Recent research showing Kilauea volcano has experienced long periods of explosive eruptions during the past 2,500 years will be the topic of a free presentation tonight at the University of Hawaii at Hilo.
Don Swanson, a geologist with the U.S. Geological Survey’s Hawaiian Volcano Observatory, will speak at 7 p.m. in UCB-100 on the main campus at 200 W. Kawili St. For a map, visit http://hilo.hawaii.edu.
For two centuries, Kilauea has erupted gentle lava flows and infrequent high lava fountains — activity that has destroyed property but has not been particularly hazardous to people, except on rare occasions.
But Swanson’s collaborative study with geologists from the Smithsonian Institution and the University of Hawaii at Manoa has revealed that Kilauea is not always so benign.
According to Swanson, during the past 2,500 years, Kilauea’s volcanic activity has alternated between periods of dominantly effusive and dominantly explosive eruptions. Research shows effusive activity, like that ongoing in Kilauea’s east rift zone, makes up only 40 percent of the volcano’s eruptive history, and periods dominated by explosive eruptions from a deep caldera make up 60 percent.
“Research like that of Dr. Swanson’s on the eruption history of Kilauea underscores the importance of painstaking analysis of the rock record in order to get a more representative view of true geologic hazards as compared with what our limited human experience might lead us to believe,” explained USGS director Marcia McNutt. “The USGS invests similar efforts to decipher the long-term geologic record of infrequent but devastating west coast tsunamis and earthquakes to overcome the very short human history in the western hemisphere.”
Swanson says this surprising finding dispels a long-held notion that Kilauea’s past explosive eruptions were just blips that only briefly punctuated otherwise long and monotonous periods of lava flow eruptions. Instead, the two periods of explosive eruptions in the past 2,500 years lasted 300 and 1,200 years, respectively.
This has profound implications for public safety, once the next period of explosive activity begins.
“At this time, however, there is no indication that Kilauea’s next explosive period will occur any time soon,” Swanson adds, “so there is no reason to not visit Kilauea and enjoy the volcano’s current effusive eruption of lava flows.”
Swanson will share how he and his colleagues made these recent findings and will discuss Kilauea’s explosive past in his talk at UH-Hilo. He will also distribute copies of a newly published USGS Fact Sheet (Kilauea — An Explosive Volcano in Hawaii) that he and his colleagues wrote. The Fact Sheet can also be read online at http://pubs.usgs.gov/fs/2011/3064/.
Swanson’s presentation is one of many programs being offered in January by HVO during Hawaii Island’s third annual Volcano Awareness Month. For more information about this talk and other events, visit the HVO website at hvo.wr.usgs.gov or call 967-8844.