Landslides Induced by Historical and Recent Earthquakes in Central-Southern Apennines (Italy): A Tool for Intensity Assessment and Seismic Hazard

Analysis of distribution of landslides (rock falls and coherent slides), induced by 12 moderate to strong earthquakes occurred in the last three centuries in Central\u2013Southern Apennines, has permitted to investigate the relationship of their maximum distance versus magnitude and ESI epicentral intensity. For coherent slides, the correlation of magnitude or ESI intensity versus distance is fairly good and consistent with global datasets. Instead, rock falls show a less evident correlation with distance. We stress here the usefulness of such relationships to define the expected scenario of earthquake-induced landslides. However, the data base needs to be improved and enlarged to allow more robust estimates

EARTHQUAKE ENVIRONMENTAL EFFECTS, INTENSITY AND SEISMIC HAZARD ASSESSMENT: THE EEE CATALOGUE (INQUA PROJECT #0418)

Earthquake Environmental Effects (EEE) are the effects produced by an earthquake on the natural environment, either directly linked to the earthquake source or triggered by the ground shaking. These include surface faulting, regional uplift and subsidence, tsunamis, liquefaction, ground resonance, landslides, and ground failure phenomena. The EEE catalogue is a data collection of Earthquake Environmental Effects from modern, historical and paleoseismic earthquakes compiled at global level by the INQUA TERPRO Project #0811 WG. The damages caused by recent catastrophic seismic events have been mostly linked to the vulnerability of physical environment enhancing the crucial role of EEEs, including tsunamis, for seismic hazard purposes. Therefore, these events have confirmed that the EEE Catalogue is an essential tool to complete traditional SHA based on PGA maps, since it allows to identify the natural areas most vulnerable to earthquake occurrence and to objectively compare in time and in space the earthquake intensity through the ESI scale

Evidence for surface faulting earthquakes on the Montereale fault system (Abruzzi Apennines, central Italy)

We conducted paleoseismic studies along the Montereale fault system (MFS; central Italy). The MFS shows geomorphological evidence of Late Quaternary activity and falls within the highest seismic hazard zone of central Apennines, between the epicentral areas of two recent earthquake sequences: 2009 L’Aquila and 2016–2017 central Italy. We excavated two trenches along the San Giovanni fault splay of the system, one intercepting the N140° striking bedrock main fault plane and the other cutting two subparallel fault scarps on the colluvial/alluvial deposits on the fault hanging wall. Excavations revealed repeated fault reactivation with surface faulting in prehistorical and historical times. We recognized and dated seven events in the last 26 kyr. The most recent ground-rupturing event (evb1) possibly occurred 650–1,820 AD, consistent with one of the three main shocks that struck the area in 1,703 AD. A previous event (evb2) occurred between 5,330 BC and 730 BC, while older events occurred at 6,590–5,440 BC (evb3), 9,770–6,630 BC (evb4), and 16,860–13,480 BC (evb5). We documented two older displacement events (evb7 and evb6) between 23,780 BC and 16,850 BC. The minimum vertical slip rate at the trench site in the last 28–24 kyr is 0.3–0.4 mm/year. The inferred average recurrence interval for surface-faulting events along the MFS is no longer than ~4 kyr. Based on the surface fault length ranging between 12 and 20 km, earthquakes with ≥M 6.0 are possible for the MFS. The MFS is an independent earthquake source, and its paleoseismic data are fully comparable with those known for faults in central Apennines.Published2758-27766T. Studi di pericolosità sismica e da maremotoJCR Journa

INGV - ISPRA joint Surface Faulting Database - Mw 6.1, 2009, April 6th L'Aquila earthquake (Central Italy)

