The ongoing eruption at Kīlauea’s summit is paused, with the next episode of lava fountaining expected next week. According to USGS research hydrologist Shaul Hurwitz, water plays a crucial role in the volcano’s eruptions.
When most people think of erupting water, they likely think of geysers like Old Faithful. However, Kīlauea’s unique style of eruptions are also significantly impacted by water. In fact, some past explosive eruptions occurred when magma erupted through groundwater or a lake in the summit crater.
Groundwater seeps into the ground due to the volcano’s shallow basaltic rocks having high permeability. This allows large amounts of rain to penetrate the soil rather than flowing in streams. When this water is beneath the ground, it’s referred to as groundwater.
Measurements made at a deep well on Kīlauea’s summit have provided valuable information about the depth of groundwater. Until the 2018 eruption, the water level varied between 1600-1620 feet below the surface. After the eruption, it dropped to around 1660-1670 feet. This is approximately 2400 feet above sea level.
Chemical analysis of well water has revealed that while the water contains significant amounts of sulfur and chlorine from the magma, it’s predominantly meteoric – meaning it originates from the atmosphere.
At Kīlauea, water affects the volcano’s explosivity, rock texture, and gas emissions. The USGS Volcano Alert Level for Kīlauea remains at WATCH.
Source: https://www.bigislandvideonews.com/2025/08/15/volcano-watch-the-role-of-water-in-kilauea-eruptions