Société

MUDDY WATERS...

In May last year a new word was added to my
vocabulary: mud volcano. In East Java, Indonesia,
a company was drilling for gas when suddenly
a cloud of hydrogen sulphide gas escaped and,
at a hundred meters from the exploration works,
an eruption of boiling hot mud took place.
The gas cloud put almost a 1000 people to
hospital and the boiling mud started flowing
for hours, days, and then weeks, and still
continues today…

RENÉ NIJENHUIS

The humanitarian impact to date has been that over 13 thousand people have been displaced, 23 schools have been inundated and hundreds of hectares of rice paddies and sugar cane fields drowned.
A possible explanation for the cause of the mud volcano eruption is that a pressurized mud layer, which also contained hydrogen sulphide, was pierced by the gas drilling well or found its way “spontaneously”, vertically upwards to the surface. At the end of June, the cone was already an estimated 6 meters high and had inundated entire villages. Thousands of people lost their homes, work and crops to the mud. Geologists estimated that the mud flow was now 40 to 50 thousand m3 per day (that is 50 million litres!) The army was quickly mobilised to construct dams and dykes to limit further damage. The authorities were not sure whether the mud itself was toxic or not and requested a team of the United Nations Disaster Assessment and Coordination team to help them. Together with the Joint UNEP/OCHA Environment Unit, a team of 5 environmental experts was mobilised and deployed, taking with them sampling equipment for air, water and soil.
The outcomes of the environmental assessment were positive and no clear indications were found that the mud was toxic. This meant that there was no direct threat to people living and working in the surroundings and the mud could possibly be re-used for bricks or other purposes.
However, with these large amounts of mud being emitted from underground layers, the risks from recurrent toxic gas emissions, earthquakes and subsidence could not be excluded. In November, a huge gas explosion took place when a gas pipeline erupted, killing 11 people. It is suspected that the earth under the pipeline has collapsed.
At this moment, relief wells are being drilled in the hope that the mud volcano can be stopped. It is hoped this will happen in March, but there are no guarantees from Mother Nature.

The United States Geological Survey describes mud volcanoes as small volcano-shaped cones of mud and clay, usually less than 1-2m tall. These small mud volcanoes are built by a mixture of hot water and fine sediment (mud and clay) that either pours gently from a vent in the ground like a fluid lava flow ; or is ejected into the air like a lava fountain by escaping volcanic gas and boiling water. The fine mud and clay typically originates from solid rock-volcanic gases and heat escaping from magma deep below turning groundwater into a hot acidic mixture that chemically changes the rock into mudand clay-sized fragments.
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