{"id":2864,"date":"2015-09-13T11:25:03","date_gmt":"2015-09-13T19:25:03","guid":{"rendered":"http:\/\/earthjay.com\/?p=2864"},"modified":"2015-09-13T11:25:03","modified_gmt":"2015-09-13T19:25:03","slug":"gulf-of-california-earthquakes-first-update","status":"publish","type":"post","link":"https:\/\/earthjay.com\/?p=2864","title":{"rendered":"Gulf of California Earthquakes! (first update)"},"content":{"rendered":"

Here is an update to the early morning post<\/a>… I have prepared an updated map that shows the fracture zones, spreading ridges, transform faults, and basins in the region of seismicity from the past 24 hours.
\nHere is the map. I include more explanation (e.g. about moment tensors) on the first post here<\/a>. As David Bazard points out, the oblique slip during this earthquake could be interpreted as transtensional (extension due to the orientation of strike-slip faults, i.e. “step overs”).
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\nThis is a nice simple figure, from the University of Sydney here<\/a>, showing the terminology of strike slip faulting. It may help with the following figures.
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\nHere is a fault block diagram showing how strike-slip step overs can create localized compression (positive flower) or extension (negative flower). More on strike-slip tectonics (and the source of this image) here<\/a>.
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\nHere is another great figure showing how sedimentary basins can be developed as a result of step overs in strike slip fault systems (source: Becky Dorsey<\/a>, University of Oregon, Dept. of Geological Sciences<\/a>).
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\nI also put together an animation of seismicity from 1065 – 2015. First, here is a map that shows the spatial extent of this animation.
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\nHere is the animation link (2 MB mp4 file<\/a>) if you cannot view the embedded video below. Note how the animation begins in 1965, but has the recent seismicity plotted for reference.
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\nhttp:\/\/earthjay.com\/earthquakes\/20150913_gulf_california\/20150913_goc.mp4<\/a><\/video><\/div><\/p>\n