Preliminary data and field observations of the 21st August 2017 Ischia earthquake

Briseghella, Bruno; Demartino, Cristoforo; Fiore, Alessandra; Nuti, Camillo; Sulpizio, Concetta; Vanzi, Ivo; Lavorato, Davide; Fiorentino, Gabriele

doi:10.1007/s10518-018-0490-x

Cited by 25 publications

(14 citation statements)

References 38 publications

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“…As for the whole of Italy (Crescimbene et al 2015), seismic risk has not been adequately perceived by the inhabitants of the island, until 21 August 2017 when a M d = 4.0 (M W = 3.9) earthquake stroke the island. The occurrence of this recent earthquake, after 134 years of almost complete seismic silence, has brought out again the problem of the relatively high seismic risk for the island (Briseghella et al 2019;De Natale et al 2019;Marotta et al 2019). Based on the current national seismic hazard map provided by the Istituto Nazionale di Geofisica e Vulcanologia (http:// esse1.…”

Section: Introductionmentioning

confidence: 99%

A common source for the destructive earthquakes in the volcanic island of Ischia (Southern Italy): insights from historical and recent seismicity

et al. 2021

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The island of Ischia, located in the Gulf of Naples, represents an unusual case of resurgent caldera where small-to-moderate magnitude volcano-tectonic earthquakes generate large damage and catastrophic effects, as in the case of 4 March 1881 (Imax-VIII-IXMCS) and 28 July 1883 (Imax X-XI MCS) historical earthquakes, and of the recent 21 August 2017 MW = 3.9, event. All these earthquakes struck the northern area of the island. With about 65,000 inhabitants, Ischia is a popular touristic destination for thermals baths, hosting more than 3,000,000 visitors per year, thus representing a high seismic risk area. Assessing its seismic potential appears a fundamental goal and, to this end, the estimate of the magnitude of significant historical events and the characterization of their source are crucial. We report here a reassessment of historical data of damage of 1881 and 1883 earthquakes to evaluate the main source parameters of these events (obtained with the BOXER and EXISM software) and quantitatively compare, for the first time, the results with the source characteristics, obtained from instrumental data, of the recent 2017 earthquake. The results allowed us to assess the location, as well as the possible dimension and the related maximum magnitude, of the seismogenic structure responsible for such damaging earthquakes. Our results also provide an additional framework to define the mechanisms leading to earthquakes associated with the dynamics of calderas.

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Section: Introductionmentioning

confidence: 99%

A common source for the destructive earthquakes in the volcanic island of Ischia (Southern Italy): insights from historical and recent seismicity

et al. 2021

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“…Epomeo, at the epicenter. The intensity assignments with traditional scales show that the less severe effects on anthropic structures are visible in particular far from the epicentral area, and limited to the rest of the island [5][6][7][8] (Figure 6). Figure 6.…”

Section: Discussionmentioning

confidence: 99%

“…In this area there were few total collapses, some partial collapses, cross injuries, loss of verticality, overturning of walls and ejection of edges; reinforced concrete buildings showed rare cases of minor damage (I = VIII EMS). Widespread damage was also observed in the Fango and Lacco Ameno locality (I = VII EMS), while sporadic and very slight damages (I = V EMS) were reported in the remaining municipalities [5][6][7][8]. [4]; black lines, active normal faults from [9][10][11][12][13][14]; grey lines, other faults of the Ischia Volcano [11][12][13]; cyano squares, historical seismicity from [14] (macroseismic scale MCS, Mercalli-Cancani-Sieberg; [15]); yellow star shows the mainshock, Md 4.0, with its focal mechanism for the 2017 seismic event from [2]; inset map, the study region in a larger location map of Italy.…”

