At approximately 6:15 a.m. today (April 26) a new overflow began on Halema‘uma‘u crater floor. The lava lake overflow continued until about 10:30 a.m. and covered about 36 hectares (90 acres) of the crater floor with lava (approximately 2/3). This is the largest overflow since the summit eruption began in 2008. This photo is looking south, and the gas plume is being produced by the lava lake in the southeast crater floor (upper left). Photo taken Thursday, April 26, 2018 courtesy of U.S. Geological Survey

This thermal image (looking south) shows the active overflows from the lava lake (upper left) onto the Halema‘uma‘u crater floor. View is toward the south. Photo taken Thursday, April 26, 2018 courtesy of U.S. Geological Survey

There were much smaller overflows on the west margin of the Overlook crater rim on Saturday night. Photo taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

A close-up of the small overflows on the west rim of the Overlook crater, along with spattering along the northwest lake margin. Photo taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

A wider view of the lava lake and recent overflows. This photo is taken from the Halema‘uma‘u Crater rim, and looks northwest. Jaggar Museum and HVO can be seen on the skyline. Photo taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

Rising summit lava lake levels peaked overnight, producing small overflows onto the floor of Halema‘uma‘u Crater. This photo shows the largest overflow, on the north margin, which reached about 80 m (262 feet) from the lake margin. Photo taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

A line of spattering along the northwest lake margin on Sunday, April 22. Note that the spatter is being ejected well above the level of the Halema‘uma‘u Crater floor, with occasional small bits landing on the rim. At the left end of the spattering, a piece of the thin, flexible crust on the lava lake is lifted and torn by a bubble burst. Photo taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

Beginning around midnight on Saturday, April 21, KÄ«lauea Volcano’s summit lava lake rose high enough that lava briefly spilled onto the floor of Halema‘uma‘u. Since then, additional overflows occurred in four pulses on April 22–23. The largest one occurred during the fourth pulse, which started at 6:30 a.m. today (Monday, April 23) and continued for about three hours, covering about a third of the crater floor with shiny black lava. Early this morning, HVO geologists (shown here) used a laser range-finder to measure the depth to the lava lake surface at its peak level. The silhouettes of HVO and Hawai‘i Volcanoes National Park’s Jaggar Museum are visible on the rim of KÄ«lauea’s summit caldera (center high point). Mauna Loa can be seen in the far distance (left). The area around Halema‘uma‘u remains closed to the public due to ongoing volcanic hazards, including high sulfur dioxide gas emissions and unexpected rockfalls and explosions. Photo taken Monday, April 23, 2018 courtesy of U.S. Geological Survey

On KÄ«lauea Volcano’s East Rift Zone, the perched lava pond in Pu‘u ‘Ō‘ō’s west pit remains active. Additional overflows of the pond levees have been slowly filling the bottom of the west pit and raising the floor. Photo taken Monday, April 23, 2018 courtesy of U.S. Geological Survey

A helicopter overflight this afternoon (April 23) of KÄ«lauea Volcano’s Halema‘uma‘u crater showed the extent of the largest overflow (silver gray) of the lava lake, which occurred from approximately 6:30 a.m. to 9:30 a.m. this morning. The overflow covered much of the April/May 2015 and October 2016 overflows, but a section of the 2015 overflow is still visible on the south (upper edge) of the Halema‘uma‘u crater floor. At the time of the flight, multiple spattering sites were active around the margin of the summit lava lake, and the lake surface had dropped to a few meters (yards) below the vent rim. The lower lake level reflected the switch from inflation to deflation at the summit of KÄ«lauea. Photo taken Monday, April 23, 2018 courtesy of U.S. Geological Survey

Inflation at Pu‘u ‘Ō‘ō continues, and the crater floor has been slowly uplifting for several weeks. This uplift has rotated sections of the crater floor and opened hot, gaping cracks on it. This animated GIF (open in a browser window to see the animation) shows the difference between thermal images taken on Friday, April 20, and today, April 24. For scale, the far rim of the crater is about 280 m (920 feet) from the near rim. The crater floor uplift and continued inflation indicate building pressure in the magmatic system beneath Pu‘u ‘Ō‘ō. Animated GIF images taken Tuesday, April 24, 2018 courtesy of U.S. Geological Survey

Time-lapse thermal image movie of Halemaumau Overlook Vent. April 19-26, 2018. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Overlook Vent. April 19-26, 2018. Images courtesy of USGS/HVO

Time-lapse movie of KÄ«lauea Caldera from Hawaiian Volcano Observatory. April 19-26, 2018. Images courtesy of USGS/HVO

This video shows an overview of the lake from the Halema‘uma‘u Crater rim, as well as some of the spattering that was occurring on the lake margin on Sunday, April 22. Video taken Sunday, April 22, 2018 courtesy of U.S. Geological Survey

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

This past week, KÄ«lauea Volcano’s summit lava lake level fluctuated with summit inflation and deflation, eventually rising high enough to overflow onto the floor of HalemaÊ»umaÊ»u multiple times beginning Saturday, April 21. On the East Rift Zone, the 61g lava flow remained active with breakouts on the upper part of the flow field. There were no active lava flows on the pali, coastal plain, or entering the ocean. The 61g flows do not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. Rates of deformation and seismicity have not changed significantly over the past week. Few small-magnitude earthquakes occurred beneath the summit and upper flanks of the volcano, primarily at depths shallower than 5 km (3 mi). GPS and InSAR measurements indicate slowing deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone.

Two earthquakes with three or more felt reports occurred in Hawaii this past week: a magnitude-2.7 earthquake 3 km (2 mi) northwest of Keokea at 28.0 km (17.4 mi) depth on April 21 at 3:34 p.m. HST and a magnitude-3.2 earthquake 5 km (3 mi) south of Volcano at 1.8 km (1.1mi) depth inside Hawai`i Volcanoes National Park on April 26 at 1:08 p.m. HST.

Time-lapse movie of Pu’u ‘O’o Crater. April 19-26, 2018. 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. April 19-26, 2018. 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. April 19-26, 2018. Images courtesy of USGS/HVO