Images

During the Mauna Loa 1950 eruption, three large, fast-moving lava flows advanced down the west flank of the volcano, each crossing the main highway before reaching the ocean. The Ka‘apuna flow, shown here, traveled from the Southwest Rift Zone vent (7,800 ft elevation) to the coast in just 17 hours, creating a huge steam plume as lava flowed into the sea.

Photomicrograph of gabbroic inclusion in Ogres Brow basaltic andesite. A rock thin section is created by gluing a small piece of rock onto a glass slide, then grinding it down to a thickness of 30 microns (the average human hair is about 100 microns in diameter) so that light shines through it when examined under the microscope.

Brian Shiro in the Wind River Range, Wyoming during a National Outdoor Leadership School expedition. Photo courtesy B. Shiro.

During the first few days of Mount St. Helen's earthquake swarm in March 2016, the September Lobe monitoring station (located on the 1980-86 dome) was buried in deep snow and not transmitting data.

This map overlays a georeferenced thermal image mosaic onto the current map of the flow field near Pu‘u ‘Ō‘ō to show the distribution of active and recently active breakouts. The thermal images were collected during a helicopter overflight on March 25. The June 27th flow field as of March 25 is outlined in green for comparison.

In the western portion of Pu‘u ‘Ō‘ō Crater, there has been a small pit for nearly a year. The pit is about 60 m (200 feet) wide, and a small circular lava pond resides beneath the overhanging west rim of this pit.

HVO geologists walk along the edge of the inner crater in Pu‘u ‘Ō‘ō, making stops periodically to perform laser rangefinder measurements of crater dimensions.

shows one of the more vigorous breakouts on the flow field today.

Breakouts persist northeast of Pu‘u ‘Ō‘ō, with scattered activity along the north margin of the flow field at the forest boundary. One narrow lobe of lava has pushed through forest over the past few weeks, and is 7.6 km (4.7 miles) northeast of the vent on Pu‘u ‘Ō‘ō.

Another view, looking west, showing the activity along the forest boundary and northern flow margin. Scattered breakouts were burning forest in this area. In the upper left portion of the image, Pu‘u ‘Ō‘ō can be seen.

Last Saturday, March 19, marked the 8-year anniversary of the start of Kīlauea's ongoing summit eruption in Halema‘uma‘u Crater. Halema‘uma‘u spans much of the width of this photo, and the small inner crater in the foreground is the Overlook crater, which contains the active lava lake.

This map shows recent changes to Kīlauea's active East Rift Zone lava flow field. The area of the flow field on February 20 is shown in pink, while widening and advancement of the flow field as mapped on March 25 is shown in red. The yellow lines show the active lava tube system. Pu‘u ‘Ō‘ō lava flows erupted prior to June 27, 2014, are shown in gray.

This small-scale map shows Kīlauea's June2th lava flow boundaries on March 25, 2016, in relation to the eastern part of the Island of Hawai‘i. The area of the flow field on February 20 is shown in pink, while widening and advancement of the flow field as mapped on March 25 is shown in red. Pu‘u ‘Ō‘ō lava flows erupted prior to June 27, 2014, are shown in gray.

The altered and fractured rim of Pu‘u ‘Ō‘ō Crater is prone to small collapses. Portions of the eastern crater rim, shown here, have collapsed onto the crater floor, covering the recent lava flows with rubble.

USGS geologist Deborah Bergfeld measures the temperature of a thermal feature near Big Boiler at Bumpass Hell in Lassen Volcanic National Park.

USGS geologist Laura Clor (right) and Rachel Teasdale (California State University – Chico, left) collect gas samples from a thermal feature at Sulphur Works in Lassen Volcanic National Park.

USGS geologist Deborah Bergfeld collects a gas sample from a superheated (hotter than the boiling point) fumarole in Little Hot Springs Valley at Lassen Volcanic National Park.

Annotated photo of air-quality particulate monitoring instruments, showing temperature and humidity sensors, air-sample inlet tube, wind sensor, power supply, and communication connections.

Kīlauea Volcano's summit eruption began on March 19, 2008, and continues today. The lava lake is contained within the Overlook crater, which is set within the larger Halema‘uma‘u Crater. In this February 28, 2016, photo, the lava lake surface was just 30 m (100 ft) below the rim of the Overlook crater. Spattering is visible in the southeast portion of the lake.

Footprints made in muddy ash during Kilauea's 1790 eruption are reminders that people experienced the largest explosive eruption in Hawai‘i in 1,000 years. More than 80, and possibly several hundred, people were killed by the eruption soon after the footprints were made.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO₂ into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows the Lake Nyos pipe in operation.