Tuesday, April 2, 2013

I RAN INTO A VOLCANO—AND LIVED!


Imagine sprinting down the edge of a steep slope so fast, it feels as if you are flying. You trip and scrape your arm, but the adrenaline keeps you going. You finally reach the bottom, take in the scene—and then realize you have to hike back up the slope of the 234.7 meter (770 feet) deep crater you descended just moments before. I visited Ubehebe Crater in Death Valley National Park in California last year at this time, and had this experience. Ubehebe Crater is the remains of a volcano that is currently inactive, so my title is not as dramatic as it sounds.

Ubehebe is 0.8 kilometers (0.5 mile) across, and is the remnant of a volcanic crater. It is defined as a maar volcano, which forms when rising magma beneath the Earth’s surface touches a groundwater source. There are also many faults in this area, which gives the magma an easier path to the Earth’s surface and to those groundwater-rich areas. The groundwater near the magma increases in temperature, turns to steam, and explodes outward due to the pressure; this type of explosion is called a hydrovolcanic eruption. An event like this destroys surrounding areas due to the debris that is ejected from the force of the explosion, and often produces a mushroom cloud. The debris from the eruption that formed Ubehebe covers the landscape near the crater site and is approximately 45 meters (150 feet) thick. The structure is part of a cluster of about a dozen such maar volcanoes in the area, and is the largest of the group.

The crater could have formed approximately 6000 years ago, when the region held more water. However, there is some debate over this number. Scientists from Columbia University's Lamont-Doherty Earth Observatory hypothesize that Ubehebe is actually much younger in age (potentially 800 to 2,100 years old), and could have formed in the dry climatic conditions that are similar to those of Death Valley today. In their study, the researchers collected exclusively surface samples with isotopes of Beryllium-10 present. This isotope is created by cosmic rays that have constantly hit the rocks, and is only present on surface sediments. From this information, the team was able to determine a potential date that the crater’s outlying sediments could have been moved to the Earth’s surface. (The movement from below would have been the eruption that produced Ubehebe.) Due to its age, this finding means that the area could still be volcanically active if there is a water source present. There are hot springs in the area, so this is possibly the case. However, this potentially volatile site also requires the presence of magma, which may no longer be in the vicinity.

No matter its age, escaping Ubehebe is no easy feat. Making your climb more difficult is the loose gravel composing the majority of the hike; for every step forward, you fall backwards two steps. My run down took mere minutes, but my ascent from the (fortunately, inactive) crater took about half an hour.


I took this photo from the top of Ubehebe Crater in April 2012. I hope you enjoy it!

References:
http://geomaps.wr.usgs.gov/parks/deva/ftube1.html

http://www.nps.gov/deva/planyourvisit/ubehebe-crater.htm

http://www.volcano.si.edu/world/volcano.cfm?vnum=1203-16-

http://onlinelibrary.wiley.com/doi/10.1029/2011GL050130/abstract

http://ez-proxy.brooklyn.cuny.edu:2048/login?url=http%3A%2F%2Fsearch.ebscohost.com%2Flogin.aspx%3Fdirect%3Dtrue&db=geh&AN=2011-060213&site=ehost-live

http://news.nationalgeographic.com/news/2012/120125-death-valley-volcano-ubebe-crater-science/

http://www.wired.com/wiredscience/2012/01/ubehebe-crater-possibly-younger-but-no-imminent-danger-of-an-eruption/

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