DOI: 10.1016/j.epsl.2021.116878
论文题名: Along-strike variations in intermediate-depth seismicity and arc magmatism along the Alaska Peninsula
作者: Wei S.S. ; Ruprecht P. ; Gable S.L. ; Huggins E.G. ; Ruppert N. ; Gao L. ; Zhang H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 563 语种: 英语
中文关键词: Alaska Peninsula
; arc magmatism
; intermediate-depth earthquakes
; subduction zone
英文关键词: Earthquakes
; Plates (structural components)
; Structural geology
; Trace elements
; Volcanoes
; Alaska peninsula
; Arc magmatism
; B value
; Intermediate depths
; Intermediate-depth earthquakes
; Seismic zones
; Shumagin
; Subduction zones
; Teleseismic
; Traces elements
; Sediments
; crustal structure
; depth
; earthquake
; intraplate process
; magmatism
; seismic data
; seismicity
; subduction zone
; teleseismic wave
; Alaska
; Alaska Peninsula
; United States
英文摘要: The Alaska Peninsula section of the Aleutian-Alaska subduction zone exhibits significant along-strike variations in plate coupling, earthquakes, and arc magmatism. Here we use regional and teleseismic data from 1990 to 2018 to investigate intermediate-depth intra-plate seismicity beneath the Alaska Peninsula. The distribution of these events shows five distinct segments from southwest to northeast: Unimak, Pavlof, Shumagin, Semidi, and Kodiak. We identify two double seismic zones (DSZs) in the Pavlof and Semidi segments but not in others. The magnitude-frequency relationship of these earthquakes (b-value) also varies along strike, suggesting more fluids in the southwestern segments and closer to the slab top interface. We also evaluate trace elements of arc lavas in the Alaska Peninsula. Th/La ratios indicate a significant amount of sediments subducted in the Semidi segment that includes Aniakchak and Veniaminof, and the sediment signature peaks beneath the Black Peak volcano. In contrast, high Pb/Th but low Th/La ratios from southwestern volcanoes suggest high fluids released from the subducted slab. In sum, our observations suggest that the slab is more hydrated and thus undergoing more intensive dehydration in the southwest than in the northeast, whereas more sediments are subducted in the northeast than in the southwest. These along-arc changes are generally in agreement with previous studies of plate coupling and the crustal structure of the incoming plate. Moreover, the complexities beyond the monotonic changes imply that the intermediate-depth intra-plate seismicity and sub-arc melting are influenced by not only the pre-existing fabrics in the incoming plate, but also the subducted sediments and plate stress state. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165714
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States; Department of Geological Sciences and Engineering, University of Nevada, Reno, NV, United States; Alaska Earthquake Center, University of Alaska Fairbanks, Fairbanks, AK, United States; School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, China
Recommended Citation:
Wei S.S.,Ruprecht P.,Gable S.L.,et al. Along-strike variations in intermediate-depth seismicity and arc magmatism along the Alaska Peninsula[J]. Earth and Planetary Science Letters,2021-01-01,563