February 20, 2003
A weekly feature provided by scientists at the Hawaiian VolcanoObservatory.
Active lava flows and new ocean entry provide prime viewing opportunities
The past ten days have seen lava cross the Chain of Craters Road to form a new lava entry at the ocean's edge. Wildfires of the Panau Iki blaze, ignited by the lava flows and fanned by winds as fast as 80 km per hour (50 mph), have scorched 876 ha (2165 acres) of forest and grassland. Unrelated to these events was a collapse at the West Highcastle lava delta, devouring 1.7 ha (4.2 acres) of land in a few short hours. Why live elsewhere than the Big Island?
The latest round of flow-field activity began about five weeks ago, on January 20. At 5:00 p.m. on the holiday celebrating Martin Luther King's birth, deflation at Kilauea's summit signaled either reduced or completely interrupted lava supply to the east rift fissure system. After 27 hours, the night sky above the flow field lit up anew, mirroring heightened lava activity. The subsequent surge of new lava overpowered the existing tube and poured onto the land's surface 0.6 km southwest of Pu`u `O`o crater. Lying in its path were a few thousand acres of pristine rainforest and a few thousand dollars worth of scientific monitoring equipment. Some of the forest and most of the equipment are history.
While some lava continued pouring through the old tube system to feed the existing ocean entry at West Highcastle, the new surface flows progressed 5 km to the brink of Pulama pali. From there the lava flowed another 5 km down steeper terrain to the coastal plain. Fires in the forest along the lava's edge advanced with the trade winds, which gusted sporadically. Dense smoke and the fire's proximity to Chain of Craters Road prompted a six-day road closure.
The lava flows momentarily forgot their ultimate goal of reaching the ocean. Instead, they went hunting the temporary Ranger hut and vault toilets that aided public access near the end of the road. "Practice makes perfect," as was demonstrated by the National Park Service's Roads Foreman Joe Gambsky, whose crew once again moved large, portable structures faster than speeding pahoehoe advances.
At 10:05 a.m. on February 13, the new lava flows reached the Chain of Craters Road 400 m (1300 ft) west of the previous end of road and within 100 m (330 ft) of where the Ranger hut had stood. It took another 38 hours for the flows to traverse the 220 m (720 ft) to the sea cliff. Lava entered the ocean at about midnight on February 14. The slow advance of lava across the coastal plain is characteristic of pahoehoe on flattish terrain at a great distance from its vent. Or maybe the lava lost its motivation, once the buildings had been moved to safety and the road crossed.
A new lava delta has started, affectionately named "Kohola" in honor of the many whales seen trolling the nearshore waters and breaching near the sea cliffs. At this writing (Feb. 20), the delta is only about 40 m wide, growing along shore before it widens substantially seaward.
These are the best days to catch the great variety of lava activity at the coast. The road still billows its black smoke whenever new lava ventures outward and cooks the asphalt. Pahoehoe along the edge of the flow field greets visitors as it buds out with new red-hot toes. Streams of incandescent lava pour sporadically down the sea cliff. Lava plowing into the surf can be seen far more easily now while the delta is narrow. If the supply of lava continues, the new delta will widen and the clashes between lava and surf will be too distant to view safely. All these opportunities will diminish as the flow matures and its molten stream is encased within a black, rocky carapace.
Eruptive activity at the Pu`u `O`o vent of Kilauea Volcano continued unabated during the past week. As mentioned in the article above, the long and narrow tongue of lava west of the Mother's Day flow reached the ocean at 11:45 p.m. on Friday, February 14. It entered the ocean west of the former entry at Wilipe`a, and the new entry delta is named "Kohola" for the numerous whales seen frolicking offshore. Lava also continues to flow in the Mother's Day tube system down to the ocean entry at West Highcastle.
The public should be aware that the ocean entry areas could collapse at any time, potentially generating large explosions in the process. The steam clouds rising from the entry areas are highly acidic and laced with glass particles. The National Park Service has erected a rope barricade to delineate the edge of the restricted area. Do not venture beyond this rope boundary onto the lava deltas and benches. Even the intervening beaches are susceptible to large waves suddenly generated during delta collapse; these beaches should be avoided.
No earthquakes were reported felt on the island during the past week.
Mauna Loa is not erupting. The summit region continues to inflate, though the rate of inflation has slowed gradually during the past month or two. No earthquakes were located in the summit area during the last seven days.
Updated: February 25, 2003 (pnf)