USGS upgrades Hawaiian geodetic network to monitor volcanoes

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The US Geological Survey’s Hawaiian Volcanoes Observatory (HVO) is working to rebuild its geodetic monitoring network after lava consumed several GNSS stations in 2018.

Work began following Kīlauea’s 2018 Lower East Rift Zone eruption and summit collapse, with funding from the Supplementary Disaster Relief Supplementary Appropriations Act of 2019 (HR 2157).

Teams are rebuilding and improving HVO’s geodetic monitoring network to better detect, assess, and respond to volcanic hazards associated with Hawaiian volcanoes. The primary geodetic datasets used by HVO scientists to measure surface deformation (ground motions) are GNSS imagery, tilt, and satellite radar (InSAR).

HVO’s geodetic network includes more than 70 GNSS stations and 15 inclinometers on the island of Hawai’i that continuously record and transmit data. These instruments require routine maintenance, must be upgraded periodically due to their age, and must be replaced if destroyed by volcanic activity such as in 2018.

Network upgrades include replacing obsolete instruments and enhancing HVO’s near real-time monitoring instrument network in critical areas of Kīlauea’s summit and rift zones to support early motion detection magma and associated dangers.

The lava comes out of the stations

In 2018, lava flows destroyed three GNSS stations in the lower East Rift Zone. Three other GNSS stations were destroyed during the collapse of the caldera atop Kīlauea.

HVO personnel quickly deployed new GNSS stations nearby to allow continuous monitoring during the eruption. These rapidly deployed sites included GNSS smart antennas mounted on survey tripods – a setup typically used only for temporary deployments lasting days to weeks.

Many of these rapidly deployed sites were decommissioned and retired after 2018. However, 13 of them are still in use for critical surveillance and remain on temporary tripods. These sites will be modernized and reinforced with bollards and fixed masts. New sites will also be installed to replace the sites destroyed in 2018.

A temporary GNSS monitoring site in the Kīlauea caldera was part of the rapid response to the December 2020 Halema’uma’u eruption. The site will be upgraded to a continuously operating reference station with state-of-the-art instrumentation and a mast reinforced antenna. (Photo: USGS/AP Ellis)

Ongoing emergency monitoring

GNSS receivers acquired with additional funds have already supported emergency monitoring of active eruptions and other volcano-related activities. Data from these instruments helps HVO detect volcanic activity and inform partners at Hawaii Volcanoes National Park (HAVO), Hawaii County Civil Defense (HCCD), and the management agency Hawaii Emergency Department (HI EMA).

For example, HVO quickly deployed three new semi-continuous GNSS stations in response to Kīlauea’s December 2020 eruption. These stations gave scientists a more comprehensive view of magma returning to Kīlauea’s summit.

Similarly, HVO deployed rapid-response GNSS equipment to two pre-existing landmarks during the Kīlauea South Caldera intrusion event of August 2021, allowing scientists to track the migration of magma from the South Caldera to greater South. New instruments give HVO a more detailed understanding and ability to monitor Kīlauea’s volcanic processes.

HVO’s geodesy program plays a vital role in monitoring Hawaiian volcanoes. HVO’s updated geodetic network ensures that scientists can monitor changes in the shape of volcanoes, respond to eruptions, and understand the storage and movement of magma underground.

“With additional funding, HVO is in the best position to leverage our state-of-the-art geodetic network to better understand Hawaii’s active volcanoes, assess their hazards, issue warnings]and advance scientific understanding to reduce the impacts of volcanic eruptions,” said Volcano Watchthe HVO’s weekly bulletin.

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