-urban centers close to large cities, where the urbanization
of previously green areas has had a direct negative influence on the hydraulic structure. This work
proposes a study that combines hydrological analysis for the definition of precipitation scenarios
with hydrodynamic simulations based on the current land use. Reconstructed flood scenarios show
that the runoffs descending from mountainous areas flow into cemented channels with hydraulic
sections and characteristics not adequate to drain specific discharges that can reach 0.90 m2/s and
water depths of the order of 2 m, caused by extreme weather phenomena, determining flooding in
nearby areas. Runoffs are also intensified by the presence of non-urbanized open spaces in a state of
abandonment, whose soil does not favor infiltration and promotes the flooding of residential centers
with water levels higher than 1 m. The results indicate an urgent need to adopt actions to reduce
flooding and favor infiltration in an area of the city that is also important for aquifer recharge.Published1120OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Inferring the depth and magnitude of pre-instrumental earthquakes from intensity attenuation curves
No full textThe Italian historical earthquake record is among the richest worldwide; as such it allows for the development of advanced techniques for retrieving quantitative information by calibration with recent earthquakes. Building on a pilot elaboration of northern Italian earthquakes, we developed a procedure for determining the hypocentral depth of all Italian earthquakes from macroseismic intensity data alone. In a second step the procedure calculates their magnitude, taking into account the inferred depth.
Hypocentral depth exhibits substantial variability countrywide but has so far received little attention: pre-instrumental earthquakes were routinely “flattened” at the upper-crustal level (∼10 km), on the grounds that the calculation of hypocentral depth is heavily dependent on the largely unknown local propagation properties.
We gathered a learning set of 42 earthquakes documented by reliable instrumental data and by numerous macroseismic intensity observations. We observe (1) that within 50 km from the epicenter the ground motion attenuation rate is primarily controlled by hypocentral depth and largely independent of magnitude, (2) that within this distance the fluctuations in crustal attenuation properties are negligible countrywide, and (3) that knowing both the depth and the expected epicentral intensity makes it possible to estimate a reliable magnitude.INGV DPC, 2019–2021 agreement; All. A, WP 7Published1007–10284T. Sismicità dell'Italia5T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa
On the seafloor horizontal displacement from cGPS and compass data in the Campi Flegrei caldera
No full textSeafloor deformation monitoring is now routinely performed in the marine sector of the Campi Flegrei volcanic area (Southern
Italy). The MEDUSA infrastructure is formed by four buoys deployed at a water depth ranging from 40 to 96 m, and equipped
with cGPS receivers, accelerometers and magnetic compasses to monitor the buoy status and a seafloor module with a bottom
pressure recorder and other onboard instruments. The analysis of the time series data acquired by the MEDUSA monitoring
infrastructure system allows to study the seafloor deformation in the Campi Flegrei caldera with geodetic accuracy. In a
previous work, we show that the time series acquired by the Campi Flegrei cGPS onland network and MEDUSA over the
period 2017–2020 are in good agreement with the ground deformation field predicted by a Mogi model which is widely used
to describe the observed deformation of an active volcano in terms of magma intrusion. Only for one of the buoys, CFBA (A),
the data differ significantly from the model prediction, at a level of 6.9 σ and of 23.7 σ for the seafloor horizontal speed
and direction, respectively. For this reason, we devised a new method to reconstruct the horizontal sea bottom displacement
considering in the analysis both cGPS and compass data. The method, applied to the CFBA buoy measurements and validated
also on the CFBC (C) buoy, uses compass data to correct cGPS positions accounting for the pole inclination. Including also
systematic errors, the internal consistency, always within ∼ 3 σ for the speed and ∼ 2 σ for the angle, between the results
derived for different maximum inclinations of the buoy pole (up to 3.5◦) indicates that the method allows to significantly
reduce the impact of the pole inclination which, if not properly taken into account, can alter the estimation of the horizontal
seafloor deformation. In particular, we find a good convergence of the retrieved velocity and deformation angle as we include
