Large volcanic eruption in Alaska linked to rise of the Roman empire in new study

The murder of Julius Caesar in 44 a. C. caused a power struggle of almost two decades that led to the fall of the Roman Republic and the rise of the Roman Empire.

Historical records say the period was marked by strange sightings in the sky, unusually cold weather, and widespread famine, and a new study suggests that a volcanic eruption in Alaska may have been the cause.

The article was published in the procedures of the National Academy of Sciences Monday.

An international team of scientists and historians used an analysis of volcanic ash (tephra) found in the Arctic ice cores to link the period of unexplained extreme weather in the Mediterranean with the eruption of Alaska’s Okmok volcano in 43 BC. C.

“Finding evidence that a volcano on the other side of the Earth erupted and effectively contributed to the disappearance of the Romans and Egyptians and the rise of the Roman Empire is fascinating,” said lead author Joe McConnell of the Research Institute of the Desert (DRI). ) in Reno, Nevada.

The advent of the Roman Empire also ended the dynasty of Ptolemy, the last of the pharaohs.

“It certainly shows how interconnected the world was even 2,000 years ago,” added McConnell.

He and Swiss researcher Michael Sigl began investigating the matter when they found an unusually well-preserved layer of ash in an ice core sample last year.

New measurements were then made on Greenland and Russian ice cores, some of which were drilled in the 1990s and stored in archives.

They were able to distinguish two distinct eruptions: a powerful but localized event of short duration in the early 45 BC. C., followed by a much more extensive and extended event in the year 43 a. C., with consequences that lasted more than two years.

Perfect combination

A geochemical analysis was performed on the ash samples found in the ice of the second eruption, and it coincided perfectly with the Okmok event, one of the largest eruptions in the last 2,500 years.

“The combination of tephra does not improve,” said volcanologist Gill Plunkett of Queen’s University Belfast.

The team gathered more supporting evidence from around the world, from tree-ring based climate records in Scandinavia to cave formations in northeast China.

These data were entered into a climate model, which suggested that the two years after the eruption were some of the coldest in the northern hemisphere for 2,500 years.

Seasonally averaged temperatures may have been up to seven degrees Celsius (13 degrees Fahrenheit) below normal during the summer and fall after the eruption, with fall precipitation reaching up to 400 percent of normal in the south of Europe.

“In the Mediterranean region, these extremely cold and humid conditions during the agricultural spring and fall seasons likely reduced crop yields and exacerbated supply problems during the ongoing political upheavals of the period,” said classical archaeologist Andrew Wilson. , from Oxford University.

They also coincided with the failure of the Nile to flood the plains and disease and the famine that followed, added Yale University historian Joe Manning.

Strange sightings

The eruption may also explain unusual atmospheric phenomena seen in the records, such as solar halos, the sun darkening in the sky, or three suns appearing in the sky, a phenomenon known as a solar dog.

But the authors added that many of these observations took place before the Alaska eruption and could be related to the smaller Mount Etna eruption in 44 BC. C.

McConnell said that while many factors contributed to the fall of the Roman Republic and the Ptolemaic Kingdom, the Okmok eruption played an important role and helps fill a knowledge gap that had baffled historians.

© Agence France-Presse