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Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1994
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PHYSICS OFTHE EARTH A N D PLANETARY INTERIORS
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ELSEVIER
Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Letter section
Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1994 Stuart A. Sipkin *, Madeleine D. Zirbes US Geological Survey, MS 967, Box 25046, DFC, Denver, CO 80225, USA Received 25 August 1995; accepted 16 October 1995
Abstract
Moment-tensor solutions, estimated using optimal filter theory, are listed for 177 moderate-to-large size earthquakes occurring during 1994.
1. Introduction
This paper is the fifth in a series published yearly containing moment-tensor solutions computed at the US Geological Survey using an algorithm based on the theory of optimal filter design (Sipkin, 1982, 1986b). An inversion has been attempted for all earthquakes With an mb of 5.8 or greater (5.7 for intermediate- and deep-focus events), as well as several smaller events of particular interest. Previous listings include solutions for earthquakes that occurred from 1981 through 1983 (Sipkin, 1986b), from 1984 through 1987 (Sipkin and Needham, 1989), from 1988 through 1989 (Sipkin and Needham, 1991), in 1990 (Sipkin and Needham, 1992), in 1991 (Sipkin and Needham, 1993), in 1992 (Sipkin and Needham, 1994a),
* Corresponding author. Elsevier Science B.V.
SSDI 0 0 3 1 - 9 2 0 1 ( 9 5 ) 0 3 1 1 6 - 2
and earthquakes that occurred in 1993 (Sipkin and Needham, 1994b).
2. Moment-tensor solutions
The hypocentral parameters, as determined by the National Earthquake Information Service (NEIS), are listed in Table 1. The epicenters listed were fixed in the inversions and the depths were used as starting depths. The moment-tensor solutions are also listed in Table 1, and their equal-area projections are shown in Fig. 1. The moment-tensor depths are those that minimize the misfit between the synthetic seismograms and the long-period P-wave data. The waveforms inverted contain both the direct P wave and the surface reflected phases, so the depth is well constrained, usually to within + 5 km (Sipkin, 1986a).
140
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
T h e s o u r c e g e o m e t r y is listed as the p r i n c i p a l axes o f the m o m e n t tensor, along with t h e i r assoc i a t e d eigenvalues. This is fully e q u i v a l e n t to listing the e l e m e n t s of t h e m o m e n t tensors. T h e
2
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individual e l e m e n t s of the m o m e n t t e n s o r s a r e given in t h e Preliminary Determination of Epicenters Monthly Listings. T h e m o m e n t ( M 0) a n d strike (~bs), dip (6), a n d r a k e (A) of t h e n o d a l p l a n e s of
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0@@@@@@@ Fig. 1. Equal-area projections of the moment-tensor solutions listed in Table 1. Continuous lines are the projections of the nodal surfaces of the moment tensors; dashed lines are the projections of the nodal planes of the best double-couples. The principal axes are indicated by P and T.
S.A. Sipkin, M.D. Zirbes/ Physics of the Earth and Planetary Interiors 93 (1996) 139-146 N
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Fig. 1 (continued).
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S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
the best double-couple are given following the conventions of Aki and Richards (1980). The deviatoric moment tensor can be decomposed into a double-couple and a remainder term in an infinite number of ways. We prefer the decomposition suggested by Knopoff and Randall (1970) in which the moment tensor is decomposed into a 'best' double-couple and a compensated linear-vector dipole (CLVD). This decomposition is preferred to decomposing the moment tensor into a major and minor double-couple because it is unique, whereas there are an infinite number of major and minor double-couple combinations. In addition, the 'best' double-couple and CLVD share the same principal axes; the major and minor double-couples will, in general,
have equivalent force systems with differing directions. Using the preferred decomposition, the moment of the 'best' double-couple, M 0, is 1 (e I - e 3) where e 1 is the largest positive eigenvalue, corresponding to the T-axis, and e 3 is the largest negative eigenvalue, corresponding to the P-axis. The contribution of the CLVD component to the normalized total moment, MCLVD, is 2 I emin I//1 emax I, where emin is the eigenvalue with the smallest absolute value and emax is the eigenvalue with the largest absolute value. The per cent double-couple is then 100 × (1 - It4CLVD). The normalized mean square error (NMSE) is the residual sum of squares divided by the number of degrees-of-freedom. This number gives a relative measure of the goodness of fit.
