This photo looks west towards the upper East Rift Zone of Kīlauea. The fume-filled crater at Puʻu ʻŌʻō is in the foreground, and the vent for the June 27th lava flow is just out of view of the lower right corner of the photo. Mauna Loa is visible in the upper right. Photo taken Friday, October 23, 2015 courtesy of USGS/HVO

A hornito was active in the upper portion of the June 27th flow, with hissing and jetting sounds coming from a small opening at the top. The hornito here was about 2.5 m (8 feet) tall. A hornito is formed by gas and lava forced through a small opening in the roof of a lava tube. One side of the hornito has a small solidified flow of lava that oozed from the top, with the remainder consisting of spatter and Pele’s hair. Photo taken Friday, October 23, 2015 courtesy of USGS/HVO

An HVO geologist collects a sample of active lava for chemical analysis. The lava is quenched with water in the metal bucket. Photo taken Friday, October 23, 2015 courtesy of USGS/HVO

A small channel feeds a lobe of pāhoehoe lava on the eastern margin of the June 27th flow. Scattered breakouts like these were active on the flow field today, with the farthest active lava about 6.4 km (4 miles) from the vent on Puʻu ʻŌʻō. Photo taken Friday, October 23, 2015 courtesy of USGS/HVO

Time-lapse thermal image movie of Halemaumau Overlook Vent. October 15-23, 2015. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Overlook Vent. October 15-23, 2015. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Crater looking Southwest. October 15-23, 2015. Images courtesy of Hawaii Volcanoes National Park

Time-lapse movie of Halemaumau Overlook Vent from the West Rim of Halemaumau Crater. October 15-23, 2015. Images courtesy of USGS/HVO

Time-lapse movie of Halemaumau Crater from the south rim. October 15-23, 2015. Images courtesy of USGS/HVO

Time-lapse movie of Halemaʻumaʻu Overlook Vent from Hawaiian Volcano Observatory. October 15-23, 2015. 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. The summit lava lake level, which fluctuates with summit inflation and deflation, varied between about 50 and 65 m (164–213 ft) below the vent rim within Halema‘uma‘u Crater. On the East Rift Zone, scattered lava flow activity remained within about 7 km (4.3 mi) of Puʻu ʻŌʻō.

Mauna Loa is not erupting. During the past week, earthquake rates continued to be elevated, though at a lower weekly rate than recorded in late summer. Deformation data remain consistent with inflation of magma reservoirs within the volcano.

Two earthquakes were reported felt in Hawaii this past week. On Thursday, October 15, 2015, at 8:41 p.m., HST, a magnitude-3.9 earthquake occurred 10.4 km (6.5 mi) west of Kalapana, Hawai’i, at a depth of 7.2 km (4.5 mi). On Monday, October 19, 2015, at 3:18 p.m., HST, a magnitude-2.9 earthquake occurred 19.8 km (12.3 mi) southwest of Makena, Maui, at a depth of 10.2 km (6.3 mi).

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 active East Rift Zone lava flow field. The area of the flow on September 30 is shown in pink, while widening and advancement of the flow as of October 23 (based on satellite imagery and ground mapping) is shown in red. The yellow lines show the active lava tube system. Puʻu ʻŌʻō lava flows erupted prior to June 27, 2014, are shown in gray. The base map is a partly transparent 1:24,000-scale USGS digital topographic map draped over a 10-m digital elevation model (DEM).

This small-scale map shows KÄ«lauea’s active East Rift Zone lava flow in relation to the eastern part of the Island of HawaiÊ»i. The area of the flow on September 30 is shown in pink, while widening and advancement of the flow as of October 23 is shown in red. The yellow lines show the active lava tube system. PuÊ»u ʻŌʻō lava flows erupted prior to June 27, 2014, are shown in gray. The black box shows the extent of the accompanying large scale map. The blue lines show steepest-descent paths calculated from a 1983 digital elevation model (DEM; for calculation details, see http://pubs.usgs.gov/of/2007/1264/). Steepest-descent path analysis is based on the assumption that the DEM perfectly represents the earth’s surface. DEMs, however, are not perfect, so the blue lines on this map can be used to infer only approximate flow paths. The base map is a partly transparent regional land cover map from National Oceanic and Atmospheric Administration (NOAA) Office of Coastal Management draped over the 1983 DEM. The bathymetry is also from NOAA. Because the flow field is changing very little at the moment, mapping of the lava flow is being conducted relatively infrequently. We will return to more frequent mapping if warranted by an increase in activity.