TRANSVERSE VOLCANIC SYSTEM OF MEXICO: CHARACTERISTICS - GEOGRAPHY - 2025

The Transversal Volcanic System of Mexico is one of the seven main morphotectonic provinces of this country. It is a mountain range made up of volcanoes. This system crosses the country through its central part from East to West between the Gulf of Mexico and the Pacific Ocean.

It was formed from the Upper Tertiary period and up to the Quaternary of the Cenozoic Era. During the Pleistocene and Recent times, it ended up being a chain of basaltic volcanoes.

Relative location of the System (Modified from: Rhoda, Richard; Burton, Tony. The volcanic calderas of Mexico's Volcanic Axis. Recovered from: geo-mexico.com).

Although "Transversal Volcanic System" is perhaps the name most commonly used today, other names by which it is also known, and it is found in the bibliography, are: Eje Volcánico, Eje Neo-Volcánico, Cordillera (or Sierra) Neo-Volcanic, Trans-Mexican Belt / Volcanic Belt, Tarasco-Nahoa System, and more colloquially, Sierra Volcánica.

Some of the commented names were assigned in pioneering studies of the region in the 20th century. It is common for the word “transversal” to accompany one of these names, due to the location of the system with respect to Mexican territory.

The system is made up of several of the largest and best known volcanoes in the country, for example: Citlaltépetl (Pico de Orizaba), Popocatépetl, Iztaccíhuatl, Nevado de Toluca, Paricutín, Nevado de Colima, and the Volcán de Fuego, among others.

In the system there are volcanoes of various categories, from active, through dormant, to extinct. You may also be interested in seeing 10 characteristics of the Andes mountain range.

Geographic location

Meadow with a part of wetland. In the background is the Transversal Volcanic System. Source: Gonzalo De La Rosa via Wikimedia Commons

The Transversal Volcanic System crosses Mexico between latitudes 19 ° and 21 ° degrees North. It separates the Sierra Madre Oriental and the Sierra Madre Occidental from the Sierra Madre del Sur.

From east to west, the system crosses part of the following thirteen federal entities in central Mexico: Veracruz, Puebla, Tlaxcala, Hidalgo, Mexico, Federal District, Morelos, Querétaro, Guanajuato, Michoacán, Jalisco, Nayarit and Colima, including in this last state the Revillagigedo Islands, in the Pacific Ocean.

It has an approximate length of 920 km from Punta Delgada in the state of Veracruz to Bahía Banderas in the state of Jalisco. Its width, in its central part, is about 400 km, while at its western end, in the state of Veracruz, it is about 100 km.

Importance of the system

The mountain range that forms the Transversal Volcanic System is of utmost importance for the region from various points of view. The most visible is that it conditions the topography of the area and, therefore, land communications.

In addition, in the vicinity of Popocatepetl, more than 25 million people live, so the potential danger in the event of a violent eruption is quite great.

The altitude of the system allows the existence of various ecosystems, which in turn affects biodiversity and the type of crops that can be harvested.

These can be irrigated with the water of the numerous rivers and streams that are born in the mountain range, such as the Lerma (which is the 4th longest river in Mexico), the Pánuco, and the Balsas, among others. All this makes the mountain chain an important water reserve for the most populated area of ​​the country.

In fact, the presence of rivers, lakes and arable land contributed, from pre-Hispanic times –and to the present- to the establishment of important human settlements, such as Tenochtitlan, capital of the Aztec Empire and predecessor of modern Mexico City.

Even today 25% of the water consumed in the nation's capital comes from the basins of the Lerma and Cutzamala rivers.

The highest mountains in the country are also here, for example, the Citlaltépetl volcano, or Pico de Orizaba is the highest peak in Mexico, and the highest volcano in North America, with 5675m.snm (meters above sea level).

These geographical characteristics provide the conditions for tourism to be an important element in the regional economy, since the more than 30 natural areas protected at the federal level (National Parks and Biological Reserves, among others) are visited by more than 5 million people each. year.

Pioneering studies of the system

Among the many pioneers in the study of the volcanoes of Mexico, and in particular of the Transversal Volcanic System, we can mention the following.

Baron Alejandro de Humboldt mentions that some soldiers from Hernán Cortez's army climbed to the top of Popocatépetl. Humboldt ascended to the summit of Pico de Orizaba, making there and throughout his tour of Mexico between 1803 and 1804, copious scientific observations that he collected in his work Political Essay on the Kingdom of New Spain.

Pedro C. Sánchez, one of the founders of the Pan-American Institute of Geography, in 1929, was the one who first called the System “Eje Volcánico”.