Table I Hypocentral parameters and moment-tensor solutions PDE Time and Hypocenter
Principal Axes I axis
T axis
No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 33 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Date (Yr Mo Dy) 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 04 04 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4
3 3 3 4 5 7 9 10 11 17 17 19 20 21 21 3 5 11 12 12 15 15 15 16 16 16 18 23 24 26 1 9 14 14 15 30 31 4 5 6
Time IUTCI 1:20:11,4 5:92:27,6 13:24:13.9 19:31:59.9 13:24:9.9 3:42:42.9 21:29:1.9 15:53:50.1 0%1:56.4 12:30:55.4 23:33:30.7 1:53:34.9 9:6:52.8 2:24:30.0 18:0:17.7 9: 5 : 4 . 2 23:34:10.0 21:17:31.1 4:16:26.9 17:58:24.0 15:8:17.8 17:7:43.8 21:11.:56.4 6:46:57.0 6:48:58.0 22: 3 : 8 . 9 13:41:27.8 8: 2 : 4 . 7 0:11:12.3 2:31:11.1 3:49:0.8 23:28:6.8 4:30:15.8 20:51;25.0 3:36:19.9 13:29:11.3 22:40:52.2 1:37:2.8 9:35:44.9 12:13:45.0
Lat (o) 40.72 30.03 -40.28 -4.30 39.08 52.03 48.48 -13.34 25.23 34.21 34.33 -3.18 -6.00 1.01 -4.86 42.76 0.59 -18.77 -10.79 -20.55 -20.58 -4.97 -20.40 -20.09 -18.99 -20.23 -20.49 30.85 30.77 30.90 29.10 -18.04 -1.28 15.99 11.11 9.00 -22.06 -15.47 51.30 -17.37
Lon (o) -126.77 I00.I0 164.22 135.15 15.15 159.02 154.49 -60.45 97.20 -118.54 -118.70 135.07 -77.05 127.73 103.66 -110.98 30.04 109.17 -128.80 169.36 189.39 104.30 168.87 168.91 168.13 168.93 169.07 60.60 60.49 60.55 52.62 -178.41 -23.57 -92.43 -88.08 126.25 -179.53 -173.01 -178.15 167.82
P axis
Depth Depth Scale Val PI As Val PI As Val PI As Mo (kin) (kin) (1O") (Si n ) (o) (o) (Nm) (o) (o) (e,l'm)f')(°) (~m) 19 8 15 11 272 54 85 596 9 18 9 23 122 19 89 7 14 205 15 27 30 23 19 12 13 10 12 0 9 9 12 562 10 164 14 40 579 24 10 17
19 8 11 15 272 34 56 607 14 21 9 29 126 22 101 19 14 219 11 41 38 21 22 19 18 29 19 22 20 22 19 571 18 109 3 44 587 6 35 22
17 17 18 18 17 17 17 19 17 19 17 19 17 19 17 17 18 19 19 19 18 19 18 18 18 18 18 18 18 17 18 20 19 19 18 17 18 17 18 18
3.70 3.50 1.05 1.01 6.09 4.04 1.08 2.65 9.42 1.15 6.77 1.38 5.25 3.34 8.78 2.74 1.95 2.70 0.99 3.57 1.33 1.01 3.90 1.35 3.81 1.37 1.33 1.16 1.84 9.97 1.12 2.33 3.72 2.30 4.86 8.22 7.67 3,85 2.41 1.76
II 50 45 6 17 76 54 32 4 76 73 65 9 15 70 6 15 53 18 75 71 1 02 40 39 62 43 72 68 71 1 18 4 40 4 60 35 30 52 66
129 315 8 138 117 347 103 223 179 125 335 234 264 33 65 296 35 32 161 112 125 263 14 30 32 84 28 210 168 188 95 122 36 94 197 334 91 348 298 102
1.25 52 1.20 32 -0.20 44 -0.10 84 -1.36 27 0.00 7 -0.10 27 -0.03 28 -0.57 18 0.04 13 -0.10 12 0.03 24 0.34 11 -0.19 69 -0.36 17 0.23 17 0.01 20 0,27 35 0.00 12 0.06 13 0.03 19 0.03 83 -0.01 28 -0.22 49 -0.01 49 0.01 1 -0.30 42 0.11 1 0.03 20 -1.78 12 -0.17 83 0.01 17 -0.02 84 O.O0 41 -0.35 22 0.16 25 -0.90 18 0.07 20 -0.02 31 0.16 0
20 113 175 313 216 225 236 114 88 284 108 74 172 166 213 204 131 188 67 327 323 170 180 192 190 352 176 302 323 317 322 26 268 316 105 192 193 246 78 350
-5.00 -4.78 -1.66 -0.91 i -4.73 -4.04 -0.99 -2.61 -8.35 -1.19 -6.67 -1.42 -5.60 -3.15 -0.42 -2.97 -1.96 -2.96 -1.00 -3.63 -1.38 -1.04 -3.89 -1.13 -3.81 -1.38 -1.03 -1.27 -1.87 -0.20 -0.95 -2.34 -3.70 -2.36 -4.32 -8.37 -6.78 -3.92 -2.40 -1.92
36 10 6 0 57 12 23 43 72 5 12 7 76 15 10 72 64 12 69 9 5 7 6 9 11 28 17 18 9 14 1 64 5 23 68 16 51 53 20 22
