A remote mountain near the Iran-Pakistan border has been rising unusually fast in the last couple of years. From July 2023 to May 2024, satellite data indicated that the ground had swelled by about 3.5 inches.
This rise has not returned to its original level, suggesting that constant pressure is building below the surface. The European Space Agency used radar technology to detect these tiny movements from space, which can measure changes as small as a few centimeters.
Scientists are surprised not only by the size but by the fact that the ground remains elevated, which means gas or magma is still gathering underground without a way to escape.​
Sulfur Warning
The nearby city of Khash, just 31 miles from the mountain, began reporting odd smells in 2023—an unpleasant sulfur odor.
This smell spread through neighborhoods and was later confirmed by sensors detecting 20 tons of sulfur dioxide daily, along with carbon dioxide and other volcanic gases. These emissions occur when underground heat causes water to boil, creating steam that escapes through cracks in the ground.
This is a sign of volcanic activity, even if an eruption hasn’t started. Local officials have acknowledged the smell and noticed that steam regularly comes from the mountain’s summit, especially after rain and snow. The presence of sulfur and other gases signals that hot fluids or magma may be interacting with groundwater.​
Pleistocene Giant
The mountain, known as Taftan, is a vast volcanic cone that formed approximately 700,000 years ago during the Pleistocene era.
It is the tallest peak in southeastern Iran, part of a volcanic chain extending into Pakistan. Taftan has two prominent peaks—the older, heavily eroded Narkuh and the fresher-looking Madehkuh.
Its last significant eruption occurred hundreds of thousands of years before humans existed, long before modern Homo sapiens emerged. The volcano has remained quiet for centuries, with no considerable activity recorded in its history.​
Tectonic Pressure
Taftan sits where two tectonic plates—the Arabian and Eurasian—meet and collide in a region called the Makran Subduction Zone.
Here, one plate slowly slides beneath the other at a shallow angle, pushing up vast amounts of rock and generating magma that feeds volcanoes like Taftan.
This subduction zone spans approximately 559 miles and is one of the least explored yet most geologically active areas on Earth.
The slow movement and flat angle cause stresses that can build up over long periods, producing rare but powerful earthquakes and volcanic unrest when the pressure is released.​
Extinct No More
Thanks to the recent satellite study published in Geophysical Research Letters, scientists have reclassified Taftan from “extinct”—thought to be permanently dead—to “dormant,” meaning it still holds potential activity.
Research led by volcanologist Pablo González found that the swelling originates from gas accumulating approximately 1,600 to 2,000 feet beneath the summit, separate from the deeper magma chambers. This persistent uplift with no drop-backs suggests pressurization that might one day lead to an eruption.
The discovery highlights the need for enhanced monitoring and preparedness in the region.​
Borderlands Threat
Taftan rises in the remote, sparsely populated Iranian province of Sistan and Baluchestan near Pakistan’s Balochistan province.
The area faces security challenges like border tensions and insurgent activity, which have kept scientists from installing ground monitoring instruments. If Taftan erupts, nearby communities, such as Khash and Zahedan, could face volcanic ash dusting, water pollution from toxic gases, and hazardous air quality due to the release of sulfur dioxide.
More severe eruptions could unleash pyroclastic flows, which are fast-moving avalanches of hot gas and rock, and lahars, deadly mudflows triggered when volcanic debris mixes with rain or melted snow.​
Social Media Detectives
Residents’ reports of sulfur smells on social media played a crucial role in alerting scientists to the volcano’s reawakening.
These “citizen science” observations prompted researchers to sift through satellite images, filling gaps since ground-based monitors aren’t present.
The European Space Agency’s Sentinel-1 satellites capture radar images that can detect subtle ground movements worldwide, enabling researchers to track volcanic activity even in hazardous or uncharted areas.
InSAR Revolution
The key technology behind detecting Taftan’s swelling is called Interferometric Synthetic Aperture Radar (InSAR), which compares radar pictures taken at different times to measure how much the ground has moved.
For Taftan, scientists used a new filtering method to remove noise from the atmosphere, which often hides small signals. InSAR is especially valuable in areas where installing sensors is difficult, such as conflict zones or remote mountainous regions.
