1974 Lesser Antilles earthquake

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1974 Lesser Antilles earthquake
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UTC  time1974-10-08 09:50:58
ISC  event 736214
USGS-ANSS ComCat
Local dateOctober 8, 1974 (1974-10-08)
Local time05:50:58
Magnitude6.9 Mw [1]
Depth35.2 km (22 mi) [1]
Epicenter 17°18′N62°00′W / 17.3°N 62.0°W / 17.3; -62.0 [1]
TypeNormal [2]
Total damageModerate [3]
Max. intensity VIII (Severe) [3]
Casualties4 injured [4]

The 1974 Lesser Antilles earthquake occurred at 05:50:58 local time on October 8 with a moment magnitude of 6.9 and a maximum Mercalli intensity of VIII (Severe). Four people were injured in what the United States' National Geophysical Data Center called a moderately destructive event.

Contents

Tectonic setting

While the northern and southern boundary of the Caribbean Plate are complex and diffuse, with zones of seismicity stretching several hundred kilometers across, the eastern boundary is that of the Lesser Antilles subduction zone. This 850 km (530 mi) long subduction zone lacks a uniform curve and has an average dip of 50–60°. The largest known earthquake on the plate interface was a M7.5–8.0 event in 1843, but it did not generate a large tsunami. In opposition, the three largest events between 1950 and 1978 were intraplate normal faulting events. [5]

See also

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The 2004 Les Saintes earthquake occurred at 07:41:07 local time on November 21, 2004 with a moment magnitude of 6.3 and maximum European macroseismic intensity of VIII. The shock was named for Îles des Saintes "Island of the Saints", a group of small islands to the south of Guadeloupe, which is an overseas department of France. Although it occurred near the Lesser Antilles subduction zone, this was an intraplate, normal fault event. It resulted in one death, 13 injuries, and 40 people being made homeless, but the overall damage was considered moderate. A small, nondestructive tsunami was reported, but run-up and inundation distances were difficult to measure due to a storm that occurred on the day of the event. Unusual effects at a volcanic lake on Dominica were also documented, and an aftershock caused additional damage three months later.

The 1843 Guadeloupe earthquake occurred at 10:37 local time on 8 February in the island of Guadeloupe in the Lesser Antilles. It had an estimated magnitude of 8.5, making it the strongest recorded earthquake in the Caribbean and a maximum perceived intensity of shaking of IX on the Mercalli intensity scale. The earthquake was felt widely throughout the Caribbean and as far away as New York. Around 1,500 to 5,000 people were killed.

<span class="mw-page-title-main">1867 Virgin Islands earthquake and tsunami</span> Earthquake and tsunami in the Caribbean

The 1867 Virgin Islands earthquake and tsunami occurred on November 18, at 14.45 in the Anegada Passage about 20 km southwest of Saint Thomas, Danish West Indies. The Ms  7.5 earthquake came just 20 days after the devastating San Narciso Hurricane in the same region. Tsunamis from this earthquake were some of the highest ever recorded in the Lesser Antilles. Wave heights exceeded 10 m (33 ft) in some islands in the Lesser Antilles. The earthquake and tsunami resulted in no more than 50 fatalities, although hundreds of casualties were reported.

The 1946 Ancash earthquake in the Andes Mountains of central Peru occurred on November 10 at 17:43 UTC. The earthquake had a surface-wave magnitude of 7.0, and achieved a maximum Mercalli intensity scale rating of XI (Extreme). About 1,400 Peruvians are thought to have died from the event.

The 1839 Martinique earthquake occurred on the morning of January 11 with an estimated magnitude of 7.8 Ms , the largest in the Lesser Antilles since 1690. The maximum intensity of this earthquake was assigned IX on both the Mercalli and MSK intensity scales, which left the cities of Saint-Pierre and Fort Royal almost completely destroyed. Estimation on the number of human losses varies from 390 to even 4,000 making this one of the deadliest earthquakes in the Caribbean.

On January 30, 1973, at 15:01 (UTC–6), a magnitude 7.6 earthquake struck 35.3 km (21.9 mi) beneath the Sierra Madre del Sur range in the Mexican states of Colima, Jalisco and Michoacán. On the Mercalli intensity scale, the earthquake reached a maximum intensity of X (Extreme), causing serious damage in the region. At least 56 people were killed and about 390 were injured. The event is commonly referred to as the Colima earthquake.

The 1979 Saint Elias earthquake occurred near noon local time on the 28th of February. It measured Mw 7.4–7.6. Though the maximum recorded Modified Mercalli intensity was VII, damage was minimal and there were no casualties due to the remoteness of the faulting. The epicenter lies near the Alaskan border between America and Canada.

References

  1. 1 2 3 ISC (2017), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2013), Version 4.0, International Seismological Centre
  2. McCann, W. R.; Dewey, J. W.; Murphy, A. J.; Harding, S. T. (1982), "A large normal-fault earthquake in the overriding wedge of the Lesser Antilles subduction zone: The earthquake of 8 October 1974" (PDF), Bulletin of the Seismological Society of America, 72 (6A): 2267–2283
  3. 1 2 National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
  4. USGS (September 4, 2009), PAGER-CAT Earthquake Catalog, Version 2008_06.1, United States Geological Survey
  5. Yeats, R. (2012), Active Faults of the World, Cambridge University Press, pp. 146–148, 159–161, ISBN   978-0521190855

Sources