2025
Why Some Volcanoes Erupt Without Warning: Veniaminof Volcano, Alaska
Veniaminof erupts often, yet most of its recent eruptions arrived with little or no warning. Using computer models of a magma reservoir, this study shows how a volcano can reach the breaking point while staying almost silent to monitoring instruments.
The question
Veniaminof is one of Alaska's most active volcanoes and is watched by eight permanent seismic stations. Even so, only two of its 13 eruptions since 1993 were preceded by signals strong enough to prompt a warning from the Alaska Volcano Observatory, and satellite radar (InSAR) showed no clear ground movement around the 2018 eruption. Why do some volcanoes stay quiet right up to an eruption?
What I did
I built finite-element models of a magma reservoir being slowly filled beneath Veniaminof and ran a series of numerical experiments, changing the reservoir's size, shape, and depth, the rate of magma supply, and how the surrounding rock responds to heat. For each case I asked whether the rock around the reservoir would break, opening a path for magma to erupt, before the ground moved enough for satellites to see (about 1 cm) or before earthquakes were triggered.
What we found
Whether warning signs appear depends most on the behavior of the surrounding rock and on the rate of magma supply, followed by reservoir size, and then its depth and shape. Long-lived, thermally mature systems with small-to-moderate reservoirs are the most likely to be 'stealthy': they can fail and feed an eruption while producing ground movement below satellite detection and little or no seismicity.
Why it matters
A volcano that looks quiet is not necessarily safe. The results help explain the poor warning record at Veniaminof and are relevant to other 'stealthy' volcanoes in Alaska, such as Cleveland, Shishaldin, and Pavlof, and around the world. The study was covered by more than 30 news outlets in seven countries and featured by the UN Office for Disaster Risk Reduction.