Figure - available from: Bulletin of Earthquake Engineering
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Location of the main faults of Ischia island (arrows display dipping; hatches on the downthrown side; dashed lines = volcano – tectonic alignments). After Acocella and Funiciello (1999)
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On 21st August 2017, an earthquake (\(M_{L}\,3.6\); \(M_{W}\,3.9\); \(M_{d}\,4.0\)) struck the municipality of Casamicciola Terme on the island of Ischia, Italy. It was a peculiar earthquake: low magnitude, very superficial (focus depth of about 1.7 km), centered in a high population density area. Despite the island was historically struck by destr...
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Citations
... The E-ENE normal fault system that borders the N flank of Mt. Epomeo has accommodated a maximum vertical displacement of ca. 1 km [30][31][32][33]45,48,52,53]. In the foothill area of Casamicciola Terme, a structure, part of the E-ENE fault system, separates Mt. ...
Over the past two decades, the airborne Light Detection and Ranging (LiDAR) system has become a useful tool for acquiring high-resolution topographic data, especially in active tectonics studies. Analyzing Digital Terrain Models (DTMs) from LiDAR exposes morpho-structural elements, aiding in the understanding of fault zones, among other applications. Despite its effectiveness, challenges persist in regions with rapid deformation, dense vegetation, and human impact. We propose an adapted workflow transitioning from the conventional airborne LiDAR system to the usage of drone-based LiDAR technology for higher-resolution data acquisition. Additionally, drones offer a more cost-effective solution, both in an initial investment and ongoing operational expenses. Our goal is to demonstrate how drone-based LiDAR enhances the identification of active deformation features, particularly for earthquake-induced surface faulting. To evaluate the potential of our technique, we conducted a drone-based LiDAR survey in the Casamicciola Terme area, north of Ischia Island, Italy, known for the occurrence of destructive shallow earthquakes, including the 2017 Md = 4 event. We assessed the quality of our acquired DTM by comparing it with existing elevation datasets for the same area. We discuss the advantages and limitations of each DTM product in relation to our results, particularly when applied to fault mapping. By analyzing derivative DTM products, we identified the fault scarps within the Casamicciola Holocene Graben (CHG) and mapped its structural geometry in detail. The analysis of both linear and areal geomorphic features allowed us to identify the primary factors influencing the current morphological arrangement of the CHG area. Our detailed map depicts a nested graben formed by two main structures (the Maio and Sentinella faults) and minor internal faults (the Purgatorio and Nizzola faults). High-resolution DEMs acquired by drone-based LiDAR facilitated detailed studies of the geomorphology and fault activity. A similar approach can be applied in regions where the evidence of high slip-rate faults is difficult to identify due to vegetation cover and inaccessibility.
... In the case of earth structures, due to the low compressive strength and almost zero tensile strength, it is common to observe the presence of vertical cracks throughout the height of the walls [14]. The seismic performance of stone masonry is known to be generally poor with respect to other structural typologies [15,16]. However, significant differences can be observed for different designs, structural details and mechanical properties of masonry [17]. ...
This research investigates the post-earthquake performances of structures in four rural villages in the Moroccan Atlas, emphasizing common construction system characteristics and design flaws that render buildings susceptible to seismic events. Village selection was based on a prior multispectral satellite-image study, proving effective for planning high-impact, post-earthquake field campaigns. The significance of this research resides in on-site data collection, facilitating the physical assessment of earthquake-induced damage and identification of inherent vulnerabilities in construction systems. The constructions in the study area exhibited structural design deficiencies, inadequate construction techniques, and urban modifiers, leading to damage extensively documented in the literature, as well as less-documented unique damage. Predominant seismic-design shortcomings in the study area included subpar material quality, insufficient earthquake-resistant design, and unskilled labor. In situ data were complemented by a global geospatial approach using differential synthetic aperture radar interferometry with Copernicus Sentinel 1 data. Once calibrated the proposed methodology with field data, the analysis of remote sensing processing results, allow assessing the damages in other earthquake-affected areas, including those not visited in the field but also impacted by the seismic event.
... Li et al. (2021a) conducted structural damage investigation of the 2008 Wenchuan earthquake in China, summarized the damage characteristics of multiple typical structures, and preliminarily evaluated the economic loss of the seismic damage. Briseghella et al. (2019) conducted an investigation and analysis of the seismic damage of masonry composite structures in the 21 August, 2017 earthquake in Iskiya Island, Italy. Combined with the ground motion parameters, the risk analysis of these types of structures was conducted and the vulnerability curve based on the empirical seismic damage was derived. ...