228 210 271 46 338 134 338 332 282 15 200 340 30 299 306 44 270 286 305 235 231 355 273 292 293 262 281 32 56 50 183 256 126 205 296 94 303 127 180 256
4.4 4.2 1.8 0.9 5.4 4.0 1.0 2.6 9.1 1.2 6.7 1.4 5.4 3.2 8.6 2.9 2.0 2.8 1.0 3.6 1.3 1.0 3.9 1.2 3.8 1.4 1.2 1.2 1.9 9.1 1.0 2.3 3.7 2.4 4.5 8.3 7.2 3.9 2.4 1.8
Best Doub|e-Couple Plane I Plane 2 4), 6 A 4', 6 ~
(°)(°) 262 333 39 181 172 214 108 7 287 119 306 45 7 76 56 45 99 52 269 310 303 40 30 63 65 349 54 123 168 156 230 237 171 247 309 153 131 122 310 320
(°1 (°)(°)
57 -29 45 139 54 148 86 178 36 -140 34 77 33 147 29 -15 44 -64 42 110 34 111 43 53 38 -71 69-180 38 119 42 -63 34-127 45 143 20 -65 38 69 43 83 35 - 4 46 130 56 136 55 158 17 87 46 157 27 91 40 121 33 113 89 0 31 -55 84 -1 43 15 46 -$0 38 45 18 -153 24 -32 37 148 25 67
3 94 148 271 48 50 227 110 73 274 100 271 164 346 202 191 322 170 61 156 157 130 160 167 168 173 160 301 309 310 320 18 261 148 87 24 15 242 67 174
DC
StaiNMSE
(°) (%) (#)
73-145 60 63 5 3 50 68 40 78 86 4:80 68 -00 55 57 99 100 73 62 81 83-118 98 52-113 88 51 73 93 58 76 97 57 119 96 55-104 88 90 -21 89 57 69 92 53-112 85 63 -68 99 66 51 82 6 4 - 1 0 3 100 55 106 97 33 113 96 86-175 94 57 56 90 70 37 67 72 37 99 73 91 99 73 40 55 63 89 83 56 66 97 60 76 64 90 -179 70 65-109 99 69-174 99 80 132 100 52-118 85 68 117 96 82 -74 77 78-110 96 71 57 98 67 100 63
15 5 12 9 23 23 4 20 8 17 16 9 10 6 10 5 13 14 34 15 10 12 18 22 21 24 4 18 13 14 9 31 21 29 33 16 25 8 39 27
0.314 0.416 0.536 0.766 0.553 0.532 0.622 0.431 0.349 0.260 0.357 0.304 0.407 0.954 0.692 0.322 0.232 0.185 0.109 0.070 0.121 0.939 0.502 0.506 0.390 0.481 0.393 0.882 0.425 0.586 0.544 0.314 0.265 0.324 0.492 0.313 0.260 0.808 0.471 0.472
S.4. Sipkin, M.D. Zirbes/ Physics of the Earth and Planetary Interiors 93 (1996) 139-146
143
Table 1 (continued) PDE Time and Hypocenter
No 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79
80
Date
Time
Lat
Lon
Depth
Depth
(YrMoDy)
(UTC)
(o)
(o)
(km)
(kin) (I0")
94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94
4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
8 1:10:40.8 10 23:45:55.8 13 4:0:47,3 13 22:22:29.9 14 3:28:26.6 18 17:29:54.1 21 3:51:44.6 23 15:0:52.8 27 9:23:26.3 27 14:11:45.2 29 7:11:29.7 1 12:0:35.8 2 17:14:0.9 3 16:36:43,7 4 0:37:36,1 6 22:39:26.6 9 12:36:37.3 10 1:49:3.5 10 6:38:28,4 11 8:18:15.7 11 21:14:33.8 18 3:54:0.6 23 1:41:42,3 23 5:36:1,6 23 15:16:57.2 24 4:0:42.2 24 21:13:19.3 25 4:3:41.3 5 26 8:26:52.4 5 29 14:11:51.0
40.61 143.68 23.71 126.85 22.77 123.63 -3.14 135.97 -6.59 129.77 -6.47 154.93 -5.70 154.12 -14.18 167.54 -21.51 -173.67 13.07 119.54 -28.30 -63.25 30.90 67.16 -1.12 97.49 10.24 -60.76 -17.05 168.28 -4.68 153.10 -2,06 99.73 -19.61 -69.79 -28.50 -63,10 -2.01 99.77 -2.06 98.67 44.73 149.40 18,17 -100,53 24,17 122.54 24.07 122,56 23.96 122.45 56.17 101.17 -4.20 135.49 35.31 -4.10 20,56 94.16
5 31
17:41:55.6
6 6 6 6 6 6 6 6
2 3 3 4 5 6 6 9
18:17:34.0 11:25:6.7 21:6:59.9 0:57:50.7 1:0:30.1 9: 3:0.5 20:47:40,5 0:33:16.2
-10.48 3.52 -10.36 -10.78 24.51 28.60 2.92 -13.84
7.41 -72.03
94 6 13
21:15:2.7
5.47
112.83 -78.78 112.89 113.37 121.90 129.10 -76,06 -67,55
