Katla Volcano stirs: glacial flood outburst, increased seismicity

July 2014 –ICELAND – There are indications that a small glacial outburst flood is occurring in the river Múlakvísl, which originates in Mýrdalsjökull glacier, where the volcano Katla is located. The Civic Protection Department of the National Commissioner of the Icelandic Police declared yesterday a level of uncertainty because of the flood, which is believed to have started on July 2. Employees of the Icelandic Met Office have placed sensors on the new bridge that is being built across Múlakvísl to measure the water flow and conductivity in the river. The uncertainty level does not affect the bridge’s construction, ruv.is reports. There are a number of calderas near Katla, created by geothermal heat, but it is uncertain where the flood originates. Hydrogen sulfide is being carried into Múlakvísl and travelers are asked not to stop by the river because of dangerous gases, mbl.is reports.

Conductivity has also increased in the river Jökulsá, which originates in the Mýrdalsjökull glacial tongue Sólheimajökull, a popular tourist destination. “It isn’t unusual that a leak or minor flood of this kind comes from Mýrdalsjökull in the summer and it’s possible that the flow of water will increase,” a statement from the Met Office reads. “Data doesn’t indicate any bigger events following the flood but it is possible that a larger flood could happen suddenly with little notice.”A small glacial outburst flood occurred in Múlakvísl last year as well but exactly three years ago to the date a major flood occurred in the river, destroying the old bridge and tearing a hole in the Ring Road which interrupted the tourist season. –Iceland Review

Increased seismicity: Earthquakes have been more frequent recently under the volcano recently. Most of them were small (below mag. 3) and shallow events. It is unknown whether these relate to magmatic movements inside the volcano, increased hydrothermal activity or are adjustments of the ice cap due to increased melting. The government has declared “Uncertainty level” for Katla volcano yesterday. The largest hazard comes in the form of melt-water floods and sulfurous volcanic gasses dissolved in and released from glacial rivers. People are advised not to stop at Múlakvísl and Jökulsá and other glacier river valleys and keep cell phones turned on in order to be able to receive potential SMS alerts. Currently, there are no signs of an impending eruption at Katla. –Volcano Discovery