Volcanic Observatory

This vantage offers splendid view of the flat area of the caldera (Lakki Plain) with the characteristic Stefanos crater, along with the hill that hosts the post caldera craters of Alexander (Flegethron), Mikros and Megalos Polyvotis and Logothetis, which can be admired by the volcanic observatory found in the yard of Prophitis Ilias chapel in Nikia.

The caldera is a structure almost circular, featuring steep walls with a drop of 300-400m between the northern and eastern rim and a diameter of approximately 3.6km. Inside the caldera, there is the Lakki plain of 110m above sea level to the east, and the voluminous rhyodacitic domes of up to 698m in height filling the western part, the formation of which was the last magmatic activity on the island. It formed as a result of two voluminous plinian-type eruptions that occurred during the Caldera Eruptive cycles of Nisyros, more than 24000 years ago, as a result of magma deficiency within the magmatic chambers that generated them. Within Lakki, the geodynamic activity expressed by high seismic unrest, fumarolic activity and hydrothermal explosions is continuously present. Today, steam and fumarolic activity occurs in the hydrothermal craters along faults, and from several minor fractures in the Profitis Ilias dome.