'Mount Doom' Likely to Blow Soon

A view of New Zealand's Mount Ruapehu.

Mount Ruapehu, a New Zealand volcano that stood in for Mount Doom in the "Lord of the Rings" movies, seems to be heading for an eruption.

New Zealand's Department of Conservation (DOC) has warned hikers to keep off the summit, saying that recent temperature readings of the volcano indicate an increased likelihood of an eruption in the coming weeks.

The crater of Mount Ruapehu is usually filled with a snow-melt lake, and a peculiar temperature difference between the lake and the ground beneath it has led scientists to issue the warning.

"We think that the temperature a few hundred meters beneath Crater Lake is about 800 Celsius [1,472 degrees Fahrenheit], but the lake itself is only about 20 C [68 F]," said volcanologist Steven Sherburn, in an alert bulletin released by GNS Science, a New Zealand geologic hazard monitoring organization. "This suggests the vent is partly blocked, which may be leading to a pressure buildup beneath Crater Lake." [10 Biggest Volcano Eruptions in History]

The pressure could give way in the form of an eruption, minor or major.

"Sooner or later that situation will be rectified, either in a small, relatively passive way, or with a significant eruption," DOC volcanic risk manager Harry Keys told Radio New Zealand.

Ruapehu, New Zealand's largest active volcano, last erupted in 2007, propelling a large rock onto the leg of a nearby climber who recovered after having his leg amputated. Historically, it has had major eruptions every 20 to 50 years, according to DOC, with the last big ones coming in 1995 and 1996.

The volcano shared the role of Mount Doom in Peter Jackson's "Lord of the Rings" movie trilogy, but Ruapehu might be thought of as more of a stunt double than a featured player. Long shots of Mount Doom in the films showed nearby Mount Ngauruhoe, while scenes that supposedly took place on the slopes of Mount Doom were filmed on Ruapehu.

Mount Ngauruhoe, also an active volcano, last erupted in 1975. Mount Doom last erupted at the end of the Third Age of Middle Earth.

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