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g) Gas Popocatepetl volcano magmatic Background

GAS MONITORING

volcanoes are built and grow by the accumulation of materials around an emission source and shredded materials are known as pyroclastic or lava. The way out of these materials can be effusive when there are lava flows or by explosions of varying intensity that break the rocks of volcanic conduits or magma (molten rock at depth and at the exit the surface is called lava.)

volcanic explosions resulting from the sudden increase in volume of gases which are separated from the magmas as they rise through the ducts of a system volcanic. Explosive volcanic eruptions are governed mainly by the gases dissolved in the magma and how these gases are separated from the magma (exsolution) and released from the chamber or reservoir magmático.Existe a wide variety of volcanic gases contained in magmas. Among the most abundant are water vapor (H2O) carbon dioxide (CO2) and sulfur dioxide (SO2).

The presence of volcanic gases and their concentration is very important to be measured from before an eruption starts with either direct methods such as those applied by Dr. Yuri Taran Sobol or indirect methods such as those used by Dr. Hugo Delgado Granados, both from the Department of Volcanology Institute of Geophysics, UNAM

Importance of measuring volcanic gases

The size and style of a volcanic eruption depends on the amount of gases containing the magma, its temperature is, its viscosity and crystal content before the eruption.
The exsolution is the result of physical changes in the volcanic system and magma convection within the chamber (movement of magma due to differences in temperature and density), crystallization of the (the crystals are formed when magma cools), intrusion of new bodies of magma, magma ascent, etc. These changes, coupled with changes in the duct system affect the flow of gases to the surface.

Some factors causing differences in the degassing of magma and restrictions on the flow of gases through ducts can be identified by routine measurement of emissions.


A rapid exsolution of gases or, sudden changes in flow conditions through the ducts can cause decompression of the magmatic system which can lead to explosive events of different magnitudes. Therefore, in order to diagnose the conditions prevailing within the volcano, it is important to monitor gas emissions.

remote gas measurement

SO2 emissions are the only ones that are measured routinely using a standardized methodology that uses a remote meter: the or COSPEC correlation spectrometer.
remote measurement of CO2 flux and H2O has successfully been achieved mainly because both are very abundant gases in the atmosphere and remote measurement is prevented by this and other factors. However, recently developed a methodology for measuring CO2 flux using an infrared gas analyzer.

remote measurement of gas emissions in Mexico

Mexico has used COSPEC since 1984 to measure the flow of SO2 Colima Volcano of Fire, and since February 1994 has been used to monitor the activity of the volcano Popocatepetl. Additionally, since 1997 have begun to measure SO2 emissions at other volcanoes such as Tacaná, Pico de Orizaba, the fallen, San Martín Tuxtla, Iztaccíhuatl, Nevado de Toluca, Jocotitlán, Ceboruco, San Juan, Sangangüey and others.

The SO2 flow measurement in the Mexican volcanoes is therefore an important need for each of the volcanoes and volcanically active areas of Mexico (Tres Virgenes, Ceboruco, San Juan, Tepetiltic, Sangangüey, Evermann, Bárcena, Nevado de Toluca, Jocotitlán, Iztaccíhuatl, La Malinche, Citlaltépetl, the fallen, San Martín, El Chichon, Tacaná, Primavera, among others).

flow measurement of SO2 in the active volcanoes of Mexico should be a routine practice and to characterize the level of emissions each of these volcanoes and build a reliable database for each volcano in particular and to all Mexican volcanoes in general. The knowledge of the background values \u200b\u200bof the volcanoes eruptive state can not permit identification of the increased activity of a particular volcano and document firmly the proximity of eruptive event.

Monitoring Popocatepetl volcano gas is carried out jointly by the Geophysical Institute and the National Center for Disaster Prevention. Dr. Hugo Delgado Granados's Geophysics Institute, who has set up remote monitoring of gases routinely in CENAPRED company staff as Lucio Cardenas Gonzalez and several people from the institute as Noé Piedad Sanchez, Beatriz Oropeza Villalobos, Isaac Abimelex Farraz, Patricia Julio Miranda, Esther Romero Teran, Carlos Linares López and Miguel Angel Alatorre Ibargüengoitia.

monitoring of soil gas emissions in

measurement gases in soils is a common practice in some volcanic areas. The measurement of soil CO2 flux in volcanic areas can meet the emission of this gas through areas deep to the surface. However, because this gas is abundant in nature, measurements must be made sensitive equipment to determine the changes in CO2 concentration above background levels due to organic activity.
Additionally, in volcanically active areas such as volcanic field Chichinautzin volcanic field and Michoacán-Guanajuato, where the possibility of origin of volcanoes, gas monitoring should be carried out through the characterization of soil CO2 emissions in the first instance and in case of reports of possible signs of volcanic activity, measurements of CO2 flux for comparing values \u200b\u200bwith the measured background and determine whether the observed corresponds to magmatic activity or other processes.