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Centroid-moment tensor solutions for April–June, 1999
Physics of the Earth and Planetary Interiors 119 Ž2000. 161–171 www.elsevier.comrlocaterpepi
Letter
Centroid-moment tensor solutions for April–June, 1999 A.M. Dziewonski ) , G. Ekstrom, ¨ N.N. Maternovskaya Department of Earth and Planetary Sciences, HarÕard UniÕersity, Cambridge, MA 02138, USA
Abstract Centroid-moment tensor solutions are presented for 218 earthquakes that occurred during the second quarter of 1999. The solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model SH8rU4L8 of wDziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. ŽEds.., Acoustical Imaging, Plenum, 19, 785–797x. A model of anelastic attenuation of wDurek, J.J., Ekstrom, ¨ G., 1996. A radial model of anelasticity consistent with long-period surface wave attenuation, Bull. Seismol. Soc. Am., 86, 144–158.x is used to predict the decay of the waveforms. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Seismic; Earthquake; Centroid-moment tensor solutions
This is the second quarterly report on the global seismicity of 1999 as investigated using the centroid-moment tensor technique. A complete list of references for 15,651 solutions for the years from 1977 to 1998 can be found in Dziewonski et al. Ž1999.. The data for the first quarter of 1999 are published in Dziewonski et al. Ž2000.. The CMT method is described in detail by Dziewonski et al. Ž1981., with the later enhancements Žincorporation of mantle wave data. given by Dziewonski and Woodhouse Ž1983. and Woodhouse and Dziewonski Ž1984.. The 1983 paper is the first example of the application of the CMT method to
) Corresponding author. Tel.: q1-617-495-2510; fax: q1-617495-0635; e-mail: [email protected]
study systematically global seismicity; it contains solutions for 201 events that occurred during 1981. The CMT method has been further refined by Woodhouse and Dziewonski Ž1984. by the introduction of corrections for the aspherical structure of the upper mantle. A brief description of this development is presented in the report for the first quarter of 1984 ŽDziewonski et al., 1984. and, beginning with the third quarter of 1991 ŽDziewonski et al., 1992., a whole mantle shear velocity model of Dziewonski and Woodward Ž1992.. The present format of publication of CMT results is fully described by Dziewonski et al. Ž1987.. The contents and format of Tables 1 and 2 and Fig. 1, which contain data for April, May and June of 1999, have been explained by Dziewonski et al. Ž1987. and we refer the reader to that paper.
0031-9201r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 3 1 - 9 2 0 1 Ž 9 9 . 0 0 1 4 1 - 7
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Table 1
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Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
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Table 1 Žcontinued.
164
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
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A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
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A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1. Equal area projection of the geometrical representation of the moment tensor solution of the earthquakes listed in Table 1. Solid lines are the projections of the nodal surfaces for the full moment tensor solution; broken lines correspond to the nodal planes of the "best double couple". The compression and tension axes are indicated by a plus and by a cross, respectively.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1 Žcontinued..
169
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A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1 Žcontinued..
Acknowledgements The analysis described here was performed using data from stations of the Global Seismograph Network operated by the Albuquerque Seismological Laboratory of the US Geological Survey, and the IDA group at the University of California, San Diego, in cooperation with the Incorporated Research Institutions for Seismology and in particular its Data
Management Center in Seattle. This research has been supported by the grant EAR98-05172 from the National Science Foundation.
References Dziewonski, A.M., Ekstrom, ¨ G., Franzen, J.E., Woodhouse, J.H., 1987. Global seismicity of 1977; Centroid-moment tensor
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171 solutions for 471 earthquakes. Phys. Earth Planet. Inter. 45, 11–36. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 1999. Centroid-moment tensor solutions for October–December 1998. Phys. Earth Planet. Int. 115, 1–16. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 2000. Centroid-moment tensor solutions for January–March 1999. Phys. Earth Planet. Int. 118, 1–11. Dziewonski, A.M., Ekstrom, ¨ G., Salganik, M.P., 1992. Centroidmoment tensor solutions for July–September 1991. Phys. Earth Planet. Int. 72, 1–11. Dziewonski, A.M., Franzen, J.E., Woodhouse, J.H., 1984. Centroid-moment tensor solutions for January–March 1984. Phys. Earth Planet. Int. 34, 209–219.
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Dziewonski, A.M., Woodhouse, J.H., 1983. An experiment in the systematic study of global seismicity: Centroid-moment tensor solutions for 201 moderate and large earthquakes of 1981. J. Geophys. Res. 88, 3247–3271. Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. ŽEds.., Acoustical Imaging, Plenum, 19, pp. 785–797. Woodhouse, J.H., Dziewonski, A.M., 1984. Mapping the upper mantle: three dimensional modelling of Earth structure by inversion of seismic waveforms. J. Geophys. Res. 89, 5953– 5986.
