7 December, 2001
Weather report: We are "hut-bound" today. Woke up to 30 knot winds and temperatures of 30 deegrees below zero. I had to plow my way out of my tent in the morning. Visibility is very low (sometimes less than 10 meters).
I had intended to begin a series of journal entries that explained how this team is going about understanding the mysteries of a volcano, when I was interrupted yesterday by a first-time trip to the summit. I would like to begin this first facet of inquiry by considering the idea of simply (and not so simply) LOOKING at something. It is important to remember that any sense employed to understand a new thing is useful largely by its comparison to things already known. So, to a person who has never studied geology, let alone vulcanology, the first sight of Mt. Erebus might indeed inspire a bit of fear--if the only thing that the viewer has to relate to this vision is the death and destruction brought about by volcanoes of lore, and some recent ones as well. To a vulcanologist, perhaps the first clue to the nature of a volcano is its shape. This can obviously be determined whether it is active or not. The shape, in turn, is largely determined by the type of material that is being expelled by the volcano. I'll leave it to the reader, if interested, to investigate the classification of volcanoes by these parameters.
It helps immensely to look at a volcano with the help of a trained eye. Much as a physician sees things in a patient that even a parent might not see, a geologist can explain what a person sees and shed real light on the origins of the scenery. Mt. Erebus has a "caldera" (big) area of former activity, and a relatively small crater. I emphasize the word "relatively" because at first sight the crater is huge. Calderas, on the other hand, can be many kilometers in diameter. Mt. Erebus has erupted in a major way several times in goelogic history. It has erupted dangerously (but not on a gargantuan scale) twice in recorded human history--most recently in 1984. In that year the "Upper Erebus Hut" was abandoned, and the "Lower Erebus Hut" (LEH) site selected.
Another readily visible thing to see is the rock that surrounds the volcano. It makes such an impression on the observer both in its content and physical properties. I will describe this briefly, as the minerology of Erebus' rock as it sits on the ground is not part of this study. Mt. Erebus is unique in that it is the only volcano in the world currently producing lava that is phonolitic in nature. The name of the rock (when it hardens) is anorthoclase phonolite. The phonolite portion is brittle and weathers quickly. The anorthoclase feldspar within it is more hardy, and crystalizes out of the magma to present itself as inclusions in the rock. Because the crystals are more durable than the phonolite, we walk across fields of these crystals freed from the degraded bombs that were hurled >from Mt. Erebus. Another feature of the rock is its glassy composition. This can be seen through the microscope when viewing the ash, "Peles Hair" (see entry of 12/2), and the interior of the bombs that lie on the slopes. I will dissect one of these bombs at my next opportunity and photograph the interior.
One of the main research tools employed during this field season to increase our ability to see the volcano is the repair, improvement, and maintenance of a constant, real-time camera that looks into the crater at the currently convecting lava lake. It is powered by a windmill located on the slope about 200 feet below the crater. We can sit in the hut and look up at a monitor to see if there is any interesting activity. If there is an eruption (we're constantly waiting for this) the time on the videotape can be correlated with the other senses being employed by the team. For example, what did the seismologists and the GPS scientists FEEL when this visible eruption occurred? What did the scientist studying the acoustical properties of the volcano HEAR? And what did the people analyzing the chemical composition of the gases SMELL with their complicated equipment? Looking is an important tool. If you would like to see clips of movies that have captured small eruptions, please visit the Mt. Erebus Volcano Observatory Homepage (easy to find).
A side note: We had visitors today. A team from the "Exploratorium, which is a cool museum in San Francisco, came to the LEH to have a live broadcast (a telephone conversation, acutally) with students visiting the museum at 11:00 this morning. They had sent video and pictures ahead, and students were able to ask questions directly to members of the team. I hope to do the same thing soon. Stay posted....
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