Yellowstone Volcano Observatory 2021 annual report

First posted April 27, 2022 For additional information, contact: Contact YVOVolcano Science Center, Yellowstone Volcano ObservatoryU.S. Geological Survey345 Middlefield Road, MS 910Menlo Park, CA 94025 The Observatory (YVO) monitors volcanic and hydrothermal activity associated with the magmatic system, carries out research into processes occurring beneath Caldera, issues timely warnings guidance related to potential future geologic hazards. This report summarizes activities findings of YVO during year 2021, focusing on system. Highlights 2021 include deployments seismometers in Norris Geyser Basin Upper investigate geyser plumbing systems, semipermanent Global Positioning System array deployment from May October, geological studies post-glacial activity, refining ages units updating existing maps deposits, installation a new continuous gas monitoring station near Mud Volcano, sampling thermal waters around National Park monitor water chemistry over space time, assessment output based satellite imagery chloride flux rivers.Steamboat Geyser, Basin, continued pattern frequent eruptions that began 2018 20 2021—a significant decrease 48 occurred both 2019 2020. Total seismicity—2,773 located earthquakes—was elevated compared 1,722 earthquakes 2020, but not significantly outside historical average about 1,500–2,500 per year. Overall subsidence caldera floor, ongoing since late 2015 or early 2016, at rates few centimeters (1–2 inches) year, whereas deformation area was below detection levels. Satellite measurements indicate possibility slight uplift amounting 1 centimeter (less than inch) along north rim, south Basin. is similar which 1990s. Throughout aviation color code for Caldera remained “green” volcano alert level “normal.”