To study the seismic vulnerability of the composite material structure of adobe and timber, we collected and statistically analysed empirical observation samples of 542,214,937 m2 and 467,177 buildings that were significantly impacted during the 179 earthquakes that occurred in mainland China from 1976 to 2010. In multi-intensity regions, combined with numerical analysis and a probability model, a non-linear continuous regression model of the vulnerability, considering the empirical seismic damage area (number of buildings) and the ratio of seismic damage, was established. Moreover, a probability matrix model of the empirical seismic damage mean value was provided. Considering the coupling effect of the annual and seismic fortification factors, an empirical seismic vulnerability curve model was constructed in the multiple-intensity regions. A probability matrix model of the mean vulnerability index (MVI) was proposed, and was validated through the above-mentioned reconnaissance sample data. A matrix model of the MVI of the regions (19 provinces in mainland China) based on the parameter (MVI) was established.
... Rehabilitating reinforced concrete (RC) columns in RC arch bridges is paramount due to the combined threats of rebar corrosion and seismic actions. These columns are criti-cal load-bearing components of bridge structures, and their integrity is vital for ensuring the overall stability and safety of the bridge system [2,15]. ...
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traditional approaches to rebar joint welding have paid little attention to the overstrength of the welding seam, which can result in a brittle response. Properly designing such joints should aim for a ductile rebar
failure. However, in-situ rehabilitation solutions often require reducing the seam length to save time and material costs and, not secondarily, avoiding the plastic hinge formation in the rehabilitated column. Therefore, providing the seam with adequate overstrength is crucial to achieving a ductile failure of the welded joint.
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a probabilistic approach, the study assesses the overstrength of indirect butt joints as a function of seam length for the two identified performance groups. Empirical failure probabilities of the rebar and the seam are estimated to fit probability density functions representative of the tensile strength of the rebar and the seam.
Based on a target reliability class, the overstrength factors are estimated.
... On August 21, 2017, a M W 3.9 earthquake struck the volcanic island of Ischia (Gulf of Naples, Italy), producing heavy damage and two casualties at Casamicciola (Briseghella et al. 2019), touristic locality famous for thermal baths known to be hit in the XIX century by a series of heavily damaging earthquakes (Cubellis and Luongo 2017;Cubellis et al. 2020), the most devastating of which produced 2300 victims in 1883 (AA. VV. 1998;Carlino et al. 2010). ...
... The reason for this implementation was quite evident during the earthquake which struck Ischia in 2017. While the shock indeed caused in the epicentral area heavy impacttwo casualties, many collapses and a number of homeless in Casamicciola and surroundings (Briseghella et al. 2019)-the automatic ShakeMap system (http:// shake map. ingv. ...
In this paper, we tackle the problem of the intensity attenuation at Ischia, a critical parameter in a high seismic risk area such as this volcanic island. Starting from the new revised catalogue of local earthquakes, we select a dataset of 118 macroseismic observations related to the four main historical events and analyse the characteristics of the intensity attenuation according to both the deterministic and probabilistic approaches, under the assumption of a point seismic source and isotropic decay (circular spreading). In the deterministic analysis, we derive the attenuation law through an empirical model fitting the average values of ΔI (the difference between epicentral intensity I0 and intensities observed at a site IS) versus the epicentral distances by the least-square method. In the probabilistic approach, the distribution of IS conditioned on the epicentre-site distance is given through a binomial-beta model for each class of I0. In the Bayesian framework, the model parameter p is considered as a random variable to which we assign a Beta probability distribution on the basis of our prior belief derived from investigations on the attenuation in Italy. The mode of the binomial distribution is taken as the intensity expected at that site (Iexp). The entire calculation procedure has been implemented in a python plugin for QGIS® software that, given location and I0 (or magnitude) of the earthquake to be simulated, generates a probabilistic seismic scenario according to the deterministic or probabilistic models of attenuation. This tool may be applied in seismic risk analyses at a local scale or in the seismic surveillance to produce real-time intensity shake-maps for this volcanic area.
... The strategic importance of bridges demands the development of time and cost-saving methods for seismic rehabilitation, as the failure of these critical structures can paralyse an entire region [12,13]. Various methods have been employed for rehabilitating damaged RC bridge columns [1,[14][15][16][17][18][19][20][21][22][23][24][25][26][27]. ...
Rehabilitating corroded or seismically damaged reinforced concrete (RC) bridge columns often involves replacing the longitudinal steel rebar. Welded joints offer a practical and efficient in-situ solution for connecting new rebar segments to existing undamaged rebar, even with irregularities in the steel reinforcement. However, traditional approaches to rebar joint welding have paid little attention to the overstrength of the welding seam, which can result in a brittle response. Properly designing such joints should aim for a ductile rebar failure. However, in-situ rehabilitation solutions often require reducing the seam length to save time and material costs and, not secondarily, avoiding the plastic hinge formation in the rehabilitated column. Therefore, providing the seam with adequate overstrength is crucial to achieving a ductile failure of the welded joint. This study presents an experimental investigation into the most effective methods for connecting existing and new rebar segments through welding, addressing on-site welding challenges such as limited operational space and weld orientation. Over 100 tensile tests have been conducted at Fuzhou University's laboratory in China to understand the response of nine welded joints. Among indirect butt joints, the study identifies two performance groups based on the ductile failure rate as the welding seams reduce. The symmetry of the joint and the presence of additional direct butt welding also in asymmetric joints can significantly improve the joint performance, determining a ductile failure with minimal welding lengths. In a second step, following a probabilistic approach, the study assesses the overstrength of indirect butt joints as a function of seam length for the two identified performance groups. Empirical failure probabilities of the rebar and the seam are estimated to fit probability density functions representative of the tensile strength of the rebar and the seam. Based on a target reliability class, the overstrength factors are estimated.
