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Helicopter pilots and mechanics crucial for monitoring and observing active volcanoes

November 6, 2016 - 8:54pm

Ask almost any volcanologist and field technician what they consider to be the most important and yet potentially dangerous aspect of their work on active volcanoes and they will probably say, “flying in a helicopter to remote areas to make observations or install and maintain monitoring instruments and radio systems.”

Consider what it takes to land in the middle of a jagged lava flow or near the edge of a deep crater to service the monitoring network many dozens of times in a year. Or, landing at more than 30 sites on many different lava flows at least twice in the span of a week to complete an annual GPS survey to determine the way in which a volcano deforms from year to year.

Lava flows are highly irregular with surface relief measured in meters (yards), and almost never level even over the narrow width of a small helicopter’s skids. A pilot has to pick a landing spot to place the skids so they’re level side-to-side and front-to-back, and with plenty of room between the tail rotor and ground. On any single flight day, the pilot might have to repeat this maneuver a few dozen times.

One of the most challenging environments for a small helicopter’s capability and a pilot’s skill is flying at high elevation (considered above 8,000 feet above sea level). The helicopter’s rapidly turning rotors create lift to keep the aircraft aloft, but lift efficiency is strongly affected by air density. At high elevations, lower air density decreases lift, reducing maneuverability and the payload that a helicopter can carry.

The top of Mauna Loa volcano is at 3,680 feet above sea level. Since the 1984 eruption, we have installed dozens of instruments and radio hubs at high elevation, many of which have solar power and radio systems that need regular maintenance and upgrades. Just a few months ago, HVO installed new webcams on the volcano’s Southwest Rift Zone and south rim of the summit caldera as high as 13,275 feet.

These and many other monitoring stations on Kilauea, Hualalai and Mauna Kea volcanoes were installed, and subsequently maintained, with helicopter support. The skill and keen observational ability of pilots, and the resolve of mechanics working behind the scenes to maintain the helicopters, make it possible for us to work at remote sites again and again, and return home safely at the end of the day, every day.

Pilot skill is also critical to position the helicopter at just the right distance from and height above an active lava flow so that we can take a series of photographs (hundreds) and thermal video that allow us to create accurate maps of the flow that we routinely share with Civil Defense, post on the HVO website, and use for research. You can find recent examples of these at

A helicopter flight may appear as routine as driving to the grocery store, but thinking so invites misfortune. The professionalism shown by pilots and mechanics and their commitment to safe flight — witnessed every time we board their aircraft — means that we can perform our mission with confidence.

Mahalo nui loa to current and past companies, most of all to their pilots and mechanics, who, over the years, have made it possible to build and sustain one of the best volcano-monitoring networks in the world here on Hawaii Island.

Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.

Volcano Activity Updates

Kilauea continues to erupt at its summit and East Rift Zone. This past week, when measured directly, the summit lava lake level varied between 36-57 feet below the vent rim. The 61g lava flow continued to enter the ocean near Kamokuna. Activity has been concentrated at the front of the east delta. The lava flow does not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. During the past week, earthquakes occurred primarily beneath the summit and upper Southwest Rift Zone at depths less than 3 miles. Additional earthquakes occurred in the Kaoiki area of the east flank between Kilauea and Mauna Loa, mostly in the 3-7 miles depth range. GPS measurements continue to show deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone, with inflation occurring mainly in the southwestern part of the magma storage complex.

No earthquakes were reported felt on Hawaii Island this past week.

Visit for past Volcano Watch articles, Kilauea daily eruption updates, Mauna Loa weekly updates, volcano photos, recent earthquakes info, and more; call for summary updates at 967-8862 (Kilauea) or 967-8866 (Mauna Loa); email questions to

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