Kīlauea 1955 Lower East Rift Zone Eruption in Lower Puna
In 1955 Kīlauea Volcano erupted on the lower East Rift Zone for the first time since 1840. This eruption posed unprecedented challenges for the Hawaiian Volcano Observatory (HVO), local civil defense authorities and the residents of lower Puna. The eruption lasted for 88 days and opened at least 24 separate vents that stretched nine miles from Kapoho to west of the Pāhoa-Kalapana road. Numerous lava flows cut all access to lower Puna covering over six miles of public roads. The eruption required the evacuation of most coastline residents from Kapoho to Kalapana for an extended period. Twenty one homes were destroyed and thirty-nine hundred acres (of the Big Island) were covered by lava.
Prelude to the Eruption
After a summit eruption in 1934, Kīlauea Volcano remained quiet for eighteen years. In 1952 the volcano woke with an extended eruption at the summit. For the next three years, scientists measured earthquakes at the summit of Kīlauea and continuous tilting of the ground surface as the volcano inflated. Despite a four day eruption in Kīlauea caldera in May of 1954, the summit continued to swell and seismicity remained high. By August of 1954, tilt in the summit region of Kīlauea was at its highest level since 1924.
At the time HVO lacked an extensive seismic network, but in April of 1954 a seismograph was installed at Pāhoa School. In the latter part of 1954, that instrument recorded many small swarms of earthquakes in the lower East Rift Zone near Pāhoa. High seismicity was recorded both at the summit of Kīlauea and in lower Puna, but was absent in the middle East Rift Zone.
First Phase – February 28 to March 1, 1955.
At about 0800 on February 28, lava emerged quietly along fissures in the forest near Puu Honuaula east of the Pāhoa - Pohoiki road. During the day the fissures extended in an "en echelon" (staggered) configuration east- northeastward. A curtain of lava fountains with heights of 25 to 40 feet fed a lava flow that blocked the road. Fissures extended towards the village of Kapoho, three miles away and residents of the village were evacuated and housed at a shelter at Pāhoa School.
Second Phase – March 2 to 6, 1955
On March 2, a school bus driver discovered a widening crack across the Pāhoa-Kapoho road 2 miles west of Kapoho. A large number of local earthquakes resumed and fissures and fault scarps spread northeastward to less than a mile from Kapoho village. That afternoon lava fountains broke out near Halekamahina and quickly lengthened causing a flow that blocked the Pāhoa-Kapoho road. By evening new vents and lines of fountains had opened on both sides of the road.
On March 3 four new vents opened near Kapoho with fountains reaching heights of five hundred feet. By the next evening new fissures extended into the center of Kapoho village and lava fountains erupted at the edge of the town. Three houses were destroyed, but a ridge of prehistoric spatter cones diverted lava northward away from the main part the town.
Other fountains upslope continued and coalesced into the Kii flow, a large ‘a‘ā lava flow which crossed the Kapoho Kalapana road just north of ‘Ahalanui Beach Park on March 4. By March 7 that flow stagnated, without reaching the ocean, but the Kii flow effectively isolated Kapoho village. By the morning of March 7 all eruptive activity had stopped.
Third Phase – March 5 to April 7, 1955
Meanwhile seismic activity continued and shifted up rift of Kapoho to an area near the Pāhoa-Kalapana road, southwest of Pu‘u Honuaula. On March 5, a new swarm of earthquakes was recorded with many shocks felt in Pāhoa. Civil Defense evacuated villagers from Kalapana to Opihikao leaving the lower Puna coastline deserted. Contingency plans were made to evacuate Pāhoa if it became necessary.
On March 12 cracks opened across the Pāhoa-Kalapana road, 5.5 km (3.5 mi) south of Pāhoa. That evening lava erupted at Pu‘u Kaliu, two miles east of the road and gradually extended westward, up rift. The next morning new vents opened just east of the road. In the afternoon a quarter mile long fissure crossed the road and extended through the fields of farmer, Masayuki Nii. Scientists and photographers were present and recorded the birth of several of the new vents. By March 14 a 9-m- (30-ft-) high spatter cone had formed in the middle of the Pāhoa-Kalapana road.
On March 14 lava fountains at a vent located a mile east of the Pāhoa-Kalapana road were reaching heights of 120 m (400 ft) causing a fast moving lava flow through Kaueleau area. The Kaueleau flow cut both the Opihikao and Kapoho-Kalapana roads and took only 39 hours to reach the ocean. This flow stagnated two days after it started.
At this point approximately 140 persons evacuated from lower Puna were housed in shelters. Lava flows from the eruption had completely cut all main roads leading to the coastal villages in Kalapana.
