<P> Studies and analysis may indicate that the greater hazard comes from hydrothermal activity which occurs independently of volcanic activity . Over 20 large craters have been produced in the past 14,000 years, resulting in such features as Mary Bay, Turbid Lake, and Indian Pond which was created in an eruption about 1300 BC . </P> <P> In a 2003 report, USGS researchers proposed that an earthquake may have displaced more than 77 million cubic feet (2,200,000 m) (576,000,000 US gallons) of water in Yellowstone Lake, creating colossal waves that unsealed a capped geothermal system and led to the hydrothermal explosion that formed Mary Bay . </P> <P> Further research shows that very distant earthquakes reach and have effects upon the activities at Yellowstone, such as the 1992 7.3 magnitude Landers earthquake in California's Mojave Desert that triggered a swarm of quakes from more than 800 miles (1,300 km) away, and the 2002 7.9 magnitude Denali fault earthquake 2,000 miles (3,200 km) away in Alaska that altered the activity of many geysers and hot springs for several months afterward . </P> <P> In 2016, the United States Geological Survey announced plans to map the subterranean systems responsible for feeding the area's hydrothermal activity . According to the researchers, these maps could help predict when another supereruption occurs . </P>

How far below the surface at yellowstone is the magma chamber