Continuous Monitoring of CO2 Emission at Mammoth Mountain, California

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9810417 Kerrick Following a period of marked earthquake activity in 1989, emission of CO2 from the flanks of Mammoth Mountain, California, resulted in large areas of tree kill. This region again experienced considerable seismic unrest in 1997. Using a portable fluxmeter, the PI's measured CO2 emission in the largest tree kill area (Horseshoe Lake) in August, 1997, and January, 1998. These measurements suggest that there was a significant increase in CO2 flux within this period. To shed light on the controls of CO2 degassing through the volcanic edifice at Mammoth Mountain, and to monitor for volcanic hazard, there is a compelling need to continuously monitor CO2 emission at Mammoth Mountain. Accordingly, this grant provides funds to purchase, install and maintain equipment to continuously monitor CO2 flux at a carefully chosen site in the Horseshoe Lake tree kill area at Mammoth Mountain. The continuous flux measurement system is based on the accumulation chamber principle where CO2 flux is derived from the rate of increase of CO2 concentration immediately following placement of the chamber on the ground surface. The continuous monitoring system automatically makes flux measurements every 30 minutes and acquires and stores data that is remotely transmitted via a UHF telemetry system. The instrumentation will be constructed and installed by West Systems of Pisa, Italy, who have successfully installed and field tested identical instruments in European localities of high CO2 flux. Following installation and training by the West Systems personnel, the P.I. and John Rogie (a Penn State graduate student carrying out research on CO2 emission) will be involved in instrument maintenance, and in the acquisition and interpretation of the data. Matching funds for this equipment acquisition will be provided through the Volcano Hazards program of the U.S. Geological Survey. Accordingly, this equipment acquisition is enthusiastically supported by U.S.G.S. personnel wh o are actively involved in surveillance of unrest at Mammoth Mountain and the Long Valley caldera. ***