September 6, 2001
A weekly feature provided by scientists at the Hawaiian Volcano Observatory.
Lava covers road: expectable as the eruption continues
Nothing is constant except change. On August 17 the Kalapana road was reopened, allowing visitors access to a short trail and fine view point overlooking the active ocean-entry bench. Two weeks later, a narrow lava flow crossed the road just east of the trailhead, and the road was closed. How did this happen, will it happen again, and what can be done about it?
Lava has been flowing continuously over Pulama pali through as many as three tubes since last spring. Some of this lava moves underground through the tube system to the coast, feeding the large and persistent ocean entry just east of Kupapa`u. Much of the lava, however, does not make it that far, instead breaking out from the tubes far inland and forming surface flows.
On almost every day for the past few months, several lava flows have been active on the coastal flat between the shoreline and the base of Pulama pali. Most of the flows do not advance to the coast but pool on the surface farther inland. Often the result is a thick sheet of pahoehoe that inflates to several times its original thickness as lava lifts up the surface crust of the flow. Lava can break out of such an inflating flow and feed smaller surface flows.
Some of these surface flows reach seaward from the area of large-scale inflation. Throughout the spring and early summer, the rough, bulldozed road along the former route of Highway 130 was repeatedly shortened as lava flows moved across it. Currently the roadway is 1.4 km (0.8 miles) shorter than it was in February. During April and May alone, 1 km (0.6 miles) of the road was covered.
The latest in this series of flows is the narrow tongue of lava that crossed the refurbished road on the night of September 1. Neither the flow itself nor its timing is unusual; lava simply happened to ooze across the road at an inopportune time. The front of the flow is only 70 m (yards) beyond the road. Had the flow stopped short of the road, it would have caused a lot less grief.
Now that the road has been reopened, we have to think about the future. Will something like this happen again? The answer is easy: certainly, as long as the eruption continues. What can be done about it? This answer is also easy: nothing. There is no stopping the lava from going where it wants across the existing flow field.
There could be long spells without surface flows anywhere near the road, however. The flows might stop following a pause in the eruption, if the tube becomes plugged above the pali so that lava is no longer supplied to the coastal flat. The flows that threaten the road might also stop if the tube system changes location, as is likely following a long pause. A new tube system could be developed farther west, shutting off the current ocean entry and sending all, or most, of the lava back into the park. We would then have to wait for an eastward shift in the tube system before seeing lava again in the Kupapa`u area.
Meanwhile, you can enjoy the closeness of the lava to the road. Whether you see the colorful ocean entry, or lava oozing across the ground surface, or both, you are in for a treat possible nowhere else in the world with such ease and safety. And, while driving along the access road, be sure to look for the site where the opening scene of Planet of the Apes II was filmed. Note the fence posts that were surrounded by lava flows and raised up 6-9 m (20-30 feet) as the flows inflated. Quietly remember that the desolate roadway was once lined with the homes of Kalapana.
Eruptive activity of Kilauea Volcano continued unabated at the Pu`u `O`o vent during the past week. Lava moves away from the vent toward the ocean in a network of tubes and descends Pulama pali in separate areas. A surface flow, cascading down the eastern section of the pali, was observed throughout the week. Lava continued to enter the ocean in the area east of Kupapa`u. The small surface flow reported last week, crossed the road leading to the viewing area on the night of September 1 and stagnated to a halt after traveling 70 m (200 ft) past the road. The County has repaired the road and reopened it to the public. USGS personnel from HVO will monitor the area and keep the County officials informed of any change in lava flow activity.
The public is reminded that the bench of the ocean entry area is extremely hazardous, with possible collapses of the new land. The steam cloud is extremely hot, highly acidic, and laced with glass particles. Swimming at the black sand beach of the bench can be a blistering or even deadly venture.
One earthquake was reported felt during the week ending on September 6, 2001. A resident of Volcano and a resident of Papa`aloa felt an earthquake at 3:07 a.m. on Tuesday, September 4. The magnitude-3.6 earthquake was located 8 km (4.8 mi) southwest of the summit of Kilauea Volcano at a depth of 27.55 km (16.5 mi).
Updated: September 10, 2001 (pnf)