Episode 44 (E-44). After 22 days of repose, E-44 . . . began 11 hours of continuous lava production on 13 April at 2054. Several hours of intermittent low-level lava spillovers from Pu`u `O`o vent had preceded vigorous fountaining, which continued until 14 April at 0756. A small satellite vent that opened 1.2 km N of Pu`u `O`o was first observed on 13 April at 1310. Fountains 5-10 m high fed a pahoehoe lava flow ~1 km long. "

Lava fountains from Pu`u `O`o vent with maximum sustained heights of 280 m were directed to the E, eroding the main channel to form two spillways, one to the NE and another to the SE. Lava flows surrounded HVO's primary observation post on a cinder cone built earlier in the eruption (the "1123 vent"), [1.5] km E of Pu`u `O`o. Lava advanced a maximum of 4.1 km (to the ESE).

By 12 April . . . the summit had recovered all of the deflation recorded during the previous episode. Slow deflation began that day at 1000, and rapid subsidence started on 13 April at 2000, less than an hour before the onset of vigorous fountaining. The summit lost 13.7 µrad of inflation before subsidence ended at 1000 on 14 April, 2 hours after fountaining stopped. Only 2.6 µrad had been regained when the tiltmeter was removed for repairs (figure 43). Strong tremor began 13 April at 2104, remained high until 0754 on the 14th, and then dropped to background level for the rest of the month.

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: C. Heliker, R. Koyanagi, and M. Sako, HVO.