And a tragedy is playing out right now at Crater Lake, a young boy is missing and being searched for.

I loved this post, it really struck a chord with me. I hope you don’t mind, but I linked to it on my blog (http://nerdcountry.blogspot.com/2006/10/dog-star.html). I write about life split between the tech world by day and country bubba-hood by night, and the night before I read this post I’d just seen the Milky Way stretching once again across our country Texas skies.

What I posted about, though, was the great picture of your wife, daughter, and dog in front of the lake. Specifically, how the dog seems captivated not so much by the spectacle of the lake as by the glory of the sandwich.

If it’s a problem having the photos on my blog just let me know, I’ll take them down. I did credit you for them and link back here, though.

Jeff the Blogging Novice

[runs away]

The USGS categorizes Crater Lake as filling a caldera. I was curious about the distinction, too:

A caldera is a large, usually circular depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir. The removal of large volumes of magma may result in loss of structural support for the overlying rock, thereby leading to collapse of the ground and formation of a large depression. Calderas are different from craters, which are smaller, circular depressions created primarily by explosive excavation of rock during eruptions.

Crater Lake is pictured here with other calderas. I think crater is used loosely for any depression, but it’s good to know the difference in case I ever getting around to seeing one…maybe next year when I go to Hawaii.

And FYI to Tristan: a caldera is a volcanic crater (crater is a more general term, but still accurate). In fact, the Oxford English Dictionary (what I like to call “the big book of words”) lists the depression at the top of a volcano as the first definition of “crater.” Keep in mind that volcanoes have been known far longer than meteorite/asteroid impacts. Interestingly, the OED also lists a caldera as the depression at the summit of an “extinct” volcano. I’d never heard that distinction before, which would (strictly speaking) mean that Yellowstone, Mount St. Helens, etc. do not have calderas. Hmmm…getting a bit too picky there, methinks.

It seems that the classic conical shape generally is consistent, being a manifestation of the outpouring of lava that solidifies and does not tumble any further as the slope is stable up to a critical angle.

If there is no significant side fissure upsetting that slope, it would be a perfect cone-shaped mountain. And I guess that that angle would be fairly consistent. Check other volcanos around the world.

Ivan.

IANAG, but what we see in the geology surrounding the Mazama site is consistent with what we see in other volcano sites with similar geology today. By making comparisons between Mazama and other volcanoes at other stages of their lifecycle, we can make informed, likely accurate guesses about what Mazama was like.

The figures may be wrong, but it’s not likely that they are, and the consequences if these guesses are incorrect are relatively minor.

“When the central peak collapsed, the height of the mountain was nearly halved, dropping from 11,000 feet (3300 meters) to about 7000 feet (2100 meters).”

Statements like these always bother me. Could someone point me to a reading resource that explains how we “know” that the mountain used to be 11,000 feet tall? How do we “know” that the column of rock and ash was a kilometer wide and reached 15 km into the sky? Sure, it’s a reasonable guess at what happened, but it seems to place a lot of (dare I say) faith in assumptions which can’t be proven or disproven… Thanks for the clarification.

And thanks for the information as to how these lakes were formed. The size of Crater Lake far out-strips the local crater lakes I grew up nearby in North Queensland in Australia :- Lakes Eacham and Barrine and a not-so-well known Euramo (!). The first two have had tourists visiting for decades. They are set in thick rainforest, national Parks no less, but surrounding them is extensive farmland. Have a look in Google Earth on the Atherton Tableland. There are many examples of volcanic activity all around. I was actually born on the side of an extinct Volcano, in nearby Atherton.

Ivan.

And that’s awful news about the little boy. That’s right when we were there! That place is huge and very dangerous. I hope they find him soon.

CRATER LAKE — The search for a missing 8-year-old boy continued today at Crater Lake National Park.