151.84
13 10 9 28 166 26 28 10 28 I 9 561 18 15 36 206 48 27 52 600 20 28 26 55 19 25 16 95 33 9 35
16 7 21 20 189 37 56 2 38 21 568 22 9 39 203 46 38 48 602 23 23 32 08 22 22 5 89 15 19 69
Ii
12
18 9 25 11 11 60 12 631
6 19 29 18 12 66 20 631
17
25
Scale
T ~xis Val PI As
Principal Axes I axis P axis Val P] As Val P1 As
(Nrn) (o) (o) (Nm)(0)(o) 46 320 0.34 28 197 5 345 0.08 11 254 5 152 -0.06 26 60 19 261 0.06 43 153 35 273 -0.15 9 9 80 159 0.00 8 308 85 210 -0.06 3 330 76 266 -0.07 12 138 74 120 1.43 4 15 57 211 0.91 33 35 23 264 O.O0 7 171 66 115 0.04 22 270 8 255 -0.12 1 345 18 334 -0.26 25 72 64 281 0.04 24 76 11 314 -0.09 10 48 44 348 -0.02 43 142 70 64 0.22 1 156 40 274 0.90 8 177 50 27 ; -0.11 2 120 54 34 0.05 7 295 53 338 -6.01 23 213 7 41 -6.37 15 133 52 332 -0,02 6 69 53 321 0.94 11 67 39 348 0.17 6 253 22 306 -0.04 2 215 5 315 0.68 74 64 3 47 0.11 78 152 35 75 -0.72 31 320 80 353 -0.06 10 165 43 356 -0.93 11 96 14 322 -0.19 5 53 3 185 0.03 16 94
(Nm)(o)(r) -4.74 -1.31 -3.87 -3.11 -2.85 -1,41 -1.11 -2.22 -3.93 -8.52 -2.53 -1.67 -1.46 -2.26 -2.34 -7.09 -2.79 -8.81 -3.32 -5.00 -1.63 -1,72 -3.45 -1,96 -8.70 -7.90 -5.01 -7.70 -9.80 -3.88 -9.04 -4.75 -5.47 -3.46
Mo
(Nm)
18 18 17 18 17 19 19 18 18 17 19 18 18 18 18 17 17 17 19 18 18 18 18 18 17 18 17 18 17 18 17 20 17 18
4.40 1.24 3.93 3.05 3.00 1.41 1.17 2.28 2,51 7.61 2,53 1.62 1.58 2.52 2.30 7.18 2.81 8.59 2.42 5.71 1.59 1.72 3.82 1,98 7.76 7.73 5,05 7.02 9.70 4.60 9,11 5.68 5.66 3.43
31 89 78 98 64 251 41 8 54 111 5 39 5 60 7 46 15 284 2 303 66 64 9 4 82 79 58 211 9 171 75 178 13 244 20 246 48 77 40 211 35 200 27 110 74 286 38 163 34 165 51 156 68 119 15 223 11 317 40 200 1 255 45 198 75 161 74 286
4.6 1.3 3.9 3.1 2.9 1.4 1,1 2.2 3.2 8.1 2.5 1.6 1.5 2.4 2.3 7.1 2.8 8.7 2.9 5.7 1.6 1.7 3.6 2.0 8.2 7.8 5,0 7.4 9.7 4.2 9.1 5.2 5.6 3.4
18
2.14 4 14 -0.01 24 I05 -2.14 65 274
2.1
18 17 19 21 18
3.07 23 132 -0.05 65 333 -3.92 2.94 1 22 0.08 35 291 -3.02 1.34 6 346 0.00 78 227 I -1.34 2.13 38 108 -0.17 14 96 I -1.96 1,32 66 309 -0.02 17 84 J -1,29
3.9 3.0 1.3 2.0 1.3
8 55 10 48 16
226 114 79 349 179
Be~t' Double-Couple Plane 1 Plane 2 ~b, 6 ~ ~b, 6 ,~
(o)(0) 127 86 268 36 328 138 153 123 7 5 8 118 345 30 286 31 15 338 60 320 261 158 114 287 296 116 40 0 93 224 356 11 45 291
Co) (o)Co)
29 17 41 -73 46 -53 46 -20 13 -131 41 103 40 94 39 71 30 81 52 47 23 -71 41 125 37 -91 35-138 41 127 35 -108 40 154 25 92 9 -27 6 110 12 55 28 32 40-113 9 128 15 140 8 -47 23 -84 76-173 80-174 31 -6 44 105 11 -175 31 -99 44 -67
80 46-125 271 142 123 345 292
22 245 40 140 190 301 327 327 197 241 168 255 166 263 61 233 123 156 176 120 116 39 324 68 65 253 214 268 2 319 155 276 236 81
DC
Sta
NMSE
(.) (%) (#)
82 118 88 42 51-104 88 20 55 -122 97 9 76 -134 96 13 80 -61 90 7 51 79 100 21 50 87 90 27 53 105 94 23 60 95 27 25 55 131 79 I 13 68 -98 100 30 58 64 95 20 53 -88 85 17 68 -63 79 26 58 62 97 21 57 -78 97 20 71 44 99 15 65 89 95 23 86 -98 46 28 85 88 96 19 80 97 94 17 76 114 99 19 54 -72 81 11 83 84 98 22 80 78 78 20 84 -96 96 26 67 -92 98 16 83 -14 82 9 84 -10 98 18 87 -121! 69 17 47 76 99 29 89 -79 67 31 59 -85 93 24 50 -111 98 22
