Geology Field Trip
Hawaii, Spring 1997
For the past ten years students at Western have been telling Allen that since we always talk about Hawaii in class we should go there on a field trip.
Allen's response has always been, "if you organize it I'll go".
In the spring of 1997 Lynn Padgett and Rick Butler finally called Allen's bluff and organized the trip. So off we went!
The trip was lead by Tom Prather and Allen Stork. Ten students, ranging from freshmen to seniors, participated.
The trip lasted twelve days. We spent the first half looking at active volcanism around Kilauea and spent the second half looking at the older volcanoes on the rest of the island.
Rick Hazlett's, Geologic Field Guide: Kilauea Volcano (1993), Hawai'i Natural History Association, was indespensible and is the source for most of the information on these pages.
For those of you who worry, never fear, we also spent "serious" time looking at active beach processes and coral reef formation.
These two images contrast the smooth slopes of Mauna Loa (above) with the rough and bumpy slopes of Mauna Kea (below). Mauna Loa is still in the shield building phase and covered by fluid tholeiitic lavas while Mauna Kea is in the post shield cinder cone phase erupting more alkaline magmas. Both pictures were taken from the top of Pu'u Huluhulu.
We spent two days on the summit of Kilauea Caldera and at Kilauea Iki looking at recent volcanic features. The photo above shows where 1971 lavas flowed from fissures in the Southwest Rift Zone on to the caldera floor. The steam is from recent rains on the still hot lavas.
The photo below shows Tom standing on 1982 lavas that have ponded against the spatter rampart produced by the 1955 summit eruption.
The Mauna Ulu Shield was produced in eruptions from 1969-74 covering the newly built Chain of Craters Road. This photo is of the north slope of Mauna Ulu taken from Pu'u Huluhulu. There is a well developed flat-surfaced perched lava pond visible. The lava pond is formed by levees of solidified magma that leave the pond higher than the normal lava drainage.
The Pahoehoe lavas in the foreground and aa lavas on the sky line are from the 1971-1972 eruptions of Mauna Ulu. In this case younger pahoehoe is ponded against and partially covering slightly older aa. Note the smooth (on the right) and ropey (on the left) flow textures in the pahoehoe. The photo was taken on the Naulu Trail approximately 1km from the Chain of Craters Road.
These two photos are of flow features produced by a fissure eruption in May of 1973. Lavas crossed the Chain of Craters Road and flowed into Hiiaka Crater. The photo above shows the lava channel that spilled into the crater. This channel has well developed levees built up by the flowing lava. The lava surface is ropey pahoehoe.
The photo on the left shows a tree mold and the pattern produced when the lava flowed around the obstacle.
On April 6, 1997 we hiked to the Napau Crater overlook to catch a glimpse of the active volcanism at Pu'u O'o. From this vantage we could see both the current activity (episode 55) and the effects of the January 30-31, 1997 eruptions in Napau Crater (episode 54). The active eruption started on March 28 with the eruption moving back to Pu'u O'o and we could see fountaining from a collapse pit on the episode 51 lava shield(GVN Bulletin V.22, N.3, 1997). In addition lava was flowing down the slope of the shield. These do not show up well in the photo. You can see vapor from the fountaining in front of the Pu'u O'o cinder cone and the surface flow is a lighter grey area just south (right) of the fountains flowing directly toward you.
In episode 54 the eruption location moved from Pu'u O'o to Napau Crater. During this eruption six different fissures opened in Napau crater and were active for about 24 hours. The black lavas seen on the floor of the crater were erupted from the A fissure which was active for about 5 hours at the start of the eruption. To the south (right) of the lavas you can see burned trees. Following the activity in Napau Crater the Pu'u O'o cinder cone collapsed and the summit and west wall of the cone were removed to produce the current topography(GVN Bulletin V.22, N.1, 1997)..
The photo below shows where a flow from the Pu'u O'o lava tube system cut the Chain of Craters Road near the coast in 1995.
We close with photos of the black sand beach at Punalu'u and the waves crashing off basalt cliffs at MacKenzie State Park on the Puna Coast.
A great time!
Thanks to Lynn Padgett and Rick Butler for organizing the trip.