Birnie, Richard W., 1971, Infrared radiation thermometry of Central American volcanoes,

Master of Arts thesis, Dartmouth College, Hanover, New Hampshire, U.S.A.

Abstract A Barnes PRT-5 radiation thermometer was used to obtain apparent surface temperatures of four Central American volcanoes from land-based stations from 500 to 4000 meters distant. Isotherms of apparent surface temperatures, drawn on photographs of the volcanic terrain under study, delineate areas of fumarolic activity and active domal upgrowth. The excess radiant heat emitted from Pacaya Volcano is calculated from apparent surface temperatures corrected for atmospheric absorption of infrared radiation and for the adiabatic cooling of the atmosphere with altitude. The excess radiant heat data indicate that the lava flow extruded in June,1969 had completely solidified by December,l969. This oalculation is consistent with theoretical estimates of the cooling of an extrusive lava sheet by conduction. Similar calculation of excess radiant heat emission shows the depth of the magma chamber underlying the Santiaguito Volcanic Dome to be 11 meters. This depth is consistent wlth field observation. Conductive heat flow to the surface of Santiaguito is calculated from the infrared radiation data and is an order of magnitude less than the average rate of thermal energy expenditure during the growth of the dome. ______________________________________________________ Material from this thesis is incorporated in Birmie, R. W. Infrrared Radiation Thermometry of Guatemalan Volcanoes, Bull. Volc. v. 37 , p.1-36, 1973

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