Chixoy-Polochic Fault

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The Chixoy-Polochic Fault, also known as Cuilco-Chixoy-Polochic Fault, is a major fault zone in Guatemala and southeast Mexico. It runs in a light arc from the east coast of Guatemala to Chiapas, following the deep valleys of the Polochic River, Chixoy River and Cuilco River. [1]

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Extent, slip rate and total displacement

The Chixoy-Polochic Fault is a large, dominantly strike-slip, left-lateral fault that runs largely parallel to the Motagua Fault situated some 45 km to its south. Both fault zones are onshore extensions of the Bartlett Deep, or Cayman Trench of the Caribbean Sea, which marks the tectonic boundary between the Caribbean Plate and the North American Plate. [1] Both faults connect at sea west of the Guatemalan coast. To the west, the Polochic fault may branch onto the Tonala fault of western Chiapas. It does not continue at sea across the Pacific coastal plain and marine shelf. [2]

The Chixoy-Polochic fault has total displacement of 125 km, well constrained by the offset of Paleocene or Eocene laramide folds and thrusts. [3] Fault velocity has been estimated at 4.8 ± 2.3 mm/y over the past 10 ky, [4] 2.5–3.3 mm/y over the last 7–10 Myr, [5] and less than 5 mm/y during the current interseismic cycle. [6]

Seismicity

While recent seismic activity is more prominent in the Motagua fault, some studies suggest the Chixoy-Polochic Fault is still capable of producing major earthquakes. The magnitude 7.5–7.8 Mw 1816 Guatemala earthquake of western Guatemala has been ascribed to the Polochic Fault, [7] although this has been disputed. [8] [9] Most recent recorded fault activity includes at least for slip events between 17 ka and 13 ka BP, [4] and aseismic surface rupture over some of the past 5 centuries. [8] One or several intermediate to large earthquakes between 850 CE and 1,400 CE, including a cluster of 4 earthquakes over 60 years during the Classic Maya collapse. [8] The fault display a 5 km to 10 km deep zone of microseismicity [10] which may represent a locked zone. Only ≤ 5.6 Mw earthquakes have occurred on the fault since the beginning of regional instrumental records (1920 CE). [7]

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Motagua Fault Geological fault In Guatemala and Mexico

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The Sierra de Chuacús is situated in the central highlands of Guatemala, and runs southeast from El Quiché to Baja Verapaz. Its northwestern border is marked by the Chixoy River basin in Uspantán, which separates it from the Sierra de los Cuchumatanes. Its eastern border is marked by the Salamá River which separates it from the Sierra de las Minas. Its southeastern border is defined by the Motagua River valley.

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2009 Swan Islands earthquake

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Lake Chichoj

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The Swan Islands Transform Fault is an active left-lateral (sinistral) strike-slip fault zone that forms part of the boundary between the Caribbean Plate and the North American Plate. It runs along the southern boundary of the Cayman Trough from the Mid-Cayman Rise spreading center in the east, to Guatemala in the west, where it continues as the Motagua Fault. It consists of two main fault strands that overlap west of the Swan Islands. It has been associated with several major earthquakes, including those in 2009 and 2018.

Chortis Block

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Oblique subduction

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The 2022 Guatemala earthquake occurred on the early morning of February 16, 2022 in the southern regions of Guatemala. The quake measured a moment magnitude of 6.2 and reached a peak intensity of V (Moderate) on the Modified Mercalli Intensity scale. Damage was widespread but light in and around the capital, Guatemala City, resulting mostly in cracked walls and rockslides.

