This photo shows the gas monitoring site layout at Sulfur Cone. On the left side of the photo is the power/telemetry system which powers the Multi-Gas instrument and sends data back to HVO via radio to be later analyzed by HVO gas scientists. The Multi-Gas instrument itself is located in the center right of the photo approximately 10 meters (30 feet) away from the power system. Gas and steam in the background is being emitted from a large fissure created during the 1950 eruption of Mauna Loa. USGS photo by M. Cappos.

The continuously monitoring Multi-Gas instrument at Sulfur Cone is housed inside the black Pelican case shown here. Air is pulled into the instrument via a small pump to be analyzed for volcanic gases (Sulfur Dioxide, Hydrogen Sulfide, Carbon Dioxide and Water Vapor). Meteorological parameters (Wind Speed/Wind Direction, Temperature/Humidity) along with fumarole temperature are also collected at the site. Monitoring the ratios of the different volcanic gases here can help HVO Gas Scientists identify any changes to the magmatic system beneath Mauna Loa. USGS photo by M. Cappos.

This photograph shows the inside of the Hawaiian Volcano Observatory (HVO) Multi-Gas site at Sulfur Cone. Currently, HVO has 2 of these continuous gas monitoring sites in operation on the Island of Hawai‘i. This one at Sulfur Cone high on Mauna Loa's Southwest Rift Zone, along with one at the summit of Kīlauea. Here is where the magic of measuring and monitoring concentrations of emitted volcanic gases (Sulfur Dioxide, Hydrogen Sulfide, Carbon Dioxide, and Water vapor) happens. Gas concentration data from these instruments are telemetered back to HVO to be viewed by HVO gas scientists. USGS photo by C. Sealing.

This photograph shows the inside of the Hawaiian Volcano Observatory (HVO) Multi-Gas site at Sulfur Cone. Currently, HVO has 2 of these continuous gas monitoring sites in operation on the Island of Hawai‘i. This one at Sulfur Cone high on Mauna Loa's Southwest Rift Zone, along with one at the summit of Kīlauea. Here is where the magic of measuring and monitoring concentrations of emitted volcanic gases (Sulfur Dioxide, Hydrogen Sulfide, Carbon Dioxide, and Water vapor) happens. Gas concentration data from these instruments are telemetered back to HVO to be viewed by HVO gas scientists. USGS photo by C. Sealing.

A Hawaiian Volcano Observatory gas scientist works on installing a newly calibrated Multi-Gas instrument at the Sulfur Cone gas monitoring site high up on Mauna Loa's Southwest Rift Zone at an elevation of 3,430 meters (11,240 feet) above sea level. USGS photo by M. Cappos.

A Hawaiian Volcano Observatory gas scientist works to install a newly calibrated Multi-Gas instrument at the Sulfur Cone site. At an elevation of 3,430 meters (11,240 feet) above sea level, the air is rare! Working conditions are far more strenuous for HVO field teams at these high elevations due to the much lower levels of oxygen in the air to breathe. Low and slow is the name of the game at these high altitudes. A buddy system is necessary while installing this highly sensitive equipment as high altitude can hinder mental acuteness...in this case, two brains are better than one! USGS photo by C. Sealing.