Time-lapse thermal image movie of Halemaumau Overlook Vent. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Overlook Vent. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse movie of Halemaʻumaʻu Overlook Vent from Hawaiian Volcano Observatory. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse movie of KÄ«lauea Caldera from Hawaiian Volcano Observatory. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Crater looking Southwest. September 7-14, 2017. Images courtesy of Hawaii Volcanoes National Park

This panorama, taken from the eastern rim of Halema‘uma‘u, shows the lava lake within the Overlook crater. The lake surface this morning was about 40 meters (130 ft) below the floor of Halema‘uma‘u. Mauna Loa spans much of the skyline near the center of the image; HVO and Jaggar Museum can be seen on the distant caldera rim (right side of image). Photo taken Wednesday, September 13, 2017 courtesy of USGS/HVO

Wispy fumes provided a clear view of the western wall of the Overlook crater this morning. Just above the lake surface (bottom of photo), a “bathtub ring” extends up the wall several meters, marking a recent high stand of the lake. Above that, a thick span of red, white and yellow rock is exposed in the crater wall. The colors originate from oxidation and alteration of older lava that filled Halema‘uma‘u in the 1960s and 1970s. Above the colorful rocks is an 8 m (26 ft) thick section of darker rock layers, which were formed by lava overflowing the vent rim in April and May 2015. The top of the photo shows the flat floor of Halema‘uma‘u, blanketed in a continuous layer of Pele’s hair. Photo taken Wednesday, September 13, 2017 courtesy of USGS/HVO

On September 8, at 6:06 p.m. HST, much of the large ledge that had built up on the south side of the summit vent within Halema‘uma‘u collapsed. The top two images, captured by HVO’s K2 and HT web cameras, show the summit vent before the collapse. A yellow arrow points to the ledge, which was formed by layers of lava stacking up during repeated high lake levels. The lower webcam images were captured minutes after the collapse. In the thermal images, note the difference in the lava lake surface before and after the collapse. K2cam shows the view from HVO and Jaggar Museum; HTcam is a thermal camera that looks down on the lava lake from the rim of Halema‘uma‘u. Photo taken Friday, September 8, 2017 courtesy of USGS/HVO

HVO K2cam image at the time of the 6:06 p.m. collapse on Sept. 8. Interestingly, this collapse did not generate a large explosion—only a small, brownish plume was observed during and immediately after the rocky ledge fell into the lava lake. The next day, HVO geologists noted a dusting of ash on the Halema‘uma‘u crater rim, but found no spatter fragments like those that have been hurled to the crater rim during past large explosions. At the time of the Sept. 8 collapse, the lava lake level was about 53.5 m (176 ft) below the vent rim, too deep to be visible from HVO. Collapses are more common when the lava lake level drops significantly, because support is removed from the crater walls. Photo taken Friday, September 8, 2017 courtesy of USGS/HVO

Spattering is common in KÄ«lauea Volcano’s summit lava lake, and consists of many large bursting gas bubbles. The fluid nature of the lake can be seen when lava hits the wall and flows downward like syrup. The thin, flexible nature of the crust is also shown here, as the bursting gas bubbles rip and fold the thin skin on the lake. This video was taken from the rim of Halema‘uma‘u, an area that remains closed to the public due to ongoing volcanic hazards. Video taken Wednesday, September 13, 2017 courtesy of USGS/HVO

(Activity updates are written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

This past week, Kīlauea Volcano’s summit lava lake level fluctuated with summit inflation and deflation and ranged about 31–53.5 m (102–175 ft) below the vent rim. On the East Rift Zone, the 61g flow remained active, with lava entering the ocean near Kamokuna and surface breakouts downslope of Pu‘u ‘Ō‘ō. Widening cracks and slumping on the Kamokuna lava delta indicate its instability and potential for collapse. The 61g flows do not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. During the past week, small-magnitude earthquakes continued to occur beneath the summit caldera and upper Southwest Rift Zone, primarily at depths less than 5 km (3 mi), with some additional deeper events (5–13 km, or 3–8 mi). GPS measurements continue to show deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone. No significant changes in volcanic gas emissions were measured.

No earthquakes were reported felt in the Hawaiian Islands during the past week.

Time-lapse movie of Pu’u ‘O’o Crater. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse movie from a camera positioned on the southeast flank of Puʻu ʻŌʻō, looking toward the active flow advancing to the southeast. The breakout point is at the left edge of the image, and the mid-field skyline at the right is roughly coincident with the top of the pali. September 7-14, 2017. Images courtesy of USGS/HVO

Time-lapse image movie from a research camera positioned on Holei Pali, looking east towards Lava Flow 61G and Kalapana. September 7-14, 2017. Images courtesy of USGS/HVO