Apoc­a­lypse not now

Park­go­ers can put off panic over erup­tion for a few ages

USA TODAY US Edition - - FRONT PAGE - Katharine Lackey

YELLOWSTONE NA­TIONAL PARK, Wyo. – You can’t miss the heat com­ing from be­neath the sur­face. It’s vis­i­ble ev­ery­where you look, from the steam­ing gey­sers to the bub­bling mud pud­dles and the col­or­ful hot springs. All that ac­tiv­ity is fu­eled by a smol­der­ing supervolcano, a heat en­gine buried deep un­der­ground that has pro­duced some of the largest erup­tions in the world. The last su­pere­rup­tion about 631,000 years ago spewed 240 cu­bic miles of pul­ver­ized rock and ash into the at­mos­phere, cov­er­ing nearly half the coun­try in the pow­dery residue.

“It’s an ac­tive vol­cano. It will erupt again,” said Michael Poland, sci­en­tist-in-charge at the Yellowstone Vol­cano Ob­ser­va­tory, a con­sor­tium of eight or­ga­ni­za­tions led by the U.S. Ge­o­log­i­cal Sur­vey.

But don’t go chang­ing your va­ca­tion plans just yet – or po­ten­tially ever.

Sci­en­tists who study Yellowstone’s 45-by-30-mile caldera, roughly the size of Rhode Is­land, say the un-

der­ground sys­tem prob­a­bly will give decades of warn­ing be­fore it blows – and that isn’t likely to hap­pen for thou­sands of years. De­spite the seis­mic orchestra of “snap, crackle and pop” that goes on un­der­ground, there are no signs it’s about to be­come more ex­plo­sive.

“Ge­o­log­i­cal events are stun­ning in their power, but they’re in­fre­quent in hu­man terms,” said Jerry Fair­ley, a pro­fes­sor of ge­o­log­i­cal sciences at the Univer­sity of Idaho who has stud­ied Yellowstone’s supervolcano for the past nine years. “We live on a very ac­tive planet, but it’s rare that we get to see the kind of power from the Earth that it is ca­pa­ble of gen­er­at­ing.”

‘It’s the story that never dies’

That long view has been par­tially drowned out in the past decade by a fever pitch of doc­u­men­taries, on­line ar­ti­cles and am­a­teur video clips that point to Yellowstone’s fre­quent mi­nor earthquakes – it av­er­ages 1,500 to 2,500 a year – or bla­tantly false ru­mors that the ground is swelling up­ward as signs the vol­cano’s time bomb is tick­ing down. The re­sult, the most ex­treme of these con­spir­acy the­o­ries say, would be the end of the world.

Such warn­ings draw con­clu­sions from the vol­cano’s past erup­tions to model what it could spew next – a faulty con­nect­ing of dots that ig­nores key in­for­ma­tion on how vol­ca­noes op­er­ate, ex­perts say.

The park ser­vice fields calls ev­ery year from would-be va­ca­tion­ers who want to know if vis­it­ing the na­tional park, which re­ceives more than 4 mil­lion peo­ple a year, would put them in dan­ger. “We see peo­ple who are think­ing about chang­ing their plans be­cause of the stuff they’re read­ing,” said Neal Her­bert, a spokesman for the park. “It’s the story that never dies.”

Heavy sum­mer crowds feel the steam com­ing off the gey­sers and see the bril­liant col­ors of the hot springs – shades of burnt orange, bright blue and vivid green – cre­ated by the micro­organ­isms that thrive in the ex­treme heat. Reg­u­lar earthquakes are usu­ally too sub­tle, at mag­ni­tude 2 or far less, to jolt them.

Those rum­blings are one of the give­aways a gi­ant vol­cano slum­bers be­low the sur­face. The fre­quent quakes may act as a safety valve to re­lease pres­sure be­fore it builds up, sim­i­lar to how a pres­sure cooker re­leases steam so it re­mains safe. “They may be a sign of safety rather than a sign of im­pend­ing doom,” Fair­ley said.

