how does plate tetonic work for such a earthquake to happen in haiti last week?
Than recent Haitian fault occured along the Enriquilla-Plantain Garden Fault Zone, which runs right along that latitude of the lower peninsula’s north shore. It’s a left-lateral strike-slip fault / transform boundary between the North American Plate (on the north side) and the Caribbean Plate (on the south side). Here, the North American plate is trying to move west, the Caribbean trying to go east.
A transform boundary (like the San Andreas Fault Zone) is just that — where to plate grind past each other. Naturally, they don’t just slide good-naturedly past each other. There’s an immense amount of pressure between the two, and it is inevitable, on every fault, big or small, that the following will happen: a fault face will lock between the two plates, “holding them in place,” but the plates still want to move, so that just inject more and more strain into this “locked” area. Keep in mind, this is a two-dimensional face, not just one singular point like your local news shows you when it points out the epicenter.
Anyway, depending on conditions, this face will eventually be pressed more than it can handle, at which point, the face ruptures — the compression holding them together can’t, and they slip very angrily past each other (displacement). It’s this sudden movement along a large area that causes an earthquake. The size of the rupture zone, the speed with which it ruptures, and the amount of energy being released, is what creates the magnitude of the earthquake. Local geology will affect the immediate affects. Being on solid bedrock will lessen potential damage, being on loose and unconsolidated sediments will increase potential damage.
This exact same mechanism is what creates every single earthquake at every single transform boundary (the other two boundary types, and also hot spots, and intraplate earthquake have… earthquakes, but they operate differently). But again, every fault zone is different. Some can be very damaging, some you live with every day and no one even cares (like Southern California, where I live).
There’s just stupid death happening – Anderson Cooper CNN