Volcanos

Roundup of Global Volcanic Activity

Bardarbunga (Central Iceland): A magnitude 3.8 earthquake followed by dozens of small aftershocks occurred yesterday at 3 km depth under the volcano's northeastern caldera rim (located under the ice cap). While it is possible that such earthquakes are caused by shallow magma intrusions, the present quakes at Bardarbunga are more likely result of volcano-tectonic movements, in this case the continuing subsidence of the caldera (a so-called slow caldera collapse) which has been going on since the large 2014-15 Holuhraun flank eruption. This also seems to reflect the opinion of Icelandic Met Office's seismologists according to a local press article.

Katla (Southern Iceland): Following Monday's large earthquakes, the volcano remains relatively calm seismically, with only small swarms of deep to shallow earthquakes occurring under the northern flank. According to experts, there is currently no sign of an eruption being imminent. Icelandic authorities are aware of the potential danger the next eruption of Katla represents (whether it occurs in the next months or only decades from now). A delegation of the volcanologists from the Icelandic Met Office was invited to discuss with a committee of the Icelandic Parliament about how to respond in case of an eruption. The biggest hazard are large-scale, potentially catastrophic glacial floods when an eruption occurs, which is likely going to be subglacial, as a result of rapid melting of ice by magma. A fast and wide-spread evacuation of all river beds draining from the Katla massif and alternative routes are likely a major topic in such plans. During the past days, an increase in glacial water into the Múlakvísl river, south of Mýrdalsjökull, has been detected. The river water has a strongly elevated content in hydrogen sulfide (H2S) and people are advised not to travel near the river due to gas pollution.