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The subduction of bathymetric highs such as aseismic ridges, oceanic plateaus, and seamounts has been posited as the primary driver of flat slab subduction. [3] The Andean flat slab subduction zones, the Peruvian slab and the Pampean (Chilean) flat slab, are spatially correlated with the subduction of bathymetric highs, the Nazca Ridge and the Juan Fernandéz Ridge, respectively.
Slabs experiencing low angle (less than 30 degrees) subduction is considered flat-slab, primarily in southern China and the western United States. [ 11 ] [ 12 ] Marianas Trench is an example of a deep slab, thereby creating the deepest trench in the world established by a steep slab angle. [ 13 ]
The Pampean flat-slab is one of three flat slabs in South America, the other being the Peruvian flat-slab and the Bucaramanga flat-slab. [ 1 ] It is thought that the subduction of the Juan Fernández Ridge , a chain of extinct volcanoes on the Nazca Plate , is the underlying cause of the Pampean flat-slab.
Slab suction is weaker than slab pull, which is the strongest of the driving forces. When measuring the forces of these two mechanisms, slab pull in subducting plate boundaries for upper mantle slabs is 1.9 × 10^21 N. [ clarification needed ] In comparison slab suction in the upper and lower mantle totaled 1.6 × 10^21 N. [ 3 ]
In plate tectonics, slab detachment or slab break-off may occur during continent-continent or arc-continent collisions. When the continental margin of the subducting plate reaches the oceanic trench of the subduction zone , the more buoyant continental crust will in normal circumstances experience only a limited amount of subduction into the ...
Slab pull is a geophysical mechanism whereby the cooling and subsequent densifying of a subducting tectonic plate produces a downward force along the rest of the plate. In 1975 Forsyth and Uyeda used the inverse theory method to show that, of the many forces likely to be driving plate motion, slab pull was the strongest. [ 1 ]
The underside of a waffle slab, showing the grid like structure. A waffle slab or two-way joist slab is a concrete slab made of reinforced concrete with concrete ribs running in two directions on its underside. [1] The name waffle comes from the grid pattern created by the reinforcing ribs.
Slabs are one of the greatest consumers of concrete in many buildings, [14] so reducing the slab mass can make a relatively large difference to the environmental impact of a building's construction. Biaxial slabs may be marginally cheaper than solid slabs, partly due to the lower mass.