A volcano in Ethiopia is spewing unusually large volumes of methane from its crater, according to satellite measurements of the potent greenhouse gas. This comes after hundreds of earthquakes have shaken the region over the past few months, prompting tens of thousands of people to evacuate ahead of a potential eruption.
A European Union satellite was the first to detect methane in the region around , an active volcano in the Great Rift valley about 120 kilometres east of Ethiopia鈥檚 largest city, Addis Ababa. This prompted Canadian satellite company GHGSat to point some of its higher-resolution instruments at the volcano for a closer look.
On 31 January, its satellites at a rate of 58 tonnes per hour, or nearly 1400 metric tonnes per day. That much methane has a global warming effect roughly equivalent to the emissions from burning around 20 million kilograms of coal.
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It is common for volcanoes to belch gases like carbon dioxide and sulphur dioxide, but 鈥渋t鈥檚 unusual鈥� to see this much methane linked to volcanic activity, says at McGill University in Montreal, Canada. He points out that this detection was only possible due to the growing constellation of satellites being used to monitor methane emissions from human sources like oil and gas fields, coal mines and landfills.
Over the past few weeks, satellites have detected methane in the crater on several subsequent flybys, according to at GHGSat. However, he says the emissions rate has been declining since 9 February.
Volcano monitoring agencies have also a recent slowdown in seismic activity since a swarm of earthquakes in late December and January, which was created by shifting magma. 鈥淭his big crack of magma just propagated through the crust,鈥� says Stix.
No one knows the source of the methane in the crater. However, Stix says the lack of sulphur dioxide suggests that it isn鈥檛 coming from a magma reservoir, but from some other source within the volcano, such as a gas deposit that was disrupted by the magma moving beneath the surface.
