M7.8 - Scotia Sea
Magnitude | 7.8 - Richter scale |
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Depth | 10 km Km |
Location | Scotia Sea LAT -60.2959, LON -46.362 |
Date-Time | Nov 17, 2013 09:04:55 UTC Nov 17, 2013 06:04:55 UTC -03:00 at epicenter |
Source | USGS NEIC (WDCS-D) |
Event ID(s) | usb000l0gq |
Distances from major cities | |
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Tectonic Summary
The November 17, 2013 earthquake in the Scotia Sea, to the northwest of the South Orkney Islands, occurred as the result of either left-lateral strike slip faulting on an east-west oriented plane, or right-lateral faulting on a north-south plane. The location of the event adjacent to the east-west oriented plate boundary between the Antarctica and Scotia Sea plates implies the left-lateral faulting scenario is most likely. At the latitude of this earthquake, the Antarctica plate moves eastwards with respect to the Scotia Sea plate at a velocity of 6 mm/yr.
The November 17 earthquake is the latest in a series of moderate-to-large earthquakes to strike the same region over the past several days. The sequence began with a M 6.1 event on November 13 approximately 50 km to the west of the November 17 quake. On November 15, a M 6.8 earthquake struck very close to the preceding M 6.1. Since then, 9 aftershocks have been recorded in the area, ranging from M 4.7 to M 5.4, both near the previous earthquakes and in the same approximate location as the November 17 event.
Though the region surrounding the Scotia Sea is familiar with earthquakes, the majority occur around the subduction zone adjacent to the South Sandwich Islands, to the east of the November 17 earthquake. Just two events of M6 or greater have occurred within 250 km of this earthquake over the past 40 years – a M 6.0 230 km to the west in September 1979, and a M 7.6 160 km to the east in August 2003. These two events involved normal and oblique-normal faulting, respectively, associated with the same plate boundary. Neither is known to have caused damage or fatalities.
