DOI: 10.1016/j.epsl.2020.116173
论文题名: Imaging crustal melt beneath northeast Japan with Ps receiver functions
作者: Chen K.-X. ; Fischer K.M. ; Hua J. ; Gung Y.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 537 语种: 英语
中文关键词: crust melt
; crustal discontinuities
; northeast Japan
; Ps receiver function
英文关键词: Drops
; Geographical distribution
; Surface waves
; Velocity
; Volcanoes
; crustal discontinuities
; Crustal velocity structure
; Gassmann's equations
; Low velocity zones
; northeast Japan
; Receiver functions
; Surface-wave tomography
; Velocity gradients
; Shear flow
; amplitude
; crustal structure
; geographical distribution
; image processing
; melt
; P-wave
; seismic tomography
; seismic velocity
; upper crust
; Japan
英文摘要: To investigate crustal structures related to melt storage, Ps converted waves were used to image crustal velocity discontinuities across the Tohoku region of northeast Japan. Ps receiver functions from 127 permanent seismic stations were migrated to depth, accounting for variations in crustal velocity structure. In the 5-15 km depth range, negative Ps phases indicative of velocity decreases with depth are prevalent in central and western Tohoku, where Holocene volcanoes occur and surface wave tomography indicates low crustal velocities. Large negative Ps phases are largely absent in the crust of the old mountain terranes in eastern Tohoku where crustal velocities are higher. In central and western Tohoku, velocity gradients inferred from Ps phases and shear velocity anomalies are consistent with models for crustal melt storage that involve trans-crustal zones of crystal-melt mush where the highest concentrations of melt are localized at the top of the mush column. Negative Ps phases are concentrated at depths of 5-10 km, and many correlate with the upper margins of localized low velocity zones beneath volcanoes. These correlated features are consistent with the roofs of high melt fraction layers. At depths of 10-30 km, positive Ps phases are consistent with gradual velocity positive gradients that correspond to decreasing melt fraction with depth in the mush column, although some groups of deeper negative Ps phases at depths of 10-20 km may reflect local maxima in melt fraction. The amplitudes of the negative Ps phases at 5-10 km depth vary significantly. In a higher amplitude example, waveform modeling of Ps receiver functions from a station near Hijori volcano indicates a 16% ± 5% Vs drop at 10 km depth, implying melt fractions of 10% ± 3% if Gassmann's equations are assumed, above a velocity increase from 10 to 20 km that indicates decreasing melt fractions with depth. However, modeling of lower amplitude Ps phases in the 5-10 km depth range indicates a 7% ± 3% velocity drop and a maximum melt fraction of 5% ± 2%. The geographic distribution of apparent melt fraction at 5-10 km depth suggests that in some cases the same upper crustal source can supply multiple volcanoes, and in others high melt fraction zones are significantly laterally offset from the nearest volcano. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164916
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: Dept. of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, United States; Dept. of Geosciences, National Taiwan University, Taipei, Taiwan
Recommended Citation:
Chen K.-X.,Fischer K.M.,Hua J.,et al. Imaging crustal melt beneath northeast Japan with Ps receiver functions[J]. Earth and Planetary Science Letters,2020-01-01,537