On August 21, 2017 at 20:57 (local time) an earthquake with Md = 4.0 (Lat. 40.74°, Long 13.90°, depth of about 2 km) hit the Ischia island heavily damaging the Casamicciola village and causing two fatalities (Azzaro et al., 2017). The Island (southern Italy) is located at the northwestern side of the Gulf of Naples inside of the Campanian volcanic province, also including the Campi Flegrei volcanic field. The island of Ischia, is the emerged portion of a volcanic complex, active since at least 150 ka. (Vezzoli, 1988). The most impacting GNGTS 2017 Sess ione 1.1 57 event in island geological history is the caldera forming eruption of the Green Tuff of the Mt. Epomeo occurred 55 ka, that caused the collapse of Island central sector, followed by the resurgence of the Mt. Epomeo block starting from 30 ka (Orsi et al., 1991). After this eruption, volcanic activity continued in three main periods. The last one from 10 ka, with eruptions mainly located in the eastern part of the island, closed with the last effusive Arso eruption in 1302 (Vezzoli, 1988; Orsi et al., 1991; de Vita et al., 2006; de Vita et al., 2010). The Island is characterized by slope instability, mainly linked to the Mt. Epomeo resurgence (Del Prete and Mele, 1999; Esposito et al., 2006; Della Seta et al., 2012) and historical and recent seismic activity (Alessio et al., 1996; Rovida et al., 2015). The main faults system bording the resurgent Mt. Epomeo consists of NW-SE to N-S striking faults in the western sector and of NE-SW to E-W faults in its northern sector (Fig.1). In the eastern sector of the island, N-S and NE-SW striking fractures and faults control the location of the vents (Carta Geologica dell'Isola d'Ischia della Regione Campania in scala 1:10.000, Foglio 464, 2011). The slope instability is mainly concentrated in the northern and western sectors of the Island and in the southern flank of Mt. Epomeo (Del Prete and Mele, 1999)
T he August 21, 2017 Casamicci ola (Ischia Island) earthquake: seismo-geologic al effects due to a small-size volcano-tectonic event
S Porfido
2017
Abstract
On August 21, 2017 at 20:57 (local time) an earthquake with Md = 4.0 (Lat. 40.74°, Long 13.90°, depth of about 2 km) hit the Ischia island heavily damaging the Casamicciola village and causing two fatalities (Azzaro et al., 2017). The Island (southern Italy) is located at the northwestern side of the Gulf of Naples inside of the Campanian volcanic province, also including the Campi Flegrei volcanic field. The island of Ischia, is the emerged portion of a volcanic complex, active since at least 150 ka. (Vezzoli, 1988). The most impacting GNGTS 2017 Sess ione 1.1 57 event in island geological history is the caldera forming eruption of the Green Tuff of the Mt. Epomeo occurred 55 ka, that caused the collapse of Island central sector, followed by the resurgence of the Mt. Epomeo block starting from 30 ka (Orsi et al., 1991). After this eruption, volcanic activity continued in three main periods. The last one from 10 ka, with eruptions mainly located in the eastern part of the island, closed with the last effusive Arso eruption in 1302 (Vezzoli, 1988; Orsi et al., 1991; de Vita et al., 2006; de Vita et al., 2010). The Island is characterized by slope instability, mainly linked to the Mt. Epomeo resurgence (Del Prete and Mele, 1999; Esposito et al., 2006; Della Seta et al., 2012) and historical and recent seismic activity (Alessio et al., 1996; Rovida et al., 2015). The main faults system bording the resurgent Mt. Epomeo consists of NW-SE to N-S striking faults in the western sector and of NE-SW to E-W faults in its northern sector (Fig.1). In the eastern sector of the island, N-S and NE-SW striking fractures and faults control the location of the vents (Carta Geologica dell'Isola d'Ischia della Regione Campania in scala 1:10.000, Foglio 464, 2011). The slope instability is mainly concentrated in the northern and western sectors of the Island and in the southern flank of Mt. Epomeo (Del Prete and Mele, 1999)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
