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20 Wednesday, April 3, 2019 The Nugget Newspaper, Sisters, Oregon Scientists argue for more comprehensive studies of volcanoes By Mark Floyd Oregon State University CORVALLIS 4 The string of volcanoes in the Cascades Arc, ranging from California9s Mt. Lassen in the south to Washington9s Mt. Baker in the north, have been studied by geologists and vol- canologists for over a century. Spurred on by spectacular events such as the eruption of Mount Lassen in 1915 and Mount St. Helens in 1980, scientists have studied most of the Cascade volcanoes in detail, seeking to work out where the magma that erupts comes from and what future eruptions might look like. However, mysteries still remain about why nearby vol- canoes often have radically different histories of erup- tion or erupt different types of magma. Now scientists would like to find out why 4 both for the Cascades and for other volcanic ranges. In a perspective essay pub- lished this week in Nature Communications, scientists argue for more <synthesis= research looking at the big picture of volcanology to complement myriad research efforts looking at single volcanoes. <The study of volcanoes is fascinating in detail, and it has largely been focused on research into individual vol- canoes rather than the bigger picture,= said Adam Kent, a volcano expert at Oregon State University and a co- author on the essay. <We now have the insight and data to go beyond looking at just Mount St. Helens and other well- known volcanoes. We can take a step back and ask why is St. Helens different from Mount Adams, why is that different from Mount Hood?= The study takes a novel approach to this topic. <One way to do this is to consider the heat it took to create each of the volcanoes in the Cascades Arc, for example, and also compare this to the local seismic wave speeds and heat flow within the crust,= Kent said. <Linking these diverse data sources together this way gives us a better glimpse into the past, but offer some guidance on what we might expect in the future.= The need for studying volcanoes more thoroughly is simple, noted Christy Till of Arizona State University, lead author of the Nature Communications essay. Worldwide almost a bil- lion people live in areas at risk from volcanic eruptions, 90 percent of which live in the so-called Pacific Ring of Fire. The subduction of the Juan de Fuca tectonic plate beneath the North American plate is the ultimate driver for the formation of the Cascade Range, as well as many of the earthquakes the Northwest has experienced. Subduction results in deep melting of the Earth9s mantle, and the magma then heads upward towards the crust and surface, eventually reaching the sur- face to produce volcanoes. But there are differences among the volcanoes, the researchers note, including in the north and south of the Cascade Range. <The volcanoes in the north stand out because they stand alone,= Kent said. <In the south, you also have rec- ognizable peaks like the Three Sisters and Mount Jefferson, but you also many thou- sands of smaller volcanoes like Lava Butte and those in the McKenzie Pass area in between. Our work suggests that, together with the larger volcanoes, these small cen- ters require almost twice the amount of magma being input into the crust in the southern part of the Cascade Range.= Why is that important? <If you live around a vol- cano, you have to be prepared for hazards and the hazards are different with each dif- ferent type of volcano,= Kent said. <The northern Cascades are likely to have eruptions in the future, but we know where they9ll probably be 4at the larger stratovolcanoes like Mount Rainier, Mount Baker and Glacier Peak. In the south the larger volcanoes might also have eruptions, but then we have these large fields of smaller 4 so called <mono- genetic= volcanoes. For these it is harder to pinpoint where future eruptions will occur.= The field of volcanology has progressed quite a bit, the researchers acknowledge, and the need now exists to integrate some of the method- ology of individual detailed studies to give a more com- prehensive look at the entire volcanic system. The past is the best informer of the future. <If you look at the geol- ogy of a volcano, you can tell what kind of eruption is most likely to happen,= Kent said. <Mount Hood, for example, is known to have had quite small eruptions in the past, and the impact of these is mostly quite local. Crater Lake, on the other hand, spread ash across much of the contiguous United States. <What we would like to know is why one volcano turns out to be a Mount Hood while another develops into a Crater Lake, with a very dif- ferent history of eruptions. This requires us to think about the data that we have in new ways.= The 1980 eruption of Mt. St. Helens was a wake-up call to the threat of volca- noes in the continental United States, and though notewor- thy, its eruption was relatively minor. The amount of magma involved in the eruption was estimated to be 1 kilometer cubed (enough to fill about 400,000 Olympic swimming pools), whereas the eruption of Mt. Mazama 6,000 years ago that created Crater Lake was 50 kilometers cubed, or 50 times as great. The researchers say the process of building and tear- ing down volcanoes continues today, though it is difficult to observe on a day-to-day basis. <If you could watch a time- lapse camera over millions of years, you would see volca- noes building up slowly, and then eroding fairly quickly,= said Kent, who is in OSU9s College of Earth, Ocean, and Atmospheric Sciences. <Sometimes, both are happen- ing at once.= Which of the Cascades is most likely to erupt? The smart money is on Mount St. Helens, because of its recent activity, but many of the PHOTO BY JEFF BASINGER OSU geologist Adam Kent uses a laser ablation machine to measure chemical compositions in volcanic rock. volcanoes are still considered active. <I can tell you unequivo- cally that Mount Hood will erupt in the future,= Kent said. <I just can9t tell you when.= For the record, Kent said the odds of Mt. Hood erupt- ing in the next 30 to 50 years are less than 5 percent. Serving Sisters Since 1994 D ESIGNERS & B UILDERS of D ISTINCTION 541-549-1575 CCB#194489 ADVERTISING in The Nugget WORKS! The essential way to reach Sisters Country “To me, it’s necessary to advertise in Th e Nugget t Newspaper if you’re going to be in business, because everyone reads it cover to cover. If you have something important to say, this is the essential way to reach the people in Sisters Country, bar none. I believe in the importance of social media. 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