in the analysis data from increasing values of the buoy pole inclination. Taking the result derived assuming the maximum
allowed cutoff and accounting for statistical and systematic errors, we found a speed v = (3.521 ± 0.039 (stat) ± 0.352 (syst))
cm/yr and a deformation direction angle α = (−115.159 ± 0.670 (stat) ± 7.630 (syst))◦ (statistical errors at 1 σ quoted from
the rms of their values, main systematic errors added linearly). The relative impact of the main potential systematic (statistical)
effects increases (decreases) with the cutoff. Our analysis provides a horizontal speed consistent with the model at a level of
5.2 σ (stat only) or of 0.5 σ (stat and syst added linearly), and a deformation angle consistent with the model at 4.3 σ
level (stat only) or at 0.3 σ level (stat and syst added linearly). Correspondingly, the module of the vectorial difference
between the velocity retrieved from the data and the velocity of the adopted Mogi model diminishes by a factor of 7.65 ±
1.23 (stat) or ± 5.78 (stat + syst) with respect to the previous work. A list of potential improvements to be implemented in
the system and instruments is also discussed.Published62OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
The 1901 Palombara Sabina earthquake
No full textIl terremoto del 24 aprile 1901, noto come “di Palombara Sabina”, è l’evento più importante (Mw 5.2, I0 8 MCS) localizzato nella Provincia di Roma secondo il catalogo CPTI15. Tuttavia, la base di dati macrosismici, a partire dai quali sono stati calcolati i parametri del catalogo, è piuttosto ridotta. Il presente lavoro ha migliorato la qualità delle conoscenze su questo terremoto attraverso una revisione critica di tutte le fonti citate dai precedenti studi e una ricerca di ulteriori documenti utili per ricostruirne l’effettivo impatto sul territorio.
I risultati dello studio hanno portato ad un drastico ridimensionamento delle intensità assegnate alle località colpite dal terremoto e conseguentemente della sua magnitudo macrosismica. Nel corso del lavoro sono inoltre state raccolte nuove informazioni sul modesto terremoto della Sabina del 1890 brevemente descritto in Appendice.Published1-34JCR Journa
Geochemical features and seismic imaging of the tectonic zone between the Tibetan Plateau and Ordos Block, central northern China
No full textThe Tibetan Plateau is growing by both vertical uplift and horizontal extension. It is a continuing debate how the
Tibetan Plateau interacts with its surrounding plates and blocks. Due to intense tectonic activity, which produced
catastrophic earthquakes, the tectonic zone between the northeast margin of the horizontal extending Tibetan
Plateau and the stable Ordos Block has garnered considerable interest. This study investigated the spatial distribution
of gas geochemical anomalies (e.g., high flux of CO2 in correspondence of the main faults) at regional
scale together with the seismic tomography in correspondence of this tectonic zone with the aim to figure out the
domain of convergent boundary between the Ordos block and Tibetan plateau, and trace the tectonic discontinuities
which are able to transfer fluids through the crustal layers between the two main geological units. From
northwest to southeast, obvious difference of spatial distributions of geochemical and geophysical features in the
tectonic zone between the northeast margin of the Tibetan Plateau and the Ordos Block is inferred. The northeast
area (Zone A) is dominated by thrust and strike-slip faults with clear velocity boundary underneath, where low
crack density (ε), saturation rate (ξ) and Poisson’ ratio (σ) in the middle-lower crust coincided with the low
values of heat flow and CO2 emissions, tectonic compression and regional locked-fault can be inducements. The
southeast area (Zone C) is dominated by extensional tectonics with roughly E-W fast-velocity direction (FVD) of
P-wave azimuthal anisotropy, where high permeability and porosity can be deduced from crustal high ε, ξ and
relatively high σ anomalies, resulting in high heat flow, CO2 concentrations and fluxes at the surface, and predominantly
crustal-derived gases. The intermediate area (Zone B) also dominated by thrust and strike-slip faults
is an extraordinary zone, where intensely locked-fault were clearly revealed, while the predominant anisotropic
FVDs in the middle crust changed obviously, more contribution of shallow gas component was detected, and CO2
flux, heat flow, and regional ε, ξ, and σ in the upper crust were higher, compared with those in Zone A, which
indicated the regional crushing fragmentation underneath Zone B. The adopted multidisciplinary approach