0.525 0.322 0.706 0.450 0,738 0.121 0,273 0.584 0.396 0.283 0.161 0.194 0,395 0,300 0.777 0.357 0.649 0.233 0.247 0.425 0.354 0.539 0,459 0.246 0.324 0,380 0.345 0.384 0.872 0.266 0,213 0.640 0.346 0.708
305 54 -60
99
25
0.825
68 11 177 80 157 53 -45 263 55 -134 79 -3 214 87 -169 15 -20 95 85 -104 33 123 74 63 71
97 95 100 84 97
34 20 36 25 23
0.494 0.380 0.605 0.193 0.335
144
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Table 1 (continued) PDE Time and Hypocenter No 81 82 83 84 85 86 87 88 89 90 91 92 03 04 95 00 97 98 99 lOO 101 102 103 104 105 100 107 108 109 110 111 112 113 114 115 116 117 118 119 120
Date (YrMoDy) 94 0 15 94 6 16 94 6 16 94 6 18 94 8 10 94 6 20 04 6 20 94 6 30 94 7 1 94 7 1 94 7 2 94 7 4 94 7 6 04 7 13 94 7 13 94 7 14 94 7 16 94 7 21 04 7 22 94 7 24 94 7 25 94 7 29 94 7 29 94 8 2 94 8 3 94 8 4 94 8 8 94 8 8 94 8 11 94 8 14 94 8 14 94 8 16 94 0 18 94 8 18 94 8 10 94 8 19 94 8 20 94 8 20 04 8 21 04 8 22
Time (UTC) 9:22:57,2 10:12:46.9 18:41:28.3 3:25:15.8 13:43:51.2 9: 9:2.9 18:22:33,6 9:23:21.4 10:12:41.2 19:50:4.4 9:14:43.0 21:36:42.0 9:13:10.2 2:35:56.0 11:45:23,4 O: 0:24.7 18: 5 : 5 . 6 18:36:3i.7 16:57:48.4 17:55:40.4 22:0:23.0 0:17:45.4 7:53:28,5 14:17:52.2 14:50:57.6 22:15:37.8 7:55:39.2 21:8:31.7 20:42:9.0 0:46:20.4 1:31:12.9 10:9:32.8 0:45:47.2 4:42:57.4 10:2:51.8 21:2:45.6 2:21:11.1 4:38:50,6 15:55:50,2 17:26:37.0
Lat Lon Depth Depth (o) (o) (km) (kin) -10.34 113.66 lg 5 -7.39 128,12 108 141 -15.25 -70.29 199 199 -42,98 171.66 13 24 -43.27 171,61 10 14 28,97 52.61 8 7 32.57 93.67 9 8 36.33 71.13 226 242 40.23 53.38 40 43 40.22 53.39 44 44 -5.78 131.10 87 101 14.89 -97.32 14 13 5.08 125.93 151 144 -16.62 167,52 33 34 -7.53 127.77 158 169 -16.58 167.45 10 24 -4.62 125.61 442 452 42.34 132.87 471 489 -7.78 158.42 19 20 -18.97 167.57 20 18 -58.36 -27.36 81 73 52.40 -168,33 11 21 -16.98 167.74 13 28 52.43 158.04 144 152 21.51 93.98 34 41 -6.34 131.57 33 76 -13.82 -68,37 507 002 24.72 95.20 121 123 -21.00 -173.77 31 24 44.71 150.10 16 28 44.00 150.01 19 21 37.84 142.46 19 21 -7.43 31.75 25 29 44,?7 150.16 14 18 -20.64 --63.42 563 503 17.97 96.42 12 14 44.61 140.32 22 26 44.66 149.18 24 34 56,76 117.90 12 11 -11.51 166.45 142 151
T ~tis Scale Val PI As (10") (Nm)(°)(0) 18 2.09 41 20 17 8.55 71 341 18 1.20 24 353 19 1.28 04 144 18 1.08 19 41 17 5.80 20 314 17 5,74 0 289 18 3.34 88 256 17 3.33 65 351 16 7.19 72 349 17 5.09 75 106 18 1.29 16 41 17 7.16 22 210 10 5.42 21 125 18 5,78 67 313 18 0,81 31 70 17 3.91 31 28 19 8.57 34 38 17 6.30 85 261 18 3.27 40 116 18 8.39 32 162 17 5.87 48 6 17 6,84 71 152 17 6.81 53 302 17 5.21 4 76 18 1.54 18 298 17 2.84 36 233 18 1.76 67 117 17 5.48 53 48 17 9.15 60 324 18 2.88 35 357 17 4.81 89 287 17 7.67 17 241 18 4.68 53 309 18 5.38 23 261 17 4.82 19 153 17 2.21 02 208 18 1.73 50 205 17 9.30 I 313 18 1,08 70 315
Principal Axes I axis Val PI Az (Nm) (o) (o) 0.11 7 116 0,71 15 121 0.03 62 208 0.07 16 17 -0.13 65 181 0.01 60 83 0.00 6 19 0.00 2 29 -0.47 3 87 -0.01 1 257 -0.03 15 286 0.00 ? 133 0.28 50 328 -0.62 59 353 -0.87 21 106 0.19 0 160 0.00 1 208 0.82 35 158 -0.29 3 132 0.01 28 380 0.06 54 312 -0.21 28 239 -0.37 18 353 -0.11 10 199 0,04 86 246 0,06 72 107 0.00 O 143 0.16 17 255 2.26 26 179 0,44 3 230 0.55 27 245 -0.17 1 194 0.00 2 151 0.06 4 215 -0.01 15 165 -0.04 66 294 -0.20 4 36 -0.01 13 48 0.01 13 43 -0.02 .9 174
