Hole-in-the-Ground

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Hole-in-the-Ground is a large maar (explosion crater) in Lake County, central Oregon, 43°24.67'N,121°11.92'W, northeast of Crater Lake, near Oregon State Route 31.

It is about 1,600 meters (nearly a mile) across, a little longer N-S than E-W. Its floor is about 150 meters below the surrounding ground level and has a rim that rises 35 to 65 meters (about 110 to 220 feet) above, the highest point on the east side. The crater formed during the late Pleistocene, between 13,500 and 18,000 years ago, at which time the Fort Rock Basin was a lake and the location was near the shore. Basaltic magma intruding near the surface flashed ground water to steam, which blew out overlying rock and soil, along with some juvenile material. As material slid into the hole formed, it closed the vent and the process repeated, eventually forming the huge hole. To the West is an even bigger maar, 1,820 meters (about 6,000 feet), but older and more eroded, called Big Hole.

Image:Holeintheground.jpg

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Volcanoes of Oregon
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High Cascades Mt Hood | Olallie Butte | Mt Jefferson | Three Fingered Jack | Hogg Rock | Hoodoo Butte | Hayrick Butte | Black Butte | Mt Washington | Belknap Crater | Black Crater | Three Sisters | Broken Top | Tumalo Mtn | Mt Bachelor | Maiden Peak | Diamond Peak | Howlock Mtn | Mt Thielsen | Mt Bailey | Mt Mazama / Crater Lake | Mt Scott | Union Peak | Pelican Butte | Mt McLoughlin | Aspen Butte
 Western Cascades  Boring Lava Field (Mt Sylvania | Mt Tabor | Rocky Butte | Powell Butte | Larch Mtn)
Eastern Cascades Pilot Butte | Lava Butte | Newberry Volcano | Yamsay Mtn
Basin and Range Big Hole | Hole-in-the-Ground | Fort Rock | Diamond Craters  Columbia Plateau  Columbia River Basalt Group