Between March 17 and March 20 more vents opened near Iilewa Crater west of the Pāhoa-Kalapana road sending additional flows across the highway again. By March 20, the western-most vents had died, but vents near the Iilewa cone were shooting to heights of 215 m (700 ft) sending new ‘a‘ā lava flows down slope. That day an explosion near the Nii farm sent a cloud of black ash skyward. Later that day an overflight observed a new pit crater 6 m (20 ft) across and 15 to 30 m (50 to 100 ft) deep which had opened across the road from Mr. Nii's home.
On March 21, vents near Iilewa Crater continued to erupt sending a lava flow towards a group of eight houses and structures called Iwasaki Camp. Five bulldozers constructed a series of earthen barriers in an attempt to divert the flow and the camp was spared at least initially as the flow slowed and bi-passed the residences and the barriers.
On March 22 the fountain at Iilewa spurted lava to a height of about 150 m (500 ft) creating one inch deposit of Pele's hair on roofs at Pāhoa, five miles away. On the same day a new explosion from the Nii pit crater sent a cloud of black ash to a height of about a thousand feet. Inspection of the pit showed that the depth of the crater had increased to 45 m (150 ft) and an area of 60 m (200 ft) around the pit was sinking inward.
The lava flow from Iilewa continued downslope threatening the coffee fields of Robert Yamada. Over the next few days bulldozers constructed six barriers of rock, earth and brush about 5 m (15 ft) high on Yamada's farm to try to divert the flow. The diversion succeeded initially as barriers halted one flow's advance and dikes diverted others. But, by March 26 new vents had opened near Iilewa Crater and another flow moved around the Yamada dikes destroying the coffee patch. This flow known as the Keekee flow entered the ocean on March 28 and stopped the next day.
Vents near Iilewa Crater continued to wax and wane, creating a new flow known as the Kehena flow. This flow destroyed cane fields after bypassing Iwasaki camp once again. It reached the ocean on April 2 and formed a new lava delta which extended 365 m (1200 ft) in front of an old sea cliff. Several homes on the coast near Kehena were destroyed. By April 7 another flow extended down the western side of the Kehena flow to about a half mile from the ocean, but the Iilewa vent stopped erupting and this flow did not reach the sea.
Final Phase – April 24 to May 26, 1955
After April 8 all eruptive activity in lower Puna ceased. Bulldozers reopened the coastal road to Kalapana and on April 15 Civil Defense allowed all evacuees from lower Puna to return to their homes.
On April 24 a small outbreak of lava erupted again from one of the Iilewa vents for a few hours and then stopped. Two days later sounds of escaping gas preceded another outbreak near Iilewa. For the next three weeks this group of vents continued to intermittently eject cinder and spatter forming four cinder cones about 30 m(100 ft) high. Sluggish lava oozed from the base of these cones and from a hump 1,200 feet east of the cones forming new lava flows which gradually extended downslope, but none crossed the Pāhoa-Kalapana road.
Residents of Kalapana were allowed to remain in their homes, with an understanding that observers would ring the church bell as an alarm if evacuation was warranted.
On May 16 the volume of lava emerging from the base of the Iilewa vents increased. Much of this lava accumulated in a pond between two of the cinder cones. Lava spill-over from this pond produced a spectacular cascade which rafted large rolling blocks of congealed material down a channel creating an active ‘a‘ā flow front ten to 3.5 m (12 ft) high and 215 m (700 ft) wide. Multiple flows crossed the Pāhoa-Kalapana road again and threatened to sever the coastal road isolating Kalapana village. Fortunately this flow stagnated on May 18.
On May 19 lava broke out southeast of the Pāhoa-Kalapana road and again headed for Iwasaki camp which was evacuated for a second time. All buildings in the camp were destroyed that evening and the flow stagnated the next day.
In the week that followed, some Iilewa vents continued to fountain intermittently to heights of 200 feet. Lava spilled into the large pool of molten material east of the vent which repeatedly overflowed, spawning new flows which destroyed another home. Families were evacuated for a second time from the Kamalii area, but flows stopped before reaching the homes on the coastal road. In the early morning hours May 26 lava covered the remainder of Iwasaki's property. Then harmonic tremor on the Pāhoa seismograph died abruptly and a few minutes later all fountain activity at Iilewa ceased.
In the months that followed Hawaii County Civil defense and HVO continued to closely monitor the area. Persistent blue gas flames played at fissures near Nii's farm, but no further eruptive activity occurred. The eruption was over.
Several features of this eruption in lower Puna were unusual. Over time flank eruptions often retreat up-rift as the magma supply wanes. In this eruption there was an irregular progression of activity with new vents opening both up-rift and down-rift as the eruption progressed.
Analysis of the 1955 lavas also revealed an unusual mix of magma types. The early 1955 lavas are among the most differentiated ever erupted at Kīlauea indicating storage in place near the source vents for a prolonged period. Lavas produced later in the eruption contained more magnesium and indicate a more primitive origin from depth.
This eruption was also the first in historic times to occur in any populous area in a U.S. territory. Large numbers of people were evacuated with their belongings and the experience gained insuring human safety was of great value.