. . . lava production continued through June . . ., feeding flows that overran eight homes, a store, and a church in the town of Kalapana. Lava production halted briefly in mid-June but promptly resumed, and activity remained vigorous through early July.

Activity during the first half of June was characterized by numerous large lava breakouts from the tube system. Lava reached the coast early in the month, probably on 2 June. By 18 June, lava flow activity in Kalapana had slowed and little movement was visible in skylights upslope. No surface activity was visible the next day, but the eruption resumed early 20 June. Large breakouts of pahoehoe lava were seen at ~620 m (2,050 ft) elevation at 0045, and at 560 m (1,850 ft) altitude 2 hours later. Lava progressively reoccupied the tube system along the E side of the flow field, and breakouts were soon occurring below 60 m (200 ft) elevation. Within 5 hours, > 500 m of the tube system had been reoccupied, to < 15 m (40 ft) asl, below the coast highway. By 22 June, two large flows were active in Kalapana. One covered older flows, while a second broke out of the May tube on the N edge of lower Kalapana Gardens, covering much of the remaining area between Hwy 130 and previous Kalapana flows. Other smaller flows in the Kalapana area continued to cover older flows and posed no threat to homes or property.

By early July, lava had advanced to within 600 m of the ocean in the May tube, but no breakouts had reached the ocean since activity halted in mid-June. A new beach had formed in front of the June entry, composed of old sand and blocks plus new material from the June flow. At higher elevations, a large, viscous pahoehoe flow advanced on top of earlier flows E of the main flow field (through the "Woodchip area"). By the first week in July, this flow was characterized by more fluid and sometimes slabby pahoehoe. For the first time, lava crossed the 1986 Kalapana flow and threatened homes in upper Kalapana Gardens, above Hwy 130. However, the flow bypassed all of the homes, crossed Hwy 130 on 10 July, and began to wrap around the N edge of earlier Kalapana flows. Numerous breakouts occurred along this flow and from the main Kalapana tube system. On the main flow field, breakouts between 620 m (2,050 ft) and 400 m (1,300 ft) elevation remained active, and on 2 July large channelized pahoehoe flows were seen on the E margin of the 1990 flows, near 480 m (1,600 ft) altitude.

The lava pond in Kupaianaha vent, source of the recent East-rift flows, has been receding throughout 1990. The pond has rarely been active, and has often been crusted over by frozen lava. A 2 July overflight revealed that the top of pond was ~40 m below the crater rim, occupying an inner pit only ~5 m in diameter. A series of roughly concentric ledges created a series of nested craters within Kupaianaha. During the same overflight, a lava pond with active spattering was visible in the bottom of Pu`u `O`o crater, 3 km uprift.

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. Moulds, HVO.