TOROIDAL/POLOIDAL PARTITIONING OF GLOBAL POSTSEISMIC DEFORMATION

被引：32

作者：

SABADINI, R

PIERSANTI, A

SPADA, G

机构：

[1] UNIV BOLOGNA,DIPARTMENTO FIS,SETTORE GEOFIS,BOLOGNA,ITALY

[2] IST NAZL GEOFIS,BOLOGNA,ITALY

来源：

GEOPHYSICAL RESEARCH LETTERS | 1995年 / 22卷 / 08期

关键词：

D O I：

10.1029/95GL00819

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

An Earth model subject to dislocations is studied in order to investigate the toroidal/poloidal content of global post-seismic deformation. Differently from previous analyses, our approach allows us to deal with some of the main complexities of the real Earth, such as sphericity, self-gravitation, and theological stratification. The time-dependent ratio between toroidal and poloidal displacements is evaluated in the near and far-field of both strike and dip-slip lithospheric sources characterized by a finite length. Our findings show that post-seismic deformation changes its nature from poloidal to toroidal (and viceversa) on time-scales of several decades and over distances comparable with the dimensions of the lithospheric plates. The effects on horizontal velocities in North America of both poloidal and toroidal components induced by the Alaska 1964 earthquake is comparable with the signatures due to postglacial rebound; these two geodynamical phenomena, are currently detectable by variations along baselines connecting VLBI stations.

引用

页码：985 / 988

页数：4

共 10 条

[1]

James T.S., Lambert A., A comparison of VLBI data with the ICE‐3G glacial rebound model, Geophys. Res. Lett, 20, pp. 871-874, (1993)

[2]

Kanamori H., The Alaska earthquake of 1964: radiation of long‐period surface waves and source mechanism, Journal of Geophysical Research, 75, pp. 5029-5040, (1970)

[3]

Ma C., Sauber J.M., Bell L.J., Clark T.A., Gordon D., Himwich W.E., Ryan J.W., Measurement of horizontal motions in Alaska using Very Long Baseline Interferometry, Journal of Geophysical Research, 95, pp. 21991-22011, (1990)

[4]

O'Connell, Hager B.H., Glacial isostasy, Sea‐Level and Mantle Rheology, (1991)

[5]

Piersanti A., Spada G., Sabadini R., Bonafede M., Global post‐seismic deformation, Geophysical Journal International, 120, (1995)

[6]

Pollitz F.F., Postseismic relaxation theory on the spherical earth, Bull. Seism. Soc. Am., 82, pp. 422-453, (1992)

[7]

Romanowicz B., Spatiotemporal patterns in the energy release of great earthquakes, Science, 260, pp. 1923-1926, (1993)

[8]

Sabadini R., Yuen D.A., Boschi E., The effects of postseismic motions on the moment of inertia of a stratified viscoelastic Earth with an asthenosphere, Geophysical Journal International, 79, pp. 727-746, (1984)

[9]

Sun W., Okubo S., Surface potential and gravity changes due to internal dislocations in a spherical earth‐I. Theory for a point dislocation, Geophysical Journal International, 114, pp. 569-592, (1993)

[10]

Tanimoto T., The 3‐D shear wave structure in the mantle by overtone waveform inversion. II. Inversion of X‐waves, R‐waves and G‐waves, Geophys. J. Int., 93, pp. 321-334, (1988)

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