Albay province sits in the shadow of the most active volcano in the Philippines, and since January 2026, Mount Mayon has been reminding everyone why. Rockfalls rumble down its flanks. Sulfur dioxide drifts from the summit. A lava dome is growing. The volcano’s latest eruptive episode, its 66th entry in a record stretching back roughly 5,000 years, has pushed alert levels upward and forced communities within the permanent danger zone to prepare, once again, for the possibility that slow-burn unrest could tip into something far more violent.
A volcano that rarely stays quiet
Mayon’s eruption history is among the best-documented of any volcano in Southeast Asia. The Smithsonian Institution’s Global Volcanism Program (GVP), the world’s standard reference for volcanic activity, lists 65 confirmed eruptions during the Holocene period. NASA’s Earth Observatory cites the same figure. The current episode, which the GVP logged as beginning in January 2026 based on data relayed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), adds to that tally.
Weekly bulletins on the GVP profile describe the early weeks of the 2026 episode in a familiar sequence: initial rockfalls near the summit, rising sulfur dioxide output, and visible changes to the lava dome. PHIVOLCS, which monitors Mayon around the clock with seismometers, tiltmeters, and gas sensors, is the primary source for these observations. The pattern is consistent with what scientists call an escalation phase, where activity intensifies in steps rather than arriving all at once.
That pattern is not accidental. A peer-reviewed study published in the Bulletin of Volcanology and cataloged by the U.S. Geological Survey characterizes Mayon as an “open-vent” system. The researchers analyzed petrological data spanning eruptions from 1928 to 2009 and found that Mayon’s internal plumbing allows magma to rise and degas with relatively little obstruction. That efficient pathway produces frequent, shorter eruptive cycles rather than the centuries-long pressure buildups seen at sealed-system volcanoes. It also means transitions from quiet degassing to explosive eruption can happen with limited warning.
The open-vent model helps explain why 65 eruptions cluster so densely across the Holocene. Each cycle can range from mild lava effusion to pyroclastic flows that race down river valleys at hundreds of kilometers per hour. The deadliest event in Mayon’s recorded history, the 1814 eruption, buried the town of Cagsawa and killed more than 1,200 people. The most recent major eruption, in January 2018, forced more than 80,000 residents to evacuate as lava fountains and pyroclastic density currents swept the upper slopes. That episode lasted months before activity subsided.
What satellite and ground data show in 2026
Thermal anomalies detected by satellite sensors, including the TROPOMI instrument aboard the European Space Agency’s Sentinel-5P, confirm that magma is standing close to the surface. Elevated sulfur dioxide plumes tracked from orbit are consistent with active degassing through the open conduit. NASA’s Earth Observatory imagery corroborates the thermal signature at the summit.
On the ground, PHIVOLCS publishes daily bulletins from its observatory in Legazpi City, roughly 13 kilometers from the summit. Those bulletins track seismic events beneath the edifice, ground tilt measurements, and visual observations of the dome. As of mid-2026, the agency has maintained an elevated alert level, restricting access to the permanent danger zone, a radius that extends six to eight kilometers from the crater depending on the sector.
Roughly 300,000 people live within the broader hazard zones mapped around Mayon, according to provincial disaster management estimates cited during the 2018 eruption. Albay’s evacuation protocols, refined over decades, are considered among the most practiced in the Philippines. But the scale of any future displacement depends on whether PHIVOLCS raises the alert further, a decision driven by instrument readings that are shared in summary form but not as raw data through international channels.
What scientists still cannot answer
Several gaps limit what anyone can say with confidence about where this episode is headed.
The most significant is the absence of detailed, publicly available seismic and ground-deformation data for the 2026 episode in international databases. Ground deformation, the subtle swelling or subsidence of a volcano’s flanks, is one of the clearest indicators that magma is accumulating faster than it is being released. Changes in earthquake depth and frequency can signal whether fresh magma is intruding or whether rock is fracturing near the surface. The GVP summaries and NASA observations provide a broad picture, but they are secondary compilations. Without the underlying instrument readings, independent researchers cannot fully assess the pace of magma supply.
The scientific framework for interpreting Mayon’s behavior also has a temporal gap. The Bulletin of Volcanology study, the best available peer-reviewed analysis of the volcano’s magma system, is based on eruption data ending in 2009. No updated analysis incorporating 2026 gas measurements or recent magma chemistry has appeared in the journals reviewed for this article. That means the models used to judge whether Mayon is shifting toward a more explosive style have not been tested against the volcano’s current output.
One scenario volcanologists are watching for is a change in magma composition. Open-vent volcanoes can shift between effusive phases, where lava oozes from the summit, and explosive phases, where pressure builds and releases suddenly. If fresh, gas-rich magma is mixing with older, partially degassed material inside the conduit, the result could be a hybrid eruption combining both styles. Confirming or ruling out that scenario requires laboratory analysis of erupted material from the current episode, including crystal chemistry, volatile content, and microtextural evidence of magma mingling. That work takes time, and no results have been published yet.
The duration of the episode is equally uncertain. Past activity at Mayon has ranged from weeks-long bursts to multi-month campaigns with intermittent pauses. The 2018 eruption lasted from January into at least March before tapering. Whether 2026 follows a similar arc, or stretches into a longer pattern, depends on magma supply rates that are not yet fully characterized.
What to watch as the episode continues
For readers following Mayon’s activity, the most reliable signals will come from institutional monitoring sources rather than dramatic footage on social media. PHIVOLCS alert-level changes are the single most actionable indicator: the Philippine system runs from Alert Level 0 (no eruption in the foreseeable future) to Alert Level 5 (hazardous eruption in progress). Each step up triggers specific evacuation protocols and expands the restricted zone.
The Smithsonian GVP’s weekly reports compile observations from PHIVOLCS and satellite agencies into a running narrative that tracks changes over time. NASA Earth Observatory posts are less frequent but provide calibrated satellite imagery that can confirm or challenge ground-based reports. Together, these sources offer the clearest available picture of whether the eruption is intensifying, holding steady, or winding down.
What they cannot yet provide is a forecast. Mayon is one of the most studied volcanoes in the world, with a 5,000-year record that gives scientists a strong baseline for comparison. But even that record shows wide variability in eruption size and style. The 2026 episode could remain a slow, dome-building affair that gradually loses steam. It could also accelerate. The volcano’s open-vent architecture means the boundary between those outcomes is narrow, and the timeline for crossing it may be short. For the communities of Albay, that uncertainty is not abstract. It is the reason evacuation bags stay packed by the door.
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*This article was researched with the help of AI, with human editors creating the final content.
