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Subway Cave in Old Station, California
The Hat Creek basalt lava flow erupted about 24,000 years ago, near the present site of Old Station, California, and flowed along the Hat Creek Valley. It reached the vicinity of Rising River Lake, about 20 miles north. The flow generated lots of lavatubes, in which flowing lava crusts over while still-molten lava underneath drains out to leave a void. Most of the resulting tubes were small, a few feet or so in diameter, but at least one was world-class: Subway Cave. The dimensions in its main passage range from 6 to 17 feet high, and often more than 25 feet wide. There is plenty of room for a person to walk upright. Unlike many lavatubes, the cave is often wider than it is tall. This is because the floor itself consists of the top of a lava flow that flowed through the cave. Either the cave didn’t drain out completely, or a later flow came along. Both situations have been observed in other lavatubes.
The Hat Creek basalt lava flow erupted about 24,000 years ago, near the present site of Old Station, California, and flowed along the Hat Creek Valley. It reached the vicinity of Rising River Lake, about 20 miles north.
The flow generated lots of lavatubes, in which flowing lava crusts over while still-molten lava underneath drains out to leave a void. Most of the resulting tubes were small, a few feet or so in diameter, but at least one was world-class: Subway Cave. The dimensions in its main passage range from 6 to 17 feet high, and often more than 25 feet wide. There is plenty of room for a person to walk upright.
Unlike many lavatubes, the cave is often wider than it is tall. This is because the floor itself consists of the top of a lava flow that flowed through the cave. Either the cave didn’t drain out completely, or a later flow came along. Both situations have been observed in other lavatubes.