Letter
Centroid-moment tensor solutions for April–June, 1999 A.M. Dziewonski ) , G. Ekstrom, ¨ N.N. Maternovskaya Department of Earth and Planetary Sciences, HarÕard UniÕersity, Cambridge, MA 02138, USA
Abstract Centroid-moment tensor solutions are presented for 218 earthquakes that occurred during the second quarter of 1999. The solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model SH8rU4L8 of wDziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. ŽEds.., Acoustical Imaging, Plenum, 19, 785–797x. A model of anelastic attenuation of wDurek, J.J., Ekstrom, ¨ G., 1996. A radial model of anelasticity consistent with long-period surface wave attenuation, Bull. Seismol. Soc. Am., 86, 144–158.x is used to predict the decay of the waveforms. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Seismic; Earthquake; Centroid-moment tensor solutions
This is the second quarterly report on the global seismicity of 1999 as investigated using the centroid-moment tensor technique. A complete list of references for 15,651 solutions for the years from 1977 to 1998 can be found in Dziewonski et al. Ž1999.. The data for the first quarter of 1999 are published in Dziewonski et al. Ž2000.. The CMT method is described in detail by Dziewonski et al. Ž1981., with the later enhancements Žincorporation of mantle wave data. given by Dziewonski and Woodhouse Ž1983. and Woodhouse and Dziewonski Ž1984.. The 1983 paper is the first example of the application of the CMT method to
) Corresponding author. Tel.: q1-617-495-2510; fax: q1-617495-0635; e-mail: [email protected]
study systematically global seismicity; it contains solutions for 201 events that occurred during 1981. The CMT method has been further refined by Woodhouse and Dziewonski Ž1984. by the introduction of corrections for the aspherical structure of the upper mantle. A brief description of this development is presented in the report for the first quarter of 1984 ŽDziewonski et al., 1984. and, beginning with the third quarter of 1991 ŽDziewonski et al., 1992., a whole mantle shear velocity model of Dziewonski and Woodward Ž1992.. The present format of publication of CMT results is fully described by Dziewonski et al. Ž1987.. The contents and format of Tables 1 and 2 and Fig. 1, which contain data for April, May and June of 1999, have been explained by Dziewonski et al. Ž1987. and we refer the reader to that paper.
0031-9201r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 3 1 - 9 2 0 1 Ž 9 9 . 0 0 1 4 1 - 7
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Table 1
162
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
163
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Table 1 Žcontinued.
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Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
165
166
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
167
168
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1. Equal area projection of the geometrical representation of the moment tensor solution of the earthquakes listed in Table 1. Solid lines are the projections of the nodal surfaces for the full moment tensor solution; broken lines correspond to the nodal planes of the "best double couple". The compression and tension axes are indicated by a plus and by a cross, respectively.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1 Žcontinued..
169
170
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171
Fig. 1 Žcontinued..
Acknowledgements The analysis described here was performed using data from stations of the Global Seismograph Network operated by the Albuquerque Seismological Laboratory of the US Geological Survey, and the IDA group at the University of California, San Diego, in cooperation with the Incorporated Research Institutions for Seismology and in particular its Data
Management Center in Seattle. This research has been supported by the grant EAR98-05172 from the National Science Foundation.
References Dziewonski, A.M., Ekstrom, ¨ G., Franzen, J.E., Woodhouse, J.H., 1987. Global seismicity of 1977; Centroid-moment tensor
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 119 (2000) 161–171 solutions for 471 earthquakes. Phys. Earth Planet. Inter. 45, 11–36. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 1999. Centroid-moment tensor solutions for October–December 1998. Phys. Earth Planet. Int. 115, 1–16. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 2000. Centroid-moment tensor solutions for January–March 1999. Phys. Earth Planet. Int. 118, 1–11. Dziewonski, A.M., Ekstrom, ¨ G., Salganik, M.P., 1992. Centroidmoment tensor solutions for July–September 1991. Phys. Earth Planet. Int. 72, 1–11. Dziewonski, A.M., Franzen, J.E., Woodhouse, J.H., 1984. Centroid-moment tensor solutions for January–March 1984. Phys. Earth Planet. Int. 34, 209–219.
171
Dziewonski, A.M., Woodhouse, J.H., 1983. An experiment in the systematic study of global seismicity: Centroid-moment tensor solutions for 201 moderate and large earthquakes of 1981. J. Geophys. Res. 88, 3247–3271. Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. ŽEds.., Acoustical Imaging, Plenum, 19, pp. 785–797. Woodhouse, J.H., Dziewonski, A.M., 1984. Mapping the upper mantle: three dimensional modelling of Earth structure by inversion of seismic waveforms. J. Geophys. Res. 89, 5953– 5986.