P axis Val P1 Az Mo (Nm) (o) (o) (Nm) -2.20 49 213 2.1 -9.26 12 214 8.9 -1.33 14 90 1.3 -1.34 19 281 1.3 -0.95 15 306 1.0 -5.86 21 216 5.9 -5.74 84 107 5.7 -3.34 2 119 3.3 -2.86 25 1?8 3.1 -7,18 18 167 7.2 -5.07 0 16 5.1 -1,38 72 245 1,3 -7.44 32 105 7.3 -4.80 21 223 5,1 -4.92 10 200 5.3 -1,00 59 251 0.9 -3,91 50 205 3,9 -9.39 37 278 9.0 -6.01 4 42 6.2 -3,28 37 246 3,3 -8.45 15 62 8.4 -5,67 28 133 5.8 -0.47 6 261 6.7 -6.70 35 102 6.8 -5.25 1 346 5.2 -1,60 3 207 1.6 -2.84 54 53 2.8 -1.92 14 350 1,8 -7.?4 24 281 6.6 -9.59 30 138 9.4 -3.44 42 127 3.2 -4.64 21 104 4,7 -7.67 73 56 " 7.7 -4.74 37 122 4.7 -5.37 02 44 5.4 -4.79 14 58 4.8 -1.93 28 128 2.1 -1.72 27 145 1.7 -9.39 76 218 9.4 -1,96 7 63 2,0
Best Double-Couple Plane 1 Plane 2 ~, 6 A ~, ~ ~ (°)(o) (o) (o)(o) (o) 57 8 -149 296 86 -83 322 36 116 111 58 73 133 63 7 40 84 153 346 29 56 204 66 108 83 66 177 174 87 25 355 6 0 - 1 7 9 265 89 -30 13 45 -08 205 46 -82 211 43 92 28 47 88 274 20 98 86 70 87 256 27 89 77 63 91 121 47 111 271 47 69 120 29-104 316 62 -82 251 50-172 155 84 -~.0 264 59 0 174 00 149 3t3 40 124 92 58 65 160 14 -90 340 76 -90 123 14 -84 207 76 -91 69 35 -177 337 89 -55 129 41 85 315 49 94 273 28 3 181 89 118 198 56 106 296 79 35 176 31 23 66 79 119 332 42 62 187 54 113 152 14 42 20 81 100 121 87 178 211 88 3 341 75 109 74 80 15 323 9 -90 143 81 -00 102 34 122 245 61 70 52 31 147 171 74 63 219 15 70 50 75 93 1'46 28 -8 243 86 -117 191 24 87 15 66 91 334 28" -87 150 62 -02 190 9 65 35 82 94 10 26 -53 159 70 -106 194 66 176 286 86 24 230 18 105 34 73 85 265 21 129 44 74 76 29 45 -109 235 48 -72 164 39 76 i 52 101
DC Sis (%)(#) 90 27 85 19 95 26 90 22 76 5 100 16 100 28 100 26 72 29 100 11 99 16 87 33 92 14 77 24 70 16 62 24 100 7 83 42 91 27 99 30 99 10 93 33 89 27 97 30 98 8 93 16 I 100 12 83 23 42 22 91 41 08 8 93 40 100 16 97 20 100 31 98 13 74 11 99 51 100 42 98 35
NMSE 0.392 0.229 0.536 0.671 0.344 0,497 0.274 0.431 0.299 0.027 0.866 0,550 0.388 0.378 0.309 0.291 0,570 0.366 0.377 0,249 0.284 0,425 0.156 0.413 0.578 0.769 0.452 0,282 0,380 0.420 0.306 0.224 0.149 0.620 0.271 0.491 0.249 0.581 0.213 0.427
145
SJt. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Table 1 (continued) Principsl Axes No 121 122 123 124 125 126 127 129 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 :148 149 150 151 152 153 154 155 156 157 150 159 160
Date (Yr M o Sy) 94 8 26 94 8 30 94 8 30 94 8 31 94 9 I 94 9 3 94 9 3 94 9 5 94 9 12 94 0 12 94 0 12 94 9 13 94 9 13 94 9 18 94 9 23 94 0 28 04 10 1 04 10 4 94 10 5 94 10 5 94 10 7 94 10 8 94 10 8 94 10 9 94 10 11 04 10 12 94 10 13 94 10 15 04 10 10 94 10 16 94 10 18 94 10 20 04 10 25 94 10 27 94 10 27 94 10 31 94 11 4 94 11 5 94 11 0 94 11 11
Time
(UTC) 16:37:20.7 6:13:36.8 10:42:46.5 9:7:25.9 15:15:53.1 9:2:53,7 17:40:41.6 22:13:47.9 0:29:54.9 12:23:43.2 22:43:50,8 4:28:1.0 10:1:32.1 6:20:18.7 7:59:38.9 16:30:51.7 10:35:20.8 13:22:55.8 20:37:29.3 20:39:40.4 2:30:9.3 9:54:34,3 21:44:7.2 7:55:39.1J 1:37:20.4 0:43:39.7 5:4:25,0 0:39:25.5 0:0:49.1 5:10:0.9 17:12:50.9 1:15:10.2 0:54:34,3 17:45:58.0 22:20:28.5 11:48:13.9 1:13:20.1 2:16:3.3 18:21:2,7 8:48:30.0
