160922 New Lava Skylight from Mick Kalber on Vimeo.

Video courtesy of Tropical Visions Video with air transportation by Paradise Helicopters.

Breakouts from the the 61g lava flow remain active on KÄ«lauea Volcano’s coastal plain, roughly 2 km (1.2 miles) upslope of the ocean entry. This photo shows a typical lobe of pāhoehoe lava filling in a small depression. Photo taken Tuesday, September 20, 2016 courtesy of USGS/HVO

This telephoto image provides a closer view of the lava lake within Halemaʻumaʻu Crater and spattering on the lake surface. Photo taken Tuesday, September 20, 2016 courtesy of USGS/HVO

During recent summit deflation, the lava lake within HalemaÊ»umaÊ»u Crater dropped out of view of overlooks in HawaiÊ»i Volcanoes National Park. But since the switch to inflation early Sunday morning (September 18), KÄ«lauea Volcano’s summit lava lake has been rising again, bringing the lake surface back into view. This morning (Sept 20) the lake level was measured at 12 m (39 ft) below the vent rim, with sporadic spattering visible from the Park’s Jaggar Museum Overlook. Photo taken Tuesday, September 20, 2016 courtesy of USGS/HVO

A few of the lava breakouts active on KÄ«lauea’s coastal plain on September 20. The activity consisted of scattered pāhoehoe breakouts. The final segment in this video is shown at x20 speed. Video taken Tuesday, September 20, 2016 courtesy of USGS/HVO

Time-lapse thermal image movie of Halemaumau Overlook Vent. September 15-22, 2016. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Crater looking Southwest. September 15-22, 2016. Images courtesy of Hawaii Volcanoes National Park

Time-lapse movie of KÄ«lauea Caldera from Hawaiian Volcano Observatory. September 15-22, 2016. Images courtesy of USGS/HVO

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

Kīlauea continues to erupt at its summit and East Rift Zone. This past week (as of September 22), the summit lava lake level varied between 10 m and 28 m (33–92 ft) below the vent rim within Halema‘uma‘u Crater. The 61g lava flow continued to enter the ocean near Kamokuna, with active breakouts about 2 km (1.2 mi) inland from the ocean entry. The lava flow does not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. Seismicity remains elevated relative to the long-term background rate, with small earthquakes occurring mostly in the volcano’s south caldera and upper Southwest Rift Zone at depths less than 5 km (3 mi). Global Positioning System (GPS) measurements show deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone, with inflation occurring mainly in the southwestern part of the volcano’s magma storage complex.

No earthquakes were reported felt on the Island of Hawaiʻi this past week.

Please visit the HVO website (http://hvo.wr.usgs.gov) for past Volcano Watch articles, KÄ«lauea daily eruption updates, Mauna Loa weekly updates, volcano photos, recent earthquakes info, and more; call for summary updates at 808-967-8862 (KÄ«lauea) or 808-967-8866 (Mauna Loa); email questions to askHVO@usgs.gov

This map shows recent changes to Kīlauea’s East Rift Zone lava flow field at the coast. The area of the active flow field as of September 12 is shown in pink, while widening and advancement of the active flow as mapped on September 20 is shown in red. The dashed blue line shows the pre-1983 coastline. The base is a Digital Globe image from January 2016.
Lava deltas – the new land accreted to the front of an older sea cliff – are prone to collapse because the loose underwater lava rubble on which they are built can sometimes become unstable and slide. The interaction of the hot rock composing the delta and cold seawater has led to violent explosions that blasted rocks in all directions, caused local tsunami, and produced billowing plumes of ash and hot, acidic steam.
The dotted line surrounding the Kamokuna lava delta indicates a distance of 300 m (790 ft), which is the maximum documented distance that rocks and spatter have been thrown inland from the older sea cliff by delta explosions that occurred during the Puʻu ʻŌʻō eruption. It is possible that debris could be thrown even farther during exceptionally large explosions.