Hekla in Iceland, seen in 2009. Image: World's Landscape / Wikimedia Commons. We can add another volcano to the list of restless volcanoes today -- Jon Frimann noted that Hekla in Iceland is showing some signs of potential activity. Seismic activity at the volcano has prompted the National Commissioner of the Icelandic Police to declare an "uncertainty phase" for Hekla. That translates to the lowest (beyond no activity) level of warning for a restless Icelandic volcano. This change in status is the result of a tight cluster of very small earthquakes (none in the past few days, but you can check this link for updates) since March 10 on the northeast side of the summit ridge. These earthquakes are still relatively deep, occurring at 11-12 km below the volcano -- however, these earthquakes don't entirely suggest that new magma is intruding as they appear to reflect brittle fracture of rock rather than dilation due to magma. Coupled with a lack of any signs of ground deformation at Hekla, there are no signs that an eruption is imminent. That being said, this unrest has also prompted the Icelandic Meteorological Office to upgrade the aviation alert status for Hekla to Yellow, mainly due to the unusual nature of this activity at the volcano. The last eruption at Hekla was in 2000, but they can be spectacular events, with multiple VEI 3 and 4 eruptions over the past century. This current unrest is unusual for Hekla and does not clearly point towards a new eruption -- but with any Icelandic volcano, it should be closely watched for changes. If anything does happen, be sure to watch the Hekla webcam pointed at the volcano.