Lava . . . continued to enter the ocean via the lava tube system throughout November. In the beginning of the month, lava entered the ocean on the W side of Kamoamoa delta along a 50-m-wide front, which grew to 270 m by mid-month. There were two prominent entry points along the W side of the front as well as two diffuse entry points on the E side. For most of the month, lava flows built a bench that extended 50 m into the ocean. Intermittent explosive activity at the entries built loosely consolidated littoral cones on the bench.

On 7 November, the National Park Service reported a bench collapse resulting in vigorous explosive activity. The active bench area continued to build out toward the W after the collapse. A littoral cone was constructed as a result of explosive events at the western-most ocean entry, possibly associated with the 7 November bench collapse. As the cone grew, cracks developed on its flank parallel to the coast. On the afternoon of 26 November, vigorous littoral explosions began, followed by a collapse of 20,000 m² of lava later that evening. The scarp formed by the collapse was over 400 m long and 80 m wide. In one location, the area of collapse extended 30 m inland of the bench. Violent littoral explosions immediately followed this event; however, only two small spatter blankets were deposited on the delta. By the end of the month, two new benches were building out beyond the 8-m-high scarp. A skylight at 60 m elevation remained open and no surface flows were reported throughout the month.

The lava pond in Pu`u `O`o was active at 83-84 m below the N spillway rim with sluggish circulation from W to E. There were two areas of spattering below the spillway area. It was observed that a meter-wide sliver of the E crater wall, between the spillways, collapsed sometime between 29 October and 16 November. Volcanic tremor persisted at low amplitude levels of ~2-3x a quiet background level. Tremor amplitudes occasionally increased slightly, but essentially steady tremor continued through November. Microearthquake counts were low, but there were 7 earthquakes M >3.0 from 26 October to 8 November.

Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Information Contacts: T. Mattox and P. Okubo, HVO.