Thick and anisotropic D″ layer beneath Antarctic Ocean

• Published in: Geophysical Research Letters
• Main Authors: Usui Yusuke, Hiramatsu Yoshihiro, Furumoto Muneyoshi, Kanao Masaki, 臼井 佑介, 平松 良浩, 古本 宗充, 金尾 政紀
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2005
• Subjects: Antarctic; Antarctic Ocean; The Antarctic; Antarc*; Alaska
• Online Access: http://hdl.handle.net/2297/3656; https://kanazawa-u.repo.nii.ac.jp/?action=repository_uri&item_id=10181; https://kanazawa-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=10181&item_no=1&attribute_id=26&file_no=1

情報・システム研究機構(ROIS)新領域融合研究センター（TRIC） 金沢大学大学院自然科学研究科 金沢大学理学部 Waveform modeling and travel times analyses of S, ScS and SKS phases recorded at the broad-band permanent station SYO in the Antarctic are used to determine the shear wave velocity structure and transverse isotropy in the D″ layer beneath the Antarctic Ocean. The SH wave structure has a discontinuity with the velocity increase of 2.0% at 2550 km. The SV structure is similar to PREM model. The magnitude of the anisotropy is highest at the top of D″ layer and lowest at the core-mantle boundary. The D″ layer beneath the Antarctic Ocean is significantly thicker than those beneath Alaska and the Caribbean Sea. We attribute this anisotropic D″ layer to paleo-slab materials. The subduction in and around the Antarctic Ocean has started ∼180 Ma and is the one of the oldest in the world. It has provided a large amount of the slab materials in the lowermost mantle. Copyright 2005 by the American Geophysical Union.