Images

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.

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.

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.

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.

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).  

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.

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

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.

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.

Map of the Southwest Rift Zone of Mauna Loa, using data from the Geologic Map of the State of Hawaiʻi (Sherrod and others, 2021). Lava flows erupted in 1950, 1926, 1919, 1916, 1907, 1887, and 1868 are shown in different colors on the map. Basemap sources: ESRI, HERE, Garmin, Intermap, increment P Corp. USGS map. 

A geologist examines a two-meter-thick (7 feet) tephra outcrop on the southeast flank of Mauna Loa. USGS photo by J.M. Chang.

At approximately 8:15 a.m. on March 2, 2022, HVO geologists conducted an overflight of Kīlauea's summit. The eruption, which resumed several hours earlier, at approximately 1 a.m., continues within Halema‘uma‘u crater. In this photo, active lava is visible near the west vent, near the center of the image, and Mauna Loa looms in the background. USGS image by F.

Types of explosive clasts found in the debris fan deposits at the summit of Mauna Loa: (A) unaltered ponded lava flow, (B) unaltered pāhoehoe, (C) altered ponded lava flow, often has a red to pink hue, (D) thermally altered pāhoehoe, often has a red-to-pink hue, (E) gabbroic xenolith, the most crystalline rocks we found, (F) bread-crust outer surfaces and vesicular

Two weeks of earthquake activity preceding the September 29, 2021, eruption at Kīlauea summit. The regions of interest indicated on the map include: KS (Kīlauea summit); ML (Mauna Loa summit); P (Pāhala).

Over the past few months, HVO geophysicists have been conducting the annual high-precision Global Positioning System (GPS) survey of Kīlauea. The annual survey supplements HVO's continuous GPS monitoring stations and provides information on vertical and horizontal deformation of the ground surface.

Annotated MKcam image, taken on May 29, 2021. The new MKcam is positioned on Mauna Kea with a south view of Mauna Loa summit and Northeast Rift Zone.

Map and plot showing earthquakes at 20-40 km (12-25 miles) depth beneath the Island of Hawai‘i over the past week. Most of the earthquakes at this depth were clustered beneath the southern edge of the island near the town of Pāhala (blue dots).  USGS graphic.