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Centroid-moment tensor solutions for January–March 1999
Physics of the Earth and Planetary Interiors 118 Ž2000. 1–11 www.elsevier.comrlocaterpepi
Centroid-moment tensor solutions for January–March 1999 A.M. Dziewonski ) , G. Ekstrom, ¨ N.N. Maternovskaya Department of Earth and Planetary Sciences, HarÕard UniÕersity, Cambridge, MA 02138 USA Received 1 July 1999; accepted 1 July 1999
Abstract Centroid-moment tensor solutions are presented for 240 earthquakes that occurred during the first quarter of 1999. The solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model SH8rU4L8 of Dziewonski and Woodward wDziewonski, 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, 3247–3271x. A model of anelastic attenuation of Durek and Ekstrom ¨ wDurek, J.J., Ekstrom, ¨ G., 1996. A radial model of anelasticity consistent with long-period surface wave attenuation. Bull. Seism. 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: Earthquakes; Waveform; Centroid-moment tensor solutions
This is the first 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 CMT method is described in detail by Dziewonski et al. Ž1984., 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 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 January, February and March of 1999, have been explained by Dziewonski et al. Ž1987. and we refer the reader to that paper.
) Corresponding author. Tel.: q1-617-495-2351; fax: q1-617495-8839; E-mail: [email protected]
The analysis described here was performed using data from stations of the Global Seismograph Net-
Acknowledgements
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 2 1 - 1
2
Table 1 Centroid coordinates and parameters derived from moment tensor solutions for 240 earthquakes of the first quarter of 1999. For explanation of the headings, see Dziewonski et al. Ž1987.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
3
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 1 Žcontinued.
4
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
5
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 2 Elements of the moment tensor obtained in CMT inversion
6
Table 2 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
7
8
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
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 118 (2000) 1–11
Fig. 1 Žcontinued..
9
10
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Fig. 1 Žcontinued..
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
work operated by the Albuquerque Seismological Laboratory of the U.S. 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., 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.
11
Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: H. Emert, H.-P. Harjes ŽEds.., Acoustical Imaging. Plenum, 19, pp. 785–797. Dziewonski, A.M., Franzen, J.E., Woodhouse, J.H., 1984. Centroid-moment tensor solutions for January–March 1984. Phys. Earth Planet. Inter. 34, 209–219. Dziewonski, A.M., Ekstrom, ¨ G., Franzen, J.E., Woodhouse, J.H., 1987. Global seismicity of 1977: centroid-moment tensor solutions for 471 earthquakes. Phys. Earth Planet. Inter. 45, 11–36. Dziewonski, A.M., Ekstrom, ¨ G., Salganik, M.P., 1992. Centroidmoment tensor solutions for July–September 1991. Phys. Earth Planet. Inter. 72, 1–11. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 1999. Centroid-moment tensor solutions for October–December 1998. Phys. Earth Planet. Inter. 115, 1–16. 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.
Centroid-moment tensor solutions for January–March 1999 A.M. Dziewonski ) , G. Ekstrom, ¨ N.N. Maternovskaya Department of Earth and Planetary Sciences, HarÕard UniÕersity, Cambridge, MA 02138 USA Received 1 July 1999; accepted 1 July 1999
Abstract Centroid-moment tensor solutions are presented for 240 earthquakes that occurred during the first quarter of 1999. The solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model SH8rU4L8 of Dziewonski and Woodward wDziewonski, 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, 3247–3271x. A model of anelastic attenuation of Durek and Ekstrom ¨ wDurek, J.J., Ekstrom, ¨ G., 1996. A radial model of anelasticity consistent with long-period surface wave attenuation. Bull. Seism. 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: Earthquakes; Waveform; Centroid-moment tensor solutions
This is the first 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 CMT method is described in detail by Dziewonski et al. Ž1984., 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 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 January, February and March of 1999, have been explained by Dziewonski et al. Ž1987. and we refer the reader to that paper.
) Corresponding author. Tel.: q1-617-495-2351; fax: q1-617495-8839; E-mail: [email protected]
The analysis described here was performed using data from stations of the Global Seismograph Net-
Acknowledgements
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 2 1 - 1
2
Table 1 Centroid coordinates and parameters derived from moment tensor solutions for 240 earthquakes of the first quarter of 1999. For explanation of the headings, see Dziewonski et al. Ž1987.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
3
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 1 Žcontinued.
4
Table 1 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
5
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Table 2 Elements of the moment tensor obtained in CMT inversion
6
Table 2 Žcontinued.
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
7
8
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
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 118 (2000) 1–11
Fig. 1 Žcontinued..
9
10
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
Fig. 1 Žcontinued..
A.M. Dziewonski et al.r Physics of the Earth and Planetary Interiors 118 (2000) 1–11
work operated by the Albuquerque Seismological Laboratory of the U.S. 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., 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.
11
Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: H. Emert, H.-P. Harjes ŽEds.., Acoustical Imaging. Plenum, 19, pp. 785–797. Dziewonski, A.M., Franzen, J.E., Woodhouse, J.H., 1984. Centroid-moment tensor solutions for January–March 1984. Phys. Earth Planet. Inter. 34, 209–219. Dziewonski, A.M., Ekstrom, ¨ G., Franzen, J.E., Woodhouse, J.H., 1987. Global seismicity of 1977: centroid-moment tensor solutions for 471 earthquakes. Phys. Earth Planet. Inter. 45, 11–36. Dziewonski, A.M., Ekstrom, ¨ G., Salganik, M.P., 1992. Centroidmoment tensor solutions for July–September 1991. Phys. Earth Planet. Inter. 72, 1–11. Dziewonski, A.M., Ekstrom, ¨ G., Maternovskaya, N.N., 1999. Centroid-moment tensor solutions for October–December 1998. Phys. Earth Planet. Inter. 115, 1–16. 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.