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| on 041217, a puff of ash rises from the lake, and the rim of the small inner lua (pit) is visible at the base of the plume |
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| at 650a this morning, steam, with the brownish haze of vog in the background |
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| and at 720a, minimal steam and a glimpse of the rim of the lua inset on the floor of Halemaʻumaʻu
What does this portend? Only time will tell. No prognostications from me, thatʻs certain.
The trembling and shaking of the ground continues, though seemingly less frequently these days. ʻŌlaʻi are unnerving. Maybe not the event itself, but the noise is what I detest. From when I was small, Iʻd plug my ears, jump around, and shout, trying to diminish the sound inside the rattling house. Still Do Not Like It.
And I continue to fuss with buttons on the Earthquake graphic page. These are at the summit for the past day:
I seem to feel those starting in the mid-to-high Magnitude 2. Especially if theyʻre shallow and Iʻm at desk in my loft. The quotidian few if weʻre lucky. If not, too many to count.
And again, most of these ʻōlaʻi are related to structural adjustments of the summit region, resulting from deflation or subsidence. A succinct Why? paper from USGS follows (thanks, MG).
and Pele and her pele continue to reshape the lands of Puna ma kai
Now fast-moving, then slow, then fast again, the ʻaʻā and pāhoehoe pele confounds. Some get complacent and try to carry on, then Sheʻs Coming! runRunRUN! I have said, and still say, for the good of all, including First Responders, heed Mandatory Evacuation notices. They arenʻt announced frivolously.
About the movement of pele
Both ʻaʻā and pāhoehoe move in fits and starts, but with slightly different looks.
Clinkery crumbly ʻaʻā flows, thick to begin with, especially on flattish or slightly sloping terrain may pause their advance, and rise up if the volume feeding the flow lessens for a time, or if the active flow front widens. The interior is still molten and the flow will inflate until a critical point is reached, then the ʻaʻā will surge forward for a short time, then slow down.
Smooth pāhoehoe is a bit different. Those flows typically issue at a foot or so thick. Its skin "freezes" and forms as soon as the 2,000+ degree lava hits the air. Pāhoehoe moves forward in many different anastamosing (The Word of the Day) fingers. If volume decreases, the flow, not being able to move forward because of the confining skin or crust, will inflate to varying degrees, sometimes forming cracked steep-sided tumuli up to several feet tall. When internal volume increases, rather than the front surging like ʻaʻā, inflated pāhoehoe will rupture, usually at a crack, sometimes several days after the initial flow is emplaced, sending out a thin flow to begin the process anew.
Hoping this makes some sense. Hereʻs silvery phh oozing from a darker tumulus a few days older, on 120617, on the coastal flats in Hawaiʻi Volcanoes NP.
All this is meant so you can understand why the fast-slow-fast movement of the current flows can be maddening. When will it reach the road? When should I evacuate? Where will it reach the road? ?????
The Fountain, yesterday in Keahialaka, up to 200 or more feet at times:
Front or Terminus of ʻaʻā pele making its way toward the Pacific:
The USGS Flow Map
And the relatively low-level seismicity of the last 24 hours or so on the LERZ (lower East Rift Zone)
 And finally, at Halemaʻumaʻu at 940 this morning, steam plume rises and inner pit rim visible. I nervously wonder: where has the lehu (ash) gone?  Till tomorrow, as always with aloha, BobbyC |
