Volcano Watch — Today marks anniversary of the spectacular '59 eruption

The nearly 11-year-long eruption on Kīlauea's East Rift Zone continues with little change. An active lava pond circulates from west to east inside the Pu`u `O`o cone and produces a bright glow at night. Two vent areas adjacent to Pu`u `O`o are active, although both are now crusted over with cooled lava.

The lava flows through an underground tube system from the vents to the ocean at Kamoamoa, where it enters the sea as a series of discrete flows along a zone about 150-200 feet wide. On occasion, small steam explosions send sprays of black sand and molten lava fragments into the air. The coastal lava entries continue to be highly hazardous, due mainly to slumping of large sections of the newly formed lava bench into the ocean.

The latest of these slumping events occurred between midnight last Sunday and Tuesday morning. Since that time, a new bench, already several hundred yards long and roughly 20 yards wide, has formed seaward of the coast. On Thursday evening, the entire new bench was inflated with lava, which caused small breakouts on the bench, but also opened incandescent cracks parallel to the coast along the landward side of the bench. Formation of such widening cracks may be one factor that leads to collapse of the bench. The National Park Service controls access to the area. For your safety, please obey their warnings and closure signs.

Today is the 34th anniversary of one of the most spectacular eruption in historic times. At 8:08 p.m. on November 14, 1959, an eruption began near the summit of Kīlauea Volcano in Kīlauea Iki Crater. This eruption was the first activity of Kīlauea since the eruption along the lower East Rift Zone in 1955.

The eruption consisted of 17 separate eruption phases which lasted from as long as one week to as short as 1 hour and 45 minutes. At the end of the eruption on December 20, Kīlauea Iki Crater contained a lava lake 335 feet deep consisting of about 50 million cubic yards of lava. This lake has been drilled on numerous occasions over the years to study the cooling and crystallization of lava. The lake still contains a thin, molten zone today, although we expect the entire lake to be solid within the next few years.

The eruption began along a single fissure halfway up the south wall of Kīlauea Iki Crater, but the fissure rapidly extended until a discontinuous half-mile-long curtain of fire was active. By the next day, a single vent at the west end of the crater was all that remained active. The eruption continued without pause until the lava lake reached the level of the vent on November 21. The first phase had spectacular fountains as high as 1,200 feet, although even these would seem small by the end of the eruption. In the ensuing four weeks, the 16 additional eruptive phases were characterized by high lava fountains which reached 1,900 feet during the 15th phase.

The prevailing trade winds carried small lava fragments south-southeast, where they stripped leaves and bark from all vegetation. This area later became a popular short walk in the National Park called the Devastation Trail. The deposits of fragmental rocks or cinders reach thicknesses of about 10 feet where the Crater Rim Road crosses through the deposit, just west of the intersection of Chain of Craters Road and Crater Rim Road. Pu`u Pua`i, the steep cinder-and-spatter cone, has slowly been degrading over the last 30-odd years, and today the reddish-hued cone is cut by numerous concentric slumps and cracks.

The rate of lava extrusion during the shorter high fountain phases toward the end of the eruption reached 1,600,000 cubic yards per hour (in comparison, the current East Rift eruption has an extrusion rate between 200,000 and 300,000 cubic yards per day). After each phase, lava flowed back down the vent and drained the lava lake back to the level of the vent.

After the Kīlauea Iki eruption stopped on November 20, the summit continued to swell as magma accumulated within the summit storage reservoir. Starting in late December and continuing through mid-January, earthquakes migrated 25 miles east of the summit to the area near Kapoho, and on January 13, another eruption was underway near Kapoho.

The only other eruption that has had fountains even approaching the height of Kīlauea Iki's 1959 eruption were some from Pu`u `O`o between 1983 and 1986.