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May 5, 2022

An eruption at Kīlauea's summit began at approximately 3:20 p.m. HST on September 29, 2021. Lava activity is confined within Halema‘uma‘u crater, in the closed area of Hawai‘i Volcanoes National Park.

HVO scientists collect detailed data to assess hazards and understand how the eruption is evolving at Kīlauea's summit, all of which are shared with the National Park Service and emergency managers. Access to this hazardous area is by permission from, and in coordination with, Hawai‘i Volcanoes National Park.

May 5, 2022 — Kīlauea Summit Gravity Survey

Color photograph of scientists in field
Over several weeks in April, USGS Hawaiian Volcano Observatory scientists, along with visiting scientist from other volcano observatories, conducted ​the annual Kīlauea microgravity survey. Gravimeters measure gravitation attraction and they help scientists detect subtle changes in gravity caused by magma movements (learn more in this "Volcano Watch" article:…). USGS scientists also installed new continuous, telemetered gravimeters, on the floor of Kīlauea caldera will allow HVO to monitor changes in gravity real-time. USGS photo by A. Ellis.
Color photograph of scientists in field
During a gravity survey, HVO scientists measure the relative strength of gravity (using a gravimeter, one of the small light-colored boxes in the center of the photo) between benchmarks. At each benchmark, the effects of elevation changes are corrected using high-precision vertical positions from kinematic Global Positioning System (using a GPS, on a tripod and antenna in the foreground of the photo). USGS photo by A. Ellis.
Color photograph of scientist in field
HVO scientists took ​GPS measurements at multiple locations on the floor of Kīlauea caldera during the recent gravity survey. By comparing the measurements made at these benchmarks with survey data from previous dates, HVO scientists can ​correct for any uplift or subsidence when estimating the change of mass ​from their gravity measurements. The results of this survey will be interesting given the activity at the summit of Kīlauea over the past several years. USGS photo by A. Ellis.