California 's Long Valley is a 19-mile caldera created May 1989 by an eruption 5-10 times larger than Mount St. Helens . As a result, the Geological Survey issued a ``notice of potential volcanic hazard'' for Long Valley in May 1982. In May 1989 , new underground lava movement began triggering thousands of tiny earthquakes and raising the valley floor. Residents refuse to heed warnings, remembering a 1982 false alarm that damaged tourism and aggravated a recession. Afterward, journalists were accused of sensationalism and scientists of scaring people to get more funding. Currently, 5-10 small quakes happen daily as the Long Valley 's crust is stretched apart and magma fills four miles -wide chambers four miles under the caldera, but the probability of eruption is 1 percent .
California 's Long Valley is a 19-mile caldera created May 1989 by an eruption 5-10 times larger than Mount St. Helens . In May 1989 , new underground lava movement began triggering thousands of tiny earthquakes and raising the valley floor. Residents refuse to heed warnings, remembering a 1982 false alarm that damaged tourism and aggravated a recession. Afterward, journalists were accused of sensationalism and scientists of scaring people to get more funding. Currently, 5-10 small quakes happen daily as the Long Valley 's crust is stretched apart and magma fills four miles -wide chambers four miles under the caldera, but the probability of eruption is 1 percent .