Nisyros Volcano | John Seach



36.58 N, 27.18 E
summit elevation 698 m

Nisyros is an 8 km-wide island located at the eastern end of the Hellenic island arc, 340 km SE of Athens. Nisyros Island is part of the Kos-Yali-Nisyros Volcanic Field in the SE part of the Aegean Sea. The Hellenic Volcanic Arc is a magmatic expression of the active northeastward-directed subduction of the African
Plate beneath the Aegean Plate.

Nisyros Island has an average width of 8 km, and covers an area of about 42 sq km. The volcano contains a 3.8 km-wide caldera.

Historical activity of Nisyros volcano produced phreatic eruptions in the caldera. Currently fumarolic activity occurs in the caldera, and hot springs are found on the coast. The volcano has erupted at least 13 times during recorded history.

2003 Unrest
In January 2003 the crater was declared off limits due to increasing temperatures and growing surface cracks. Temperatures of the hydrothermal system increased from 210 to 315 degrees C.

2001 Lakki Plain Fracture
On 20th November 2001 a ground fracture opened up in the central part of the Lakki Plain. The fracture was up to 5 m wide, 10 m deep, and was 350 m long. One year later (December 18, 2002), the rupture extended southwards for another 250 m. The sudden fracturing was caused by stress release without producing
any seismic activity.

Seismic Crisis 1995-1998
A volcano-seismic crisis on Nisyros occurred between 1995 and 1998, and was accompanied by 14 cm of ground uplift on the island. More than 1600 seismic events were located within the Kos-Nisyros-Tilos area. Several shallow tectonic earthquakes at depths up to 10 km with larger magnitudes up to 5.5 occurred along the fault system between Tilos and Kos.

1873 Eruption
During the latest hydrothermal explosion in 1873, fire and gas eruptions were reported along the coast near the town of Mandraki.

Nisyros Volcano Eruptions

1888, 1873, 1871, 1422?