Compressional deformation of island-arc lithosphere in northeastern Japan resulting from long-term subduction-related tectonic forces: finite-element modeling
Northeastern Japan experienced an approximately constant, compressional deformation during the last 5 million years resulting from the steady subduction of the Pacific plate. Because the direction of the maximum compression axis is approximately perpendicular to the strike of the island arc, 2-D fin...
Saved in:
| Published in: | Tectonophysics Vol. 287; no. 1-4; pp. 43 - 58 |
|---|---|
| Main Author: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
20-03-1998
|
| Subjects: | |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Northeastern Japan experienced an approximately constant, compressional deformation during the last 5 million years resulting from the steady subduction of the Pacific plate. Because the direction of the maximum compression axis is approximately perpendicular to the strike of the island arc, 2-D finite-element modeling can be used to examine the deformation over time of the island-arc lithosphere, which, in turn, allows a test of the hypothesis that the large-scale features of topography, gravity and seismicity in northeastern Japan result from tectonic compression. The model geometry is based on heat flow data and laboratory-derived flow low, and each model run requires an assumed interplate coupling. Novel in our modeling is the ability to include erosion/deposition loading and the creation of strike-slip faults, based on a dynamically applied fracture criterion. The criterion for acceptability of a model is how well it matches observed present-day topography, gravity, and seismicity patterns. Models with the following viscosity structure are consistent with present-day observations: The long-term effective elastic thickness is 10 km in the inner arc, increasing to about 50 km near the trench. The effective elastic thickness in the inner arc is therefore much smaller than the about 30 km short-term elastic thickness estimated from seismological data. The viscosity of the lower crust is on the order of 10 super(22) Pa s or less. Our model explains the observed positive gravity anomaly of the Kitakami range as a consequence of uplift resulting from a coupling which increases with depth along the interface between the subducting and overriding plates. The model also predicts the slip on the faults adjacent to the Backbone range, as well as the crustal shortening. |
|---|---|
| Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
| ISSN: | 0040-1951 |
| DOI: | 10.1016/S0040-1951(97)00203-5 |