Sulfur mine (Guadeloupe)

The top

The top of the Sulfur mine, called the Discovery , culminates at an altitude of 1467 m. It is more the high summit of the Guadeloupe and all the Lesser Antilles. Its dome takes the shape of a truncated cone 900 m in diameter at its base. There are not a true crater, but several eruptive mouths, pits from where escape from the sulfurous vapors and the deep notches. The landscape is rock and chaotic, quasi-lunar, with roughcast pitons and deep notches. It is often covered with fogs. Several marked tracks traverse the volcanic top.

It is an active volcano of type Péléen (explosive with volcanic clouds) and of recent formation (100 000 to 200.000 years). Its activity is marked by sulfurous fumerolles, vapors and hot sources on various points of the top. It has been the only one with being active in Guadeloupe for 10.000 years.

The top is accessible by excursion a one hour via the Way of the Ladies.

Eruptions

The last eruption of the Sulfur mine goes back to 1976. It led to the evacuation of the southern part of the Low-Ground (as of the prefecture) - approximately 76.000 people - but no death was deplored. Starting from 1975, a certain number of jolts alerted the seismographs of the Volcanologique Observatory. These jolts were intensifying during the year 1976. As of November 1975, the prefect was informed potential dangers and need for setting up a plan of evacuation. The first eruption took place the July 8th 1976. The earth tremors most probably reactivated a series of faults clogged by old materials (magmatic clays and rocks). This crisis of earthquakes was the probable cause of the brutal fall of the pressure accumulated inside a heated captive tablecloth, a such pressure cooker, by escaped gases of the abyssal magma, causing the pulverization of rocks, and the exit of flow mud (Lahar), gases acid and steams. The commune of Saint-Claude was entirely covered with ashes and diving in the darkness. 25.000 people of the south Low-Ground spontaneously evacuated the zone to take refuge towards the Large-Ground, out of reach. The volcanic activity still continued a few months following this eruption, with others flow mud and emissions of ashes. The August 15th, the total and obligatory evacuation was ordered. It lasted until the November 18th 1976.

A very mediatized polemic burst between the scientists Claude Allègre and Haroun Tazieff on the need for the evacuation. Claude Lively recommended evacuation of population, affirming categorically that eruption would be serious, whereas Haroun Tazieff supported that the eruption was without danger, all the analyzes of samples taken on the volcano establishing that there was no rise of fresh magma. The prefect decided the evacuation anyway but the eruption made other damage only material.

In 1797, a phreatic eruption of importance took place. It cannot be excluded that this eruption was it also that of a captive tablecloth and not of a ground water, i.e. put at, atmospheric pressure. One establishes the last explosive magmatic eruption of the Sulfur mine towards 1440 (+ 100 years).

Monitoring and precautions

The observation of the Sulfur mine began in 1950 with creation from the Physical Laboratoire from the Earth to Saint-Claude (depend on the Physical Institute of the Earth of Paris). Two seismographs were installed immediately. It is thanks to this observatory that the eruption of 1976 was detected in advance. In 1989, a more modern observatory was built on the commune of the Gourbeyre, to 9 km in the south-west of the Sulfur mine. Its missions are:

monitoring of the volcanic activity of the Sulfur mine
monitoring of the regional seismicity
the participation in research tasks
preventive information on the seismic and volcanic risks.

Internal bonds

External bonds

Site of the National park of the Guadeloupe, manager of the top of the Sulfur mine
Volcanologique Observatory and Sismologique of Guadeloupe
Site of the multi-field programme of studies (ACI CNRS) of the Sulfur mine of Guadeloupe

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