I~t
Ion
Depth Depth
Scale
(*) (*) (kin) (kin) (10") 44.78 160.08 18 13 18 50 25 17 44.74 150.12 505 612 18 -6.07 124.11 70 85 18 43.72 140,01 lO 15 19 40.40 -125.68 6 13 17 -31.42 -111.03 33 33 18 -21.21 173.04 12 20 17 46.78 135.23 40 46 18 -31.10 -71.71 14 6 18 38.02 -119.85 -15.45 -172.09 15 11 17 34 43 18 29.29 129.91 13 30 18 7.05 -76.08 13 8 19 22.53 118.71 33 19 18 -3.38 148.54 037 642 19 -5.70 110.35 16 17 18 -17.75 167.08 14 61 21 43.77 147.32 13 8 17 43.59 147.45 43.95 147.34 40 20 17 43.61 147.29 52 47 17 9 23 17 43,87 148.17 -1.26 127.98 18 20 19 33 43 19 43.90 147.02 -32.10 -71.45 47 57 17 15 20 18 13.77 124.53 10 12 18 -1,21 127.91 8 15 18 -3.80 152.15 -9.30 -75,78 128 126 17 116 112 10 45.75 149,17 60 61 17 43.58 147.10 101 168 17 -30.19 -70.81 30.36 70.06 238 242 18 20 16 18 43.51 -127.43 518 540 19 -25.78 179,34 29 24 18 3,02 00,19 591 587 18 -9.38 -71.33 -57.19 157.86 24 18 18 43.58 147.14 53 56 17 120 132 17 -15.63 -72.54
T axis Val PI As
I axis Val PI As
P axis Val PI As
Mo
(Nm)(0) (o) (Nm)(0) (0) (Nm)(0) (0) (Nm) 8.00 55 288 -6.11 14 39 -7.09 4.33 32 349 -6.04 37 231 -4.29 2.16 9 113 -6.02 18 205 -2.14 2,11 20 35 0.04 20 132 -2.15 4.32 1 50 0.23 85 302 -4.55
4.40 3.45 3.08 0.97 1.45 6.97 1.48 1.38 1.46 1,10 1.03 4.60 1.81 9.00 9.43 3.07 1.52 1.70 5.70
I 297 4 25 57 16 57 60 8 11 13 7 55 44 0 28 44 65 0 63
76 355 100 03 296 302 229 186 333 34 45 5 182 39 34 198 317 293
5.25 47 125 3.84 4.02 1.70 2.03 1.31 0.37 9.97 1.00 3.13 1.00 1.80 1.53 6.58 5.01 5.89
58 284 11 134 5 168 0 53 31 23 47 328 46 233 81 267 22 61 47 81 50 37 2 245 1 183 57 336 22 88
7.0 4.3 2.1 2.1 4.4
0.00 77 204 -4.46 13 27
4.5
72
3.8 3.1 1.1 1.4 7.0 1.4 1.3 1.5 1,1 1.0 4.6 2.0 8.9 8.1 2.8 1.5 1.9 5.8
121 110 280 135 220 210 4 271 17 104 351 163 251 76 200 185 92 215
3.3
275
4,1 4,6 1.8 2.5 1.3 6.4 9.7 1.0 3.3 1.0 1.8 1.4 6,9 5.1 5,8
128 270 303 117 57 147 241 85 201 91 301 340 228 162 130
83 13 20 63 4 2 08 4 76 17 13 37 20 47 24 19 82 2
198 250 336 217 32 36 117 277 147 126 296 229 274 164 278 334 227 28
-3.72 -3.14 -1.31 -1.20 -6,95 -1.40 -1.27 -1.52 -1.19 -1.00 -4.60 -2.20 -6.76 -6.00 -2.63 -1,42 -2.03 -5.95
0 62 25 21 33 21 20 78 1 71 32 23 09 29 36 17 8 27
345 144 236 350 125 126 323 28 243 281 108 120 78 291
170 70 47 119
0.06 42 315 -5.31 5 220 0,47 -0,02 0,13 -0.91 -0.09 0.04 -0.00 0.03 0,40 0,02 -6.01 -0.19 0.63 0.08 -0.16
0 159 78 335 82 37 30 144 48 154 16 221 20 346 9 04 52 299 36 303 1 305 4 155 87 300 22 208 67 249
-4.31 -4.00 -1.83 -2.02 -1.22 -6.41 -9.36 -1.03 -3.53 -1,02 -],80 -1.33 -7.21 -5.09 -5.73
30 4 0 60 26 39 37 1 29 31 31 85 3 23 7
64 225 259 323 276 118 92 4 164 310 215 4 93 108 356
DC
Sts N M S E
c*)(*) (*) (*)(*) c * ) ( % ) ( # )
203 135 182 95 185
137 107 358 264 140
0.27 0.06 0.35 -6.16 -6,02 -0.06 0.00 0.07 0.09 -0.03 0.00 0.39 -0.33 -2.57 -0.44 -0.10 0.26 0.24
31 37 70 81 5
Best Double-Couple Plane 1 Plane 2 ~, 6 A ~, 6 A 10 138 30 37 -5 229 40-119 38 3 1 - 1 3 2 321 86 -2 275 80 -9 103 83 -176 30 23 -50 254 27 40 162 03-170 43 13 107 31 24 94 35 70 -8 97 34 -98 100 79 171 109 4 1 - 1 1 8 319 18 44 119 39 19 58 43-121 110 47 -179 i 345 24 11 100 33 126 324 84 -6 103 18 98 27 54 34 163 17 58 342 79 5 179 82 0 ! 34 5 2 - 1 2 0 350 48 170 150 16 15 42 21 167 344 45 77 282 53 -5 294 28 160 108 14 85 126 43 -84 151 8 7 - 1 7 9 138 29 40 36 70 169 224
