Introduction: a volcanic island is a seismic island

Together with Campi Flegrei and Vesuvius, the island of Ischia is one of the three active volcanoes in the province of Naples, whose last eruption dates to 1302. From a geological point of view, the duration of its cycles of alternation between quiescence and active phase is typically 10,000 years (Civetta et al, 2016). This involves long phases of apparent absence of activity, sporadically interrupted by low-magnitude earthquakes located at a shallow depth in the north of the island and accompanied by widespread manifestations of fumaroles and thermal waters. It should also be noted that, as it is still active, the volcano of Ischia is potentially capable of erupting in the future, with particularly worrying effects due to the intense urbanization that affected its territory during the twentieth century.

The event that changed the contemporary history of Ischia is undoubtedly the catastrophic earthquake of 28 July 1883, which caused over 2,300 deaths and the cancellation of various urban areas of the island. It had a great reverberation in the national and foreign press and a notable emotional impact, which gave rise to a saying, soon spread throughout the country ‘A Casamicciola has happened’, as an expression of ruin, disorder and confusion. It was the first serious catastrophe that the newborn Italian nation had to face, since the national government quickly promulgated the country's first anti-seismic legislation: the ‘Building Regulations for the Municipalities of the Island of Ischia damaged by the earthquake of 28 July 1883’, which came into force on 15 September 1884 (Castagna, 1984).

At the time, Ischia was the destination of a wealthy and international tourism, attracted by the presence of establishments for thermal treatments and the healthiness of its sea, but after the disaster, and the reconstruction, the situation changed profoundly: its tourism grew a lot, causing a deterioration of the relationship between the natural and built environment. Architectural historian Andrea Maglio believes that the earthquake was a watershed: with the disaster, ‘the golden age of nineteenth-century tourism ends and the relationship with the landscape and with the natural and built environment begins to change’ (Maglio, 2017, p 329).