The National Commissioner of the Icelandic Police (NCIP) and the Police Commissioner at Hvolsvöllur declare an uncertainty phase, which is the lowest level of warning, because of seismic activity in Mount Hekla. There are no observable signs that an eruption of Hekla is imminent.
The Icelandic Met Office has informed the Civil Protection and Emergency Management of NCIP about unusual seismic activity in Mount Hekla. The Icelandic Met Office has raised the ICAO aviation color code to yellow concerning air traffic, which means that mount Hekla is showing an unusual activity.
The uncertainty phase means that supervision has been raised on that course of events that may threaten public health and safety, or that environment or inhabited area may be threatened. Declaring an uncertainty phase is a part of the work process in the setup of public safety to secure a formal communication between response teams and to secure dissemination of information.
In light of all of this the National Commissioner of the Icelandic Police and the Police Commissioner at Hvolsvöllur warn people from hiking on mount Hekla while this uncertainty phase is in force.
The Icelandic Meteorological Office has changed the aviation colour-code of Hekla volcano from green to yellow, signifying elevated unrest above a known background level.
Since 10 March 2013, at least seven micro-earthquakes, ranging in size from magnitude 0.4 to 1, have been detected over a small area ~4.5 km to the north-east of the volcano's summit. Sourced mainly at 11 to 12 km depth, these earthquakes have a high-frequency character suggestive of brittle fracturing rather than magma movements. At Hekla, such a clustering of earthquakes in time and space is unusual in between eruptions.
Continuous measurements of borehole strain and ground-based GPS show no changes in crustal deformation. The only measurable change is increased earthquake activity, although the earthquake rate is too low to assess whether this episode has peaked already. The change from green to yellow is a precautionary step due to increased earthquake activity. To date, there are no observable signs that an eruption of Hekla is imminent.