Santa María Volcano is a large active

volcano A volcano is commonly defined as a vent or fissure 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 oft ...

in the western highlands of

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

, in the Quetzaltenango Department near the city of Quetzaltenango. It is part of the mountain range of the Sierra Madre. The volcano was known as Gagxanul in the local

Kʼicheʼ language Kʼicheʼ ( ; natively , also known as among its speakers), or Quiché, is a Mayan language spoken by the Kʼicheʼ people of the central highlands in Guatemala and Mexico. With over a million speakers (some 7% of Guatemala's population), Kʼi ...

, which means "Naked Volcano or Mountain", before the 16th century Spanish conquest of the region. The VEI-6 eruption of Santa María Volcano in 1902 was one of the three largest eruptions of the 20th century, after the 1912 Novarupta and 1991

Mount Pinatubo Mount Pinatubo is an active stratovolcano in the Zambales Mountains in Luzon in the Philippines. Located on the tripoint of Zambales, Tarlac and Pampanga provinces, most people were unaware of its eruptive history before the pre-eruption volc ...

eruptions. It is also one of the five biggest eruptions of the past 200 (and most likely 300) years.

Geological history

Santa María Volcano is part of the Sierra Madre range of volcanoes, which extends along the western edge of

, separated from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

by a broad plain. The volcanoes are formed by the

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

of the Cocos Plate under the Caribbean Plate, which led to the formation of the Central America Volcanic Arc. Eruptions at Santa María are estimated to have begun about 103 ka. Construction of the volcanic edifice occurred in four phases, from 103–72, 72, 60–46, and 35–25 ka, building up the large cone that reaches about above the plain on which the nearby city of Quetzaltenango sits. Following the cone-building eruptions, activity seems to have changed to a pattern of long periods of repose followed by the emission of small

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

s from vents on the mountain.

1902 eruption

The first eruption of Santa María in recorded history occurred in October 1902. Before 1902 the volcano had been dormant for at least 500 years and possibly several thousand years, but its awakening was clearly indicated by a seismic swarm in the region starting in January 1902, which included a major earthquake in April 1902. The eruption began on 24 October, and the largest explosions occurred over the following two days, ejecting an estimated of

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

. The eruption was one of the largest of the 20th century, only slightly less in magnitude to that of

in 1991. The eruption had a

Volcanic Explosivity Index The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption c ...

(VEI) of 6, thus being 'Colossal'. The

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...

formed in the climactic eruption fell over an area of about , and

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

as far away as

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

, California, away. The eruption occurred out of a vent on the southwest side of the volcano, leaving a crater about in diameter and about deep, stretching from just below the summit to an elevation of about . The first evidence of the eruption was a sprinkling of sand on Quezaltenango. The wind then changed from the south to the east and ashes began to fall at Helvetia, a coffee plantation southwest. Many coffee plantations were destroyed. Because of the lack of recorded eruptive activity at Santa María, local people did not recognise the preceding seismicity as warning signs of an eruption. Estimates are that 6,000 people died as a result of the eruption. They were burned or suffocated. Due to the eruption, in an area for up to 160km from the volcano, there was total darkness for 53 hours. After the eruption, the area was also affected by gangs who went to the affected areas to steal from people, murder and plunder plantations. For the native people the eruption consequences were catastrophic: they not only lost relatives, friends, homes and harvest, but they were also enslaved in the recovery while " criollo" landlords were compensated for the loss with lands that were confiscated from native communities in San Miguel Uspantán

Quiché Department Quiché () is a department of Guatemala. It is in the heartland of the Kʼicheʼ (Quiché) people, one of the Maya peoples, to the north-west of Guatemala City. The capital is Santa Cruz del Quiché. The word Kʼicheʼ comes from the languag ...

, Panam in Suchitepéquez Department and in Sololá Department.

1902 eruption sequence of events

* 24 October: 5:00 pm: At San Felipe a sound was heard, similar to the roar of a waterfall, for five minutes, coming from the volcano; but the mist surrounding the volcano did not allow any direct observation of what was happening. * 24 October: 6:00 pm: Cinders and ashes started falling over Quetzaltenango * 24 October: 7:00 pm: Witnesses recall seeing lightning and a strong fiery red light coming from the volcano, and noise similar of that of an industrial furnace. * 24 October: 8:00 pm: From San Felipe one could see a giant plume of black ash with numerous whirlwinds crossed by thousands of lightning bolts and curved lines of red light. All the area surrounding the volcano kept shaking and large explosions could be heard as far as away; strong winds carried ash and debris as far as away, or even more; a part of the cloud hovered on the north side of the cone for days, and a pitch black darkness ensued. * 25 October: 1:00 am: The eruption became more violent and large rocks from the volcano started falling as far as away, destroying towns and farm houses. * 26 October: 12:00 am: The volcano calmed down. * 26 October: 3:00 pm: Another eruption, but this time it was a white plume that came out, which was likely composed of water vapor.

