She's Dead, Jim

May 13, 2018  •  Leave a Comment

Geological activity at Kilauea Volcano has definitely taken a new direction. If you have been following the news you should be aware of the recent outbreaks of fissures on her southeastern rift zone. Unfortunately, the outbreaks have occurred in populated areas and many people have lost their homes and also forced to evacuate.

Personally, I have been watching Kilauea and Mauna Loa pretty much constantly for the last three years. The USGS provides a site which you can check (and I do daily) on the latest activity at the Hawaiian Volcano Observatory. I've been following particularly closely over the last month as both Kilauea proper and the massive Pu'u O'o crater (down the southeastern rift) began swelling in late March. While lava entry into the ocean had stopped a few months ago, lava outbreaks around Pu'u O'o were frequent and the inflation just added constant pressure for outbreaks. This activity was exciting to see as this year's travel plans included Hawaii in November 2018 and I had planned for much more up close and personal lava flow experiences. On 30 April Kilauea experienced a massive swarm of relatively shallow earthquakes both at the caldera and along her southeast rift zone. I had a sinking feeling that something was about to happen and I was missing it.

On 1 May, Pu'u O'o's crater floor collapsed and seismicity indicated activity further down-rift (southeast). Below you can see what Pu'u O'o looked like during clear weather earlier in April 2018.

Pu'u O'o CraterPu'u O'o Crater on 18 April 2018

You can clearly see a lava pond (bottom-center) and, image-left, you can make out USGS gear monitoring Pu'u O'o. From late March up to this point I had watched Pu'u O'o's crater floor go from a concave configuration to a convex, almost dome-like, structure. In fact, the reddish-beige formation, image-right, once loomed high above the crater immediately to the left (north). Apparently, the magma causing Pu'u O'o to swell (as well as Kilauea) had found a path further down-rift and the sudden evacuation of magma and severe drop in pressure caused Pu'u O'o to fail completely. A couple of days later, Hawaii experienced three 5+ magnitude earthquakes including one not far from Pu'u O'o and a fourth earthquake registering 6.9 just off the south shore of the island.

Further down-rift USGS continued to monitor increased seismic activity and tilting of the rift zone. On about 5 May USGS were able to inspect Pu'u O'o since the weather had cleared enough to allow flights and visibility was good. It became obvious that Pu'u O'o had suffered a devastating collapse. Additionally, a one kilometer-long crack had opened directly west of the crater and had seeped lava at some point overnight. Sulphur dioxide and steam were still outgassing during the over flight.

Pu'u O'o after the collapse.Pu'u O'o after the collapse of the crater floor. Note that the USGS equipment miraculously still sits to the left of the crater. You can still see the USGS equipment to the left which miraculously survived the collapse. You can also see the structure of rock I mentioned above to the right but it, and everything around it is now covered in a layer of reddish-brown ash and dust. Another look at Pu'u O'o a few days later looking straight down into the crater.

Pu'u O'o post collapse - May 2018A perfectly straight down shot of the crater after the collapse. This shot (above), taken several days after the initial collapse, you can see that additional collapse and rock slide activity has occurred since the walls of the crater have significantly steepened. Additional slides and collapses are expected to occur before things finally settle. Overnight web cam images show absolutely no sign of incandescence, likely meaning that magma is now bypassing the crater. Additionally, all lava activity on the surface has stopped and the usual glow of skylights (areas where lava tubes are partially exposed) at night have all stopped as well. This leads me to believe that Pu'u O'o is now a dead crater like many of the other craters further up-rift (to the northwest). Assuming I am correct, she put on quite a show for an extended time and it is saddening that I will not get to experience her activity first hand. She menaced nearby communities for over 30 years and utterly destroyed the Royal Gardens subdivision in the late 80s and early 90s. Pu'u O'o recently threatened the Pahoa community with lava flows just meters from structures outside town-central before halting. The vent then gave us one final fantastic show of lava entering the ocean in 2017 which lasted several months on-and-off. Who knows what is next for Kilauea and her southeast rift zone. As of today, 18 fissures have appeared in, and around, the Leilani Estates subdivision, destroying almost 40 structures to this date. Given all her activity, it is unlikely that Pu'u O'o will play a part in the next chapter of Kilaueua's nearly 40 years of continuous eruptive activity as it appears that a new vent will be opening up somewhere much further down-rift from the Volcano. Kilaueua herself also threatens the island's southside with lava being lower than ever recorded since Halema'u ma'u vent opened in the crater floor. Vent wall collapses and steam explosions are highly likely which could change the structure of the vent. It will be interesting to see what happens next and I hope that I'll be able to get some fascinating photos of the activity when I am next there.

 

(All photos are copyright USGS)


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