Images

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.

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.

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.

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.

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.