Coseismic surface faulting associated to the 6 April 2009, Mw 6.1 L'Aquila earthquake from the joint analysis of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and of the Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA) field observations. The primary surface faulting reaches a total length of ca. 6 km and shows a ca. 3 km-long zone of continuous and consistently oriented surface ruptures in proximity of the village of Paganica, along a prominent NW-SE oriented, SW dipping normal fault. The deformation occurred in a ca. 500 m-wide zone. Secondary surface ruptures (antithetic and sympathetic) occurred along nearby faults. INGV - ISPRA joint database - 2009 L'Aquila earthquake surface rupture - Observation points: this file contains the tectonic ruptures observation points containing information about the typology, the geometrical characteristics, and a brief description of the observed feature. Credits: Blumetti et al., Report ISPRA 2009; Emergeo W.G., Terranova 2010 doi:10.1111/j.1365-3121.2009.00915.x; Cinti et al., JGR 2011 doi:10.1029/2010JB007988; Vittori et al., BSSA 2011 doi:10.1785/0120100140. INGV - ISPRA joint database - 2009 L'Aquila earthquake surface rupture - Surface faulting trace: this file displays as a line coverage the primary surface faulting associated to the 6 April 2009, Mw 6.1 L'Aquila earthquake. It is composed of multiple discrete rupture traces (mainly SW-facing free-faces and open cracks) with individual length ranging from 3 m to ca. 200 m. The traces are built based on the observation point layer, and contain information about the typology, the geometrical characteristics and the affected lithology (for this latter field attribute see Pucci et al., JoM 2015 doi:10.1080/17445647.2014.927128). INGV - ISPRA joint database - 2009 L'Aquila earthquake surface rupture - Secondary surface rupture trace: this file displays as a line coverage some of the secondary ruptures (antithetic and sympathetic) occurred along faults within the epicentral area

Geological survey, morphotectonic analysis and gravity prospecting applied to the assesment of seismic hazard of the city of L’Aquila (Abruzzo, Central Italy).

volume speciale Studi Geologici Camert

The M6.9, 1980 Irpinia earthquake (southern Italy): joint surface ruptures dataset

This dataset gathers all the published existing information on the coseismic surface ruptures produced by the Mw 6.9 earthquake that struck the Irpinia region (southern Italy) on the 23rd November 1980. The dataset is the sum of the observations made by several authors over the years (e.g., Carmignani et al., 1981, Westaway and Jackson, 1984, Pantosti and Valensise, 1990, Blumetti et al., 2002). The data were collected during field surveys carried out from right after the event till 2021 and were integrated by aerial photo interpretation. The most recent surveys by the authors of this database were focused on the evaluation, repositioning through GNSS handheld devices, and validation in the field of the observation points to overcome unprecise manual positioning of pre-GNSS times. The observations are organized in a database of 175 homogenous georeferenced points and 49 georeferenced lines (coseismic ruptures). The points data are available in .xlsx meanwhile the lines are available in .shp format. Each point is described by the following parameters, when available: Observation type, Latitude, Longitude, Elevation, Throw, Strike, Dip, References, Ranking, Comment, and Bibliography. The ranking assigned to each coseismic feature is based, with integrations, on Baize et al. 2021. Each feature is attributed to two ranking values, one referring to the compilers of this database and the other to the original author's interpretation. The scores are 1 to 4: 1) principal faulting; 2) simple distributed faulting; 3) sympathetic faulting; 4) ground shaking or shaking/gravity-induced slip (category assigned in this work). The lines are described by Type of observation, Uncertainty, Strike, Downthrow Side, Ranking, Comment, and Bibliography. The ranking values are the same as above. The downthrow side value for each line is the mode of the observation points located on the line itself. As a consequence of the different ages and origins of the data, including the variable scaling of the surveys, we have built the dataset at different scales; we suggest looking at the project at the scale spanning from 1:5.000 to 1:10.000

Surface faulting hazard in italy: Towards a first assessment based on the ithaca database

The Italian territory is characterized by a great number of capable faults (i.e., faults able to produce significant ruptures/deformations at or near the surface). However, the potential of tectonic surface rupture/deformation (Surface Faulting Hazard, SFH) is not properly considered in national seismic hazard maps and legislation. In this paper it is proposed an assessment of SFH in Italy based on the ITHACA database, where the shape and width along capable faults as well as maximum expected surface displacements are defined in function of the seismotectonic behaviour and the severity of maximum expected earthquake. The proposed assessment indicates where SFH is expected to be relevant. In this sense, it is an helpful tool for site selection of critical facilities but also for ordinary land planning. Of course, the evaluation of SFH at local scale in the setback areas requires a more detailed characterization through ad hoc seismotectonic and paleoseismic investigations

Fault rupture and aseismic creep accompanying the December 26, 2018, Mw 4.9 Fleri earthquake (Mt. Etna, Italy): Factors affecting the surface faulting in a volcano-tectonic environment

