El Jorullo is a

cinder cone A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are ...

Michoacán Michoacán, formally Michoacán de Ocampo (; Purépecha: ), officially the Free and Sovereign State of Michoacán de Ocampo ( es, Estado Libre y Soberano de Michoacán de Ocampo), is one of the 32 states which comprise the Federal Entities of ...

, central

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, on the southwest slope of the central plateau, 33 miles (53 kilometers) southeast of

Uruapan Uruapan is the second largest city in the Mexico, Mexican state of Michoacán. It is located at the western edge of the Tarascan Plateau, Purépecha highlands, just to the east of the Tierra Caliente (Mexico), Tierra Caliente region. Since the colo ...

in an area known as the Michoacán-Guanajuato volcanic field. It is about 6 miles (10 km) east-northeast of La Huacana. Its current elevation is . El Jorullo has four smaller cinder cones which have grown from its flanks. The vents of El Jorullo are aligned in a northeast to southwest direction.

Lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

from these vents cover nine square km around the volcano. Later eruptions produced lavas that had higher silica contents making them thicker than the earlier

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

s and

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s. El Jorullo's crater is about 1,300 by 1,640 feet (400 by 500 m) wide and 490 feet (150 m) deep. El Jorullo is one of two known volcanoes to have developed in Mexico in recent history. The second, born about 183 years later, was named

Parícutin Parícutin (or Volcán de Parícutin, also accented Paricutín) is a cinder cone volcano located in the Mexican state of Michoacán, near the city of Uruapan and about west of Mexico City. The volcano surged suddenly from the cornfield of loca ...

after a nearby village that it eventually destroyed. Parícutin is about 50 miles (80 km) northwest of El Jorullo. El Jorullo was first erupted on 29 September 1759. Earthquakes occurred prior to this first day of eruption. Once the volcano started erupting, it continued for 15 years, eventually ending in 1774.

Alexander von Humboldt Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 17696 May 1859) was a German polymath, geographer, naturalist, explorer, and proponent of Romantic philosophy and science. He was the younger brother of the Prussian minister, p ...

climbed El Jorullo during the Mexican portion of his scientific expedition to Spanish America. When he visited on 19 September 1803, its multiple cones were still smoldering and the air was extremely hot and filled with volcanic gases. He wrote a detailed description of the climb, noting that his face and those of his travel companions were burned. The volcano enriched the local soil and there was considerable vegetation. Humboldt sketched the volcano in the distance, showing multiple smoking cones. Humboldt undertook the climb with his scientific travel partner

Aimé Bonpland Aimé Jacques Alexandre Bonpland (; 22 August 1773 – 11 May 1858) was a French explorer and botanist who traveled with Alexander von Humboldt in Latin America from 1799 to 1804. He co-authored volumes of the scientific results of their ex ...

, as well as a local Basque settler Ramón Epelde, and two local indigenous servants, whose names have not been recorded. Humboldt noted their assistance on site. Humboldt also notes that he consulted a 1782 publication ''Rusticatio Mexicana'', by Rafael Landívar, who calculated the height of the volcano and the temperature of the thermal waters. El Jorullo did not develop on a corn field like Parícutin did, but it did destroy what had been a rich agricultural area. It grew approximately 820 feet (250 meters) from the ground in the first six weeks. The eruptions from El Jorullo were primarily

phreatic ''Phreatic'' is a term used in hydrology to refer to aquifers, in speleology to refer to cave passages, and in volcanology to refer to a type of volcanic eruption. Hydrology The term phreatic (the word originates from the Greek , meaning "well" ...

and

phreatomagmatic Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

. They covered the area with sticky mud flows, water flows and ash falls. All but the youngest

flows were covered by this ash fall. Later eruptions from El Jorullo were

magmatic Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

with neither mud nor water flows. This 15 year eruption was the longest one El Jorullo has had, and was the longest cinder cone eruption known. Lava flows can still be seen to the north and west of the volcano. The eruption had a VEI of 4. Parícutin and El Jorullo both rose in an area known for its volcanoes. Called the

Trans-Mexican Volcanic Belt The Trans-Mexican Volcanic Belt ( es, Eje Volcánico Transversal), also known as the Transvolcanic Belt and locally as the (''Snowy Mountain Range''), is an active volcanic belt that covers central-southern Mexico. Several of its highest peaks h ...

, the region stretches about 700 miles (1,120 km) from east to west across southern Mexico. The eruptive activity deposited a layer of volcanic rock some 6,000 feet thick, creating a high and fertile plateau. During summer months, the heights snag moisture-laden breezes from the Pacific Ocean; rich farmland, in turn, has made this belt the most populous region in Mexico. Though the region already boasted three of the country's four largest cities:

Mexico City Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital and largest city of Mexico, and the most populous city in North America. One of the world's alpha cities, it is located in the Valley o ...

Puebla Puebla ( en, colony, settlement), officially Free and Sovereign State of Puebla ( es, Estado Libre y Soberano de Puebla), is one of the 32 states which comprise the Federal Entities of Mexico. It is divided into 217 municipalities and its cap ...

, and

Guadalajara Guadalajara ( , ) is a metropolis in western Mexico and the capital of the list of states of Mexico, state of Jalisco. According to the 2020 census, the city has a population of 1,385,629 people, making it the 7th largest city by population in Me ...

(the area around Parícutin, some 200 miles west of the capital), it was still a peaceful backwater inhabited by

Purépecha The Purépecha (endonym pua, P'urhepecha ) are a group of indigenous people centered in the northwestern region of Michoacán, Mexico, mainly in the area of the cities of Cherán and Pátzcuaro. They are also known by the pejorative "Tarascan ...

in the early 1940s. The crater and lake can now be reached by car.Echenberg, ''Humboldt's Mexico'', p. 144.

References

"El Jorullo: Credits"
Volcano World. Retrieved 16 Apr 2008.
"El Jorullo: Credits"
Popular Science Monthly. Retrieved 17 Apr 2008.

Bartleby.com. Retrieved 17 Apr 2008.

External links

{{commons category Landforms of Michoacán Volcanoes of Michoacán Mountains of Mexico Pyroclastic cones Cinder cones Michoacán–Guanajuato volcanic field

See also

References

External links