# Grande Sentinella Geophysical Observatory **At a glance:** The Geodynamic, later Geophysical, Observatory of the Grande Sentinella was established by royal decree and founded in 1884 in the upper part of Casamicciola. Designed and directed by Giulio Grablovitz, it was a first-class observatory: its seismological recordings continued from 1889 to 1936. ## Useful information - **Type:** History and science - **Area:** [Upper Casamicciola](https://visitcasamicciola.com/en/areas/upper-casamicciola/) - **Address:** Località Grande Sentinella, 80074 Casamicciola Terme NA - **Period:** 1884–1936 - **Coordinates:** 40.746610, 13.901580 - **Founded:** 1884 - **Director:** Giulio Grablovitz - **Activity:** Meteorological observations from 1 January 1888; seismological section from 1889 to 1936 - **Where:** Grande Sentinella, upper Casamicciola - **Linked station:** Former Casina Reale, Ischia Porto ## Why it was founded in Casamicciola After 1883 the need was felt for systematic study of the island's natural phenomena. At the request of the Geodynamic Commission, a royal decree established a “first-class” geodynamic observatory in Casamicciola, on a par with those at Rocca di Papa and Catania. For the town's rebirth in those years, read [Casamicciola after 1883: the rebirth](https://visitcasamicciola.com/en/history/casamicciola-after-1883/). ## History of the observatory According to INGV (Italy's National Institute of Geophysics and Volcanology), the observatory was founded in 1884 and inaugurated three years later. [Giulio Grablovitz](https://visitcasamicciola.com/en/history/giulio-grablovitz/), a young scientist from Trieste already known for his studies of astronomy, earthquakes and tides, was called in to design and direct it. Building the main premises at the Grande [Sentinella](https://visitcasamicciola.com/en/history/la-sentinella/) took a long time, amid administrative and scientific difficulties: in the meantime Grablovitz set up a station in the former Casina Reale (royal lodge) at Ischia Porto, which remained in use afterwards and where he carried out much of his work. The observatory therefore had two seismic stations, Ischia Porto and the Grande Sentinella. Regular meteorological observations began on 1 January 1888; the seismological section was active from 1889 to 1936. ## Grablovitz's instruments In Casamicciola and Ischia Grablovitz experimented with original instruments: the seismic tank, horizontal pendulums derived from the Rebeur-Paschwitz model and regarded as forerunners of modern seismographs, water-based geodynamic levels and planispheres for calculating the distance and direction of epicentres. These instruments won him a gold medal at the 1906 International Exhibition in Milan. He also recorded the temperatures of the thermal waters and the tides. ## A landmark of Italian seismology The Casamicciola observatory was one of the first scientific outposts built by the newly unified Italian State to understand the phenomena of the earth. Today volcanic and seismic monitoring of the island is the responsibility of the Osservatorio Vesuviano, the Naples section of INGV, with networks of sensors for seismicity, ground deformation, waters and gases. To discover the island's geology, read [The Volcanic Origins of Casamicciola](https://visitcasamicciola.com/en/history/volcanic-origins-of-casamicciola/). ## Where it is and how to get there The former observatory building stands on the Grande Sentinella hill, in the upper part of Casamicciola, near Via Grande Sentinella and Via Castanito. It can be reached by climbing from the centre or from Piazza Bagni. Before planning a visit inside, check with the Municipality whether the building is actually accessible. ## Frequently asked questions ### When was the Casamicciola Observatory founded? It was founded in 1884 and inaugurated three years later. It was a first-class geodynamic observatory, like those at Rocca di Papa and Catania. ### Who directed the Observatory? The Trieste-born seismologist Giulio Grablovitz, who designed and directed it. He lived on Ischia until his death in 1928. ### Is the observatory still in operation? No: according to INGV, the seismological section was active from 1889 to 1936. Today monitoring of the island is the responsibility of INGV's Osservatorio Vesuviano. ## Also worth seeing - [Giulio Grablovitz, the Sentinella Seismologist](https://visitcasamicciola.com/en/history/giulio-grablovitz/) - [La Sentinella](https://visitcasamicciola.com/en/history/la-sentinella/) - [Casamicciola after 1883: the rebirth](https://visitcasamicciola.com/en/history/casamicciola-after-1883/) - [The Volcanic Origins of Casamicciola](https://visitcasamicciola.com/en/history/volcanic-origins-of-casamicciola/) ## Sources and further reading - [Osservatorio Geodinamico di Casamicciola – INGV SISMOS](https://sismoslab.ingv.it/index.php/storia-della-sismologia/introduzione/gli-osservatori/o-150321) - [Altri protagonisti: Giulio Grablovitz – INGV SISMOS](https://sismoslab.ingv.it/index.php/storia-della-sismologia/introduzione/altri-protagonisti/p-01227) - [Giulio Grablovitz – Wikipedia](https://it.wikipedia.org/wiki/Giulio_Grablovitz) - [Le trame di Casamicciola (G. Gugg), in Bloc Notes – Startmag](https://www.startmag.it/?p=214087) - [Ischia – Dipartimento della Protezione Civile](https://www.protezionecivile.gov.it/it/approfondimento/ischia/)