A volcano that has been dormant for hundreds of thousands of years could be gearing up for a massive explosion, according to new research.

Scientists have measured signs of unrest at the Taftan volcano in eastern Iran, near the Afghanistan border, despite no eruptions in the last 700,000 years, according to a paper published earlier this month in Geophysical Research Letters.

Rapid uplift was detected near Taftan’s 13,000-foot-tall summit between July 2023 and May 2024, while an analysis method to reduce random noise due to atmospheric condition indicated that neither rainfall nor earthquakes triggered the unrest.

Therefore, an explosive eruption is likely imminent, the researchers said.

Changes in gas permeability within the shallow part of the volcano, as well as undetected deep magma movement, have likely led to the hydrothermal pressure buildup.

Taftan experiences frequent fumarolic — or venting of gas — activity, but geologic evidence indicates that it has not experienced a major eruption since 700,000.

“Uncertain” eruptions may have occurred in January 1902 and April 1993, according to the Smithsonian Institution’s Global Volcanism Program.

Currently, Taftan is not monitored at the same level of scrutiny as other volcanoes due to its remote location. Space-based satellite sensing is the only source of data to detect transitions from dormancy to unrest for many remote and unmonitored volcanoes, according to the paper.

The study reveals an urgent need to revise the current volcano risk of the Makran subduction volcanic arc — a stretch of about 275 miles along the Indian Ocean — and establish volcano monitoring networks in the region.

“Our findings reveal that Taftan is more active than previously recognized,” the authors wrote.