Peering into the Earth

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We lift off from the Hilo airport onHawaii’s Big Island, and our pilot, RobertBlair, swings the helicopter toward a hori-zon gray with mist, steam and volcanicgas. For the first several minutes, we passover 2,500 acres of green macadamiaplantations while Hilo’s famous rain, be-tween 130 and 200 inches a year, splattersthe front window. The morning’s torrentis clearly subsiding, though—fortunatelyfor us, because most of the drops are com-ing in where the helicopter’s doors used tobe. Four passengers and a pilot, we areabout to fly over an active volcano—onespewing sulfurous fumes, scarlet lava andsearing steam—with just a seatbelt tether-ing us to a metal contraption whose doorshave been removed so we can communewith nature. Against the volcano and its

fields of lava, all things seem puny, but atthe moment, this helicopter most of all.

The wind is blowing to the west, tak-ing the giant plume of gas and smoke withit, so we hover to the east side of the Pu`u`O`o vent, which is on the eastern rift zoneof the Kilauea volcano and has beenerupting for 20 years. The ashy brownsides of the vent rise conelike; inside themand through four windows—or skylights,as they are also called—that have openedin the crater floor, we see the incandescentglow of liquid rock. Lava fields stretcharound the vent, a vast plain of olderbrown and newer shiny black cooled rock.

Blair flies tight circles around Pu`u`O`o, taking us lower and lower. Soon wecan make out equipment from the U.S.Geological Survey’s Hawaiian VolcanoObservatory—which is located in HawaiiVolcanoes National Park on the rim ofthe now quiet Kilauea caldera—and wefeel the heat and smell the sulfur. (Thevent releases more than 1,500 tons of sul-fur dioxide a day, enough to fill 100

blimps, according to theUSGS.) After several passes,we veer to the south, fol-lowing a lava tube, a tunnelof hardened lava throughwhich the roughly 2,100degree Fahrenheit moltenrock travels, down to thePacific Ocean. There redlava flows into turquoisewater, and thick clouds ofbright white steam lacedwith shards of silica andhydrochloric acid rise highabove the black sand of the

beach. These are the colors of early earth:red, black and blue.

The hour-long helicopter tour is over,and we return to Hilo, flying back overa largely bleak landscape, a battlefield ofburned trees and buried houses—al-though a few structures stand stranded insmall patches of rain forest, spared by theflow. Pu`u O`o destroyed the Royal Gar-dens community here between 1983 and1986 and covered part of the park’sChain of Craters Road. From the air it iseasy to appreciate the power and reach ofthe volcano, the primal force shaping thisisland, creating new land (about 600acres’ worth so far), incinerating every-thing in its path. From the ground thispower feels even more vast and unruly.Down here you can hear the crackle ofcooling lava as you walk over it.

Volcanoes National Park is perhapsthe only place on earth where visitors ar-rive in continuous carloads to peer at ashycraters, calderas, cones, plumes of gas,and skeletons of trees and to clamber oversharp rock, desperate to see lava. Despitemany posted warnings, people in open-toed sandals and shorts eagerly trot alongnewly hardened, still hot lava to peekthrough a sudden opening and catch aglimpse of the red flow. The desire to beas close as possible to this force of naturehas cost five people their lives in the pastdecade because they ignored warnings ei-ther about lava hazards or about medicalconditions that can be aggravated by sul-furic fumes, says Jim Martin, the park’ssuperintendent. At the same time, how-ever, Hawaiian volcanoes are, as volca-noes go, gentle ones—so if you are going

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GAS FROM the Pu u O o vent often affects Big Island residents. The volcanic smog—or vog,as it is called—contains sulfur dioxide, whichturns rainwater acidic and causes respiratoryhealth problems.

Peering into the EarthA RIM WITH A VIEW IN HAWAII VOLCANOES NATIONAL PARK BY MARGUERITE HOLLOWAY

COPYRIGHT 2002 SCIENTIFIC AMERICAN, INC.

lava hunting, this is the place to do it. Themagma here is more fluid than most andcontains less gas, so it is less explosive andgives rise to what are called shield volca-noes because of their sloping profiles.

The volcanoes that make up the Ha-waiian Islands are not the result of thesubduction of one tectonic plate underanother—as are Mount Pinatubo, MountFuji, Mount Saint Helens and other vol-canoes in the Ring of Fire. Instead mag-ma spurts up from an unmoving hot spotlocated about 60 miles below the seafloor,in the earth’s mantle. The magma cools,building huge mountains that rise out ofthe sea. As the Pacific plate moves north-west, over millions of years, these vol-canic islands pull away from the hot spotand become dormant. New mountainsthen form above the hot spot. Theyoungest of these are Kilauea and, 20miles or so off the coast of the Big Island,a seamount called Lo`ihi, which mightbreak through the waves in 10,000 years.

Volcanoes National Park containsvolcanoes in various stages, from Pu`u`O`o to Mauna Loa, the largest volcanoin the world, and its many cooled lavafields. Mauna Loa last erupted in 1984 butwas stirring again this past year, and head-lines warned that it might become activeagain. (Some volcanologists estimate thatthe hot spot is about 200 miles in diame-ter, so vents can open or reopen in sever-al places across it.) Visitors can walkthrough the hollow Thurston Lava Tube,and every Wednesday a park volunteerleads a limited tour through the less ac-cessible Pu`u lava tube (call 808-985-6000well in advance to reserve a spot). The

park is also a good place to see the rainforests and grasslands that eventually col-onize the mineral-rich lava fields.

The Volcanoes National Park visitorcenter is open from 7:45 A.M. until 5 P.M.,and there are regular video shows andranger talks that explain the geology ofthe region and provide information aboutnative plants and animals (www.nps.gov/havo). The Jagger Museum, located rightnext to the USGS observatory, is openfrom 8:30 A.M. to 5 P.M. The exhibits de-scribe the various techniques volcanolo-gists use to study their subjects, and there

are seven operational seismographs ondisplay (http://hvo.wr.usgs.gov).

Several companies offer helicoptertours, including flights with the doors on,with the doors off, and with detours tonearby waterfalls. Blair works for TropicalHelicopters: 808-961-6810 (www.tropicalhelicopters.com). Other companies foundat the Hilo airport are Paradise Heli-copters (808-969-7392), Sunshine Heli-copters (808-882-1223) and Blue Ha-waiian Helicopters (808-961-5600). Fifty-minute flights run from about $100 to$175 a person.

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LAVA CONES from Pu u O o are among thevolcanic iterations found in the park(bottom image)—along with jets of lava(left), devastated forests (right), andclouds of steam and hydrochloric acid(below), where molten rock hits thePacific Ocean.

COPYRIGHT 2002 SCIENTIFIC AMERICAN, INC.