demonstrated that Zone B is the convergent boundary between the Tibetan Plateau and the Ordos Block.Published121386OST3 Vicino alla fagliaJCR Journa
Fault displacement hazard estimation at lifeline–fault crossings: A simplified approach for engineering applications
No full textLifelines, such as pipelines, roads, and tunnels, are critical infrastructure and when crossing active tectonic faults, a reliable estimation of the fault displacement in case of an earthquake is required. The first and simplest approach is to use empirical fault scaling relations to compute the design fault displacement, but this may result in an unknown level of safety. Thus, the probabilistic fault displacement hazard analysis (PFDHA) is the appropriate tool to assess the fault displacement hazard within a performance-based framework. Based upon an established PFDHA model, we present a simplified approach for engineering applications focusing on the lifeline–fault crossing along with appropriate simplifications and assumptions to extend its applicability to numerous faults. The aim is to provide a structure-independent approach of PFDHA that can be used when a site-specific study is not required, not possible (e.g., absence of recent sediments for dating past events), or too cumbersome, e.g., for lifeline route selection. Additionally, an in-depth investigation is presented on the key parameters, such as maximum earthquake magnitude, fault length, recurrence rate of all earthquakes above a minimum magnitude, and lifeline-fault crossing site, and how they affect the hazard level. This approach will be the basis for deriving hazard-consistent expressions to approximate fault displacement for use within the Eurocodes. The latter is intended to serve as a compromise between hazard-agnostic fault scaling relations and a comprehensive PFDHA, which requires detailed calculations and site-specific seismological data.Open access funding provided by HEAL-Link Greece. The current work has been undertaken as part of the Horizon 2020 Seismology and Earthquake Engineering Research Infrastructure Alliance in Europe (SERA, Grant Agreement No. 730900). The first and the third author have received partial funding from the European Union’s Horizon 2020 research and innovation programme “METIS-Seismic Risk Assessment for Nuclear Safety” under Grant Agreement No. 945121. Also, the financial support provided by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “2nd Call for H.F.R.I. Research Projects to support Faculty Members & Researchers”, Project "TwinCity—Climate-Aware Risk and Resilience Assessment of Urban Areas under Multiple Environmental Stressors via Multi-Tiered Digital City Twinning ", (Number: 2515) is gratefully acknowledged.Published4821–48492T. Deformazione crostale attiva5T. Sismologia, geofisica e geologia per l'ingegneria sismica6T. Studi di pericolosità sismica e da maremotoJCR Journa
Technical documentation of SEISMOFAULTS.EU: the IT infrastructure employed by the European Databases of Seismogenic Faults (EDSF) installation
No full textSEISMOFAULTS.EU is the IT infrastructure designed and implemented to publish datasets that are
part of the European Databases of Seismogenic Faults (EDSF) installation hosted by the Istituto
Nazionale di Geofisica e Vulcanologia.
It consists of carefully selected and configured hardware and software in order to ensure a
reliable, and secure service. The implemented backup solutions and continuous monitoring
of the entire platform at various levels safeguard the system from disruptions due to various
types of possible malfunctions.
The main functionalities of SEISMOFAULTS.EU include the publication of datasets of seismogenic
sources of the European and Mediterranean area through the standard web services developed by
the Open Geospatial Consortium. Websites related to the same datasets as well as web services
related to sibling projects, are also published through the infrastructure.
Following government recommendations for public administration, most of the software used
in the platform has an opensource license. The main software applications involved in web
services publishing are PostgreSQL/PostGIS and GeoServer.
SEISMOFAULTS.EU was designed under the auspices of EPOS, Thematic Core Service
Seismology, and actively contributed to it by integrating datasets on seismogenic faults in the
EuroMediterranean area into the EPOS Integrated Core Service Central hub platform.
The combination of efforts between EPOS and SEISMOFAULTS.EU strengthens the scientific
geoscience community in coordinating efforts aimed at advancing knowledge in the field of
seismology and the study of seismogenic sources and earthquake hazard analyses.Istituto Nazionale di Geofisica e VulcanologiaPublished4IT. Banche dat