Supplementary material to “The Unexpected Awakening of Chaitén Volcano, Chile”
Published 16 June 2009
Simon A. Carn, Michigan Technological University, Houghton
John S. Pallister, U.S. Geological Survey Cascades Volcano Observatory, Vancouver, Washington
Luis Lara, Servicio Nacional de Geología y Minería (SERNAGEOMIN), Santiago, Chile
John W. Ewert, U.S. Geological Survey Cascades Volcano Observatory, Vancouver, Washington
Sebastian Watt, Oxford University, Oxford, UK
Alfred J. Prata, Norwegian Institute for Air Research, Kjeller, Norway
Ronald J. Thomas, New Mexico Institute of Mining and Technology, Socorro
Gustavo Villarosa, Instituto de Investigaciones en Biodiversidad y Medio Ambiente, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Comahue, Bariloche, Argentina
Citation:
Carn, S. A., J. S. Pallister, L. Lara, J. W. Ewert, S. Watt, A. J. Prata, R. J. Thomas, and G. Villarosa (2009), The unexpected awakening of Chaitén volcano, Chile, Eos Trans. AGU, 90(24), 205–206. [Full Article (pdf)]
For additional imagery and information on the 2008 Chaitén eruption, the reader is invited to visit the website of the IAVCEI Remote Sensing Commission.
 (a) May 3, 14:35UT: Chile |
 (b) May 5, 14:25UT: Chile |
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Fig. S1. Visible images from the Terra and Aqua MODIS sensors showing ash plumes from Chaitén over Chile and Argentina. Images are courtesy of the MODIS Rapid Response Project at NASA/GSFC (http://rapidfire.sci.gsfc.nasa.gov/).
MODIS ash mass retrievals
Dr Fred Prata, Norwegian Institute for Air Research, Norway
Email: fred.prata@nilu.no
The total mass, mass loading, particle size and (infrared) optical depth of fine ash (particles with radii ‹ 10 µm) from the eruption of Chaitén volcano, Chile, is retrieved using the infrared channels of the Terra and Aqua MODIS instruments. The retrieval relies on brightness temperature measurements at 11 and 12 µm (MODIS channels 31 and 32) and utilizes a microphysical model of volcanic ash and the discrete ordinates method for radiative transfer calculations. The results shown are for the Chaitén ash plume on 3 and 5 May, 2008. Mass loadings are determined from the particle size and infrared optical depth by assuming a plume of 2 km thickness and integrating over the size distribution. The total mass is determined by summing the masses in each pixel over the entire image. In the thickest parts of the plume, mass loadings can be very high, sometimes exceeding 50 mg m-3. Even several hundred kilometers downstream from the volcano fine ash mass loadings are significant and high enough to cause damage to jet aircraft engines. The Chaitén ash travelled as far as South Africa and at least one aircraft encounter was reported.
 (a) May 3, 14:35UT |
 (b) May 5, 14:25UT |
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Fig. S2. Retrievals of ash concentration (in mg m-3) in the Chaitén ash plumes (for comparison, these correspond to the MODIS visible images provided above):
Fig. S3. Scanning Electron Microscope (SEM) microphotographs of Chaitén ashfall samples analyzed at the Centro Atómico Bariloche, CNEA, Argentina (courtesy of G. Villarosa). These images show a very fine ash fraction with blocky morphology and major pyroclasts that are often highly vesicular. The presence of fine ash is consistent with the persistent aerosol signal observed in CALIPSO data.
