10 November — 9 December 1973

This eruption occurred about 6 months after the May 1973 eruption and lasted a month. Like the May activity, the eruption was preceded by the sudden draining of a lava lake at Mauna Ulu. Two fissures opened in Pauahi Crater within minutes of each other, and lava began to pool in both the east and west pits of the crater (map, left). The eastern fissure extended about 1.5 km toward Pu`u Huluhulu. This fissure stopped erupting by 16 November, but the west fissure continued to feed lava into Pauahi Crater. The west vent quickly built a low lava shield in the west pit, which, beginning on 28 November, sent lava flowing across the septum into the east pit .

Lava flows erupted from Pauahi Crater during the November-December 1973 eruption shown in red; lava flows erupted on 5 May 1973 from Hi`iaka Crater shown in black.

| med | large |		Pauahi Crater, west fissure This view from the south rim of Pauahi Crater shows the west fissure erupting from the base of the northwest crater wall (upper left), a lava lake in the west pit, and spectacular lava cascades spilling over the low divide from the east to the west pit (right). In this photograph, the lava lake is about 150 m in diameter and circulates slowly in a clockwise direction.
| med | large |		Pauahi Crater, east fissure This view from the northwest rim of Pauahi Crater shows the east fissure erupting in the east pit and lava spilling over the low divide between the west and east pits. This fissure stopped erupting shortly after midnight.
| med | large |		Pauahi Crater, west fissure This view from the southeast rim of Pauahi Crater shows the west fissure erupting from the base of the northwest crater wall. Intermittent bursts from the lava fountain reached as high as 35 m. Lava is oozing into the east pit (note lava in lower right) from the location of the now defunct east fissure. Note the high lava mark in the east pit (bottom). Shortly after midnight, lava stopped erupting from the east-pit fissure and began draining back into the fissure. A "bathtub ring" of lava was left on the walls 21 m above the lava lake. This photograph was taken at about 5 p.m.
| med | large |		Pauahi Crater, west-vent shield The west vent continued to erupt through December 9, building a low lava shield in the west pit. By November 19, ten days after the eruption began, a perched lava lake about 30 m in diameter had developed at the top of the shield. By November 28, frequent overflows had built the shield more than 30 m tall, and lava began spilling into the east pit (out of view in upper right). This view is toward the east-northeast; the north wall of the east pit is visible in extreme upper right.

16 November 1979

A swarm of small earthquakes started abruptly on 15 November in the upper east rift zone. During the peak of the swarm, as many as 20 earthquakes per hour shook the ground beneath the Pauahi Crater area. The earthquake swarm occurred along a 6-km-long segment of the east rift zone. The summit area started to deflate only after the earthquakes began beneath Pauahi Crater; this relation shows that the initial downrift migration of the earthquakes did not draw much magma from the summit reservoir. The coincidence of intense seismicity and deflation implies a close hydraulic connection between the summit reservoir and the east rift magma system beneath Pauahi. The first lava to reach the surface was stored beneath this part of the east rift zone.

The eruption began at 0818 in the morning on 16 November. Three sets of fissures were active during the 22-hour-long eruption (map, right). The first opened east of the crater and died shortly before noon. At 0821 the second set of fissures broke across the base of the northwest wall of the west pit of Pauahi Crater and remained active until the eruption stopped at 0630 on 17 November. The third set of fissures opened west of the crater just after noon; these fissures stopped erupting about 7 hours later.

Lava flows erupted from Pauahi Crater during the November 1979 eruption shown in red; lava flows erupted on 5 May 1973 from Hi`iaka Crater and during the November-December 1973 eruption at Pauahi Crater shown in black. The Chain of Craters Road was moved as a consequence of the 1979 eruption; compare with the 1973 map (above).

| med | large |		Fissure in Pauahi Crater Aerial view of fissures in the northwest wall of Pauahi Crater about 4 hours after the eruption began. These fissures are nearly aligned with the fissure that opened up west of the crater (top center; see image below). This view is toward the west; the Chain of Craters Road and the parking area for the Pauahi Crater overlook are in top center. The line of spatter cones in upper right formed during the November-December 1973 eruption described above.
| med | large |		Fissure west of Pauahi Crater Aerial view of fissures west of Pauahi Crater. These fissures opened a little after noon, almost 4 hours after the start of the eruption. The fissures stopped erupting by 5 p.m. Note the fissures are offset in a right-stepping sense from each other. This view is toward the east; the Chain of Craters Road and the parking area for the Pauahi Crater overlook are in top left. Scientists are visible in lower right of the larger image sizes.
| med | large |		Lava fountains, Pauahi Crater The vents on the northwest wall of Pauahi Crater remained active through the early morning hours of 17 November. Lava from these vents poured into the small crater atop the November 1973 shield on the crater floor (circular feature in lower right; see image of this feature above) and covered both floors of both the west and east pits. This view is toward the north. The photograph was taken at 5 p.m.

Modern view of Pauahi Crater

References

Tilling, R.I., Christiansen, R.L., Duffield, W.A., Endo, E.T., Holcomb, R.T., and Koyanagi, R.Y., Peterson, D.W., and Unger, J.D., 1987, The 1972-1974 Mauna Ulu eruption, Kilauea Volcano: an example of quasi-steady-state magma transfer, in Decker, R.W., Wright, T.L., and Stauffer P. H., (eds.), 1987, Volcanism in Hawaii: U.S. Geological Survey Professional Paper 1350, p. 405-469.