Day 6:  September 10, 2005

Reporting:

Josh Feldman, Steve Poletski, and Justin McCullough

Kilauea is behind us, with Mauna Loa towering above us in the distance. The flow we are standing on engulfed the Chain of Craters Road during the 1969 – 1974 eruption of Mauna Ulu. Before the flow there was a pit crater along the road. When the lava began to flow, it filled up the crater and built up the lava shield visible. The levee we were standing on is of uncertain origin, however there are a few theories to explain its presence. One possibility included surges flowing over a pre-existing topography causing banding levee features. Another theory is that a perched lava pond may have existed, and spilled over periodically as it filled up. The latter explanation leaves time for spattering, which appears under the top pahoehoe band visible in cross sections we saw.

Many lake stands were visible in cross section. In the 1970’s scientists believed the crater may have been fed by Mauna Ulu because they observed Mauna Ulu filling up first and Alae afterwards. Following their key observations, they dumped barrels of rare earth elements into the Ulu lava lake expecting to see the chemical signature in the Alae Crater. No evidence of the elements was ever found. There was a drilling rig at the bottom of the crater that was unfortunately sacrificed to Pele, much to the USGS’ chagrin.

Another deep pit crater approximately 500 years old based on Carbon 14 samples from charcoalized trees. On the east side of the crater there is much vegetation growth spreading to the center, stopping abruptly. The western rim of the crater exhibited no vegetation due the 1969 – 1974 Mauna Ulu lava flows entering the crater.

Pulu is the reddish brown fibers harvested from the crown of the local tree fern. This fiber was used to make pillows and mattresses in the 1800’s, shipped to New Zealand and California. The site in which we were standing is the ruin of the pulu industry.

We were standing on the edge of the Napau Crater, overlooking the Pu’u O’o cinder cone. In 1971, an obstruction plugged Pu’u O’o’s main venting phase, causing fissure eruptions. The chemical composition of the original lava that flowed from the vents on the crater flow was that of the 1969 flow. However, once that was purged from the ground, Pu’u O’o chemistry was observed. This spectacular event was known as Event 54 and lasted for one day until the obstruction was cleared.

We took the Napua Crater Trail into the crater following our fearless leader who was dashing through the rugged tephra terrain. Passing a steam vent with grass growing on the side, we went through a forest of burned out trees. After reading the warning sign of death, we ventured up the side of the volcano. We then proceeded to hike the 8 miles back to the cars and came to KMC.