A remote volcano in southeastern Iran has awakened from its 700,000-year slumber, rising by 3.5 inches (9 centimeters) in just 10 months. This seemingly minor shift holds significant implications. A recent study, utilizing satellite data, has detected this change and suggests that pressure is building near the summit. The volcano, known as Taftan, has never erupted in human history, but this newfound activity indicates that the system is stirring and demands attention. Scientists are closely monitoring Taftan, employing InSAR, a radar method that measures ground motion from space, using Sentinel-1 satellites that operate day and night and can penetrate clouds. The uplift, centered near the summit, has persisted since July 2023 and has not subsided, indicating ongoing pressure. Pablo J. González, a senior author from the Spanish National Research Council's Institute of Natural Products and Agrobiology, leads the research. Taftan's remoteness and lack of ground-based instruments make space radar the ideal tool for monitoring this rarely visited mountain, despite its proximity to several towns. The study's findings suggest that the pressure source is located only 1,600 to 2,070 feet (490 to 630 meters) below the surface, indicating the presence of gases within a hydrothermal system. This shallow source is consistent with the timing and pattern of the uplift. The team ruled out heavy rain and nearby earthquakes as triggers, attributing the rise to internal processes within the volcano's edifice. Deeper within Taftan lies the magma reservoir, a substantial body of molten rock located over two miles (3.2 kilometers) underground. The current push is likely caused by gases above the reservoir rather than fresh magma reaching the surface. The pattern of uplift resembles a slow squeeze, with the ground initially rising and then stabilizing as new cracks open and gases find exit paths. The term 'extinct volcano' can be misleading, as Taftan, a 12,927-foot (3,940-meter) stratovolcano, continues to exhibit movement through summit fumaroles. Eruption records for the past 10,000 years are limited, and silence on paper does not equate to a dormant system in rock and gas. Volcanoes can exhibit prolonged inactivity followed by rapid changes in months. Scientists emphasize the importance of monitoring not only ash plumes but also gas, heat, and ground motion. The new deformation is a measurement, not a label, and it demands attention as pressure seeks an outlet, and the chosen route is crucial. 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 cause eye and lung irritation and damage crops downwind for a short time. The city of Khash, located 31 miles (50 kilometers) away, is close enough to smell sulfur when the wind aligns. González emphasizes that the study serves as a wake-up call for authorities in the region to allocate resources for monitoring. The team aims to measure gases at vents and slopes, providing continuous readings of sulfur dioxide, carbon dioxide, and water vapor levels to assess pressure changes. They also advocate for a basic network of seismometers and GPS units to capture ground shake and slow stretch, enhancing timing and reducing blind spots. Satellites will continue to monitor Taftan, with InSAR, a radar method tracking ground movement, enabling the detection of small changes that field crews can verify within days. Authorities can utilize this data to plan evacuation routes, create hazard maps, and provide guidance to nearby communities. Taftan's location in a subduction zone, where one tectonic plate slides under another, contributes to the presence of magma at depth and gas-rich fluids higher up. The volcano boasts two main peaks and long-lived gas vents, indicating ongoing heat flow from below. Many volcanoes worldwide exhibit similar slow changes that do not culminate in eruptions, while others rapidly intensify after quiet phases, necessitating swift action. Steady, routine monitoring is crucial for saving lives, transforming unforeseen issues into manageable problems with known solutions. The study's findings are published in Geophysical Research Letters. The satellite's ability to penetrate clouds and smoke, coupled with its day-and-night operation, makes it invaluable for monitoring remote, high-altitude areas with harsh weather conditions and failed stations. Sentinel-1's C-band radar, with its frequent passes, creates a motion 'movie,' which is essential for detecting minor changes. As more satellites are launched, revisit times decrease, enabling scientists to receive faster updates when conditions shift. Combining space and ground-based instruments provides the most comprehensive data. The future of Taftan volcano monitoring involves continuous gas measurements, with sharp changes in tiny quakes under the summit raising concern. Scientists will investigate whether the plumbing has remained tight or opened, guiding the potential magnitude of the next gas pulse. For nearby residents, simple precautions are advised, such as understanding wind patterns, keeping masks handy for sulfur odors, and adhering to official guidance. The study's publication in Geophysical Research Letters invites further exploration and discussion.
