(BIVN) - The ongoing Kīlauea summit eruption wihtin Hawaiʻi Volcanoes National Park remains paused.
Scientists with the USGS Hawaiian Volcano Observatory report "preliminary estimates suggest a new eruptive episode may begin as early as Sunday, February 23". The USGS Volcano Alert Level for Kīlauea remains at WATCH.
From this week's Volcano Watch article written by USGS HVO scientists and affiliates:
Kīlauea has been erupting episodically for the past two months in Halemaʻumaʻu, nested within the south end of Kaluapele, the summit caldera. Captivating lava fountains burst from the vent(s) during each eruption episode. Fascinating as those episodes are, scientists at the USGS Hawaiian Volcano Observatory (HVO) are equally as interested in what's happening beneath the surface between episodes.
Ten lava fountaining episodes have taken place in Halemaʻumaʻu since December 23, 2024, from two vents: the north vent and the south vent. Most fountaining episodes have been active for less than a day (16 hours on average), though a couple were longer duration (up to 8 days).
HVO staff rely on several key monitoring datasets to track the status of Kīlauea using a network of instruments across the volcano. A variety of seismoacoustic instruments record earthquakes and other ground vibrations, as well as low-frequency sound. Gas sensors sniff the volcanic gas emissions in areas downwind. Webcams, including the livestream camera, provide near real-time visual and thermal views. Ground deformation is documented using GPS units and tiltmeters. Together, these datasets can be used by scientists to analyze the processes occurring within Kīlauea.
In between each lava fountaining episode, monitoring datasets, like tilt, seismicity, and gas emissions, have shown similar behaviors. This repeating nature of activity has allowed HVO scientists to identify patterns that can be used to estimate windows of probability for future eruptive episodes in Halemaʻumaʻu.
When lava fountains are erupting in Halemaʻumaʻu, ground deformation instruments -- tiltmeters, in particular -- show deflation as magma that was stored in the volcano is erupted on the surface. In between lava fountaining episodes, those sensors show inflation as magma again accumulates beneath the surface and repressurizes the magma chambers. The amount of repressurization required for a new episode to start has ranged from 2-10 microradians, taking anywhere from a day to nearly two weeks. This range of repressurization is what informs HVO's probability estimates for when a new episode most likely will begin. The rate of inflation can vary, though, which causes the probability window for the start of the next episode to be shifted in time.
While deformation shows us how magma is behaving underground between episodes, we also have data telling us that surface activity continues even while fountaining is paused. During episodes of lava fountaining, the rumblings of magma making its way out of the conduit produce an intense tremor signal seen on seismic stations across Kīlauea. The tremor rumbles at lower frequencies, caused by rapid expansion and contraction of magma within the vents. These continuous vibrations result from the formation and release of gas bubbles that drive the fountains high into the air.