September 16, 2026      11:30am        POST 723

Helge Gonnermann

Professor, Rice University

Why is Kilauea’s current eruption episodic?

Basaltic volcanoes erupt episodically as lava fountains, where fountaining episodes are separated by intervals of no eruptive activity. Rather than continuous lava effusion at rates that are in balance with magma supply, Kilauea volcano has erupted with episodic fountaining since December 2024. I will show that the episodic character of the eruption is due to the existence of two possible eruption states. One of low eruption rates that are unstable and one of high eruption rates that are stable. Because the eruption rates during fountaining far exceed magma supply rates, fountaining depletes the underlying magma reservoir in pressure and magmatic vapor, causing the eruption to cease after a period of time. During repose periods, magma supply slowly replenishes the reservoir until magma once again begins to erupt at unstable low rates that are unstable and quickly transition to fountaining. This instability is called the Ledinegg instability and I propose that it is the cause for episodicity at Kilauea and likely elsewhere.