References

  1. 1 2 Ortega-Gutiérrez, Fernando; et al. (2007). "The Maya-Chortís Boundary: A Tectonostratigraphic Approach" (PDF). International Geology Review. 49 (11): 996–1024. Bibcode:2007IGRv...49..996O. doi:10.2747/0020-6814.49.11.996.[ permanent dead link ]
  2. ↑ Keppie, J. Duncan; Morán-Zenteno, Dante J. (2005-05-01). "Tectonic Implications of Alternative Cenozoic Reconstructions for Southern Mexico and the Chortis Block". International Geology Review. 47 (5): 473–491. Bibcode:2005IGRv...47..473K. doi:10.2747/0020-6814.47.5.473. ISSN   0020-6814.
  3. ↑ Burkart, Burke (1978-06-01). "Offset across the Polochic fault of Guatemala and Chiapas, Mexico". Geology. 6 (6): 328. Bibcode:1978Geo.....6..328B. doi:10.1130/0091-7613(1978)6<328:OATPFO>2.0.CO;2. ISSN   0091-7613.
  4. 1 2 Authemayou, Christine; Brocard, Gilles; Teyssier, Christian; Suski, Barbara; Cosenza, Beatriz; Morán-Ical, Sergio; González-Véliz, Claussen Walther; Aguilar-Hengstenberg, Miguel Angel; Holliger, Klaus (2012-07-01). "Quaternary seismo-tectonic activity of the Polochic Fault, Guatemala" (PDF). Journal of Geophysical Research: Solid Earth. 117 (B7): B07403. Bibcode:2012JGRB..117.7403A. doi:10.1029/2012JB009444. ISSN   2156-2202.
  5. ↑ Brocard, Gilles; Teyssier, Christian; Dunlap, Walker James; Authemayou, Christine; Simon-Labric, Thibaud; Cacao-Chiquín, Eric Noé; Gutiérrez-Orrego, Axel; Morán-Ical, Sergio (2011-12-01). "Reorganization of a deeply incised drainage: role of deformation, sedimentation and groundwater flow". Basin Research. 23 (6): 631–651. Bibcode:2011BasR...23..631B. doi:10.1111/j.1365-2117.2011.00510.x. ISSN   1365-2117.
  6. ↑ Lyon-Caen, H.; Barrier, E.; Lasserre, C.; Franco, A.; Arzu, I.; Chiquin, L.; Chiquin, M.; Duquesnoy, T.; Flores, O. (2006-10-01). "Kinematics of the North American–Caribbean-Cocos plates in Central America from new GPS measurements across the Polochic-Motagua fault system" (PDF). Geophysical Research Letters. 33 (19): L19309. Bibcode:2006GeoRL..3319309L. doi:10.1029/2006GL027694. ISSN   1944-8007.
  7. 1 2 White, Randall A. "The Guatemala earthquake of 1816 on the Chixoy-Polochic fault". Bulletin of the Seismological Society of America. 75 (2): 455–473.
  8. 1 2 3 Brocard, Gilles; Anselmetti, Flavio S.; Teyssier, Christian (2016-11-15). "Guatemala paleoseismicity: from Late Classic Maya collapse to recent fault creep". Scientific Reports. 6 (1): 36976. Bibcode:2016NatSR...636976B. doi:10.1038/srep36976. ISSN   2045-2322. PMC   5109539 . PMID   27845383.
  9. ↑ Guzmán-Speziale, Marco (2010-12-01). "Beyond the Motagua and Polochic faults: Active strike-slip faulting along the Western North America–Caribbean plate boundary zone". Tectonophysics. 496 (1–4): 17–27. Bibcode:2010Tectp.496...17G. doi:10.1016/j.tecto.2010.10.002.
  10. ↑ Franco, A.; Molina, E.; Lyon-Caen, H.; Vergne, J.; Monfret, T.; Nercessian, A.; Cortez, S.; Flores, O.; Monterosso, D. (2009-11-01). "Seismicity and Crustal Structure of the Polochic-Motagua Fault System Area (Guatemala)". Seismological Research Letters. 80 (6): 977–984. doi:10.1785/gssrl.80.6.977. ISSN   0895-0695.

Coordinates: 15°28′N89°22′W / 15.467°N 89.367°W / 15.467; -89.367

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