M 6.8 Scotia Sea

Nice big one along the complex fault zone west of the Scotia subduction zone. The Scotia subduction zone is an interesting oceanic subduction zone that is possibly related tot he opening between South America and Antarctica. Today’s earthquake occurred in a fault system that involves both transform faults and oceanic spreading ridges. In the region of this earthquake, this system is mapped as a transform fault (“strike-slip,” similar to the San Andreas fault).

The moment tensor, which tells us about the type of earthquake that slipped (eg. strike slip, reverse/thrust, or normal), shows this earthquake to be primarily strike-slip. Based on the mapped plate boundary fault here, I would interpret this to be a left-lateral strike-slip earthquake.
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Here is the USGS page.

Here is a map of this part of the southern hemisphere:
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Here is a map of the tectonics of the region. USGS plate boundaries are shown as green (transform), magenta (ridges), and blue (subduction zones):
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All the contributing moment tensor solutions generally agree with the interpretation that this is a strike-slip earthquake.
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Another earthquake also just happened in this locality! This time a Mi 7.8.

Category(s): College Redwoods, earthquake, education, geology, subduction

3 Responses in other blogs/articles

  1. […] 2013/11/17 M 6.8 […]

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  3. […] M 6.8 Scotia Sea USGS site (southern strike-slip boundary; foreshock to the […]

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