On December 26, 2018 (2:19 UTC), during a volcanic eruption on the Mt. Etna eastern flank (Sicily, southern Italy), the largest instrumental earthquake ever recorded in the volcano ruptured the Fiandaca Fault, with epicenter between Fleri and Pennisi villages (hypocenter at ca. 300 m a. s. l., Mw 4.9). This was the mainshock of an earthquake swarm and it was accompanied by widespread surface faulting and extensive damage along a narrow belt near the fault trace. Few hours after the mainshock, an episodic aseismic creep event occurred along the Aci Platani Fault, a SE extension of the Fiandaca Fault, which caused several damages in the Aci Platani village. We surveyed and mapped the coseismic and aseismic ground ruptures, and collected structural data on their geometry, displacement, and fault zone fabric. We compared the mapped surface ruptures with topography, lithology, and morphology of the buried top of the sedimentary basement. We conclude that the geometry of the volcanic pile influenced the surface expression of faulting during the December 26, 2018 event. The top surface of the marly clay basement should be considered as a detachment surface for shallow sliding blocks. The earthquake occurred on top of a depression of the sedimentary basement forcing the sliding eastward, causing at surface the re-arrangement of the fault strand pattern and deformation style, switching from shear faulting to a tensile failure. The Fleri earthquake therefore provides an unprecedented dataset for 1) understanding active faulting in the European largest onshore volcano, 2) modeling its complex dynamics, and 3) contributing to a more refined surface faulting hazard assessment at Mt. Etna. Results from this investigation might be useful for characterizing capable faulting in similar volcano-tectonic settings worldwide

The Contribution of Palaeoseismology to Seismic Hazard Assessment in Site Evaluation for Nuclear Installations

In the framework of site evaluation/re-evaluation procedures for nuclear power plants and other nuclear installations, this publication aims at encouraging and supporting Member States, especially from newcomer countries, to include paleoseismic investigations into the geologic database. In fact, paleoseismology is not just a crucial discipline for Fault Displacement Hazard Assessment (FDHA) but also an indispensable tool for Seismic Hazard Assessment (SHA), as recommended in the reference IAEA Safety Guide (IAEA SSG-9 [1]). Within this scope, this document provides an updated review of the state of the art of paleoseismology, integrated with practical recommendations addressed to Member States, aiming to emphasize the value of earthquake geology studies for nuclear safety. Paleoseismic investigations in the context of site evaluation of nuclear installations, as described in the IAEA SSG-9 [1], have the following main objectives: \u2022Identification of seismogenic structures based on the recognition of effects of past earthquakes in the region; \u2022Improvement of the completeness of earthquake catalogs, through the identification and dating of ancient moderate to large earthquakes, whose trace has been preserved in the geologic record; \u2022Estimation of the maximum seismic potential associated with an identified seismogenic structure/source, typically on the basis of the amount of displacement per event (evaluable in paleoseismic trenches), as well as of the geomorphic and stratigraphic features interpretable as the cumulative effect of repeated large seismic events (concept of \u2018seismic landscape\u2019); \u2022Rough calibration of probabilistic seismic hazard assessment (PSHA), by using the recurrence interval of large earthquakes detectable by paleoseismic investigations, and providing a \u2018reality check\u2019 based on direct observations of earthquake environmental effects

Traces of the active Capitignano and San Giovanni faults (Abruzzi Apennines, Italy)

<p>We present a 1:20,000 scale map of the traces of the active Capitignano and San Giovanni faults in the area of the Montereale basin (central Apennines, Italy) covering an area of about 80 km². Detailed fault mapping is based on high-resolution topography from airborne LiDAR imagery validated by extensive ground truthing and geophysical prospecting. Our analysis allowed the recognition of several features related to fault activity, even in scarcely accessible areas characterized by dense vegetation cover and rugged terrain. The identified fault traces run at the base of the NW-SE striking Montereale basin-bounding mountain front and along the base of the southwestern slope of the Monte Mozzano ridge, and have a length of about 12 and 8 km, respectively. Improving the knowledge of fault geometry is a critical issue not only for the recognition of seismogenic sources but also for surface fault hazard assessment and for local urban planning. The knowledge of the exact location of the fault traces is also crucial for the seismogenic characterization of the active faults by means of paleoseismological trenching.</p