Saturday, February 24, 2007

The gases of Masaya

Yesterday I found two reports about the Masaya volcano. One made by INETER in 1990 and the other from 1999. I paste a map from 1990 that shows the area of the gas emission from this volcano. I don’t have tools, so the look is a little bit clumsy, but it illustrates what I want to show. The orange means the area most affected by the gases. We are not living there (firstly, on account of our health and secondly, it’s not easy to find an accommodation there). We’re living in an area of “medium risk” as the map states (I’m not yet 100 % if I marked our location correctly). People here say that it’s only a few times a year that the wind changes and the gases come to La Concha. “Then you just close the windows and don’t go out” (said a lady who owns windows! There are not much of them here).

Based on “Analisis de riesgo volcanico. Caso complejo volcanico de Masaya” by Garcia-Spatz, R.M. 1990, UNIO, Managua, s. 6
The other report states:

“The large quantities of SO2 released in the atmosphere by Masaya produces volcanic air pollution, which consists of poor air quality, hazy atmospheric conditions or smog, and acidic rains (McBirney, 1956, Johnson and Parnell, 1986; Stoiber et al., 1986). The effects of this volcanic pollution are geographically widespread downwind from Santiago crater and include damage to forests, cultivated crops, machinery, and buildings. In addition, many people report headaches and respiratory difficulties during periods of poor air quality.
We monitored the average SO2 dispersion and dry deposition of the plume with a network of diffusion tubes (Downing et al., 1994) and sulfation plates (Huey, 1968). These passive reactor devices were exposed during four weeks in March-April 1998 and February-March 1999. The 1999 surveys reveal that Masaya's plume affects a region of about 900 km2 (…). Time-averaged concentrations of SO2 exceeding 30 ppb are commonly observed under the plume up to 30 km distance from Santiago crater. Such high gas levels are considered unheathful (e.g., Turco, 1997 (…)).”

“Integrated geochemical, geophysical and petrological studies illuminate magmatic process at Masaya volcano, Nicaragua”. By Delmelle, P. et. al 1999. EOS, Transactions, American Geophysical Union, s. 7

At least I have already one scientific evidence! J I am sure I’ll find more at the INETER or CIGEO’s libraries, but there are mostly geological and such analysis of the crater, not the influence on the people. We’ll see. I’m going to read the rest of the reports and prepare myself to meet the doctors tomorrow.

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