CRITICAL ANALYSIS OF TIPOLOGIES, DAMAGE AND COLLAPSE MECHANISM AFTER THE CASAMICCIOLA EARTHQUAKE
(Giulio Zuccaro, Francesco Cacace, Stefano Nardone, Mauro Iacuaniello)
Mission of the Plinivs Study Centre – 23.08.2017
The full study report is available at the link: report_en
On Monday 21 August 2017 at 20:57:05 italian time, a Magnitude 4.0 earthquake occurred on the island of Ischia, with an hypocentral depth of about 1.7 km.
As reported by INGV, the epicenter was located in the Municipality of Casamicciola (40.74° lat. N ,13.90° long E).
Due to a very shallow depth and to a strong local amplification effect, the earthquake registered high values of ground acceleration close to the epicenter (0.28 g at the Station OV-OC9, 0.8 km from the epicenter) and a rapid attenuation, so the damages caused were not particularly significant in sites very close to the epicenter, in the Municipality of Casamicciola.
The figure shows the position of the epicenter and the macroseismic intensity, as indicated in the operative report by QUEST – ENEA.
As the map shows, produced by Plinivs Study Centre after the mission of 23.08.2017, the earthquake caused severe damages in a very limited area.The earthquake was felt, with different intensity, on the entire Island, but caused important damages in the upper part of Casamicciola, near Piazza Maio – La Rita Square, and in the district of Fango in the Municipality of Lacco Ameno.
At the edges of these localities, (e.g. in locality Sentinella , Piazza Bagni and the area surrounding the Town hall) are detected many buildings with damage of slight and moderate entity.
As far as possible to observe, moving away from the epicenter zone (e.g. in Lacco Ameno City Centre and in Perrone – Casamicciola), no buildings with significant cracks or activation of damage mechanism were observed.
In the Municipality of Ischia there are no damages and, for example, in the locality of Ischia Ponte the earthquake caused only fear (some citizens did not even felt the earthquake).
Due to the circumstances, at the moment no studies or cataloguing about damages and accessibility of buildings are available, so it is not possible to evaluate the entity of the damages, anyway after the mission, a study on the seismic impact on buildings has been developed.
The map, produced by Plinivs Study Centre, shows a first evaluation of the observed damages (according to the classification E.M.S. 98) on a widest range of buildings surrounding Piazza Mario, Via Montecito and Via D’Aloisio.
Taking into account the emergency, it was not possible to enter the affected buildings.
Further information and developments are in progress.
