Changes

===Zonation of Deformation===

===Zonation of Deformation===

Subduction produces areas of different deformation mechanism. Different mechanisms lead to different potential of earthquake. Keary and Vine<ref name=KV /> constructs cross-section of subduction zone consisting three zonations of deformation: a, b, and c. This classification is based on deformation mechanism and materials involved.

Subduction produces areas of different deformation mechanism. Different mechanisms lead to different potential of earthquake. Keary and Vine<ref name=KV /> constructs [[cross-section]] of subduction zone consisting three zonations of deformation: a, b, and c. This classification is based on deformation mechanism and materials involved.

Zone ‘a’ represents plastic deformation of oceanic crust plunging into the trench. Flexural bending of oceanic crust creates topographic bulge, causing regional positive gravity anomaly of +500 gu. Zone ‘b’ is the contact of oceanic and continental crust. Compressive forces are built in the overriding crust and extensional regime develops landward on continental crust. As the plate descending to zone ‘c’, the interaction with asthenosphere produces deformation due to unbending of the slab. This mechanism leads to internal deformation of oceanic crust.

Zone ‘a’ represents plastic deformation of oceanic crust plunging into the trench. Flexural bending of oceanic crust creates topographic bulge, causing regional positive gravity anomaly of +500 gu. Zone ‘b’ is the contact of oceanic and continental crust. Compressive forces are built in the overriding crust and extensional regime develops landward on continental crust. As the plate descending to zone ‘c’, the interaction with asthenosphere produces deformation due to unbending of the slab. This mechanism leads to internal deformation of oceanic crust.

==Structural Features of Subduction Zone==  

==Structural Features of Subduction Zone==  

===Ocean Trenches===

===Ocean Trenches===

Underthrusting of oceanic crust beneath continental crust creates the deepest morphology on Earth: ocean trench. Ocean trench on average has width of 50 – 100 km. As an example, Peru-Chile trench is 4500 km long and has depth of 7 – 8 km below sea level. Great depth of ocean trench implies to its gravity anomalies, reaching negative 2000 gu. On cross-section, trench has V-shaped morphology with angle of steepest slope ranging from 8 – 20o on the opposite side of underthrusting oceanic crust. Sediment supply of oceanic trench depends on accumulated materials (terrigenous, pelagic, or carbonate sediments) on ocean floor.

Underthrusting of oceanic crust beneath continental crust creates the deepest morphology on Earth: ocean trench. Ocean trench on average has width of 50 – 100 km. As an example, Peru-Chile trench is 4500 km long and has depth of 7 – 8 km below sea level. Great depth of ocean trench implies to its gravity anomalies, reaching negative 2000 gu. On [[cross-section]], trench has V-shaped morphology with angle of steepest slope ranging from 8 – 20o on the opposite side of underthrusting oceanic crust. Sediment supply of oceanic trench depends on accumulated materials (terrigenous, pelagic, or carbonate sediments) on ocean floor.

===Accretionary Prism===

===Accretionary Prism===