Images

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.

The four-tiered USGS Volcanic Activity Alert-Notification System uses Volcano Alert Level terms and Aviation Color Codes to inform people about a volcano's status and potential volcanic ash hazards. For more information about this system, please see http://pubs.usgs.gov/fs/2006/3139/.

This map overlays a georeferenced thermal image mosaic onto a map of the flow field to show the distribution of active and recently active breakouts. The thermal images were collected during a helicopter overflight of the flow field on September 11. The June 27th flow is outlined in green to highlight the current flow margin.

This small-scale map shows Kīlauea's active East Rift Zone lava flow in relation to the eastern part of the Island of Hawai‘i. The area of the flow on August 26 is shown in pink, while widening and advancement of the flow as of September 11 is shown in red. The yellow lines show the active lava tube system.

There has been no significant change on the flow field northeast of Pu‘u ‘Ō‘ō, and some of the active flows continue to creep into the forest along the north edge of the flow field, as seen here, looking roughly northwest. Activity has been remarkably stable and consistent, with no overall advancement of the flows, for the last several weeks.

View of Pu‘u ‘Ō‘ō crater, looking northwest. The floor of the crater was paved in late August by lava that erupted from a vent at the northeast edge of the crater, which is the heavily fuming area to the right.

Photo of Pu‘u ‘Ō‘ō west of the crater, looking north-northwest. The west edge of the crater is to the right. The western pit, with the lava pond, is just above and left of center. Notice the vaguely arcuate line of fume that wraps from the south edge of the crater, around the western pit, and back to the northwest edge of the crater in the background.

George Kojima, circa 1959, analyzing volcanic gases using the Hawaiian Volcano Observatory's state-of-the-art (at the time) mass spectrometer. USGS photo.

USGS\AVO seismologist works to replace an old seismometer at seismic station LSSA on Little Sitkin Volcano in the western Aleutian Arc.

AVO seismologists work to repair a seismic station on Little Sitkin Volcano in the western Aleutians Islands.

This satellite image was captured on Wednesday, September 2, 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.

A large breakout from the lava tube on the north side of Pu‘u ‘Ō‘ō yesterday (August 27) formed a large channelized flow, but it did not last long. The activity died in the evening, the same day, and traveled only about 500 m (about 550 yards).

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.

A tiny lava pond, about 10 m (33 ft) across, was visible within a vent near the south edge of Pu‘u ‘Ō‘ō's crater. Can you spot it? It's near the center of the photograph.

View of Pu‘u ‘Ō‘ō crater, looking south. The floor of the crater was resurfaced yesterday (August 27) by lava flows erupting from a vent at the northeast edge of the crater (fuming area to the left).

View of Pu‘u ‘Ō‘ō from the south side, looking north. The current crater in Pu‘u ‘Ō‘ō is only about half the diameter of Pu‘u ‘Ō‘ō's previous crater, which is defined by the rim of the tephra cone remnants in the foreground and background. That older crater's western edge extended to about the left edge of the photograph.

A piece of the new flow on the crater floor was collected for chemical analysis. Can you spot the USGS geologist collecting the sample? He is just below the center of the photograph. The small lava pond is just above center, partly hidden by a small spatter mound.

Yesterday's lava flows in Pu‘u ‘Ō‘ō erupted from a vent at the northeast edge of the crater and added a new layer to the crater floor. This photograph looks northeast across the relatively smooth crater floor toward the vent that erupted, which is a spatter cone that appears as a faintly visible mound in the fume in the background.

This photo is from within the crater, looking back at the USGS scientist who took the adjacent photo.