Section: Introductionmentioning

confidence: 99%

The 2017, MD = 4.0, Casamicciola Earthquake: ESI-07 Scale Evaluation and Implications for the Source Model

et al. 2021

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On 21 August 2017 at 20:57 (local time) a very shallow (H = 1.2 km), moderate (Md = 4.0), earthquake hit the volcanic island of Ischia (Southern Italy), causing the death of two people. The study of the damage to the buildings with the European Macroseismic Scale 98 (EMS-98), carried out immediately after the earthquake, highlighted that hilly area of Casamicciola Terme, on the northern side of the Mt. Epomeo, was the most damaged part of the island with locally quite relevant damage (I = VIII EMS). This seismic event is the first damaging earthquake in Ischia during the instrumental era. In fact, this provides, for the first time, the opportunity to integrate historical seismicity, macroseismic observations, instrumental information, and detailed mapping of the geological coseismic effects. In this work we evaluate the effects induced by the 2017 Casamicciola earthquake on the environment using the Environmental Seismic Intensity 2007 (ESI-07) macroseismic scale. This macroseismic analysis, together with the superficial coseismic faulting characteristics and the available geophysical information, allows us to reconsider the source model for the 2017 earthquake and the previous damaging historical earthquakes in the Casamicciola Terme area. The application of the ESI scale to the Casamicciola Terme earthquake of 21 August 2017 and the assignment of seismic intensity offers better spatial resolution, as well as an increase of the time window for the assessment of the seismic hazard, allowing to reduce the implicit uncertainty in the intensity attenuation laws in this peculiar volcano-tectonic setting. Since intensity is linked to the direct measure of damage, and it is commonly used in hazard assessment, we argue that building damage at Casamicciola Terme is strongly influenced by earthquake surface faulting and near field effects, and therefore controlled by the geometry of the seismic source.

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“…On 21 th August 2017, Ischia Island was again hit by an earthquake that caused, in addition to victims, widespread collapses and extensive damages to the building heritage [8] [9]. The earthquake registered a magnitude of 4.2 on Richter scale.…”

Section: Damage State Of the Church After The 2017 Ischia Earthquakementioning

confidence: 99%

Structural Assessment of Santa Maria Maddalena Church in Ischia Island (Italy) by Experimental Modal Analysis Under Operational Conditions

Casapulla¹,

Ceroni²,

Rainieri³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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During the seismic event of 21 st August 2017 in Ischia, many masonry churches were damaged. Within the inspected damaged churches, a very interesting case study is represented by Santa Maria Maddalena church, located on the hill of Casamicciola Terme, near to the epicentre. The church of Santa Maria Maddalena can be considered a 'unicum', since it was built in 1896, after the catastrophic earthquake of 1883, with a 'mixed' structure made mainly of yellow tuff blocks walls strengthened by iron profiles or wooden elements. Several examples of structures made of masonry walls with wooden elements embedded in the wall thickness, i.e. the so called 'baraccato system' are present in the island, while the use of iron profiles is rare. The paper is firstly aimed to present the results of detailed historical investigation, geometrical survey, damage status analysis and provisional safety assessment after the earthquake of 21 st August 2017. These activities were carried out in collaboration with the Campania Regional Directorate for Cultural Heritage (MiBACT). Within such a collaboration, an in situ dynamic test was also performed under operational conditions. The setup and the results of this test are here presented in order to point out the main features of the structural system in terms of relevant modal parameters, both at global and local level.

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Preliminary data and field observations of the 21st August 2017 Ischia earthquake

Cited by 25 publications

References 38 publications

A common source for the destructive earthquakes in the volcanic island of Ischia (Southern Italy): insights from historical and recent seismicity

A common source for the destructive earthquakes in the volcanic island of Ischia (Southern Italy): insights from historical and recent seismicity

The 2017, MD = 4.0, Casamicciola Earthquake: ESI-07 Scale Evaluation and Implications for the Source Model

Structural Assessment of Santa Maria Maddalena Church in Ischia Island (Italy) by Experimental Modal Analysis Under Operational Conditions

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