The crust and upper mantle discontinuity structure beneath Alaska inferred from receiver functions

Yinshuang Ai, Dapeng Zhao, Xing Gao, Weiwei Xu

研究成果: Article査読

47 被引用数 (Scopus)

抄録

In this study, three receiver function stacking methods are used to study the detailed crust and upper mantle structure beneath south-central Alaska. We used teleseismic waveform data recorded by 36 stations in the Broadband Experiment Across the Alaska Range (BEAAR) and 4 permanent stations in Alaska. H - κ stacking method using P-to-S converted wave and its multiply reflected waves between the Earth's surface and the Moho discontinuity is adopted to estimate the crustal thickness (H) and average crustal VP/VS ratio (κ) in this region. The receiver function results for 24 stations show that the crustal thickness under Alaska ranges from 26.0 to 42.6 km with an average value of 33.8 km, and the VP/VS ratio varies from 1.66 to 1.94 with an average value of 1.81 which corresponds to an average Poisson's ratio of 0.277 with a range from 0.216 to 0.320. High Poisson's ratios under some stations are possibly caused by partial melting in the crust and the uppermost mantle. Common converted point (CCP) stacking results of receiver functions along three lines show clear Moho and slab images under this subduction zone. The depths of the slab from our CCP stacking images are consistent with those estimated from the Wadati-Benioff Zone (WBZ). In the area between two stations DH2 (147.8°W, 63.3°N) and DH3 (147.1°W, 63.0°N), a Moho depth offset of about 10 km is found by both the H - κ and CCP stacking techniques. Common depth point (CDP) stacking of receiver functions shows not only the 410-, 520- and 660-km discontinuities, but also significant variations (-30 to 15 km) in the transition zone thickness under the southwest and southeast parts of the study region. The transition zone becomes thinner by 20-30 km, indicating that the temperature there is 150-200 K higher than that of the normal mantle.

本文言語English
ページ(範囲)339-350
ページ数12
ジャーナルPhysics of the Earth and Planetary Interiors
150
4
DOI
出版ステータスPublished - 2005 6月 15
外部発表はい

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 地球物理学
  • 物理学および天文学(その他)
  • 宇宙惑星科学

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