“The magma chamber under volcano Hekla is now almost full, according to Páll Einarsson, professor in geophysics at University of Iceland.
Hekla, which is the most active volcano in Iceland, could erupt with very short notice, Páll told Morgunblaðið, adding that people should not climb the mountain.
During the last eruption, in 2000, it took just 79 minutes from the first quake until eruption, and Páll says that was longer than in previous eruptions.
Hekla has erupted more than 20 times in the last 1,000 years. The last big eruption in Hekla was in 1947.”
The problem with Hekla is that it is a northern hemisphere volcano, and any significant eruption of material into the atmosphere would add more cooling.
In 1104 AD and 1100 BC and 2300 BC and 4110 BC and 6150 BC Hekla erupted with a VEI of 5. There have been numerous 3s and 4s as well.
A VEI5 is considered “very large” Mount Vesuvius and Mount St. Helens (1980) were VEI5.