第89回ジオダイナミクスセミナー
　　　Geodynamics　Seminar

　　　　　　　　　　
　「コア反射波を用いた西太平洋最下部マントルの短波長
　　不均質構造 」
　"Short-wavelength heterogeneity in the lowermost mantle
　 beneath western Pacific using core-reflected phases"

　　　　　　　講師：出原光暉（愛媛大学修士１年）

　　 　　　　　 　　　　　
　　　　　主催　：　愛媛大学地球深部ダイナミクス研究センター
　　　　　日時　：　２００４年２月６日（金）　午後17時〜
　　　　　場所　：　愛媛大学理学部講義棟　２０１教室

要　旨
　Many previous seismic observations have shown that lateral heterogeneity of the lowermost mantle is characterized by two significant features, colder Circum-Pacific region and hotter central Pacific. Clarifying the origin of the two anomalous regimes is one of the most important issues for deep Earth geodynamics. Detailed information on the compressional and shear velocities at the base of the mantle provides important constraints on the physical properties of the anomalies. In this seminar, I present results from a study beneath the western part of the Circum Pacific region using short-period core-reflected ScP and PcP phases recorded by the Hi-net seismic network. Stacking high-frequency seismograms from a small-aperture array enables us to detect short-wavelength lateral heterogeneity in this region. These results are interpreted in terms of thermal/chemical heterogeneity in the lowermost mantle. The present results are also compared with other studies, mainly focusing on the wavelength of the heterogeneity, seismic properties and physical constraints.



　　　　　　　　問い合わせ先：山崎　大輔 　TEL　　　（089）927-8408
　　　 　　　　　　　　　　　　　　　　E-mail　　yamazaki@sci.ehime-u.ac.jp