Images

The 1949 eruption of Mauna Loa began, and remained, within the summit region. However, the 1949 eruption did generate several small lava flows that traveled a few miles south, southeast, and southwest. The 1949 eruption lasted for approximately 144 days, and generated the cone pictured here, extending from above the southwest caldera wall to the caldera floor.

Plot showing the magnitude and time of earthquakes in the October 2022 Pāhala sequence. The magnitude 5.0 mainshock is shown in blue and the aftershocks with 6.2 miles (10 km) of that event are shown in yellow to red with the color based on their time of occurrence. USGS plot. 

Hawaiian Volcano Observatory Mauna Loa monitoring data showing increased ground deformation rates (top) and earthquake rates (bottom) from August 8 through October 5, 2022.

“Noisy” InSAR interferogram examples covering the Island of Hawaiʻi. (A) shows data that spans 12 days. This InSAR image show similar concentric ring patterns over both Mauna Loa and Mauna Kea.

On September 8, 2022, Hawaiian Volcano Observatory staff replaced the gas measurement station at Sulphur Cone on the Southwest Rift Zone of Mauna Loa. Field staff (in orange) and the gas monitoring station are visible right of center in this aerial view, which also shows the 1950 fissure and Sulfur Cone.

Sulphur Cone, high on the Southwest Rift Zone of Mauna Loa, was blanketed by sulfur crystals when it was named in 1921. A subsequent visit noted that molten sulfur had flowed down the flank of the cinder and spatter cone. The remnants of that yellow flow can be seen here on the flank of the cone.

The gas monitoring site at an elevation of 3,430 meters (11,240 feet) above sea level on the Southwest Rift Zone of Mauna Loa measures volcanic gases (sulfur dioxide, hydrogen sulfide, carbon dioxide and water vapor), fumarole temperature, and meteorological parameters.

A photograph showing the inside of the Hawaiian Volcano Observatory (HVO) gas monitoring site at Sulphur Cone, high on the flanks of the Southwest Rift Zone of Mauna Loa. This MultiGas station is one of several that HVO has deployed on the Island of Hawai‘i.

At the Sulphur Cone MultiGas station on the Southwest Rift Zone of Mauna Loa, a thermocouple is housed within plastic tubing to protect it from the harsh environment. The thermocouple, which measures temperature, is inserted into a nearby fumarole (an area emitting volcanic gases) to detect subsurface changes in temperature. USGS image by T. Elias.

Sulfur features northeast of Sulphur Cone at an elevation of 3,430 meters (11,240 feet) above sea level. Sulfur has a low melting temperature, about 112 degrees Celsius (234 degrees Fahrenheit), slightly above the boiling point of water.

Hawai‘i residents may find this photo reminiscent of the Ha‘akulamanu (Sulphur Banks) area of Hawai‘i Volcanoes National Park, though the photo was taken high up on the Southwest Rift Zone of Mauna Loa! In an area known as Sulphur Cone, at an elevation of 3,430 meters (11,240 feet) above sea level, there are bright-yellow crystalline sulfur deposits present.

A Hawaiian Volcano Observatory scientist peers into the fissure that erupted in 1950 from the Southwest Rift Zone of Mauna Loa near Sulphur Cone. Water vapor and sulfur gases are still emitted from this fissure and surrounding area, which is at an elevation of 3,430 meters (11,240 feet) above sea level.

Plots showing Mauna Loa ground deformation and earthquake monitoring data between midnight August 1 and midnight August 3, 2022. The top panel shows ground tilt in microradians at station MOK, on the northwest side of Mauna Loa’s summit caldera. A histogram showing the number of located earthquakes that occurred per hour is shown in the middle panel.

Map showing located earthquakes below Mauna Loa summit region between midnight August 1 and midnight August 3, 2022. Orange earthquakes are below sea level whereas red earthquakes are above sea level; earthquakes are sized by magnitude.  

Recent Sentinel-1 interferogram for the period from June 7 to July 13, 2022 covering the Island of Hawai‘i. Each color fringe represents 2.83 centimeters (1.11 inches) of ground displacement. There is evidence for a few millimeters of inflation at Mauna Loa, and no noteworthy deformation at Kīlauea during this time span.

HVO geologist Frank Trusdell collects a sample of lava from the fissure 8 channel during Kīlauea Volcano's lower East Rift Zone eruption in July 2018 (A. Hara). Inset photo shows Trusdell presenting an update on Mauna Loa for a West Hawaii Community Forum in February 2018 (Laura Ruminski/West Hawaii Today).  

Aerial view of the western portion of Halema‘uma‘u crater at the summit of Kīlauea, taken during a Hawaiian Volcano Observatory geology monitoring overflight on July 19, 2022.

Aerial view of Mauna Loa taken during a Hawaiian Volcano Observatory overflight of Kīlauea summit on July 19, 2022. USGS image by K. Mulliken. 

An aerial view of the Sulphur Banks area and Ha‘akulamanu trail within Hawai‘i Volcanoes National Park taken during an overflight of Kīlauea summit on July 19, 2022. Hawaiian Volcano Observatory gas geochemists sample fumaroles in the Sulphur Banks area approximately every three months to track long-term changes in volcanic gas chemistry at Kīlauea.

Image of the cover of "Report of the Hawaiian Volcano Observatory of the Massachusetts Institute of Technology and the Hawaiian Volcano Research Association."

Rubbly ‘a‘ā from the 1855–56 Northeast Rift Zone eruption of Mauna Loa dominates the foreground of this image, taken from a pull-off of the Saddle Road on June 26, 2022. This lava flow bypassed some vegetation, forming the forested kīpuka in the middle of the image. The slopes of Mauna Loa are visible in the background, amongst a cloudy sky. USGS photo by K.