Hekla 3 Eruption

The Hekla 3 eruption (H-3) circa 1000 BC is considered the most severe eruption of Hekla during the Holocene. It threw about 7.3 km3 of volcanic rock into the atmosphere, placing its Volcanic Explosivity Index (VEI) at 5. This would have cooled temperatures in the northern parts of the globe for a few years afterwards.

An eighteen-year span of climate worsening is recorded in Irish bog oaks, and H-3 was blamed for it.

The eruption is detectable in Greenland ice-cores, the bristlecone pine sequence, and the Irish oak sequence of extremely narrow growth rings. Baker's team dated it to 1021 + 130/-100 BC.

Baker preferred a "high chronology" (earlier) interpretation of these results. In Sutherland, northwest Scotland, a spurt of four years of doubled annual luminescent growth banding of calcite in a stalagmite is datable to 1135 ± 130 BC. A rival, "low-chronology" interpretation of the eruption comes from Dugmore, 2879 BP = 929 BC ± 34.

In 1999 Dugmore suggested a non-volcanic explanation for the Scottish results. In 2000 skepticism concerning conclusions about connecting Hekla 3 and Hekla 4 eruptions with paleoenvironmental events and archaeologically attested abandonment of settlement sites in northern Scotland was expressed by John P. Grattan and David D. Gilbertson.

Some Egyptologists in 1999 firmly dated the eruption to 1159 BC and blamed it for famines under Ramesses III during the wider Bronze Age collapse. Dugmore dismissed this notion and maintains his dating to this day. Other scholars have held off on this dispute, preferring the neutral and vague "3000 BP".