In some areas the plates move toward each other. This is called convergence. At convergent plate boundaries (also called destructive plate boundaries), crustal plates collide in super slow motion causing earthquakes, folding and volcanic activity. It is estimated that about three quarters of all earthquakes occur along convergent plate boundaries.
The earth has two kinds of crust. The continents are mostly made of thick granite. When continents pull apart, the gap is filled by thin crust made of basalt. In plate tectonics, a continent is any piece of continental crust surrounded by oceanic crust or plate boundaries. Greenland is a continent. When North America and Europe began to pull apart about 80 million years ago, Greenland originally moved as part of Europe for about 20 million years. Then the crust broke on the east side of Greenland, leaving it attached to the North American Plate.
The North American plate’s interactions with other plates generate various geologic features on its surface, from mountain belts to faults. The Motagua Fault (also, Motagua Fault Zone) is a major, active left lateral-moving transform fault which cuts across Guatemala, continuing offshore along the southern Pacific coast of Mexico, returning onshore along the southernmost tip of Oaxaca, then continuing offshore until it merges with the Middle America Trench near Acapulco. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It is considered the onshore continuation of the Cayman Trench which runs under the Caribbean Sea.
Santa María is located in the volcanic highlands of Guatemala, which parallel the Pacific coast of the country. The highlands were formed by the subduction of the Cocos plate under the Caribbean plate, which resulted in the formation of a line of stratovolcanoes that stretches along much of the Pacific coast of Central America. In Guatemala, these volcanoes overlie a basement of carbonate as well as igneous and metamorphic rocks; many xenoliths ("foreign" rock fragments) found in lavas erupted from the stratovolcanoes are composed of limestone, granite, and gneiss
References:
https://en.wikipedia.org/wiki/Caribbean_Plate
http://geology.com/volcanoes/santa-maria/
https://www.uwgb.edu/dutchs/GeolColBk/NAmerPlate.HTM
https://en.wikipedia.org/wiki/Motagua_Fault
http://www.geoforcxc.com/our-planet/plate-tectonics/
The earth has two kinds of crust. The continents are mostly made of thick granite. When continents pull apart, the gap is filled by thin crust made of basalt. In plate tectonics, a continent is any piece of continental crust surrounded by oceanic crust or plate boundaries. Greenland is a continent. When North America and Europe began to pull apart about 80 million years ago, Greenland originally moved as part of Europe for about 20 million years. Then the crust broke on the east side of Greenland, leaving it attached to the North American Plate.
The North American plate’s interactions with other plates generate various geologic features on its surface, from mountain belts to faults. The Motagua Fault (also, Motagua Fault Zone) is a major, active left lateral-moving transform fault which cuts across Guatemala, continuing offshore along the southern Pacific coast of Mexico, returning onshore along the southernmost tip of Oaxaca, then continuing offshore until it merges with the Middle America Trench near Acapulco. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It is considered the onshore continuation of the Cayman Trench which runs under the Caribbean Sea.
The Motagua Fault is regarded by some geologists as part of a system of faults designated the "Motagua-Polochic system" rather than as a discrete single boundary. The Polochic fault (also referred to as the Chixoy-Polochic Fault) lies north and parallel to the Motagua Fault and shares some of the motion between the North American and Caribbean Plates.
The Motagua Fault has been responsible for several major earthquakes in Guatemala's history, including the 7.5 Mw Guatemala 1976 earthquake.[1]
The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America.
Roughly 3.2 million square kilometers (1.2 million square miles) in area, the Caribbean Plate borders the North American Plate, the South American Plate, the Nazca Plate and the Cocos Plate. These borders are regions of intense seismic activity, including frequent earthquakes, occasional tsunamis,[2] and volcanic eruptions
The northern boundary with the North American plate is a transform or strike-slip boundary which runs from the border area of Belize, Guatemala (Motagua Fault), and Honduras in Central America, eastward through the Cayman trough on south of the southeast coast of Cuba, and just north of Hispaniola, Puerto Rico, and the Virgin Islands. Part of the Puerto Rico Trench, the deepest part of the Atlantic Ocean (roughly 8,400 meters), lies along this border. The Puerto Rico trench is at a complex transition from the subduction boundary to the south and the transform boundary to the west.
Santa Maria Volcano: Plate Tectonic Setting
Santa María is located in the volcanic highlands of Guatemala, which parallel the Pacific coast of the country. The highlands were formed by the subduction of the Cocos plate under the Caribbean plate, which resulted in the formation of a line of stratovolcanoes that stretches along much of the Pacific coast of Central America. In Guatemala, these volcanoes overlie a basement of carbonate as well as igneous and metamorphic rocks; many xenoliths ("foreign" rock fragments) found in lavas erupted from the stratovolcanoes are composed of limestone, granite, and gneissThe northern boundary with the North American plate is a transform or strike-slip boundary which runs from the border area of Belize, Guatemala (Motagua Fault), and Honduras in Central America, eastward through the Cayman trough on south of the southeast coast of Cuba, and just north of Hispaniola, Puerto Rico, and the Virgin Islands. Part of the Puerto Rico Trench, the deepest part of the Atlantic Ocean (roughly 8,400 meters), lies along this border. The Puerto Rico trench is at a complex transition from the subduction boundary to the south and the transform boundary to the west.
References:
https://en.wikipedia.org/wiki/Caribbean_Plate
http://geology.com/volcanoes/santa-maria/
https://www.uwgb.edu/dutchs/GeolColBk/NAmerPlate.HTM
https://en.wikipedia.org/wiki/Motagua_Fault
http://www.geoforcxc.com/our-planet/plate-tectonics/
Great tectonic entry and nice relevant images. They help explaining a lot of what you'll discover next...
ReplyDeleteGreat post! my country is similar to yours in the sense that it is in between two plates creating a convergent effect. It is interesting to read and learn about the Motagua Fault, this is my first time reading about it. And by reading your post and seeing the picture without a doubt it is visible and credible to believe it is responsible for the major earthquakes that have happen in Guatemala.Great pictures really helped to reinforce your data presented.
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