(Activity updates are written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)
HVO scientists performed some preliminary tests of the water at the caldera rim minutes after it was collected. The thermal image shows that the water sample, in the plastic bottles, remained hot. Initial testing of the Kīlauea summit crater lake water sample revealed a pH of 4.2. This value is acidic, though not as low as at some other volcanic lakes around the world, which can have pH values near or lower than zero. The conductivity of the water, related to the amount of dissolved solids, was above the upper limit of our current sensor. We were unsuccessful in obtaining a direct measurement of the lake’s temperature, but recent measurements by a thermal camera on the rim of the crater indicate a maximum water temperature of 65-75 ° C. More in-depth analyses of the water will be conducted by USGS colleagues at the California Volcano Observatory. USGS images by M. Patrick, 26 Oct 2019. 
The USGS and OAS team prepares the sampling mechanism and inspects the unmanned aerial system a few minutes before mission start and takeoff. Precautions were taken to ensure the aircraft and sampling mechanism were sterile and would return safely from the pond. Photo courtesy of U.S. Geological Survey
Kīlauea Volcano is not erupting and its USGS Volcano Alert level remains at NORMAL (https://volcanoes.usgs.gov/vhp/about_alerts.html). Updates for Kīlauea are now issued monthly.
Kīlauea monitoring data have shown no significant changes in volcanic activity over the past week. Rates of earthquake activity or seismicity across the volcano remain largely steady with three periods of increased microseismic activity each lasting a couple of days. Sulfur dioxide emission rates are low at the summit and are below detection limits at Puʻu ʻŌʻō and the lower East Rift Zone. The pond at the bottom of Halema‘uma‘u, which began forming on July 25, 2019, continues to slowly expand and deepen.
Mauna Loa is not erupting. Its USGS Volcano Alert level remains at ADVISORY. This alert level does not mean that an eruption is imminent or that progression to an eruption is certain.
During the past week, approximately 147 small-magnitude earthquakes (nearly all smaller than M2.0) were detected beneath the upper elevations of Mauna Loa. Most of the earthquakes occurred at shallow depths of less than 5 km (~3 mi) below ground level, but a couple were as deep as 12 km (~7.5 mi).
Mauna Loa updates are issued weekly. For more info on the status of the volcano, please go to: https://volcanoes.usgs.gov/volcanoes/mauna_loa/status.html
HVO continues to closely monitor both Kīlauea and Mauna Loa for any signs of increased activity.
Please visit HVO’s website (https://volcanoes.usgs.gov/hvo) for past Volcano Watch articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake info, and more. Call 808-967-8862 for weekly KILAUEA updates. Email questions to askHVO@usgs.gov.
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