... The 2017 Ischia Island earthquake (an earthquake (ML3.6; MW3.9; Md4.0) hit 3 municipalities (Casamicciola Terme, Lacco Ameno and Forio) [Briseghella et al. (2019)]. The damage and usability assessment of the ordinary buildings started few days after the earthquake to assess whether they could be safely used in the case of aftershocks. ...
... These houses were identified as ''the retrofit success stories'' of the 2014 event. Other field investigation studies have similarly reported on the benefits of seismic retrofit based on individual (or a handful of) observations of undamaged retrofitted buildings (Briseghella et al., 2019;Dizhur et al., 2011). ...
Collecting and analyzing observational data are essential to learning and implementing lessons in earthquake engineering. Historically, the methods that have been used to analyze and draw conclusions from empirical data have been limited to traditional statistics. The models developed using these techniques are able to capture associative relationships between important variables. However, the intervention decisions geared toward seismic risk mitigation should ideally be informed by an understanding of the causal mechanisms that drive infrastructure performance and community response. This article advocates for a paradigm shift in earthquake engineering where the language, tools, and models that have been (and continue to be) developed to draw causal conclusions from observational data are adopted. Several categories of data-driven earthquake engineering problems that can benefit from causal insights are examined. Two widely adopted frameworks from the broader causal inference literature are presented and linked to hypothetical earthquake engineering problems. The critical role of semi-parametric models and sensitivity analysis in justifying causal claims is also discussed. The article concludes with a discussion of specific opportunities and challenges toward the widespread use of causal inference as a tool for knowledge discovery in earthquake engineering. The ability to leverage the underlying physics of a problem within a causal inference framework is identified as both an opportunity and challenge for earthquake engineering researchers.
... However, a moderate earthquake (Mw 3.9) on the island of Ischia, Italy, on 21 August 2017 ( Figure 4) caused two casualties and extensive building damage. This impact was associated with poor construction materials (Briseghella et al., 2019). This knowledge about earthquake destructiveness is as high as expected among geologists and seismologists, and (surprisingly) moderate among civil engineers (Figure 6b). ...
Understanding the seismic risk perceptions of emergency managers and first responders is fundamental to entrusting pre-disaster policy-making and emergency communication practices. Therefore, an online survey in Greece was conducted to assess the impact of knowledge, worry, experience, and other variables on seismic risk perceptions and to reveal emergency managers’ and first responders’ opinions on the overall emergency mechanism. The results reveal that, while seismic risk perception is high, important knowledge gaps are detected among members of the emergency and crisis management mechanisms. Poor coordination issues, ambiguity in responsibilities, the content of emergency seismic information (beyond uncertainty), and the need to improve prompt warning methods and modernised communication practices are indicated.
... The event caused widespread collapses and extensive damages to the building heritage. In the days following the earthquake, inspections on churches and monumental buildings were carried out in order to identify damages and assess usability (Briseghella et al. 2019;Del Gaudio et al. 2018;Salzano et al. 2019). Many damages and structural collapses were also recorded in Forio and Lacco Ameno, which are other municipalities close to the epicentral area. ...
An atypical ‘baraccato’ system made of masonry walls encaged in iron frames was realized in the Ischia Island after the earthquake of 1883; an interesting example is represented by the Santa Maria Maddalena Church. Unfortunately, while several experimental and numerical studies can be found in the recent literature for traditional ‘baraccato’ systems (mixed timber and masonry elements), no information is available for iron-framed masonry structures. To fill this gap, the paper presents several parametric non-linear static analyses with reference to, firstly, simple iron-framed masonry panels and, successively, the façade of the Santa Maria Maddalena Church. All the numerical analyses were carried out by means of two modelling approaches with different levels of detail, i.e. finite element (FE) and discrete macro-element (DME) models. The numerical analyses allowed to: assess the reliability of the two models (FE and DME) into predicting similar results for the panels and the church façade with reference to both the unstrengthened and the iron-framed strengthened configurations; analyse the influence of the investigated parameters; evaluate the contribution of the iron frames on the overall behaviour of the strengthened masonry elements; and drive the choice of the most suitable modelling strategy for the whole church.
