Residual polar motion caused by coseismic and interseismic deformations from 1900 to present

doi:10.1093/gji/ggw077

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	Residual polar motion caused by coseismic and interseismic deformations from 1900 to present
	Cambiotti, G.1; Wang, X.2; Sabadini, R.1; Yuen, D. A.3,4
刊名	GEOPHYSICAL JOURNAL INTERNATIONAL
	2016-05-01
卷号	205 期号:2 页码:1165-1179
关键词	Seismic Cycle Earth Rotation Variations Plate Motions Seismicity And Tectonics Dynamics: Seismotectonics
DOI	10.1093/gji/ggw077
文献子类	Article
英文摘要	We challenge the perspective that seismicity could contribute to polar motion by arguing quantitatively that, in first approximation and on the average, interseismic deformations can compensate for it. This point is important because what we must simulate and observe in Earth Orientation Parameter time-series over intermediate timescales of decades or centuries is the residual polar motion resulting from the two opposing processes of coseismic and interseismic deformations. In this framework, we first simulate the polar motion caused by only coseismic deformations during the longest period available of instrumental seismicity, from 1900 to present, using both the CMT and ISC-GEM catalogues. The instrumental seismicity covering a little longer than one century does not represent yet the average seismicity that we should expect on the long term. Indeed, although the simulation shows a tendency to move the Earth rotation pole towards 133 degrees E at the average rate of 16.5 mm yr(-1), this trend is still sensitive to individual megathrust earthquakes, particularly to the 1960 Chile and 1964 Alaska earthquakes. In order to further investigate this issue, we develop a global seismicity model (GSM) that is independent from any earthquake catalogue and that describes the average seismicity along plate boundaries on the long term by combining information about present-day plate kinematics with the Anderson theory of faulting, the seismic moment conservation principle and a few other assumptions. Within this framework, we obtain a secular polar motion of 8 mm yr(-1) towards 112.5 degrees E that is comparable with that estimated from 1900 to present using the earthquake catalogues, although smaller by a factor of 2 in amplitude and different by 20 degrees in direction. Afterwards, in order to reconcile the idea of a secular polar motion caused by earthquakes with our simplest understanding of the seismic cycle, we adapt the GSM in order to account for interseismic deformations and we use it to quantify, for the first time ever, their contribution to polar motion. Taken together, coseismic and interseismic deformations make the rotation pole wander around the north pole with maximum polar excursions of about 1 m. In particular, the rotation pole moves towards about Newfoundland when the interseismic contribution dominates over the coseismic ones (i.e. during phases of low seismicity or, equivalently, when most of the fault system associated with plate boundaries is locked). When megathrust earthquakes occur, instead, the rotation pole is suddenly shifted in an almost opposite direction, towards about 133 degrees E.
WOS关键词	CHANDLER-WOBBLE ; STRAIN ACCUMULATION ; VISCOELASTIC EARTH ; TOHOKU EARTHQUAKE ; SUBDUCTION ZONE ; SEISMICITY ; EXCITATION ; ROTATION ; MODEL ; CALIFORNIA
WOS研究方向	Geochemistry & Geophysics
语种	英语
WOS记录号	WOS:000375092400035
资助机构	CAS/CAFEA international partnership program for creative research teams(KZZD-EW-TZ-19) ; CAS/CAFEA international partnership program for creative research teams(KZZD-EW-TZ-19) ; National Science Foundation ; National Science Foundation ; CAS/CAFEA international partnership program for creative research teams(KZZD-EW-TZ-19) ; CAS/CAFEA international partnership program for creative research teams(KZZD-EW-TZ-19) ; National Science Foundation ; National Science Foundation
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/53487]
专题	地质与地球物理研究所_其他部门
作者单位	1.Univ Milan, Dept Earth Sci, Milan, Italy 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China 3.Univ Minnesota, Dept Earth Sci, Minneapolis, MN USA 4.Minnesota Supercomp Inst, Minneapolis, MN USA
推荐引用方式 GB/T 7714	Cambiotti, G.,Wang, X.,Sabadini, R.,et al. Residual polar motion caused by coseismic and interseismic deformations from 1900 to present[J]. GEOPHYSICAL JOURNAL INTERNATIONAL,2016,205(2):1165-1179.
APA	Cambiotti, G.,Wang, X.,Sabadini, R.,&Yuen, D. A..(2016).Residual polar motion caused by coseismic and interseismic deformations from 1900 to present.GEOPHYSICAL JOURNAL INTERNATIONAL,205(2),1165-1179.
MLA	Cambiotti, G.,et al."Residual polar motion caused by coseismic and interseismic deformations from 1900 to present".GEOPHYSICAL JOURNAL INTERNATIONAL 205.2(2016):1165-1179.