Overview

• Geologists conducting routine temperature station maintenance in April 2025 discovered the previously undocumented milky blue pool in the Porcelain Basin subbasin.
• High-resolution satellite images show no feature before December 19, 2024, a small cavity by January 6, 2025, and a fully water-filled pool by February 13, 2025.
• An infrasound station recorded several weak acoustic signals on December 25, 2024, January 15 and February 11, 2025, without accompanying seismic activity, indicating multiple small blasts.
• The new feature spans about 13 feet across, holds 109 °F water that sits roughly 1 foot below its rim and is ringed by light-gray, silica-rich mud and rocks.
• Located well away from boardwalks and trails, the pool poses no risk to visitors and remains under continuous USGS monitoring.