Systematic deviations of earthquake slip vectors from NUVEL1 at the Australia-Antarctica and Pacific-Antarctica plate boundaries

• Main Authors: Kubo,Atsuki, Nogi,Yoshifumi, Kaminuma,Katsutada
• Format: Report
• Language: English
• Published: National Institute of Polar Research/National Institute of Polar Research/National Institute of Polar Research 1998
• Subjects: slip vector; relative plate motion; Antarctica; microplate; plate boundary reorganization; Antarctic; The Antarctic; West Antarctica; Pacific; Antarc*; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3019; http://id.nii.ac.jp/1291/00003019/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3019&item_no=1&attribute_id=18&file_no=1

Systematic deviations of slip vectors from predictions based on plate motion model (NUVEL1 and GPS observation) are discussed at the circum Antarctic plate boundaries. Earthquakes with seismic moments larger than 10^<24 9> dyne-cm are considered in the analysis. Results show clear systematic deviations at the eastern end of the Australia-Antarctica plate boundary and the eastern part of the Pacific-Antarctica plate boundary. Around the eastern end of the Australia-Antarctica plate boundary, slip vectors deviate from the relative plate motions predicted by either NUVEL1 or GPS observations. Slip vector deviations due to 1) unrecognized microplate hypothesis near the plate boundary and 2) relative motion between East and West Antarctica are inconsistent with stress and slip direction of intraplate earthquake in the Antarctic plate. Deformation of the plate boundary related to reorganization near the triple junction of the Pacific-Australia-Antarctic plates is the most plausible explanation for the slip vector deviations. In contrast, the cause of slip vector deviations observed around the eastern part of the Pacific-Antarctica remains unclear suggesting complicated origins.