Open-Path Fourier Transform Infrared Spectroscopy (OP-FTIR)

Dr. Marie Edmonds received the prestigious Mendenhall Postdoctoral Fellowship to work at the Hawaiian Volcano Observatory during 2004-2005. The FTIR was used in the detection and measurement of the chemical composition of gas discharges occurring from Kilauea’s summit crater, from Pu’u O’o, and from the lava flow’s ocean entry. This work resulted in two publications: “The airborne lava-seawater interaction plume at Kilauea Volcano, Hawaiʻi”, M. Edmonds and T.M. Gerlach, in Earth and Planetary Science Letters, vol. 244, no. 1-2, pp.83-96, 15 Apr 2006; and “Vapor segregation and loss in basaltic melts”, M. Edmonds and T.M. Gerlach, Geology, vol.35, no.8, pp.751-754, Aug 2007.

According to the 02/04/04 Volcano Watch, Edmonds’ work at Montserrat Volcano Observatory "led her to develop state-of-the-art spectroscopic techniques to receive gas-emission rates every minute or so throughout the day, about as often as other modern geophysical data. This enables cross-correlations between gas emissions, and say, ground tilt or seismicity, at a time scale previously impossible." What makes the OP-FTIR unique is its ability to detect and measure several different components of volcanic gas (typically water, carbon dioxide, and sulfur dioxide) simultaneously.

The aims of Edmonds’ research project included:

  1. Manufacturing methods to collect FTIR spectra effectively, based on tried and tested techniques used at Etna, Erebus, Stromboli and Vulcano, Soufriere Hills, and White Island.
  2. Writing customized software to retrieve gas concentrations for volcanic monitoring, to integrate with SO2 mass flux algorithms and produce real-time ratios and fluxes of many different species.
  3. Developing OP-FTIR to become part of the routine monitoring of Kilauea Volcano: installing instruments to get real-time, automated measurements of gas composition/fluxes that will contribute to understanding/predicting the volcano's behavior.
  4. Developing generic models of volcanic degassing that can be taken from one volcano to the next.
A line of instruments and technicians on Kilauea
Gas emissions from Kilauea can now be analyzed more precisely.
A photo of the crater with arrows pointing to active vents
The instrument is aimed at vents (arrows) which provide infrared background.