Outside the Interzone
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Dana overlooking the lower part of the lava gutter, where it empties out onto a plain of aa-aa. The lava flowed a couple miles, reaching the Deschutes River, where it created a temporary dam. Where that dam was ultimately breached and eroded down, the stretch of whitewater that remains today is called Benham Falls. It's a spot I haven't visited... yet.Photo unmodified. August 21, 2011. FlashEarth location.
...Daddy doesn't sleep at night. I'm not entirely clear on how squeeze-ups form, but I can generally recognize them. My understanding is that once the lava becomes confined within the exterior shell or crust- essentially, a lava tube that hasn't drained- more lava erupted at the top of the flow increases the pressure lower in the tube. If there is a fracture or joint in the area experiencing the increased pressure, the lava squeezes up and out, like toothpaste from a tube.Photo run through […]
(Click the pic for full-size. You know you want to.) Most cinder cones eruptions follow roughly the same story line: they start with a volatile-rich phase, tossing out bubbly, vesicular lava, with gasses acting as the propellant. A large heap of these cinders form around the vent. Since the slope is limited by the angle of repose- the steepest that a loose material of a given nature can be piled without collapsing- cinder cones tend to all look quite similar. The material they're made of is all […]
Viewing the two lava balls in the left of yesterday's photo from a different angle. I'll reiterate that I'm not sure if "lava balls" is a term used broadly among volcanologists; Lava Butte is the only place I've seen it. At the same time, I want to acknowledge that the mechanism described on the interpretive sign there seems logical and the best explanation *I* can think of. The rabbit brush is typically 2-3 feet in height, so these are pretty big- maybe 10-15 feet in diameter. The thought of […]
Sitting on the rim of the basalt flow here are three objects that the interpretive sign describes as lava balls. These are said to form in the same way as cartoon snowballs: a bit up high breaks loose and rolls down the slope of the active flow, accreteing more lava as it goes, growing into a large, roughly spherically-shaped, ball. It makes good sense to me, but the reason I'm putting it into such equivocal terms is that I have never seen the name "lava balls" anywhere else, nor have I seen […]
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