1946 Dominican Republic earthquake

1946 Dominican Republic earthquake
The Septentrional-Oriente fault zone in the Caribbean and across Hispaniola
1946 Dominican Republic earthquake is located in the Dominican Republic
1946 Dominican Republic earthquake
Location within the Dominican Republic
UTC time
  • 1946-08-04 17:51:10
ISC event
USGS-ANSS
Local date
  • August 4, 1946 (1946-08-04)
Local time
  • 13:51 AST
Magnitude
Depth
  • 15.0 km (9.3 mi)[1]
Epicenter19°12′00″N 69°18′58″W / 19.2°N 69.316°W / 19.2; -69.316
Areas affectedDominican Republic
Max. intensityMMI IX (Violent)[2]
Peak acceleration0.4 g (est)[2]
TsunamiYes
Casualties1,790

The 1946 Dominican Republic earthquake occurred on August 4 at 13:51 AST near Samaná, Dominican Republic. It was the largest earthquake to occur in the instrumental era in the Caribbean. It generated a tsunami that was observed as far as New Jersey. A total of 1,790 deaths were reported.[3]

Tectonic setting

The Dominican Republic is located on the eastern part of Hispaniola, which is the site of a complex tectonic environment. The North American plate undergoes subduction below the Caribbean plate.[4] In addition, the seismically active strike-slip Septentrional–Oriente fault zone runs through the northern part of the island. It has been estimated that the fault accumulates about 12 millimetres (1.2 cm; 0.47 in) of strain every year.[5] Major earthquakes (M>=7) have occurred in the northeastern Caribbean at least eleven times over the past 250 years, at least five of which have been located on the megathrust.[6]

Earthquake

The earthquake occurred on August 4 at 13:51 AST with an epicenter near the coast of Samaná Province in the northern Dominican Republic. The mainshock measured 7.8 on the moment magnitude scale; 8.1 on the surface-wave magnitude scale,[7] and originated at a depth of 15 km (9.3 mi).[8] It was caused by movement on a northeast-dipping thrust fault striking northwest.

At least 63 aftershocks followed the largest earthquake including a magnitude 7.0 event that struck the coast on August 8.[9][10] These aftershocks were distributed offshore along a west–northwest trending zone measuring 250 by 75 km (155 by 47 mi). Several aftershocks with focal depths greater than 70 km (43 mi) delineate a south or southwest dipping plate that is subducted beneath the region.[10]

Tsunami

A tsunami was generated by the initial earthquake and caused widespread devastation across Hispaniola. The tsunami was observed in much of the Caribbean and the northwestern Atlantic Ocean.[11][12][13][14] Maximum tsunami heights exceeded 5 metres (16 ft) in several locations, with a height of 8 metres (26 ft) observed at Playa Boca Nueva, although it was likely associated with splash-up.[15] A small tsunami was also recorded by tide gauges at San Juan in Puerto Rico, Bermuda and in the United States at Daytona Beach, Florida and Atlantic City, New Jersey.[16]

See also

References

  1. ↑ "M 7.8 – 16 km NNW of Miches, Dominican Republic". United States Geological Survey. Retrieved 9 August 2022.
  2. 1 2 Lynch, Joseph J.; Bodle, Ralph R. (1948), "The Dominican earthquakes of August, 1946", Bulletin of the Seismological Society of America, 38 (1): 4, 5, Bibcode:1948BuSSA..38....1L, doi:10.1785/BSSA0380010001
  3. ↑ "NCEI Hazard Tsunami Event Information". NCEI NOAA. Retrieved April 9, 2025.
  4. ↑ Johnson, Kendra; Pagani, Marco; Chartier, Thomas (October 2021). "Probabilistic seismic hazard model for the Dominican Republic" (PDF). Global Quake Model (GEM). p. 7. Retrieved April 9, 2025.
  5. ↑ Oliveira de Sá, A.; d’Acremont, E.; Leroy, S.; Lafuerza, S. (2021). "Polyphase Deformation and Strain Migration on the Septentrional-Oriente Fault Zone in the Windward Passage, Northern Caribbean Plate Boundary". Tectonics. 40 (8): 3. doi:10.1029/2021TC006802. ISSN 1944-9194.
  6. ↑ Ali, Syed; Freed, Andrew; Calais, Eric; Manaker, David; McCann, William (September 24, 2007). "Coulomb stress evolution in Northeastern Caribbean over the past 250 years due to coseismic, postseismic and interseismic deformation" (PDF). p. 1. Retrieved April 9, 2025.
  7. ↑ Dolan, James F. (1998). Paul Mann (ed.). Active Strike-Slip and Collisional Tectonics of the Northern Caribbean Plate Boundary Zone. Geological Society of America. p. 44. ISBN 978-0-8137-2326-6.
  8. ↑ "M 7.8 – 16 km NNW of Miches, Dominican Republic". United States Geological Survey. Retrieved 9 August 2022.
  9. ↑ "M 7.0 – 24 km NNW of Las Terrenas, Dominican Republic". United States Geological Survey. Retrieved 9 August 2022.
  10. 1 2 Russo, R. M.; Villasenor, A. (1995). "The 1946 Hispaniola earthquakes and the tectonics of the North America-Caribbean plate boundary zone, northeastern Hispaniola" (PDF). Journal of Geophysical Research: Solid Earth. pp. 5901–6515. doi:10.1029/94JB02599.
  11. ↑ "Northern Chile Rocked By Earthquake: West Indies Too". Morning Bulletin (Rockhampton, Qld. : 1878 – 1954). 6 August 1946. Retrieved 29 October 2019.
  12. ↑ Historic Earthquakes: Samana, Dominican Republic 1946 Archived 2008-06-02 at the Wayback Machine, USGS, Retrieved June 10, 2008
  13. ↑ Woods Hole Oceanographic Institution (February 8, 2005). "Major Caribbean Earthquakes And Tsunamis A Real Risk". Science Daily. Retrieved December 9, 2012.
  14. ↑ O'Loughlin, Karen Fay; Lander, James F. (2003), Caribbean tsunamis: a 500-year history from 1498–1998, Boston: Kluwer, p. 82, ISBN 978-1-4020-1717-9
  15. ↑ Fritz, H. M.; Martinez, C.; Salado, J.; Rivera, W. (2016-12-01). "Field survey of the 1946 Dominican Republic tsunami based on eyewitness interviews". American Geophysical Union. Bibcode:2016AGUFMNH51D..07F.
  16. ↑ Lander, James F.; Lockridge, Patricia A. (1989). United States Tsunamis, (including United States possessions) 1690–1988: Publication 41-2 (PDF). United States Department of Commerce. pp. 219, 220.

Further reading

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