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Volcano Watch: Kilauea’s summer break pau for now?

Since the vent collapse in late June, Kilauea’s summit plume had been wispy, translucent and low in SO2 content,  resulting in improved air quality in Kona and Ka‘u.  However, the summit vent has picked up in activity again this week. (Photo courtesy of Hawaiian Volcano Observatory)

Since the vent collapse in late June, Kilauea’s summit plume had been wispy, translucent and low in SO2 content, resulting in improved air quality in Kona and Ka‘u. However, the summit vent has picked up in activity again this week. (Photo courtesy of Hawaiian Volcano Observatory)

 

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

While baseball fans nationwide at this time of year think about “trades” in terms of swapping average for exceptional ball players, we here in Hawaii rely on “trades” (northeasterly trade winds) for dispersing volcanic emissions from the active vents on Kilauea Volcano. 

Beginning in early July, sulfur dioxide (SO2) gas emissions from Kilauea’s summit vent decreased by about 60 percent from the average measured since the vent opened in March 2008. 

The withdrawal of magma from within the vent, and multiple collapses of the vent rim at the end of June 2009, resulted in a wispy, lazy plume and an eerily quiet vent with no glow. 

But as the “trade” season for baseball players came to a close July 31, emissions from Halemaumau began to pick up again and, as of this writing (Aug. 13) appear to have returned to the average value measured since the vent opened. 

The return of incandescence, gas rushing noises, and elevated vent temperatures over the past week also suggest that lava is once again higher in the vent conduit. 

The recent reprieve in volcanic activity from the summit vent tantalizes us with memories of pre-eruptive conditions, and both anecdotal reports and measured concentrations confirm improvements in air quality in Ka‘u and Kona districts. 

However, even with the reduced SO2 summit emissions during July, interruptions in the trade winds resulted in several episodes of elevated volcanic pollution in Hawaii Volcanoes National Park and adjacent communities. 

The return of Kilauea’s SO2-rich summit plume and proximity of tropical depression Felicia set the stage for extreme SO2 concentrations in the National Park this week. 

On Tuesday, Aug. 11, light southwesterly winds blew the plume toward the Kilauea Visitor Center where concentrations exceeded 5 ppm, resulting in a “hazardous” condition advisory, the highest defined level. Other communities in East Hawaii also experienced elevated levels of volcanic pollution as a result of the interrupted trade winds, with some residents of Volcano Village reporting extreme vegetation burn. 

The current cycling in summit activity is reminiscent of last December, when SO2 emissions dropped a commensurate amount for a similar period of time, and the vent was also dark, quiet, and produced little ash and tephra. 

While Kilauea’s summer break may be over for now, historically, long-lived summit eruptions have typically waxed and waned. Thus, we can look forward to the possibility of future time-off from our volcano’s copious gas and modest ash emissions.

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