HR: 1340h
AN: V53B-1327    [Abstracts]
TI: Using Continuous Monitoring of Ambient CO2 and H2S to Assess Toxic Gas Hazards in Yellowstone National Park, Wyoming, USA
AU: Elias, T
EM: telias@usgs.gov
AF: U.S. Geological Survey, Hawaiian Volcano Observatory, Hawaii National Park, HI 96718, United States
AU: * Sutton, A
EM: ajsutton@usgs.gov
AF: U.S. Geological Survey, Hawaiian Volcano Observatory, Hawaii National Park, HI 96718, United States
AU: Lowenstern, J
EM: jlwnstrn@usgs.gov
AF: U.S. Geological Survey, VHZ, MS 910 345 Middlefield Road, Menlo Park, CA 94025-3561, United States
AU: Heasler, H
EM: henry_heasler@nps.gov
AF: Yellowstone National Park, Yellowstone Center for Resources P.O. Box 168, Bldg. 27, Mammoth, WY 82190, United States
AU: Eagan, S
EM: sean_eagan@nps.gov
AF: Yellowstone National Park, Yellowstone Center for Resources P.O. Box 168, Bldg. 27, Mammoth, WY 82190, United States
AB: The mysterious death of five bison in the Norris Geyser Basin area of Yellowstone in 2004 was apparently due to an increase in the output of CO2 or H2S, coupled with unusually cold, still weather. This event of nature may support a long-held claim of geochemists: near-surface changes in pressure, temperature, hydrologic flow, ground permeability, and wind conditions can reasonably be expected to produce attendant variability in the output and ambient concentration of gases emitted from hydrothermal areas. Monitoring these changes at the surface provides a window to processes occurring below, and a continuous assessment of gas hazards for frequently visited places like Norris. To characterize subsurface processes and identify hazards, we developed a transportable monitoring system to measure ambient gas concentrations and meteorological parameters. The solar-powered system uses industrial grade sensors for CO2 and H2S gas, along with sensors for wind speed and direction, barometric pressure, and ambient temperature. In order to reduce power use and prolong sensor life, every 10-minutes the gas sensors are powered on and allowed to stabilize, and the average values for the gas and met sensors are then recorded. The system can be configured for on-site data logging or radio telemetry. During the first year of operation in a thermal area adjacent to where the bison died, the system recorded diurnal variations. Although CO2 build-up was observed at night during cool windless conditions, ambient concentrations of CO2 and H2S remained below hazardous levels. Encouraged by the robust performance of the sensors, a second system was built to use as a roving monitor within the park as conditions permit and opportunities arise to track thermal variations. The performance of this system during the first year of operation reinforces the importance of continuous monitoring for processes such as gas-release events. Such occurrences, while evidenced in nature by events like the bison deaths, can be both acute and fleeting, and might go unnoticed by campaign-style survey measurements. Economical, low impact, sturdy monitors like the one described here can supplement GPS, seismic and other continuous monitoring, and can help fill in temporal holes of synoptic measurements.
DE: 8419 Volcano monitoring (7280)
DE: 8430 Volcanic gases
DE: 8488 Volcanic hazards and risks
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting