The Nisyros Hydrothermal Crater Field

The Nisyros Hydrothermal Crater Field
Fumarolic Activity
The Nisyros Hydrothermal System

Introduction

Hydrothermal craters (Fig. 36) are formed mainly by steam and gas explosions of a hydrothermal system near the surface within or in the vicinity of a volcanic caldera, mostly due to steam overpressure and not to a magmatic eruption.

Such explosions can occur if fresh hot magma is injected from deep crustal magma reservoirs into a shallow magma chamber. At shallow depth, the magma is able to release gases due to lower lithostatic pressure and transmit heat to the surrounding hydrothermal system.

Fig. 36 The Nisyros hydrothermal crater field within the caldera (Ikonos image, 30.4.2000, resolution 1 m), red points: monitored fumaroles. Swiss Federal Institute of Technology (ETHZ)
(Click on image to enlarge).

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