Images

USGS Hawaiian Volcano Observatory scientists are closely monitoring recent signs of unrest on Mauna Loa, the largest active volcano on Earth. In this 1985 aerial photo, Mauna Loa looms above Kīlauea Volcano's summit caldera (left center) and nearly obscures Hualālai in the far distance (upper right). USGS photo.

TOP: Mauna Loa weekly earthquake rates between 2010 and September 17, 2015. Blue bars indicate the number of earthquakes that were located by the USGS Hawaiian Volcano Observatory seismic network. Earthquakes of all magnitudes are plotted. Subtle increases in earthquake rates started in mid-2013, while more obvious changes in rates started in 2014.

After 25 years of slumber, Mauna Loa woke with a spectacular, but short-lived, eruption that began just before midnight on July 5. Lava fountains soon erupted from fissures extending across the length of Moku‘āweoweo, Mauna Loa's summit caldera, and into the upper ends of the volcano's northeast and southwest rift zones.

On June 1, 1950, a 2.4-km (1.5 mi) long fissure erupted high on Mauna Loa's Southwest Rift Zone at 9:04 p.m. Minutes later, the roar of lava fountains could be heard up to 24 km (15 mi) away.

As magma rises toward Earth's surface, gases dissolved in the molten rock bubble out and escape through surface vents called fumaroles. HVO established sensors atop Mauna Loa in late 2005 to continuously monitor the concentration of carbon dioxide and sulfur dioxide gases and fumarole temperature within Moku‘āweoweo, the summit caldera.

USGS Hawaiian Volcano Observatory geophysicist Ingrid Johanson measures gravity with a gravimeter on the slope of Mauna Loa with Mauna Kea visible in the background. USGS photo.

Volcanic ash deposit at base of Uwēkahuna Bluff below Jaggar Museum. Photo by T.A. Jaggar on July 29, 1913. Ash deposit buried by lava flow in 1919. Standing man is circled. From HVO Record Book courtesy of Bishop Museum.

Earthquakes beneath Mauna Loa's summit prior to 1975 and 1984 eruptions. Green circles 0-5 km (0-3 mi) deep, red circles 5-10 km (3-10 mi) deep.

HVO gas geochemist Tamar Elias (entering data on laptop) coaches CSAV participants from Peru, Argentina, and Ecuador on gas geochemistry monitoring. 

Earthquakes at Mauna Loa from June 2013 to June 2015. Green circles are 0-5 km (0-3 mi) deep and similar to ones prior to 1975 and 1984 eruptions, but cluster of 5-10 km (3-6 mi) deep quakes missing.

Kīlauea Volcano's summit lava lake dropped from nearly overflowing on April 26, 2015 (left), to about 62 m (203 ft) below the newly created (by multiple overflows) vent rim on May 15, 2015 (right). USGS photos.

Kīlauea Volcano's summit lava lake continued to drop today (May 15, 2015).

Kīlauea Volcano's summit lava lake, which was about 12 m (40 ft) below the vent rim on April 25 (left), overflowed the vent rim for the first time at about 9:40 p.m., HST, on April 28. As of noon on April 29 (right), the lava lake had overflowed the vent rim several more times. These Webcam images capture the summit vent before and after the overflows.

Rocks from the crater wall fell into the summit lava lake and generated an explosion that threw large fragments of molten lava onto the rim of Halema‘uma‘u Crater, 85 m (280 ft) above the lake. Gas in the lava lake was rapidly released during the 10:20 am explosive event, causing the lava lake surface to drop a few meters (yards) after the explosion.

‘A‘ā lava flows erupt from the Northeast Rift Zone of Mauna Loa on March 25, 1984—the first day of the volcano's most recent eruption. USGS photo.

HVO geologists get fresh lava samples as close to the vent as possible. Once the sample is scooped from the pāhoehoe lobe, it is quickly quenched in a bucket of water to stop the growth of any crystals and to preserve the composition of the liquid lava.

The lava lake within Halema‘uma‘u Crater at the summit of Kīlauea on February 1, 2014.

This satellite image was captured on Tuesday, March 3, 2015 by the Landsat 8 satellite. Although this is a false-color image, the color map has been chosen to mimic what the human eye would expect to see. Bright red pixels depict areas of very high temperatures and show active lava. White areas are clouds.

This satellite image was captured on Saturday, February 14, by the Advanced Land Imager instrument onboard NASA's Earth Observing 1 satellite. The image is provided courtesy of NASA's Jet Propulsion Laboratory. Although this is a false-color image, the color map has been chosen to mimic what the human eye would expect to see.

This large-scale map uses a satellite image acquired in March 2014 (provided by Digital Globe) as a base to show the area around the front of Kīlauea's active East Rift Zone lava flow. The area of the flow on February 5 is shown in pink, while widening and advancement of the flow as of February 10 is shown in red.

This large-scale map shows the distal part of Kīlauea's active East Rift Zone lava flow in relation to nearby Puna communities. The area of the flow on February 5 is shown in pink, while widening and advancement of the flow as of February 10 is shown in red.