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The objectives of the Vog Measurement and Prediction (VMAP) project have been to create a real-time volcanic gas modeling and forecast capability to predict the concentration and dispersion of SO2 and sulfate aerosols from the Kilauea volcano based on state-of-the art gas dispersion and numerical wind models; and to develop and deploy an array of FLYSPEC UV spectrometer systems1,2 which would provide near real-time measurements of SO2 emissions from the Halema`uma`u 2008 vent at the summit of Kilauea Volcano at high temporal resolution to feed into dispersion models. Recent models of SO2 plume are shown below. Current predictions can be accessed at http://weather.hawaii.edu/vmap/

Early Monitoring Results from the Halema`uma`u Vog Measurement and Prediction FLYSPEC Array

Keith A. Horton1, Harold Garbeil1, A. Jeff Sutton2, Tamar Elias2, Steven Businger3 1.University of Hawaii at Manoa, Hawaii Institute of Geophysics & Planetology; 2. USGS Hawaiian Volcano Observatory;

3. University of Hawaii at Manoa, Dept. of Meteorology

Introduction

Monitoring Approach The FLYSPEC array consists of 9 units (F1-F9) deployed approximately 3km from the vent in a 3km arc which encompasses the expected extent of the plume under prevailing NE trade winds. A 10th FLYSPEC (F0) is situated 200m upwind from the center of the array and is used as the WiFi communications node and lead instrument for determining the plume speed3. Raw spectral data and SO2 path-concentration results are stored on each field unit. The results are telemetered to a base computer located at HVO which ingests data from all field systems.

System Description Left: Two of the self-contained FLYSPECs, each showing spectrometer (USB2000+), gas correlation cells, and control computer. Additional components mounted below include cell motor controller, temperature sensor, voltage and/or current sensors, GPS, and POE unit for network connection. Right: One unit deployed in field. FLYSPEC is the small black box on the left. Large container on right houses the deep cycle 12V batteries and solar charge controller. Both are housed below the solar panel. WiFi unit is in the small grey box on left and a directional antenna is mounted at top of 2m mast, pointed back to the F0 unit.

Each field system is currently programmed to boot up each morning and shut off at the end of daylight hours. Each morning the field computers access a time server in order to synchronize their clocks. Integration time for spectral data collection is adjusted throughout the day to maintain appropriate signal level as light levels change. Spectrometer dark levels are collected every hour which causes a break in the data flow for about 2 minutes The FLYSPEC base computer at HVO acts as the array server. The server program accepts data from all field units form 0800 to 1800, although this is adjustable. Data rate for each field system is nominally 1Hz. A screen shot of the Array Server interface is shown below.

The Array Server displays the incoming data from each field sensor (ppm-m of SO2, raw DN, integration time (ms)), a plot of any or all ppm-m values through the day, a current cross-section (ppm-m) of the plume as a function of azimuth looking downwind, a plot of measured SO2 flux through the day at 1m/s wind speed, and a plot of the correlation of the time lag between SO2 signals at sensors F0 and F1 from which a plume speed estimate is calculated every 10min

Early Results We present in this section results, which at this stage, primarily involves different types of visualization and simple comparisons with other readily available data. Initially installed in September 2011, shake out of field systems, communications protocols, and software bug fixes have taken us into the Spring of 2012 before we have a fairly reliable data flow.

Above Left: One of the earliest evaluations of the data shows SO2 path-concentration (ppm-m) from September 2011. This image shows 5 minutes of data from the array of 9 sensors at 1s time resolution. It does provide a good feel for the shape and short-term variability of the plume. On the right is the same 5min data shown in a color plot which highlights an apparent periodicity in SO2 concentration

Time (HST) 0830------------------------1000---------------------------------1200---------------------------------1400------------------------------1600----------1630

SE

NW Above: An entire day from last week (Aug. 15, 2012) showing position and greyscale path-concentration of SO2. There are 4 distinct regions in the image: high emission for 2.5hr, low emission for about 2.8hr, very high emission for about 1hr, and then low emission to the end of collection. There are 3 transitions which occurred during the day which are related to different stands of the level of the lave lake. The first and third transitions reflect a rise in lava level, while the second transition with a large increase is SO2 emissions records a fall in the lake level. Below: Shows a plots of unpublished USGS/HVO 10min RSAM seismic signal (black) for Aug.15 with 10s array SO2 emission rate (red), both normalized to their maximum values. The correlation between SO2 flux and seismicity has been demonstrated4,5, but perhaps not quite so clearly as this with very high temporal resolution. A similar comparison is given below, right for a more active day (9/9/11) in which standard traverse measurements were collected during one of the transitions at about 0950.

Solar noon dropout from sensor saturation (don’t stare at the sun)

transition

transition transition

References 1. Horton, K. A., G. Williams-Jones, H. Garbeil, T. Elias, A. J. Sutton, P.

Mouginnis-Mark, J. N. Porter, S. Clegg, 2006, Real-time measurement of volcanic SO2 emissions: Validation of a new UV correlation spectrometer (FLYSPEC), Bull. Volc. 68: 4, 323-327, DOI 10.1007/s00445-005-0014-9

2. Horton, K.A., Porter, J., Mouginis-Mark, P., Oppenheimer; C., Garbeil, H., 2006,“Apparatus for Measuring Radiation and Method of Use” (FLYSPEC), Utility Patent No. 7,148,488.

3. Williams-Jones, G., K. A. Horton, H. Garbeil, P. J. Mouginis-Mark, A.J.L. Harris, T. Elias and A. J. Sutton, 2006, Accurately measuring volcanic plume speeds with multiple UV spectrometers, Bull. Volc. 68: 4: 328-332, DOI 10.1007/s00445-005-0013-x

4. Palma, J. L., E. S. Calder, D. Basualto, S. Blake, and D. A. Rothery (2008), Correlations between SO2 flux, seismicity, and outgassing activity at the open vent of Villarrica volcano, Chile, J. Geophys. Res., 113, B10201, doi:10.1029/2008JB005577.

5. Nadeau, P. A., J. L. Palma, and G. P. Waite (2011), Linking volcanic tremor, degassing, and eruption dynamics via SO2 imaging, Geophys. Res. Lett., 38, L01304, doi:10.1029/2010GL045820.

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