December 29, 1995

A weekly feature provided by scientists at the Hawaiian Volcano Observatory.

Thirteen Years and Counting

Wednesday, January 3, marks the thirteenth anniversary of the start of the nearly continuous eruptive activity at Kilauea Volcano. The Pu'u 'O'o-Kupaianaha eruption is the longest-lived and most voluminous historic eruption on Kilauea's East Rift Zone. The thirteen years of the eruption can be divided into three distinct phases.

The first phase was characterized by episodic activity of high fountaining and large 'a'a flows. Eruptive activity initially started as a 5-mile-long discontinuous line of fissures on January 3, 1983. This 'curtain of fire' soon consolidated to a central dominant vent - first at what was called the '1123' vent, then to another site about a mile uprift called the 'O' vent.

From March 1983 to July 1986, lava erupted vigorously in 44 episodes from the 'O' vent which eventually built a 835-foot-high cone named Pu'u 'O'o. Fountain heights often exceeded 1200 feet. 'A'a flows entered the Royal Gardens subdivision and destroyed 16 homes.

The second phase of the eruption began in July 1986, when activity shifted from Pu'u 'O'o to a new vent located two miles downrift. This phase of the eruption was characterized by a lava pond and low-level, continuous, effusive activity with tube-fed pahoehoe flows that led to the destruction of Kalapana. A broad, shield-shaped edifice nearly 200 feet high was built by overflows from the vent. This structure was named Kupaianaha.

Flows from Kupaianaha reached the ocean in December 1986, and the eruption continued from this vent until February 1992. During this period, many memorable landmarks in Puna were destroyed by the flows. These include the black sand beaches and coconut trees of Kaimu and Kalapana, Harry K. Brown Park, Mauna Kea Congregational Church, Queens Bath, Waha'ula Visitor Center, 165 residences from Kapa'ahu to Kaimu, and the Kalapana Drive-in. The heiau at Waha'ula, however, remains intact although surrounded by new lava.

After repeated pauses in activity and a decreasing output of lava, the eruption at Kupaianaha came to an end in February 1992. The current eruptive phase began when a 500-foot-long fissure opened at the uprift base of Pu'u 'O'o on February 17, 1992. This phase is characterized by gentle, continuous effusive activity from multiple vents as three more fissures opened in the same area. A 200-foot-high shield was built abutting the uprift flank of Pu'u 'O'o, and an extensive lava tube system developed.

Lava flows from this phase are confined to Hawai'i Volcanoes National Park and have destroyed several important archaeological sites. The ancient villages of Kamoamoa and Lae'apuki were inundated by lava. The eruption continues unabated at this time with an ocean entry near Kamokuna.

As we enter the fourteenth year of the eruption, over 500 acres of new land have been created, and about 1.7 billion cubic yards of lava have been erupted. This is enough material to make a base that is 850 feet thick for a four-lane highway from Hilo to Kailua-Kona.

Flows have destroyed 181 residences and caused over $61 million in losses. Nearly eight miles of public highway and many more of private roads have been covered. One death is directly attributed to the eruption, and eight others are indirectly related.

The eruption shows no signs of ending. The U.S. Geological Survey's Hawaiian Volcano Observatory continues to monitor the eruptive activity during this time of partial government shutdown. All of our employees are very essential in our mission of providing unbiased Earth science information to the public.