Time-lapse image movie from a research camera positioned on Holei Pali, looking east towards Lava Flow 61G and Kalapana. December 22-29, 2016. Images courtesy of USGS/HVO
(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)
January 3, 2017, marks the 34th anniversary of the start of KÄ«lauea Volcano’s East Rift Zone (PuÊ»u ʻŌʻÅ) eruption. Given the duration of this eruption, people who were children when it began are now old enough to be parents, or possibly, grandparents. And, many Island of HawaiÊ»i residents have never known a time when PuÊ»u ʻŌʻŠwas not erupting.
During the past 34 years, KÄ«lauea’s East Rift Zone has seen a dizzying array of changes. High lava fountains gave way to tube-fed pÄhoehoe flows. Vents opened, fed flows to the ocean, and were abandoned. Neighborhoods were buried by lava, rebuilt, and partly buried again.
This past year was no exception. A new vent opened and formed a new lava flow that is still active today.
As the East Rift Zone eruption begins its 35th year, let’s review what happened over the past 12 months.
When 2016 began, lava was erupting from the June 27th vent on the north flank of the PuÊ»u ʻŌʻŠcone. This was the same vent that fed flows toward PÄhoa in 2014 and early 2015.
During late 2015 and early 2016, however, the vent fed surface breakouts over a broad area up to about 8 km (5 mi) northeast of PuÊ»u ʻŌʻÅ. These flows were upslope from communities in the island’s lower Puna District, but were relatively weak and posed no threat to infrastructure.
As 2016 progressed, lava also began to erupt within the small crater atop PuÊ»u ʻŌʻÅ, suggesting that more magma was arriving at PuÊ»u ʻŌʻŠthan was being erupted. This culminated in two new breakouts on the north and east flanks of the PuÊ»u ʻŌʻŠcone on May 24. The June 27th flow northeast of PuÊ»u ʻŌʻŠgradually stagnated and ceased over the following week.
The northern May 24 breakout at PuÊ»u ʻŌʻÅ, called episode 61f, was dead by June 4. But the eastern breakout, called episode 61g, captured the entire output from PuÊ»u ʻŌʻŠand kept going. Lava advanced downslope to the southeast, initially at rates of up to several hundred meters (yards) per day, and reached the top of the PÅ«lama pali on KÄ«lauea’s south flank in late June.
Spectacular channelized Ê»aÊ»Ä flows were visible for the next several days as lava streamed down the pali and puddled at its base. By early July, the 61g flow was back on the move and headed toward the ocean.
Lava crept across the coastal plain over the following weeks and crossed the gravel emergency access road (constructed in 2014 when flows were threatening PÄhoa) on July 25. The 61g lava flow reached the ocean early the next day and began to build two lava deltas, known as the eastern and western Kamokuna ocean entries.
The western, and weaker, of the two lava deltas grew to about 6 acres in size before it was abandoned in late September. The eastern Kamokuna lava delta persisted, however, and by the end of 2016 was about 26 acres.
Kīlauea’s East Rift Zone eruption settled in to a relatively consistent pattern of behavior this past year. Lava erupted from the Pu‘u ‘Ō‘Švent was carried downslope through a lava tube, where it emptied into the ocean. Occasionally, short-lived breakouts of lava occurred along the tube, creating surface flows.
In a few instances, more substantial breakouts occurred from the vent itself, burying the upper end of the 61g flow field beneath new lava. The largest of these breakouts, to date, occurred on November 21, and sent lava to the east of Pu‘u ‘Ō‘Å. This breakout was still active as of late December, advancing slowly—a few tens of meters (yards) per day—to the southeast along the edge of the older 61g flow. The 61g flows currently pose no threat to Puna communities.
As the New Year begins, we see no indication that Kīlauea’s East Rift Zone eruption is about to change significantly or stop. This leads us to wonder, will it outlast another generation?
If you’d like to hear more about Hawaiian volcanoes, you’re invited to attend the Volcano Awareness Month talks offered by USGS Hawaiian Volcano Observatory scientists throughout the month of January. The schedule is posted at https://hvo.wr.usgs.gov/.
For now, we wish you a great 2017!
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