This method has helped predict other volcanic eruptions, such as the one on Iceland’s Reykjanes Peninsula in 2024, demonstrating its life-saving potential.​
Dormancy Debate
Volcanologists debate what counts as “extinct” versus “dormant.” The U.S. Geological Survey considers volcanoes active if they erupted in the last 10,000 years.
Dormant ones haven’t erupted recently, but could still wake up. Geologists classify a volcano as extinct when it lacks a magma source and cannot erupt again.
However, many volcanoes once thought to be “dead” have surprised people, such as Alaska’s Fourpeaked, which was dormant for 12,000 years before erupting unexpectedly in 2006. Taftan’s long dormancy is extraordinary, but it doesn’t guarantee it won’t erupt again.​
Before Humanity
Taftan last erupted more than 700,000 years ago—long before modern humans existed.
Early Homo sapiens appeared around 300,000 years ago, meaning the previous eruption predates humanity by approximately 300,000 years.
This helps put the mountain’s quiet period into perspective: it has been inactive for almost the entire span of recorded human history, making its current reawakening a rare geological event far outside the normal human experience.​
Monitoring Gap
Unlike many volcanoes worldwide, Taftan lacks ground-based seismic and gas monitoring stations—tools crucial for detecting early warning signs of eruptions.
The U.S. Volcano Early Warning System recommends dozens of sensors near active volcanoes, but political instability and mountainous terrain make installing such infrastructure near Taftan risky and complex.
Satellites remain the only reliable method for monitoring the volcano, but they cannot provide real-time warnings for sudden events. Scientists warn that this absence of on-site monitoring is a dangerous blind spot for nearby communities.​
Stratovolcano Structure
Taftan is a stratovolcano, built up over hundreds of thousands of years through the accumulation of layers of lava flows and volcanic ash.
These volcanoes have tall, steep cones and tend to produce violent eruptions when gas pressure suddenly builds up and then escapes. Taftan’s magma is silica-rich, making it sticky and trapping gas until eruptions occur with explosive energy.
Additionally, it has an active hydrothermal system: water heated underground turns to steam, which can cause sudden steam-blast eruptions (called phreatic eruptions) without warning. Such eruptions can be devastating even if no lava flows.​
Phreatic Danger
The uplift detected beneath Taftan is likely due to gas and hot fluids pressurizing the rock near the surface.
Such pressure can cause phreatic eruptions, which happen when trapped steam rapidly expands, blasting apart rock and releasing deadly clouds of superheated vapor and ash. Past examples include Mount Ontake in Japan (2014), which killed 63 hikers with little warning.
Scientists cannot yet say if Taftan’s uplift signals magmatic intrusion or hydrothermal activity, making hazard predictions uncertain. The volcano’s shallow pressurization zone suggests that even if no magma reaches the surface soon, more minor but dangerous steam explosions remain possible.​
Wake-Up Call
Lead volcanologist Pablo González stresses that the new findings are “not meant to cause panic,” but rather serve as a “wake-up call” for Iranian authorities to allocate resources toward monitoring and preparedness.
He emphasized that the persistent uplift “has to release somehow in the future,” whether softly or violently. Officials have yet to announce plans for ground-based monitoring or emergency response.
Continuous observations will be crucial because increasing unrest can build over weeks or months before triggering an eruption, allowing time for evacuations if detected early.​
Uncharted Territory
Taftan joins a surprisingly growing list of ancient volcanoes reawakening after hundreds of thousands of years—a phenomenon sometimes referred to as “zombie volcanoes.”
Like Yellowstone—which erupts every 600,000 to 700,000 years—Taftan challenges assumptions about when a volcano truly ‘dies.’ Scientists note that climate change may influence volcanic activity by altering snowfall and rain on volcanic peaks, which in turn can trigger shifts in underground water flow and heat.
Yet, limited monitoring data in remote regions makes it hard to predict such events. Taftan’s ongoing swelling underscores the urgent need for improved global volcano surveillance, particularly in politically unstable and under-instrumented regions.​