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Arc stresses determined by slabs: Implications for mechanisms of back‐arc spreading
Author(s) -
Seno Tetsuzo,
Yamanaka Yoshiko
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl02491
Subject(s) - slab , geology , arc (geometry) , wedge (geometry) , seismology , compression (physics) , island arc , subduction , mantle wedge , geophysics , optics , geometry , materials science , physics , tectonics , mathematics , composite material
There is an anti‐correlation in stress field between the back‐arc area and the shallow portion of the slab. Generally slabs showing down‐dip compression have tensional back‐arcs, and the reverse. We explain this anti‐correlation by a force balance in the fore‐arc wedge between the slab pull, collision force in the upper plate, and the ridge push. Back‐arc spreading can occur as a passive response to the down‐dip compressional slab. The Mariana, Kyushu and Aegean arcs are the exceptions to the anti‐correlation; in these arcs, the back‐arc is tensional although the slab is in down‐dip tension. This may be because the fore‐arc is driven by the mantle drag toward the trench, resulting in compression balanced with the slab pull. The flow in the mantle would cause back‐arc spreading in this case.