Images

A USGS Hawaiian Volcano Observatory geologist inspects the thermal camera at the summit of Mauna Loa on May 15, 2021.

On May 15, USGS Hawaiian Volcano Observatory geologists did a routine hike to the summit of Mauna Loa and inspected summit monitoring equipment. Clear weather provided good views across the floor of Moku‘āweoweo, Mauna Loa's summit caldera, and nothing unusual was observed.

Another GPS survey benchmark being occupied on Mauna Loa's north flank, with clear views of Mauna Kea in the background. The metal disk on the ground beneath the tripod is the benchmark, which is cemented to the lava flow surface.

On the west side of Mauna Loa summit, a campaign GPS (center-right) measures its location for a period of 2–3 days. This site has been occupied every year by helicopter since 1994. Mauna Kea, Hualālai and Haleakalā can be seen in the distance. USGS photo taken by S.

During the annual Mauna Loa GPS campaign, 33 campaign stations are occupied with GPS instruments for days to weeks. The stations are spread across the flanks of the volcano and provide a synoptic picture of deformation on the volcano over the past year.

Recently, HVO geophysicists completed the annual high-precision Global Positioning System (GPS) survey of Mauna Loa. The annual survey supplements HVO's continuous GPS monitoring stations and provides information on vertical and horizontal deformation of the ground surface.

GPS campaign survey stations high on the flanks of Mauna Loa offer expansive views of neighboring volcanoes. From this station located west of Mauna Loa summit, Hualālai volcano is visible. Most Mauna Loa GPS campaign survey sites have been occupied every year since 1996, whereas less active volcanoes Hualālai and Haleakalā are surveyed every 3–5 years.

This map shows the response time people can expect based on Mauna Loa eruptions over the past 200 years.  Different sectors around Mauna Loa are colored according to how quickly lava flows can reach populated areas.  The warmer the color, the more quickly the flows travel.

The former gas monitoring station in Moku‘āweoweo, Mauna Loa's summit caldera. Power and telemetry components of the station are to the right in the image, with solar panels. The gas sensors themselves were housed in the black box toward the lower left of the image.

A gravimeter measuring the force of gravity on Mauna Kea. These measurements are used to calibrate the instruments so they can precisely monitor changes in gravity from magma accumulation at Mauna Loa (background). USGS photograph taken on December 10, 2020.

This photo was taken from the west rim of Kīlauea caldera at dawn, and shows the moon setting over Mauna Loa's broad Northeast Rift Zone. USGS photo by M. Patrick.

Map of Waiʻōhinu area, Island of Hawaiʻi, showing the location of the 3,740 year old age.

Map of the USGS Hawaiian Volcano Observatory’s current camera network coverage.   Lava-flow hazard zone 1 is outlined in yellow.   Color-shaded areas are visible to at least one camera in the current network.  We would like to expand the network so that it covers the grey-shaded areas in zone 1 as well.  If your property has a good view

Aerial view of a bomb detonating on Mauna Loa near the source of the 1935 Humu‘ula lava flow on the morning of December 27, 1935. This was one of 20 demolition bombs dropped on the lava flow that morning by the Army Bombing Squadron from Luke Field, O‘ahu.

A U.S. Army Air Corps biplane is prepared for a mission to drop bombs on a lava flow advancing toward Hilo during the Mauna Loa 1935 eruption.

USGS Hawaiian Volcano Observatory scientists examine an outcrop of reddish-brown Hilo ash during a recent study to investigate the origins of volcanic ash deposits on the Island of Hawai‘i. Age dates of lava flows above and below the Hilo ash deposit indicate that the ash was erupted between 3,000 and 14,000 years ago. 

The recently published "Geologic map of the central-southeast flank of Mauna Loa" (https://pubs.er.usgs.gov/publication/sim2932B), shown here, uses color to depict ages of geologic units, with warm colors denoting younger units and cool colors indicating older units.

Volcano Awareness Month programs offered in January 2020 are depicted by these images. Clockwise from top left: ground cracks opened at HVO's former location atop Kīlauea in 2018; fissure erupting on Mauna Loa in March 1984; crater lake within Halema‘uma‘u at Kīlauea's summit; and visitors hiking a Kahuku trail in Hawai‘i Volcanoes National Park (NPS).

The 1880-1881 eruption of Mauna Loa produced lava flows that came within 1.7 km (1.1 mi) of the Hilo Bay shoreline. This painting by Charles Furneaux, "Night View 1880–1881, Eruption from Hilo Bay," illustrates the first two flows as they would have been in November 1880. In reality, however, both flows would not have been visible from this vantage.

_{Sulphur Cone (left), viewed toward southwest, from 3,480 m (11,420 ft) above sea level on Mauna Loa’s southwest rift zone. At right, an HVO geoscientist and technician rebuild volcanic gas monitoring equipment installed near an outgassing fissure.}
 

An early morning view looking north across Moku‘āweoweo, Mauna Loa's summit caldera, from a spot near the summit cabin on the volcano's south caldera rim. Frost covered much of the caldera floor that was still shadowed, and weak steaming issued from the usual areas. Overall, there were no significant changes observed at the summit.