Friday, July 6, 2018

Kīlauea: Dramatic, long-term changes continue. Catastrophic event possible but unlikely.

It is tough to grasp the enormous changes going on at Kīlauea volcano, including the impact on the prized national park as well as the catastrophic impacts on downslope residents.

(The view at right is from Volcano House. If you've looked over Kīlauea from this site, you'll recognize how completely different it looks now. The image is from an automated National Park Service camera.)
In the day-to-day news cycle, we tend to use a tight focus on what has been destroyed lately--the hundreds upon hundreds of lost homes, the thousands of acres of forest gone, the loss of transportation systems and the destruction of the Jaggar Museum--but scientists at the Hawaiian Volcano Observatory recently took a wider look, and the future doesn't look bright.

The U.S. Geological Survey report is entitled Volcanic Hazard at the Summit of Kīlauea, June 29, 2018 Update.
The Kīlauea caldera is collapsing at two to three inches daily, dramatically changing the look of the landscape. The lava lake has dropped 1,000 feet from its high. The parking lot at Halema`uma`u has been torn up like a sheet of paper, and it is covered by ash and rocks that have been ejected from the firepit.

If you remember the Halema`uma`u overlook, remember it well. It has now been closed since 2008, and if you ever see it again, it will look very different. The crater, for example, is four times as big as it was.

For the next few months, we can anticipate more earthquakes, ground cracking, ash plumes, vog and large scale deformation as Halema`uma`u engulfs more and more of Kīlauea Crater. It may eventually take up all of what we now know as the crater.

A sudden, massive, severely damaging collapse is considered possible, although unlikely. New lava fountains hundreds of feet high are possible. So is an earthquake much bigger than the ones felt recently.

"Strong earthquakes can occur at any time, and the risk of these events is larger now due to ongoing stress changes in and around the caldera. These earthquakes will not necessarily occur during swarm seismicity or in association with (collapse-explosion) events, may be large, and may happen outside of the caldera," the report says.

The only good news in this scenario is that if a massive, destructive collapse of the caldera occurs, there ought to be some notice of it:

"…Large-scale hazardous caldera collapse is a possible future outcome, although it is considered to be very unlikely and should be preceded by detectable warning signals. HVO should recognize these warning signs by direct observation and instrumental monitoring and, should they be detected, will alert authorities and the public."
That said:.

"The most likely course of activity for the immediate future at the summit of Kīlauea Volcano is continued subsidence of the caldera floor, episodic slumping into Halema`uma`u, felt moderate-sized earthquakes, and small ash plumes. The duration of this activity may be related to the duration of the (Lower East Rift Zone) eruption but cannot be confidently predicted," the USGS says.

In short, the most likely scenario is that we keep seeing what we’ve been seeing for the past couple of months. The less likely scenario is that it gets worse.

You can keep track of the technical details of the eruption at the USGS Hawaiian Volcano Observatory website

Another great resource is the lyrical narratives of retired Hawai`i Volcanoes National Park ranger Bobby Camara, Dispatches from Volcano

© Jan TenBruggencate 2018

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