December 2025

 

Mount Etna Eruption

The most dramatic event of the month was the sudden intensification of Mount Etna in Sicily. After weeks of elevated seismic signals, the volcano’s Northeast Crater fully reawakened on Christmas Eve. By December 26, the eruption transitioned into a violent explosive stage, sending jets of lava more than 1,000 feet into the air and casting massive ash plumes over eastern Sicily. The activity caused significant disruption to air travel, leading to dozens of delays at Catania Fontanarossa Airport.

Kilauea – Episode 38 & 39

In Hawaii, Kilauea marked the one year anniversary of its current episodic eruption cycle with two powerful events in December. On December 6, Episode 38 produced massive lava fountains that destroyed a USGS research camera and generated “tephra-nadoes,” which are swirling vortices of volcanic glass and ash. This was followed by Episode 39 on December 23, which saw fountains reaching heights of 1,400 feet. As of the final days of the month, the eruption has entered a pause, but rapid ground inflation suggests that the volcano is “recharging” for its 40th episode, expected to occur in early January.

Icelandic Unrest and Magma Accumulation

In Iceland, the Sundhnúkur crater row near Grindavík remained under a state of high alert throughout December. While a fresh fissure did not break the surface this month, the Icelandic Meteorological Office reported that magma accumulation beneath the Svartsengi region reached critical levels, surpassing 17 million cubic meters. This volume is comparable to levels seen before previous major eruptions in the area. This has led experts to warn that a new dike intrusion or eruption remains highly likely as the new year begins.

Other Activity

Several other volcanoes maintained high levels of activity throughout the month. Indonesia’s Mount Merapi sent dramatic pyroclastic flows down its southern flanks on December 21, prompting restricted access to nearby rivers. Meanwhile, Popocatepetl in Mexico and Fuego in Guatemala continued their daily rhythm of ash emissions and incandescent rock falls. In the Western Pacific, Russian volcanoes Bezymianny and Karymsky remained in continuous eruption, contributing to a busy month that saw over 40 volcanoes globally in an active state.