Warn­ing signs would oc­cur well be­fore an erup­tion. Mul­ti­ple, large earthquakes would rat­tle the park; the ground would move up or down by tens of feet over months or years as the magma un­der­neath shuf­fled around; gases would be emit­ted from the ground; the chem­i­cals in the springs would change; and more heat would be gen­er­ated, Poland said.

It’s sim­ply busi­ness as usual for the park right now, Fair­ley said. “Yellowstone, in a sense, is breath­ing,” he said.

An erup­tion would prob­a­bly be on a smaller scale that more closely re­sem­bled Hawaii’s Ki­lauea vol­cano this sum­mer, which caused a lava flow that forced evac­u­a­tions and sub­merged neigh­bor­hoods but didn’t re­sult in the cat­a­clysmic de­struc­tion of Yellowstone’s past su­per erup­tions. The last time Yellowstone ex­pe­ri­enced a lava flow was about 70,000 years ago.

We’d prob­a­bly have decades of warn- ing be­tween the first sign of an erup­tion and Yellowstone ac­tu­ally blow­ing its top, said Christy Till, a ge­ol­o­gist and as­sis­tant pro­fes­sor at Ari­zona State Univer­sity who has re­searched the vol­cano for the past six years.

The magma un­der­neath Yellowstone would need to be heated up – a lot: Seis­mic stud­ies in­di­cate it’s mostly so­lid­i­fied, not the hot liq­uid re­quired for an erup­tion.

“You would need to col­lect a huge vol­ume of magma all in the same place, and then you’d need to gen­er­ate enough pres­sure to get it mov­ing up to the sur­face,” Poland said. “And we see nei­ther of those con­di­tions in place right now.”

It’s en­tirely pos­si­ble those con­di­tions may never ex­ist again: The supervolcano may be dy­ing, said Ilya Bin­de­man, a Univer­sity of Ore­gon ge­ol­ogy pro­fes­sor who has worked on Yellowstone’s caldera for 20 years. Each su­pere­rup­tion melts part of the crust, hard­en­ing it and mak­ing it more dif­fi­cult to gen­er­ate enough heat to remelt the ma­te­rial.

The heat be­low can’t break through the tough outer skin formed by pre­vi­ous erup­tions.

‘It would not be a fun time’

If the worst-case sce­nario did hap- pen, it wouldn’t be a pretty day – for decades – in the USA.

“The erup­tion of Mount St. He­lens would be a small fire­cracker com­pared to one of the ma­jor caldera erup­tions of Yellowstone,” Fair­ley said.

Mil­lions of peo­ple would die in the im­me­di­ate ex­plo­sion and in its af­ter­ef­fects, Fair­ley pre­dicted. Ash would fall over much of the coun­try, grind­ing air traf­fic to a halt. Water would be con­tam­i­nated, live­stock would die, crops would fail and the coun­try’s heart­land would be un­farmable for years. The cli­mate would change be­cause ash would fil­ter out the sun’s pow­er­ful rays, and it would be sev­eral years or even decades be­fore it could bounce back.

Dur­ing Yellowstone’s su­pere­rup­tion about 631,000 years ago, ash cov­ered North Dakota through most of Texas and from South­ern Cal­i­for­nia through most of Mis­souri and Arkansas.

But a mas­sive erup­tion at Yellowstone would still not be the mass-ex­tinc­tion-level event some fear. “Hu­man­ity would sur­vive, but it would not be a fun time,” Poland said.

Hu­man­ity has ac­tu­ally done just that – we were around for two such erup­tions in the past 100,000 years, both even larger than the last big one at Yellowstone.

KATHARINE LACKEY/USA TO­DAY

Grand Pris­matic Spring is one of Yellowstone Na­tional Park’s main at­trac­tions.

KATHARINE LACKEY/USA TO­DAY

Old Faith­ful erupts Aug. 4 in Yellowstone Na­tional Park. The geyser got its name be­cause view­ers can count on it to put on its show about ev­ery 90 min­utes.

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