Summit Inflation at Kīlauea Improves Forecasts of Rare Lava Fountain Episodes

Scientists monitoring the summit of Hawaii's Kīlauea volcano say that recent swelling of the crater floor is giving them a clearer window into when the volcano may produce episodic lava fountains, a phenomenon that occurs only at a handful of active volcanoes worldwide.

Unlike continuous lava flows, episodic lava fountaining involves bursts of molten rock and gas that can last for several hours, followed by quiet periods that may stretch from days to weeks. The irregular rhythm makes prediction difficult, but the bursts are strikingly energetic, sending molten material high into the sky and posing hazards to nearby residents, aviation routes, and infrastructure.

Researchers rely on a suite of geophysical tools to track subtle changes beneath the surface. High‑precision GPS stations measure uplift of the summit, while tiltmeters record the tilt of the ground, and seismic networks capture the tremors that accompany magma movement. Increases in summit elevation signal that magma is accumulating, raising pressure in the conduit that feeds the vent.

In the past several months, the summit has risen by a few centimeters, a change that exceeds the background noise of the instrument network. Modeling this uplift suggests that the magma chamber is nearing a pressure threshold that historically precedes a lava‑fountain episode at Kīlauea. Past eruptions have shown a pattern where summit inflation is followed by a short lull and then the onset of fountaining, giving authorities valuable lead time to issue alerts.

The ability to anticipate these rare eruptions is more than an academic exercise. Early warnings allow emergency managers to advise communities on evacuation routes, protect air traffic from volcanic ash, and prepare infrastructure for possible lava impacts. Ongoing monitoring and refined models are expected to improve forecast accuracy further, turning what was once a surprise event into a manageable hazard for the island's residents and visitors.