Over the past several weeks, a pit within Halema’uma’u Crater (on the summit of Kilauea Volcano) has steadily emitted sulfur dioxide and other volcanic gases. About 120 meters (390 feet) below the pit’s opening, a lava pond rises and falls as magma moves underneath Kilauea.
Sulfur dioxide emissions were 550 metric tons per day (1,200,000 pounds) on January 3rd, 2011, well above the daily average of 125 metric tons (280,000 pounds) from 2002–2006. Sulfur dioxide emissions at Kilauea peaked at about 2,000 metric tons (4,400,000 pounds) per day in March 2008, when the pit in Halema’uma’u first opened.
Kilauea Caldera, Halema’uma’u Crater, and the volcanic plume are all visible in this natural-color satellite image acquired on January 15, 2011 by the Advanced Land Imager (ALI) aboard theEarth Observing-1 (EO-1) satellite.
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using ALI data from the EO-1 team. Caption by Robert Simmon.
Kilauea is one of the world’s most active volcanoes, but it is of the sort that tends to ooze lava more often than it explodes. But starting on March 19, a small explosion rained rock and ash over the summit. The Hawaiian Volcano Observatory warned on March 28 that sulfur dioxide concentrations in the air downwind from the volcano were likely to be hazardous. Even before the March 19 explosion, elevated sulfur dioxide levels prompted the National Park Service to close part of Crater Rim Drive.