Images

Teachers take a guided walk on the Hummocks Trail, learning about the depositional features of the May 18, 1980 eruption.

Todd Cullings, with the Mount St. Helens National Volcanic Monument, leads teachers in activities they can do with students before hiking the Hummocks Trail.

This geologic map of Mauna Loa shows surface flows that have been mapped as of 2013. The flows are color-coded to reflect age. Warm colors indicate younger flows, with red indicating flows erupted since 1832.

To better understand the physics of debris flows and to make more accurate hazards forecasts in the natural environment, scientists perform controlled experiments at the large-scale USGS debris flow flume facility.

This photo looks south towards Pu‘u ‘Ō‘ō, where a vent is supplying lava to the Kahauale‘a II flow, north of the cone. This slow-moving flow has reached the forest line, producing small scattered brush fires.

A close-up of the Kahauale‘a II flow burning vegetation at the forest line, just north of Pu‘u ‘Ō‘ō. The flow consists of numerous slow-moving pāhoehoe lobes.

Two ocean entry points remain active near Kupapa‘u Point, near the boundary of Hawai‘i Volcanoes National Park. The eastern entry has produced a larger plume than that at the western entry, which tends to be weak and wispy.

This photo looks south towards Pu‘u ‘Ō‘ō, where a vent is supplying lava to the Kahauale‘a II flow, north of the cone. This slow-moving flow has reached the forest line, producing small scattered brush fires.

The summit eruption in Halema‘uma‘u crater remains active. The lava lake is within the Overlook crater (the source of the gas plume), which is in the southeast portion of Halema‘uma‘u Crater.

Pagan Volcano is the largest and one of the most active volcanoes in the Northern Mariana Islands. Prior to 2013, the volcano was not monitored with any ground-based instruments, so activity was observed only by satellite or by the few island inhabitants. Although geographically remote, eruptions from Pagan can threaten international air traffic.

Camera captures SO2 released from Kīlauea's summit vent. HVO scientist tests the network link between the instrument and the Hawaiian Volcano Observatory.

Pu‘u ‘Ō‘ō was still close to its maximum height of 255 m (835 ft) in 1992 (top), although its western flank had been partly buried by a lava shield. Since then, the cone has lost a third of its former height due to collapses, and lava has continued to bury its flanks (bottom). USGS photos.

The spatter cone near the north rim of Pu‘u ‘Ō‘ō crater continues to produce pulsating gas jetting sounds. Compare this photo to one taken of the same cone on May 2 to see how much taller the cone has grown.

The small lava lake on the northeast rim of Pu‘u ‘Ō‘ō crater has been built into a small cone, with only a few small openings at the top. One of these small openings had sloshing lava near the surface.

Why did the lava tube cross the road? This image shows the Peace Day lava tube coming down the pali in Royal Gardens subdivision. The lava tube parallels Ali`i avenue, shown by the straight line of warm temperatures that represent asphalt heated in the sun.

HVO geologists use a laser rangefinder to measure the height of the shield and cone built up around the northeast lava lake, on the east rim of Pu‘u ‘Ō‘ō crater. The peak of the cone is now about 18 m (60 ft) above the former crater rim.

The spatter cone near the north rim of Pu‘u ‘Ō‘ō crater continues to produce pulsating gas jetting sounds. Compare this photo to one taken of the same cone on May 2 to see how much taller the cone has grown.

The small lava lake on the northeast rim of Pu‘u ‘Ō‘ō crater has been built into a small cone, with only a few small openings at the top. One of these small openings had sloshing lava near the surface.

Why did the lava tube cross the road? This image shows the Peace Day lava tube coming down the pali in Royal Gardens subdivision. The lava tube parallels Ali`i avenue, shown by the straight line of warm temperatures that represent asphalt heated in the sun.

The Kahauale`a II flow began as a breakout on the east rim of Pu‘u ‘Ō‘ō crater on May 6, and has advanced northward towards the forest. Today, slowly moving pāhoehoe lobes (light colored flows in this image) were burning moss and lichen on older Pu‘u ‘Ō‘ō ‘A‘ā flows and approaching the forest boundary. Pu‘u ‘Ō‘ō cone is obscured by thick clouds in this photo.

Do not be misguided by the risky actions of this person (upper right), who is standing on an active lava delta that could collapse without warning, amidst a plume of superheated steam, hydrochloric acid, and tiny particles of volcanic glass. To avoid these ocean entry hazards, HVO advises staying at least 400 m (one-quarter mile) from where lava enters the sea.