José Luis Osorio Mondragón was one of the founders of the Department of Geographical Sciences. Then, in 1942, he was director of the Institute for Geographical Research. As part of his geological studies, he studied the System, which he named Tarasco-Nohoa, in honor of the ethnic groups that inhabited the region.

Ramiro Robles Ramos called it the Neo-Volcanic Mountain Range. He published in Irrigation de México, Vol. 23, No. 3, May-June 1942 his work Orogénesis de la República Mexicana in relation to its current relief.

The latter was a broad spectrum work that covered various topics, including geomorphology and structural geology of the country, including the System. He had already exhibited this work in the First Congress of Geography and Geographical Explorations, organized by the Secretary of Public Education in July 1939.

It was not his only contribution to the study of the System, since in 1944 he published Glaciology and Morphology of Iztaccíhuatl, in the Geographical Magazine of the Pan American Institute of Geography and History, Volume IV, numbers 10, 11, 12.

Until today, it is the most detailed study on a Mexican glacier. Finally, in 1957 he published Agony of a Volcano. The Sierra de San Andrés, Michoacán.

The Mexican Society of Geography and Statistics published in 1948 the first edition of the work Volcanes de México, by Esperanza Yarza de De la Torre. Subsequent editions of this book have been made, the most recent, the fourth, by the Institute of Geography of UNAM (National Autonomous University of Mexico), in 1992.

Main volcanoes

A good part of the volcanic activity in Mexico, and definitely the Transversal Volcanic System, is directly related to the subduction zone formed by the Rivera and Cocos plates when they sink below the North American plate.

The emergence of the system is considered to be a consequence of subduction along the Acapulco Trench, during the middle Miocene.

The main types of volcanoes existing in the mountain range are: pyroclastic cone, stratovolcano, shield volcano and caldera. Next, I list the names of some volcanoes with their corresponding type:

• Paricutin. Type: strombolian.
• Amealco. Type: boiler.
• Los Azufres. Type: boiler.
• Bárcena. Type: Pyroclastic cone (s).
• Ceboruco. Type: stratovolcano.
• Perote's chest. Type: shield volcano.
• Colima. Type: stratovolcano (s).
• The Summits. Type: boiler.
• Huichapan. Type: boiler.
• Los Humeros. Type: boiler.
• Iztaccihuatl. Type: stratovolcano.
• La Malinche. Type: stratovolcano.
• Mazahua. Type: boiler.
• Michoacán-Guanajuato. Type: pyroclastic cone (s).
• Las Navajas. Type: shield volcano.
• Pico de Orizaba. Type: stratovolcano.
• Popocatepetl. Type: stratovolcano (s).
• Sierra la Primavera. Type: boiler.
• San Juan. Type: stratovolcano (s).
• Sanganguey. Type: stratovolcano.
• Tepetiltic. Type: stratovolcano.
• Tequila. Type: stratovolcano.
• Nevado de Toluca. Type: stratovolcano.

Source: With information from "The volcanic calderas of Mexico's Volcanic Axis", and the Global Volcanism Program.

Current volcanological risks

In the System there are several of the most active volcanoes in the country, including Colima, whose neighborhood has had to be evacuated periodically in recent years. In addition, Popocatepetl has been erupting recently (from 1997 to the present), even causing suspension of flights at the Mexico City airport.

Other volcanoes in the System that have been active in recent history are: Bárcena, Ceboruco, Michoacán-Guanajuato, Pico de Orizaba, San Martin and Everman, on the islands of Revillagigedo.

For Popocatépetl, in particular, a “Volcanic Warning Traffic Light” system has been adopted. The CENAPRED (National Center for Disaster Prevention), together with UNAM, and with the support of the US Geological Survey, monitor and inform the population daily about the status of the volcano.

This system is a basic communication protocol and relates the volcanic threat with 7 levels of preparedness for the authorities, but only three levels of alert for the public.

References

1. Guzmán, Eduardo; Zoltan, Cserna. "Tectonic History of Mexico". Memoir 2: Backbone of the Americas: Tectonic History from Pole to Pole. AAPG Special Volumes, 1963. Pages113-129.
2. Yarza de De la Torre, Esperanza. The Volcanoes of the Transversal Volcanic System. Geographic Investigations. No. 50. Mexico. April 2003. Page 1 of 12.
3. Rhoda, Richard; Burton, Tony. The volcanic calderas of Mexico's Volcanic Axis. Recovered from: geo-mexico.com.
4. Volcanes de México, recovered from: portalweb.sgm.gob.mx.
5. Aguayo, Joaquín Eduardo; Trapaga, Roberto. Geodynamics of Mexico and Minerals of the Sea. First Edition, 1996, FONDO DE CULTURA ECONÓMICA. México, DF Recovered from: Bibliotecadigital.ilce.edu.mx.