The volcano of Nisyros should be seen in the wider geographical context of the whole area, since it is only the most recently active remnant of a large, prehistoric volcanic field (the ‘Kos Caldera’) whose boundaries are the approximately circular area defined, to the north by the western end of Kos (Kephalos peninsula and Bay of Aghios Stephanos), to the west by the islands of Pyrgousa and Pachia, and to the east, by Nisyros itself, incorporating the islands of Giali and Strongyli in between. The eruption of this whole area 160,000 years ago was the most significant volcanic event of the Eastern Mediterranean’s history. The last major, magmatic activity of Nisyros, however, corresponds to about 25,000 years ago, and it was then that the summit of the volcano imploded producing the caldera visible today. In the process, the collapse of tall (15–20 km) columns of material ejected from the volcano created the volcanic domes of dacite and pyroclastic deposits which we recognize today as the mountain peaks of the western side—Prophitis Elias, Niphios, Trapezina etc.
A slowly rising magma chamber currently lies at a depth of 3–4km below Nisyros. Though the volcano has been active many times since the last magmatic eruption, this activity has been in the less drastic form of hydrothermal eruptions. The craters, such as the magnificent Stephanos, in the southern part of the depression—known as ‘explosion sinks’—are therefore only the latest elements in this long chain of activity, and mostly date from 4,000 years ago. Activity has continued into recent history, with hy drothermal eruptions in 1422, and a whole series in 1871–73 (creating the Phlegethron and Polyvotis cra ters), and again in 1887–88 (Mikros Polyvotis). The vulcanological monitoring unit, Geowarn, notes that the temperature of the fumaroles in Stephanos has risen from 98Β°C in 2000 to 103Β°C in 2004.
Exploration of the site is neither especially difficult nor dangerous, and affords visions of vapour seams, mud pools, cliffs of kaleidoscopic colour, and the ubiquitous and ephemeral formations of brilliant yellow, feathery sulphur-crystals beside the smaller vapour holes. The largest crater, Stephanos (330m across and 27m deep), is easy to descend by a path on the west side. In the centre of the flat floor are breaches and holes in which a pale grey or black viscous water (condensed from vapour as it encounters the cold exterior air) simmers at just under 100Β°C, while the whole of the lower eastern side is perforated with fumaroles, creating together a perceptible hiss sound. It is here that the greatest quantity of sulphur crystals forms.
Climbing up the ash-heaps to the northwest of Stephanos, you reach (furthest south) the Phlegethron crater (also called ‘Alexandros’)—whose depth of 30m in pro portion to its diameter of 100 m makes it seem impres sively deep—and the Polyvotis complex of craters. Here the vapour seams, which give off steam at all times of year, reach higher up the cliffs. These craters all date from eruptions in the late 19th century, the most recent of all to be formed (1887) being Mikros Polyvotis (to the right of the summit of the path): it is narrow, highly colourful and with constant and audible activity. The sulphur from this area has been intermittently exploited from early Antiquity (Phoenicians) up until the Ottoman occupation, when it was prized as anredient in explosives. In the late 19th century a British company collected and shipped it through the island’s south-coast harbour of Aghia Irini.
From the junction east of Emboreios and just below the north crater rim, the asphalt road continues south with wide views of the mountainous Cnidos peninsular of Turkey, which from here has the appearance of an is land. After 1.5km a track leads down right (east) to the 18th century monastery of Panaghia Kyra, marked by a large palm-tree, planted many decades ago for its sup posed apotropaic properties. The setting is delightful, with the finely finished catholicon surrounded by mon astery buildings, a bread oven and an outside ‘xystos’ for eating. There is a spring just below and, on the rise to the east, are the remains of ancient foundations around a small fort or watch-tower.
Nikia (13km by road from Mandraki) occupies a spectacular position on the southeastern rim of the vol canic caldera: the odour of sulphur intermittently arrives here on the breeze. The entrance to Nikia is marked on the right by the new Nisyros Vulcanological Museum, housed in the single space of a former school building. The display gives a clear and effective didactic presentation of the Nisyros volcano, and places it in the context of the Aegean in general and of other Mediterranean volca noes. Some interesting geological samples are exhibited; but this is primarily a helpful, pictorial introduction to the genesis and evolution of eruptions.
Beyond the good taverna at the village’s entrance, a winding alley between stone houses and kafeneia leads to the memorable oval plateia—often referred to as the ‘Porta’—arranged like a small opera-set, with sweeping views out to sea opposite; it is reminiscent of the plateia of Olympos on the island of Karpathos—occasionally visible across the water from here. The fine chochlakia floor was designed and laid in 1923 by a certain Paschali Paschalaki. An idiosyncratic group of buildings composes the square: cafes (current and defunct); the church of the Ypapanti (the Presentation of the Virgin), with its campanile (also by Paschalaki), elaborately decorated with carved elements at every level; the old school building (left); and the former Demarcheion (right). The church is entered through a wide, arched atrium, where cabinets display church regalia, objects and icons: the interior has been modernised with a grandiose, marble templon, throne and pulpit from Constantinople. Of greatest inter est are two fine, 18th century, silver-revetted icons of the Presentation and the Purification.
Nisyros Island is part of the Dodecanese Island Group, Greece.