Kilauea Volcano's east rift zone eruption continues in a regular pattern, with most lava traveling through tubes from the vent area to the coast
This update current as of November 3, 1997[Eruption updates are posted approximately every two weeks. More frequent updates will accompany drastic changes in activity or increased threat to residential areas.]
[Previous eruption updates may be accessed through our archive index.]
For readers familiar with events of the past few months, recent changes include these:
The 55th episode of Kilauea's 14.5-year-long east rift zone eruption continues. This episode, which began February 24, 1997, was characterized in its early months by shifting vent locations on the west and southwest flanks of Pu`u `O`o cone and by rapid enlargement of the episode 50-55 lava shield. The flow field expanded slowly until, in July, lava reached the sea. The supply of lava to these flows became restricted to tubes, and surface flow activity diminished greatly.
During the last thirteen weeks, eruptive activity has been concentrated at two main vents: a vent on the Pu`u `O`o crater floor and the "south shield," a lava shield about 300 m south of the Pu`u `O`o cone. The most obvious of these has been the "crater vent," which began as a spatter cone on the Pu`u `O`o crater floor. In September, however, the spatter cone subsided into its own throat, leaving a pit. The pit is about 40 m in diameter, and from this cauldron, lava froths and sloshes. This vent is the source of glow seen in the night sky from many vantage points on the east slope of Kilauea volcano.
Oblique aerial photo looking southwest at Pu`u `O`o and active vent on its crater floor. East-directed overflows from August visible in foreground; photo taken Oct. 2, 1997. The overflows from October 18-19 mantled many of the August flows in the foreground and also surged through the west-side gap to cover a small area on the volcano's west flank. Distance is 200 m between north summit (high point on right) and south summit (on left).
Lava issuing from the crater vent flows eastward a short distance into Pu`u `O`o crater and drains through holes in the crater floor. Overflows occur when the subvolcanic drainage becomes clogged, which last occurred on October 18-19. The overflowing lava never travels far but has been visible throughout much of east Hawaii.
View looking west across Pu`u `O`o crater at active vent on its floor. The inner cliff is about 20 m high. When overflowing, the cliff and throat of the vent are completely covered by active lava. Felty texture on flows in foreground results from abundant Pele's hair shredded from the gas-rich lava as it streams eastward. Photo taken Oct. 15, 1997.
The other main vent is the south shield, source of the flows entering the ocean at the Waha`ula and Kamokuna sites near the eastern boundary of Hawai`i Volcanoes National Park. The flows are encased within lava tubes for most of their length and are visible only through skylights in the roof of the tube.
Skylight into lava tube. View north, with Pu`u `O`o cone in background. Skylights are locations where weakened roof of the lava tube collapses, opening the tube to view. The lava stream within the tube is moving toward the camera at a rate of about 3 meters per second. It travels down-tube 10 km across the flowfield, cooling only a few degrees in route to the shoreline. Photo taken Oct. 2, 1997.
The tubes discharge their lava at the shoreline. The hot lava, about 1,150 degrees Celsius when it reaches the ocean, generates thick plumes of steam upon contact with seawater. The new lava builds benches beyond the former seacliffs. Small explosions periodically disrupt the rapidly chilling lava and throw it onto the bench, constructing low nearshore (littoral) cones. These small explosions pose a minor threat for visitors. A far greater threat exists, however; these benches can collapse into the sea without warning, triggering large steam explosions that hurl dense rock and molten spatter tens of meters inland. No one should venture onto the benches, no matter how stable the new land may appear.
Coastal plain, showing Waha`ula and Kamokuna lava benches. These benches are new land built since July 1997. View west-southwest; the inland edge of each bench has been highlighted with a white line. For scale, the Waha`ula bench is about 100 m wide and 600 m long. Steam plumes are generated where lava contacts the ocean. Photo taken Oct. 30, 1997.
Eruption-viewing opportunities change constantly, so those readers planning a visit to the volcano should contact Hawai`i Volcanoes National Park for the most current eruption information (808-985-6000).
Big Island residents and tourists who wish to learn more about vog and its effects on health, agriculture, equipment, and air quality are invited to attend one of two Vog and Laze Symposia, to be presented by the Center for the Study of Active Volcanoes. The first symposium will be held November 8 at the University of Hawai`i at Hilo Campus Center, Room 306-307; the second will be held in Kona on November 22 at the Kona Surf Hotel in the Kamehameha Ballroom.
Both symposia begin at 9 a.m., with presentations by scientists and medical professionals who will discuss the composition of vog and laze and its impact on the community. An informal discussion and resource booths will also be featured. These admission-free symposia are sponsored by a grant from the Federal Emergency Management Agency. For additional information call (808)-974-7631 (Hilo, Hawai`i).
This map current as of November 3, 1997
Updated: 31 March 1998