|Mount Pelee in the fog|
|A tiny reminder of lives lost in 1902|
|On the way there...lots of traffic|
Mount Pelee is named after Pele, the Hawaiian goddess of fire. It is part of a volcanic chain at the edge of the Caribbean plate. This boundary contains seventeen active volcanoes including Mt Pelee and the submarine volcano Kick-'em-Jenny. The oceanic crust of the South American plate is being subducted under the Caribbean plate.
We visited the observatory and later saw the volcano in the fog. The observatory is part of the Institut de Physique du Globe de Paris. They do seismic monitoring, geochemical surveying and gather GPS data. The GPS network is about 2 years old and thus can only provide upper limits for the uplift of the crust of a few centimeters at best. There has been no gravity champaign ever performed on Mount Pelee - although some gravity data is available for the nearby volcanoes on the island of Guadalupe. Such a champaign perhaps will be carried on Martinique as well, but there are no immediate plans for one and no urgency for it.
|nuee ardente (Heilprin 1902)|
|Photograph by Heilprin - 30.08.1902|
Mount Pelee is a stratovolcano, which is shaped like a cone built from many layers from previous eruptions. It is characterized by explosive emissions unlike the cooled lava flows like those for the volcanoes in Hawaii. This makes it very dangerous when active. The most dramatic eruption happened in 1902, which killed almost all the inhabitants (about 30, 000 people) of the city of St Pierre leaving behind very few survivors (the accounts of one prisoner, a shoemaker and a little girl were recorded). The officials declared that the city of St. Pierre was safe from the volcano because lava could not reach it. However, the nuee ardente, a type of pyroclastic flow, which is a fast moving cloud of hot gas and rock, reached a speed of over 670 km/hour and covered the city of St. Pierre in under a minute (see the Oregon State page of Mt. Pelee).
|The black beaches of St. Pierre|
The Mount Pelee volcano has shown no significant activity since its last eruption ended in 1929-1932. This latest eruption is
|Me and Edward in front of Mt. Pelee|
believed to be a second phase of the 1902 eruption. It could be that the volcano will be quiet for another 300 years or so, but there is no certainty of that, which is why the observatory in Martinique is still taking data. Also, even if there is no major eruption from previous history it seems that there is some activity every 100 years. Before the disaster of 1902, which had ample warning in the days before the eruption, there were precursory emissions in 1851-1852, 1792, 1635 (for a broad discussion of the eruptions see, for example, this pdf). Although the volcano appears to be cooling and degassing, an eruption this century is not ruled out. The structure underneath the volcano is not understood. While there are some models, we do not know the shape/size of the magma chambers or how full they are. It is therefore important to keep observing.
|Edward in the back of the observatory|
At the observatory we met with Dr. Clouard, who is one of the scientists in charge. In addition to volcano monitoring, she is also involved in Tsunami monitoring and prediction. She explained that while the world is currently afraid of Tsunamis because of the tragedies we witnessed this century, Tsunamis come in many sizes from a few centimeters to meters, and most of them do not inflict much damage. However, a substantial Tsunami would inflict major damage on small islands with a mostly coastal community like Martinique. It is therefore very important to continue the active monitoring and improve predictions & existent theoretical models, which often give poor predictions. The speed of such a wave can be between 650 to 850 km/h. This means that once an underwater volcano like Kick-'em-Jenny erupts, which is about 230 km away from Martinique, there will not be enough time to evacuate the island (see, e.g., on the vulnerability of the island to Tsunamis).
The last major earthquake in the area (magnitude 7.4, which is quite big) happened in 2007.
|The rest of the team!|
|In the St. Pierre waters|
|Edward's first time swimming!|