Hawai'i Volcano Blog

Volcano Watch: Volcano monitoring can be a risky business: How scientists work safely

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

Active volcanoes are inherently hazardous places to work. Even when a volcano is quiet, volcanic gases, ground cracks, earthquakes, and uneven surfaces can be unsafe. Advanced planning and preparation for fieldwork in these environments is critical to reducing the personal risk of volcanic hazards to field crews.

At the USGS Hawaiian Volcano Observatory (HVO), field work is critical for monitoring and understanding our volcanoes. All the time spent in the field exposes staff to many potential hazards, whether or not they are working in areas near active eruptions. Staying safe while performing mission-critical work is our main priority.

An HVO scientist clears tephra from a solar panel during the September 2021 Kīlauea summit eruption. A glove is used to brush away the Pele’s hair and other fine volcanic glass fragments to avoid small cuts and splinters. While working within the closed high-hazard area at Kīlauea summit within Hawaiʻi Volcanoes National Park, hardhats are used to protect the wearer from falling tephra. Gas masks are worn around the neck for quick protection if volcanic gas concentrations escalate or the wind shifts suddenly, even during non-eruptive periods. HVO access to the closed area is by permission from, and in coordination with, HVNP. USGS photo.

Most of HVO’s field sites are more than one hour from definitive medical care, so staff take Wilderness First Aid training which prepares them for a variety of injuries and illnesses. Heat-related illnesses, hypothermia, and altitude sickness are major concerns with the wide range of environments on Hawaiian volcanoes from sea level to over 13,000 ft (3,960 meters) elevation.

When working in hazardous conditions fieldwork typically includes at least two people for situational awareness, to decrease the amount of time needed to complete a task in potentially dangerous conditions and helping a field partner in case of injury or illness. Each crewmember carries at least two modes of communication just in case there is no service or the device batteries are depleted. Commonly used communication devices include cell phones, radios, satellite messaging devices, and satellite phones.


Before fieldwork starts, the crew will discuss the work that needs to be done, identify any potential hazards that may be encountered, and what can be done to mitigate those hazards. For example, if a crew is dropped off at a remote site by helicopter, they will bring extra food and water along with overnight gear in case weather conditions prevent the helicopter from extracting them.

Each field crew designates a point of contact (POC). The crew will check in with the POC before they begin fieldwork, and again when they end for the day. The POC will communicate any relevant information to field parties, including significant changes in monitoring data and weather that might warrant an immediate cancellation of fieldwork. In extreme cases, the POC will initiate search and rescue procedures if the crew fails to check out or cannot be reached.

We avoid working in high-hazard locations whenever possible, but sometimes field crews need to access these areas for mission-critical work. When this is the case, additional safety precautions are taken. Hazardous areas, such as the closed areas of Hawaiʻi Volcanoes National Park (HVNP) are only accessed by essential crews who carry personal protective equipment (PPE) with them. Common PPE used in the field by HVO staff include respirators to filter volcanic gases, gas badges to monitor sulfur dioxide (SO2) concentrations, along with helmets and eye protection. When molten lava sampling, crews will carry a face shield, fire-resistant clothing, and gloves to protect the wearer from radiating heat. HVO access to the closed area is by permission from, and in coordination with, HVNP.

Numerous other hazards can be encountered on volcanoes in Hawaii. Earthquakes can occur without warning and increase the hazard of rockfalls, ground cracking, and cliff instability, especially around the rim of Halema‘uma‘u crater at the summit of Kīlauea.


Even seemingly benign environments have associated hazards. For example, the surfaces of lava flows, even ones that are decades old, are uneven and sharp. They can be difficult to walk on, with tripping hazards and possibility of lacerations if you fall. There are many sub-surface void spaces below seemingly solid ground, which can cause injuries such as ankle sprains or cuts if you break through. Volcanic gas levels can also remain hazardous near vents even after an eruption has ceased. When visiting HVNP it’s important to stay on marked trails and not enter any closed areas.

Visiting Hawaii’s volcanoes is an awe-inspiring experience, but it can also be a hazardous one if you aren’t careful. HVO staff are aware and prepared; you, too, should stay informed and be familiar with volcanic hazards and HVNP safety tips before hitting the trails.

Volcano Activity Updates

Kīlauea is not erupting. Its USGS Volcano Alert level is ADVISORY.

The unrest associated with the intrusion that began in early October southwest of Kīlauea’s summit continues. Seismic activity in the south part of Kīlauea’s caldera has been elevated over the last week and a small swarm of earthquakes occurred around on November 21 in the upper East Rift Zone. Unrest may continue to wax and wane with changes to the input of magma into the area and eruptive activity could occur in the near future with little or no warning. The most recent sulfur dioxide (SO2) emission rate for the summit—approximately 100 tonnes per day—was measured on November 17.


Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.

Webcams show no signs of activity on Mauna Loa. Summit seismicity has increased slightly in the past month, while ground deformation indicates slow inflation as magma replenishes the reservoir system following the 2022 eruption. SO2 emission rates are at background levels.

Two earthquakes were reported felt in the Hawaiian Islands during the past week: a M3.3 earthquake 13 km (8 mi) S of Fern Forest at 7 km (4 mi) depth on Nov. 20 at 9:45 a.m. HST and a M3.0 earthquake 6 km (4 mi) S of Volcano at 2 km (1 mi) depth on Nov. 21 at 8:01 a.m. HST.

HVO continues to closely monitor Kīlauea and Mauna Loa.

Visit HVO’s website for past Volcano Watch articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake information, and more. Email questions to [email protected].

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