{"id":9284,"date":"2015-02-20T16:08:48","date_gmt":"2015-02-20T21:08:48","guid":{"rendered":"http:\/\/www.tcnjmagazine.com\/?p=9284"},"modified":"2015-09-24T14:35:24","modified_gmt":"2015-09-24T18:35:24","slug":"thar-she-flows","status":"publish","type":"post","link":"https:\/\/www.tcnjmagazine.com\/?p=9284","title":{"rendered":"Thar She Flows"},"content":{"rendered":"

 <\/p>\n

\"McGary
McGary adopts the Indiana Jones look in Utah’s Arches National Park.<\/figcaption><\/figure>\n

LIKE MOST VOLCANOES, Washington\u2019s Mount Rainier serenely sits atop a slow motion train wreck, as pieces of the earth\u2019s crust collide and buckle miles below. Scientists know that this tectonic plate mash-up creates the magma that feeds the still-active volcano. But the question of what path the magma takes from its subterranean origins to Mount Rainier\u2019s peak has long been a mystery.<\/p>\n

Now, new research by Assistant Professor of Physics R Shane McGary and three colleagues offers an unprecedented look into what\u2019s brewing beneath Mount Rainier. The team\u2019s findings, published last summer in the journal Nature, could help scientists gain a better grasp of how magma moves beneath volcanoes, and determine which should be labeled as potential threats.<\/p>\n

To map Mount Rainier\u2019s magma flow, the researchers combined previously collected seismic data with data they collected using magnetotellurics, a newer technique that measures electromagnetic activity deep within the earth. Similar to the way a metal detector finds hidden treasure buried under sand, magnetotellurics images electrically conductive molten magma within the earth.<\/p>\n

Using a network of sensors and electrodes to probe depths of up to 75 miles beneath Mount Rainier\u2019s base, the researchers detected a giant slab of oceanic crust coming in from the Pacific and colliding with the portion of continental crust that is western Washington State. Where the two come into contact is the origin of the molten rock that flows upward, in a giant column, toward the base of Mount Rainier.<\/p>\n

The team also discovered a gaping reservoir\u20145 to 10 miles wide and equally tall\u2014that holds magma just a few miles beneath the volcano\u2019s base. McGary, lead author of the Nature report, noted how this architecture differs from what\u2019s under other volcanoes in the area. Nearby Mount Jefferson in Oregon, for example, lacks Mt. Rainier\u2019s distinct plume\u2014or flow path\u2014for magma.<\/p>\n

\u201cThis evidence supports the idea that Mount Rainier is more of a short-term eruption threat than Mount Jefferson,\u201d he says. Mount Rainier, which towers over millions in the Seattle-Tacoma area, last erupted in 1894, but the U.S. Geological Survey believes it will erupt again. While the new plumbing imagery from McGary\u2019s team can\u2019t be used to predict when (see sidebar), it does contribute to knowledge about how magma moves on the way to an eruption.<\/p>\n

\u201cThe flow of magma from the oceanic slab to the surface has to be fairly quick\u2014as in, hundreds rather than thousands of years,\u201d says McGary. \u201cWe can\u2019t say when a volcano is going to erupt, but certainly we can predict which volcanoes are going to cause issues in the near future.\u201d
\nThe two plates butting heads beneath Mount Rainier are the Juan de Fuca plate, an oceanic plate, and the massive North American continental plate. In this geological match-up, the continental crust wins out due to the higher density of the oceanic crust. As a result, the Juan de Fuca plate is being driven underneath into the hot, dense mantle layer below.<\/p>\n

As the oceanic plate becomes more immersed in the mantle, the high heat and pressure cause some of its water to release. The water melts the surrounding rock, converting it into molten magma, which flows upward to form volcanoes. In the case of Mount Rainier, the pathway is more or less straight up, from the slab to the peak, the researchers found.<\/p>\n

\u201cThe oceanic plate is being driven down below the United States, and that\u2019s what causes the volcanoes to form in the first place,\u201d says McGary. \u201cThe continents do move, and the process is really dynamic.\u201d With the Mount Rainier study concluded, McGary wants to use a similar process\u2014combining seismic data and magnetotelluric imaging\u2014to look back in time.<\/p>\n

\u201cWhen the supercontinent Pangaea split apart about 200 million years ago, Africa left part of itself behind as a gift,\u201d says McGary. That \u201cgift\u201d is the present-day state of Florida, and McGary hopes to discover more about the suture that once connected the two continents. \u2014Meeri Kim<\/p>\n

CAN WE PREDICT ERUPTIONS?<\/h2>\n

Although we now know what Mount Rainier\u2019s volcanic plumbing looks like, when it will blow next remains a mystery. The type of imaging McGary and his colleagues used, magnetotellurics, can help scientists better understand how volcanoes operate in general\u2014and which could cause problems in the near future\u2014but it can\u2019t yet pinpoint eruptions.<\/p>\n

\u201cTo get a clear picture of what is going on 80 kilometers down, we need a few weeks\u2019 worth of data,\u201d says McGary. You\u2019d also need faster computers to analyze the data. But as technology advances, and processing speeds improve, something closer to \u201creal-time\u201d imaging could only be decades away.<\/p>\n

We\u2019ve gotten better at forecasting eruptions, McGary says. \u201cWhen Mount Pinatubo in the Philippines erupted in 1991, the monitoring of seismic activity that preceded the eruption led to an evacuation that saved thousands of lives.\u201d But predicting eruptions is far from an exact science, especially since not all volcanoes give seismic warnings before blowing their tops.<\/p>\n","protected":false},"excerpt":{"rendered":"

A physics professor probes the magma beneath one of the nation\u2019s most dangerous volcanoes.<\/p>\n","protected":false},"author":284,"featured_media":9231,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,76],"tags":[],"class_list":["post-9284","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-on-campus","category-winter-2015"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/posts\/9284","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/users\/284"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9284"}],"version-history":[{"count":0,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/posts\/9284\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=\/wp\/v2\/media\/9231"}],"wp:attachment":[{"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tcnjmagazine.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}