1974 Lesser Antilles earthquake
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.
  | |
| UTC time | 1974-10-08 09:50:58 |
|---|---|
| ISC event | 736214 |
| USGS-ANSS | ComCat |
| Local date | October 8, 1974 |
| Local time | 05:50:58 |
| Magnitude | 6.9 Mw [1] |
| Depth | 35.2 km (22 mi) [1] |
| Epicenter | 17.3°N 62.0°W [1] |
| Type | Normal [2] |
| Total damage | Moderate [3] |
| Max. intensity | VIII (Severe) [3] |
| Casualties | 4 injured [4] |
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]
References
- ISC (2017), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2013), Version 4.0, International Seismological Centre
- 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
- National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
- USGS (September 4, 2009), PAGER-CAT Earthquake Catalog, Version 2008_06.1, United States Geological Survey
- Yeats, R. (2012), Active Faults of the World, Cambridge University Press, pp. 146–148, 159–161, ISBN 978-0521190855
Sources
- Tomblin, J. F.; Aspinall, W. P. (1975), "Reconnaissance report of the Antigua, West Indies, earthquake of October 8, 1974", Bulletin of the Seismological Society of America, 65 (6): 1553–1573
External links
- Antigua & Barbuda remembers ’74 quake – The Daily Observer
- The International Seismological Centre has a bibliography and/or authoritative data for this event.