Open AccessCyclic crustal movement, steady uplift of marine terraces, and evolution of the island arc‐trench system in southwest Japan
Author(s) -
Sato Toshinori,
Matsu'ura Mitsuhiro
Publication year - 1992
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1992.tb02116.x
Subject(s) - geology , subduction , asthenosphere , plate tectonics , trench , lithosphere , convergent boundary , tectonophysics , pacific plate , seismology , north american plate , seafloor spreading , oceanic crust , geophysics , tectonics , chemistry , organic chemistry , layer (electronics)
SUMMARY In southwest Japan, where the Philippine Sea Plate is descending beneath the Eurasian Plate at the Nankai Trough, we can observe cyclic crustal movement related to the periodic occurrence of interplate earthquakes with the time interval of 10 2 yr, steady uplift of the marine terraces formed by eustatic sea‐level changes for the last 10 5 yr, and gradual evolution of the island arc‐trench system through the last 4 X 10 6 yr. We demonstrate that these phenomena with very different characteristic time‐scales can be consistently explained by a single‐plate subduction model. In our model, the lithosphere‐asthenosphere system is represented by a stratified viscoelastic half‐space under gravity, consisting of a high‐viscosity surface layer and a low‐viscosity substratum, and interaction between oceanic and continental plates by steady slip motion over the whole plate boundary and its perturbation associated with the periodic occurrence of earthquakes. The effects of accretion of oceanic sediments at plate boundaries, erosion on land, and sedimentation on inner trench walls are also considered in the model. From comparison of theoretical results with observed data we obtained the following conclusions valid for young subduction zones: observed deformation cycles cannot be explained by a simple rebound model in which the effect of steady‐plate subduction is ignored. The steady‐plate subduction brings about steady uplift of marine terraces. The present patterns of surface topography and gravity anomalies are held nearly stable by the balance of erosion (sedimentation) rates and substantial growth rates.