Because this would require a tectonic regime in which both convergence and strike-slip was going on in the same area. This just plain won't happen. At least, not with active faults. Imagine trying to come up with a way to pres one piece of paper under another while at the same time splitting one of the sides of that zone into two pieces, one of which will be heading toward the zone, while the other pulls away. You can't. The motion beneath the lithosphere simply cannot exist to create that type of system.
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Because this would require a tectonic regime in which both convergence and strike-slip was going on in the same area. This just plain won't happen. At least, not with active faults. Imagine trying to come up with a way to pres one piece of paper under another while at the same time splitting one of the sides of that zone into two pieces, one of which will be heading toward the zone, while the other pulls away. You can't. The motion beneath the lithosphere simply cannot exist to create that type of system.
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