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{{Short description|Geological fault In Guatemala and Mexico}}
{{Infobox fault|name=Motagua Fault|other_name=Motagua Fault Zone|location=Guatemala and Mexico|type=transform fault|earthquakes=1717, 1773, 1902, 1976, 1980, 2009|image=Guatemala1976EarthquakeMap.jpg|status=Active|plate=North American Plate, Caribbean Plate}}
The '''Motagua Fault''' (also, '''Motagua Fault Zone''') is a major, [[active fault|active]] left lateral-moving [[transform fault]] which cuts across [[Guatemala]]. It forms part of the [[tectonic]] boundary between the [[North American Plate]] and the [[Caribbean Plate]]. It is considered the onshore continuation of the [[Swan Islands Transform Fault]] and [[Cayman Trough|Cayman trench]], which run under the [[Caribbean Sea]].<ref name="Lyon-Caen_ea_2006">{{Cite journal |first1=H. |last1=Lyon-Caen |first2=E. |last2=Barrier |first3=C. |last3=Lasserre |first4=A. |last4=Fraco |first5=I. |last5=Arzu |first6=L. |last6=Chiquin |first7=M. |last7=Chiquin |first8=T. |last8=Duquesnoy |first9=O. |last9=Flores |first10=O. |last10=Galicia |first11=J. |last11=Luna |first12=E. |last12=Molina |first13=O. |last13=Porras |first14=J. |last14=Requena |first15=V. |last15=Robles |first16=J. |last16=Romero |first17=R. |last17=Wolf |title=Kinematics of the North American-Caribbean-Cocos plates in Central America from new GPS measurements across the Polochic-Motagua fault system |journal=Geophysical Research Letters |volume=33 |issue=L19309 |doi=10.1029/2006GL027694 |year=2006 |s2cid=3161221 |doi-access=free }}</ref> Its western end appears not to continue further than its surface trace,<ref name="Guzman-Speziale_2010">{{Cite journal |first1=Marco |last1=Guzmán-Speziale |title=Beyond the Motagua and Polochic faults: Active strike-slip faulting along the Western North America-Caribbean plate boundary zone |url=https://www.sciencedirect.com/science/article/abs/pii/S0040195110004245 |journal=Tectonophysics |volume=496 |issue=1–4|pages=17–27 |doi=10.1016/j.tecto.2010.10.002 |year=2010 }}</ref> where it is covered by Cenozoic volcanics.<ref name="Lyon-Caen_ea_2006">{{Cite journal |first1=H. |last1=Lyon-Caen |first2=E. |last2=Barrier |first3=C. |last3=Lasserre |first4=A. |last4=Fraco |first5=I. |last5=Arzu |first6=L. |last6=Chiquin |first7=M. |last7=Chiquin |first8=T. |last8=Duquesnoy |first9=O. |last9=Flores |first10=O. |last10=Galicia |first11=J. |last11=Luna |first12=E. |last12=Molina |first13=O. |last13=Porras |first14=J. |last14=Requena |first15=V. |last15=Robles |first16=J. |last16=Romero |first17=R. |last17=Wolf |title=Kinematics of the North American-Caribbean-Cocos plates in Central America from new GPS measurements across the Polochic-Motagua fault system |journal=Geophysical Research Letters |volume=33 |issue=L19309 |doi=10.1029/2006GL027694 |year=2006 |s2cid=3161221 |doi-access=free }}</ref>
The measured length of the fault is approximately 350 km and is the longest fault in Guatemala. Motion of the fault and others in the plate boundary have formed North-South trending [[Graben|grabens]] across the region that show evidence of counter-clockwise rotation over time. [[Guatemala City]] lies in one of these grabens, which may contribute to the seismic hazard posed to the city's inhabitants. <ref name=":0">{{Cite journal |last1=Guzmán-Speziale |first1=Marco |last2=Molina |first2=Enrique |date=2022-04-01 |title=Seismicity and seismically active faulting of Guatemala: A review |url=https://www.sciencedirect.com/science/article/pii/S0895981122000311 |journal=Journal of South American Earth Sciences |volume=115 |pages=103740 |doi=10.1016/j.jsames.2022.103740 |issn=0895-9811}}</ref>
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 [[Chixoy-Polochic Fault|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.<ref name="Lyon-Caen_ea_2006">{{Cite journal |first1=H. |last1=Lyon-Caen |first2=E. |last2=Barrier |first3=C. |last3=Lasserre |first4=A. |last4=Fraco |first5=I. |last5=Arzu |first6=L. |last6=Chiquin |first7=M. |last7=Chiquin |first8=T. |last8=Duquesnoy |first9=O. |last9=Flores |first10=O. |last10=Galicia |first11=J. |last11=Luna |first12=E. |last12=Molina |first13=O. |last13=Porras |first14=J. |last14=Requena |first15=V. |last15=Robles |first16=J. |last16=Romero |first17=R. |last17=Wolf |title=Kinematics of the North American-Caribbean-Cocos plates in Central America from new GPS measurements across the Polochic-Motagua fault system |journal=Geophysical Research Letters |volume=33 |issue=L19309 |doi=10.1029/2006GL027694 |year=2006 |s2cid=3161221 |doi-access=free }}</ref> Studies of GPS displacement of the zone reveal that the motion of the North American / Caribbean Plate Boundary is, for the most part, accommodated by the Motagua Fault. <ref name=":0" />
==Earthquakes==
[[Image:Fault trace geq00014.jpg|thumb|300px|Along the Motagua Fault trace ([[1976 Guatemala earthquake]]) where it crosses the [[Gualán]] soccer field. This [[zigzag]] type of fault trace is known as "mole track", which is best developed in hard-packed, brittle surface materials.]]
The Motagua Fault has been responsible for several major [[List of earthquakes in Guatemala|earthquakes in Guatemala]]'s history, including the 7.5 [[Moment magnitude scale|M<sub>w</sub>]] [[Guatemala 1976 earthquake]], and is also notable for its significant visible [[fault trace]].<ref>[https://web.archive.org/web/20060421092334/https://earthquake.usgs.gov/regional/world/events/1976_02_04.php USGS Historic Earthquakes]</ref> The event caused 2 meters of vertical displacement and ruptured 230 km of the fault's length. The quake damaged a large amount of the country's infrastructure and resulted in the deaths of 23,000 people. <ref name=":0" />
Information about historical earthquakes is determined by digging trenches along the fault zone and consulting historical records and documents. <ref name=":0" />
==References==
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