Present-Day Plate Motions

Present-Day Plate Motions

November 10, 1977 | J. Bernard Minster, Thomas H. Jordan
This paper presents a revised model of present-day plate motions, designated RM2, which is an improvement over the previous model RM1. The new model is based on a larger and more reliable dataset, including 110 spreading rates, 78 transform fault azimuths, and 142 earthquake slip vectors. The inversion algorithm used is linearized, iterative, weighted least-squares, and has been shown to be effective in previous studies. The model represents an improvement in most regions, but it systematically misfits data along the India-Antarctica and Pacific-India plate boundaries, suggesting internal deformation within the Indian plate. The model also fails to satisfy the EW-trending transform fault azimuths in the FAMOUS area, likely due to closure constraints about the Azores triple junction. The existence of a Bering plate, previously hypothesized, is not necessary if Engdahl et al.'s findings on slab effects are accepted. The paper discusses the detailed assessment of RM2 on a region-by-region basis, highlighting areas where the model performs well and where it misfits the data. It concludes that the misfits in the Indian Ocean can be resolved by hypothesizing internal deformation within the Indian plate, particularly near the Ninetyeast Ridge, which may be undergoing NW-SE compression at a rate of about 1 cm/yr. The paper also discusses the implications of these findings for plate tectonics and global motions.This paper presents a revised model of present-day plate motions, designated RM2, which is an improvement over the previous model RM1. The new model is based on a larger and more reliable dataset, including 110 spreading rates, 78 transform fault azimuths, and 142 earthquake slip vectors. The inversion algorithm used is linearized, iterative, weighted least-squares, and has been shown to be effective in previous studies. The model represents an improvement in most regions, but it systematically misfits data along the India-Antarctica and Pacific-India plate boundaries, suggesting internal deformation within the Indian plate. The model also fails to satisfy the EW-trending transform fault azimuths in the FAMOUS area, likely due to closure constraints about the Azores triple junction. The existence of a Bering plate, previously hypothesized, is not necessary if Engdahl et al.'s findings on slab effects are accepted. The paper discusses the detailed assessment of RM2 on a region-by-region basis, highlighting areas where the model performs well and where it misfits the data. It concludes that the misfits in the Indian Ocean can be resolved by hypothesizing internal deformation within the Indian plate, particularly near the Ninetyeast Ridge, which may be undergoing NW-SE compression at a rate of about 1 cm/yr. The paper also discusses the implications of these findings for plate tectonics and global motions.
Reach us at info@study.space
Understanding Present%E2%80%90day plate motions