Scientists have discovered the source of a mysterious and cataclysmic volcanic eruption â?? and have uncovered ancient texts showing the volcano could have entombed what the researchers call "a forgotten Pompeii" in southeastern Asia.
Scientists have long known that there was a massive eruption in the 1200s, but they didn't know where. The culprit, named today in the Proceedings of the National Academy of Sciences, was the Samalas volcano on the Indonesian island of Lombok. The new research shows that the Samalas eruption rivals what's often called the biggest volcanic eruption in recorded history, the Tambora eruption in 1815 on an island close to Lombok.
"This is a major discovery for science," University of Rhode Island volcanologist Haraldur Sigurdsson, who was not involved in the research, says via e-mail.
Scientists have long known about a layer of volcanic material deep in the ice of Antarctica and Greenland, evidence of a colossal eruption during the late Middle Ages. The material told scientists the year of the eruption â?? 1257 or 1258 – and the chemical composition of the ejected material, but no more.
The search "was like a criminal investigation," says Franck Lavigne, a geographer specializing in volcanoes at the Laboratory of Physical Geography CNRS, who led the team that found Samalas. "You know the date of the murder â?¦ and you've got the fingerprint."
Lavigne's team went looking for a telltale sign: the hollow created when a volcanic peak collapses. They found one atop Lombok Island, then they scoured the island for volcanic deposits. By scrutinizing the volcanic material and its distance from the fallen peak, they calculated how much material the volcano expelled and how fast it did so. They also found that the chemical composition of deposits on Lombok matched the composition of the ash in the ice samples.
Their calculations show that the Samalas eruption was one of the biggest of the last 12,000 years. It belched more ash and rock than any other volcano since roughly 1600 B.C., and it spewed hot ash even faster than Tambora, says Lavigne's colleague Jean-Christophe Komorowski of France's Institut de Physique du Globe.
The column of ash soared about 25 miles into the sky, and "anybody nearby would've been pretty terrified â?¦ to be in complete darkness," says the University of Cambridge's Clive Oppenheimer, who took part in the research. Eventually, a terrifying avalanche of super-heated gas and rock barreled down the volcano, killing nearly everyone in its path.
The number of dead is unknown, but Tambora, which was similar in size, killed upward of 70,000 people in the region. Perhaps many more would've perished globally, as components of Samalas' plume lingered in the atmosphere, blocking the sunlight and turning 1258 into a "year without a summer," Lavigne says.
The scientists found a reference to an eerily similar cataclysm in an Indonesian historic poem written on palm leaves in Old Javanese. "Mount Rinjani avalanched and Mount Samalas collapsed," reads the poem, which dates the events to before the end of the 13th century. "These flows destroyed (the seat of the kingdom) Pamatan."
"There's a good chance that the capital of the kingdom is still buried by volcanic deposits," Lavigne says. "I hope archaeologists will find it."