USGS-HVO Re-samples The Keller Well On The Edge Of The Kilauea Caldera, Nearest Well To The Halema'uma'u Crater Lake. HVO field engineers and staff conducted quarterly work at a deep borehole, known as the Keller Well, at the summit of Kīlauea Volcano today (Sept. 24). They lowered a sensor into the well to measure the distance between the ground surface and the top of the water table, which was 505 m (1657 ft) below the ground surface today. With a water pond at the bottom of Halema‘uma‘u, continued measurements at the Keller Well site provide important data on how the local water table is recharging the summit area following the 2018 collapse events. The HVO team also collected a sample of water from the well. Chemical analyses of the water will be conducted to determine and track changes in its composition. For more information about the Keller Well, please see HVO's Dec. 20, 2018, "Volcano Watch" article: https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?vwid=1396 Images and caption by USGS-HVO, S. Warren Dane's Note: The Keller Well is the most relevant sampling site regarding the rising crater lake inside Halema'uma'u. The decades of USGS recording data at this deep borehole provides some insight on what could potentially happen with the new lake of water at the Kilauea Summit, like how big can expect it to get. The depth of water inside well varies over time, but the temperature is more constant at ~70degC, roughly the same temperatures as the water inside Halema'uma'u now. The lake inside Halema'uma'u now is roughly a football field in size (if you include one end-zone and a sideline) and over 30 ft deep. In a previous trip to the Keller Well following 2018 eruption, USGS found the water level to be 1,667 ft down (now at 1,657 ft), meaning in the year following the 2018 eruption the ground water level slightly risen ~10 ft, reversing the drop of the groundwater level observed after the eruption. Based on these measurements, and the depth of the Halema'uma'u collapse pit, I expect to water in the visible pool to continue to rise for months to come - until it reaches some equilibrium level with the water table. If this is the case, It's not close to halfway done filling yet as local ground water continues to recharge the summit area.