DOI: 10.1016/j.epsl.2021.117089
论文题名: Love-wave normal modes discriminate between upper-mantle and crustal earthquakes: Simulation and demonstration in Tibet
作者: Wang S. ; Klemperer S.L.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 571 语种: 英语
中文关键词: love-wave normal modes
; mantle earthquakes
; Sn and Lg
; Tibet
英文关键词: Structural geology
; Amplitude ratios
; Crustal earthquakes
; Earthquake simulation
; Love wave
; Love-wave normal mode
; Mantle earthquake
; Normal modes
; Sn and lg
; Tibet
; Upper mantle
; Earthquakes
英文摘要: We discriminate upper-mantle earthquakes from crustal earthquakes based on the amplitude ratio of seismic waves Sn and Lg (‘Sn/Lg’), a prominent feature of regional seismograms that is visible to the naked eye. Crucially, our new method uses only the waveforms of the candidate earthquake, unlike previous methods to identify upper-mantle earthquakes that introduce potentially large errors by comparing hypocentral depths with independent measures of crustal thickness. Our synthetics show that the Love-wave higher modes that form individual Sn and Lg Airy phases on the transverse component are preferentially excited when the source is respectively below or above the Moho. We use three previously recognized mantle events from southern Tibet to validate our new approach and show that focal mechanism, intrinsic attenuation, geometrical spreading etc., can be ignored to first order. We then identify two new upper-mantle earthquakes in NW Tibet where, previously, only lower-crustal events had been reliably demonstrated, thereby showing this NW-Tibet lithosphere is seismogenic at all depths i.e. that upper-mantle and lower-crustal earthquakes co-exist. Our method has potential for expanding the global catalog of continental earthquakes reliably determined to be close above or close below the Moho. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165706
Appears in Collections: 气候变化与战略
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作者单位: Department of Geophysics, Stanford University, Stanford, CA 94305, United States
Recommended Citation:
Wang S.,Klemperer S.L.. Love-wave normal modes discriminate between upper-mantle and crustal earthquakes: Simulation and demonstration in Tibet[J]. Earth and Planetary Science Letters,2021-01-01,571