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The Yellowstone Caldera Chronicle is a weekly column written by scientists and collaborators at the Yellowstone Volcano Observatory. This week’s contributor is Michael Poland, a geophysicist with the U.S. Geological Survey and chief scientist at the Yellowstone Volcano Observatory.
this On July 23, 2024, a hydrothermal explosion occurred in the Biscuit Basin is a spectacular and dangerous event, with water, rock, and mud gushing out more than 330 feet (100 meters) from its source, the Black Diamond Pool. It is known that there have been several hydrothermal explosions here, probably caused by an explosion between 1902 and 1912.
Although this phenomenon has never been documented in such detail in Yellowstone, it appears to be extremely rare. Hydrothermal Eruption Relatively common. Small explosions may occur several times a year in some parts of the park, leaving craters at least one to several yards (meters) wide, but they are usually not witnessed because they occur in remote areas, at night, or in winter. July 23, 2024 Biscuit Basin explosion-sized event It may happen every ten to several dozen years. In Yellowstone Park.
Hydrothermal eruptions, caused by changes in pressure when liquid water turns to steam, are not limited to Yellowstone. They occur in hot water systems elsewhere in the United States and around the world.
One of the most spectacular hydrothermal eruptions of the last century occurred in an unremarkable cluster of hot springs in Surprise Valley near Lake City in northeastern California. There is no recent volcanic activity nearby; the hot springs and mud volcanoes may be related to Large faults are part of a tectonic extension of the western United StatesOn the night of March 1-2, 1951, an explosion threw debris thousands of feet (about a kilometer) into the air and caused fine particles to fall four miles (more than 6 kilometers) away. The explosion disturbed about 20 acres (0.03 square miles or 0.08 square kilometers) of land in the hot springs area and swept in 300,000 tons of mud. Because the explosion occurred at night and there were few people living in the area, there were no casualties.
Even a small hydrothermal explosion can be deadly if it occurs in a densely populated area. In October 1990, such an explosion occurred at the Agua Shuca geothermal area in a small community in El Salvador. The explosion killed about 25 people, injured many others, and created a crater 40 meters (131 feet) in diameter. According to geological evidence, the same geothermal area exploded in 1868, and probably many times before that. This area of El Salvador is known for intense geothermal activity and occasional explosions.
Perhaps no place on Earth experiences hydrothermal eruptions as frequently as New Zealand’s North Island, where eruptions of varying sizes occur almost every year. Some of these eruptions are noteworthy. For example, an eruption on April 19, 2005, in a remote area of the North Island created a crater 164 feet (50 meters) in diameter. The column of mud and debris reached 650 feet (200 meters) high and was visible from 6 miles (10 kilometers) away. In another example, on the night of February 22, 1973, a hydrothermal eruption occurred at the edge of Lake Frying Pan, one of the world’s largest hot springs, burning or killing nearby vegetation and depositing up to 1.5 feet (0.45 meters) of mud. Despite its magnitude, the eruption was not heard by people only 850 meters (0.5 miles) away.
Hydrothermal eruptions also occur in areas where geothermal heat is used to generate electricity, including New Zealand, the Philippines and Central America. In these areas, changes in underground pressure can be caused by pumping and injecting water, as well as abandoned wells.
Precursors to hydrothermal eruptions are not well documented. Occasionally there are reports of changes in geyser and hot spring activity a few months to years before an eruption. For example, new springs formed at the edge of Lake Frying Pan in New Zealand a few months before the 1973 eruption. Porkchop Geyser in Norris Geyser Basin shows changes in water chemistry before its 1989 eruption. this April 15, 2024 Porcelain Table ExplosionAlso located in Norris Geyser Basin About two years ago, hot springs and geyser activity was more active. In some geothermal areas in Japan, local ground deformations have occurred in the area of the subsequent small explosions. Unfortunately, changes are common in hydrothermal areas and are usually recognized as precursors to explosions only after the fact.
The common feature of these explosions is that they are not directly triggered by the interaction of magma or magmatic gases with shallow groundwater. Instead, when water boils, the mixture of liquid and steam is in a sealed, confined space, and the pressure generated by the expansion of steam bubbles eventually overcomes the strength of the rock, causing an explosion.
In natural hot areas around the world, the hazards posed by hydrothermal explosions are often underestimated, although some incidents have resulted in loss of life. New Zealand GNS Science focuses on monitoring and research of hydrothermal explosions,as well as Yellowstone Volcano Observatory Monitoring Plan 2022-2032. Additional monitoring instruments, Like those recently installed at Norris Geyser Basin In Yellowstone National Park, it could help better detect and potentially warn of such activity.
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