Carbon Dioxide Emissions at Mammoth Mountain, California :: Nature Volcano Essays

Carbon Dioxide Emissions at Mammoth Mountain, California According to Dr. David P. Hill and Dr. Roy R. Bailey of the United States Geological Survey, the most common geological question in Mammoth, California is Where is the volcano? Although Mammoth Mountain does not resemble the classically recognized cone-shaped volcano, the mountain experienced significant volcanic and seismic activity in the past two decades, which have brought the mountain the recognition as a potentially hazardous volcano. A massive volcanic explosion 760,000 years ago created the Long Valley Caldera in California. A build up of magma beneath the earth's surface caused an uplift of the crust which led to the explosion. Afterwards, the crust sank over a mile, into a depression measuring 10 miles wide and 20 miles long. A magma chamber still exists beneath the caldera. The fumaroles and hot springs confirm the presence of a magma body. The underground magma heats groundwater which rises to the surface and releases in hot springs or steam vents (Hill et al. 2000). Recent uplifting caused the Resurgent Dome in the middle of the caldera to rise 2.5 feet over the past two decades. This volcanic unrest, on a previous stable volcanic system, prompted the USGS to put in place an Emergency Response plan and to closely monitor the region for further signs of unrest (Hill et al. 2000). The Mono-Inyo Crater volcanic chain lines the southwest side of the Long Valley Caldera. Mammoth Mountain, a volcano within the Mono-Inyo chain, formed 50,000 years ago from multiple dacite eruptions (Sorey et al. 1999) Dacite magma is an intermediate between rhyolite and andesite (Kearey 2001). Over the last 5,000 years, eruptions in the Mono-Inyo volcanic chain occurred periodically every 250-700 years. The active volcanic chain is being closely monitored for signs of future eruptions which include earthquakes, uplift of magma and gas emissions (Hill et al. 1998). Starting in the 1980's numerous earthquake swarms took place throughout the Long Valley Caldera concentrated in the southern section of the caldera. In May of 1989, seismic activity started in Mammoth Mountain, a volcano on the southwest edge of the Long Valley Caldera, with a period of earthquake swarms. Scientists collected data indicating that a dike was rising beneath the mountain and intruded 2 km below the surface of Mammoth Mountain (Sorey et al.