The sudden awakening of a dormant volcano in southeastern Iran after 700,000 years of silence has sparked concern and intrigue among scientists and the public alike. The Taftan volcano, previously thought to be inactive, has unexpectedly risen by 3.5 inches (9 centimeters) in just 10 months, as revealed by a new study using satellite data. This seemingly minor shift carries significant implications, indicating that the volcano's system is stirring and demands further scrutiny.
The study, led by Pablo J. González from the Institute of Natural Products and Agrobiology's Spanish National Research Council (IPNA), employed InSAR, a radar method that measures ground motion from space. Sentinel-1 satellites, capable of operating day and night and seeing through clouds, were instrumental in detecting the subtle yet significant change in the volcano's ground level.
The uplift, centered near the summit, has persisted without a return to its original position, suggesting that the pressure beneath the volcano is still building. The team's modeling indicates that the source of this pressure is gases located only 1,600 to 2,070 feet (490 to 630 meters) below the surface, within a hydrothermal system where hot water and gas circulate.
This discovery challenges the notion that 'extinct' volcanoes are truly dormant. Taftan, a 12,927-foot (3,940-meter) stratovolcano, continues to exhibit signs of movement through summit fumaroles, which emit gas. The scarcity of eruption records for the past 10,000 years further underscores the importance of monitoring, as volcanoes can transition from idling to eruption in a matter of months.
The study highlights the limitations of labels like 'extinct' and emphasizes the need for measurements. The current deformation is a measurable phenomenon, not just a label. The shallow source of the pressure suggests that gases are accumulating in tight rocks and fractures, causing the ground to rise. Alternatively, a small pulse of melt could have released volatiles, which then percolated upward, exerting pressure into pores.
The primary near-term hazards associated with Taftan are not lava flows but phreatic blasts, which are steam-driven explosions that can occur when hot fluids flash to vapor near the surface. Gas bursts can have adverse effects on human health and agriculture, and the city of Khash, located 31 miles (50 kilometers) away, is at risk of sulfur odors during favorable wind conditions.
To address these concerns, scientists propose a comprehensive monitoring plan. This includes measuring gases at vents and on the slopes to track pressure changes, as well as installing a network of seismometers and GPS units to capture ground motion. Satellites will continue to play a crucial role in monitoring, with InSAR providing early warnings of small changes that can be verified by field crews.
The study's findings emphasize the importance of steady, boring monitoring in saving lives. By turning surprises into known problems with known responses, scientists can better prepare nearby communities. Taftan's location in a subduction zone, where one tectonic plate slides under another, further underscores the significance of monitoring, as this setting creates magma at depth and gas-rich fluids higher up.
As the study concludes, it is essential to recognize that the Taftan volcano's awakening is a call to action, not a reason for panic. By heeding the warnings and implementing the proposed monitoring measures, authorities can ensure the safety of nearby populations and mitigate potential hazards.