Image gallery

File:Santamaria1902erupcion2.jpg File:Santamaria1902xela.jpg

Santiaguito

The 1902 eruption was followed by 20 years of dormancy. New eruptions began in 1922, with the extrusion of a lava dome complex in the crater left by the 1902 eruption. The lava dome complex, named Santiaguito, is still active today with over 1 km³ of lava erupted so far. The lava dome complex has four main domes: El Caliente, La Mitad, El Monje and El Brujo. The currently active vent is El Caliente. The dome growth has been both ''endogenous'' and ''exogenous''. The former implies dome interior expansion to accommodate new lava and the latter refers to superficial piling up of lava. Activity has been concentrated at several different vents, and Santiaguito now has the appearance of several overlapping domes. At the beginning of dome growth the composition was

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

, identical to the composition of the Santa Maria eruption. By 1990 the composition had shifted to a less evolved

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

. It has been proposed that this is due to a stratified magma chamber beneath the volcano. The early (pre-1990) exogenous volcanism has consisted of lava spines and lava flows. Nowadays, only lava flows are erupted. All the volcanic activity is cyclic with 10+ year cyclic timescales between periods of high volcanism with high extrusion rates and low volcanism with low extrusion rates. The latest with high extrusion rate was in 2011–2015 with the emplacement of more than four new lava flows. Frequent small eruptions and pyroclastic flows have been ongoing throughout dome growth. Although most of Santiaguito's eruptive activity has been relatively gentle, occasional larger explosions have occurred. In 1929 part of the dome collapsed, generating

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s which killed anywhere from several hundred up to 5,000 people. Occasional rockfalls have generated smaller pyroclastic flows, and vertical eruptions of ash to heights of a few kilometres above the dome are common. Santiaguito is now a tourist attraction, as minor eruptions occur with regularity and can be observed by visitors from the summit of Santa Maria.

Volcanic hazards at Santa María

The areas to the south of Santa María are considerably affected by volcanic activity at Santiaguito. Currently, the most common volcanic hazards at Santa María are

lahar A lahar (, from ) is a violent type of mudflow or debris flow composed of a slurry of Pyroclastic rock, pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a valley, river valley. Lahars are o ...

s, which frequently occur in the

rainy season The rainy season is the time of year when most of a region's average annual rainfall occurs. Rainy Season may also refer to: * ''Rainy Season'' (short story), a 1989 short horror story by Stephen King * "Rainy Season", a 2018 song by Monni * '' ...

due to heavy rainfall on loose volcanic deposits. Lahars are particularly large and frequent during periods of high volcanism at Santiaguito. The town of El Palmar, from Santiaguito, has been destroyed twice by lahars from Santiaguito forcing the town to be moved to the present Nuevo El Palmar, and

infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and pri ...

such as roads and bridges have been repeatedly damaged. Lahar deposits from Santiaguito have affected rivers all the way downstream to the Pacific Ocean. Near constant

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 Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

flows occur from Santiaguito, and can reach up to 4 km from the vent. Lava flow activity occurs in cycles, with the longest lava flows occurring during times of high volcanic activity. Much shorter lava flows occur during the longer periods of low volcanic activity. These lava flows flow only a short distance from the vent before collapsing. The magma at Santiaguito is rich in

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

and is thus highly

viscous Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup h ...

. The lava flows are slow moving and mostly cause property damage, although in the past catastrophic

s have been triggered from lava flows, which have extended several kilometers towards the west. One hazard which could be devastating is the collapse of Santa María itself. The 1902 crater has left the southern flank of the mountain above Santiaguito highly over-steepened, and a large

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

or eruption from Santiaguito could trigger a huge

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

, which might cover up to . However, this is thought to be unlikely in the short term. In light of the threat it poses to nearby populations, Santa María has been designated a Decade Volcano, identifying it as a target for particular study by volcanologists to mitigate any future natural disasters at the volcano.

References

;Notes ;Bibliography * * * Bunzendahl, E.; Bluth, G. J.; Rose, W. I.; Reif, S. L.; Matias, O. (2001), ''Developing a Long-term Hazard Mitigation Plan for Consequent Volcanic Sedimentation Hazards at Santiaguito Dome Complex, Guatemala'',

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, Atmospheric science, atmospheric, Oceanography, ocean, Hydrology, hydrologic, Astronomy, space, and Planetary science, planetary scientists and enthusiasts that ...

, Fall Meeting 2001, abstract #V41A-0974 * Harris, A. J.; Flynn, L. P.; Rose, W. I.; Matias, O.; Cornejo, J. (2002), ''The extrusion of lava dome and block lava flow units at Santiaguito, 1922–2002'',

, Fall Meeting 2002, abstract #V12A-1399 * *

External links

* *
Santa María: Pictures and recent activity, from VolcanoWorld

{{DEFAULTSORT:Santa Maria (volcano) Quetzaltenango Department Sierra Madre de Chiapas Active volcanoes Decade Volcanoes Stratovolcanoes of Guatemala Subduction volcanoes VEI-6 volcanoes Mountains of Guatemala

Volcano A volcano is commonly defined as a vent or fissure 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 oft ...

1902 natural disasters 20th-century volcanic events Volcanic eruptions in North America Volcanism of Central America Pleistocene stratovolcanoes Holocene stratovolcanoes Natural disasters in Guatemala North American 3000 m summits