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, which turns rainwater acidic and causes respiratory health problems. Image: U.S. GEOLOGICAL SURVEY, HAWAIIAN VOLCANO OBSERVATORY
We lift off from the Hilo airport on Hawaii's Big Island, and our pilot, Robert Blair, swings the helicopter toward a horizon gray with mist, steam and volcanic gas. For the first several minutes, we pass over 2,500 acres of green macadamia plantations while Hilo's famous rain, between 130 and 200 inches a year, splatters the front window. The morning's torrent is clearly subsiding, though--fortunately for us, because most of the drops are coming in where the helicopter's doors used to be. Four passengers and a pilot, we are about to fly over an active volcano--one spewing sulfurous fumes, scarlet lava and searing steam--with just a seatbelt tethering us to a metal contraption whose doors have been removed so we can commune with nature. Against the volcano and its fields of lava, all things seem puny, but at the moment, this helicopter most of all.
The wind is blowing to the west, taking the giant plume of gas and smoke with it, so we hover to the east side of the Pu`u `O`o vent, which is on the eastern rift zone of the Kilauea volcano and has been erupting for 20 years. The ashy brown sides of the vent rise conelike; inside them and through four windows--or skylights, as they are also called--that have opened in the crater floor, we see the incandescent glow of liquid rock. Lava fields stretch around the vent, a vast plain of older brown and newer shiny black cooled rock.
This article was originally published with the title Peering into the Earth.