78 70 07 87-127 98 56 -68 98 07 -68! 96 88 -176 90 8 1 - 1 7 0 100 86 -7 J 85 71-104 90 73 111 47 87 -27 78 78 86 99 66 08 92 82-160 100 56 -83 91 82 11 85 55 -68 94 76 103 100 78 128 65 54 -64 03 00 -43 45 86 114 71 64 09 87 84-174 74 72 87 92 63 139 98 70 00 78 85 169 99 00 -172 80 52 -51 38 87 42 66 86 106 99 85 70 88 47 102 04 86-142 77 81 64 96 76 91 99 48 -96 75 89 -3 83 72 113 97 80 21 95
43 0.470 27 !0.406 16 0.572 41 0.017 13 0,810 20 0.354 10 0.450 24 0.591 13 0.220 14 0.591 24 0.235 38 0.538 32 0.345 31 0.233 14 0.656 21 0.014 31 0.333 41 0.310 33 0,449 12 0.401 15 0,325 8 0.456 24 0.900 18 0,701 19 0.337 10 0.380 16 0.807 26 0.631 14 0.351 45 0.252 34 0.387 18 0.543 23 0.597 7 0.357 43 0.530 26 0.259 28 0,606 13 0,101 21 0.310 4 0.073
Table 1 (continued) Principal Axes
P D E Time and Ilypocenter
161 102
Lon Depth Depth Lat (UTC) (0) (*) (kin) (kin) 31 14 04 11 14 19:13:30.7 13.32 121.07 560 585 04 11 15 20:10:11.3 -5.30 110.19
163 104 165 166 167 108 160 170 171 172 173 174 175 176 177
94 04 94 04 04 04 94 94 94 94 04 04 94 94 04
No
Date (Yr Mo Dy)
11 11 11 11 12 12 12 12 12 12 12 12 12 12 12
20 20 21 22 7 10 12 14 15 18 27 28 28 28 30
Time
16:59:5.6 18:34:34.5 8:10:34,1 11:11:37.8 5:37:54.8 16:17:38.5 7:41:55.4 7:28:53.2 11:20:22.1 20:38:32,1 17:32:50.8 12:19:23.0 20:52:25.8 22:37:46.3 15:12:25.3
-2,00 135.93 4.33 07.50 25,54 90,66 43.00 147.29 -23.42 -66.64 18.14 -101,38 -17.48 -69.60 -9.52 159.41 -37.28 177.52 -17.84 -178.70 -31.97 179,86 40.33 143.42 40.09 142.00 40,38 143.04 18.55 145.30
16 153 14 49 235 48 148 16 33 545 212 26 21 10 219
17 157 15 34 244 55 147 12 38 580 230 7 20
7 227
T axis Scale Val Pl As (10") (Nm)(*)(*) 19 2.66 1 201 18 8.62 6 201 18 3.64 2 148 18 1.39 41 56 17 5.84 24 352 17 2,50 64 210 18 1.02 23 100 18 5,28 24 208 10 2.86 30 102 18 1.37 42 95 18 6.24 12 321 17 3.08 75 353 18 3.99 12 116 20 4.27 54 297 18 1.97 63 286 18 4.57 52 275 18 3.24 40 1 7 0
Acknowledgments W e thank the staff of the U S G S Albuquerque Seismological Laboratory, the I D A program at the Scripps Institution of Oceanography, and the Incorporated Research Institutions for Seismology w h o make all of this possible by operating
I axis P axis Val PI As Val PI As M0 (Nm)(')(o) (Nm)(o)(0) (Nm) 0.57 60 193 -3.45 10 21 3.2 -0.06 20 109 -6.57 69 305 6.0 -6.01 87 9 -3.64 2 238 3.6 0.00 41 270 -1.39 22 160 1.4 -0,20 00 163 I -5,63 3 260 5.7 0.06 24 10 ; -2.55 10 105 2.5 0.00 6 200 -1,02 61 301 1,0 0,91 14 304 -6.19 62 62 5.7 -0.16 28 354 -2.70 46 220 2.8 -0,01 42 312 -1.35 20 203 1.4 -0.01 74 186 -6.23 11 53 6,2 0.75 15 173 -3.83 0 83 3.4 0.00 16 209 -3,98 70 351 4.0 0.10 1 205 -4.37 36 115 4.3 -0.11 3 21 -1.88 27 113 1.0 -0.03 10 18 -4.55 37 115 4.6 0.21 41 324 -3.46 13 66 3.4
Best Double-Couple Plane I ~, 6 A
Plane 2 ¢, 6 A
DC
Sis
NMSE
84-172 07 54 -115 08 90 177 99 78 133 100 70 19 93 50 62 95 73 -84 100 71 -75 71 01-119 89 77 133 99 90 104 100 47 111 01 59 -71 100 81 91 95 72 87 89 83 80 09 70 46 88
25 10 19 9 17 30 29 29 21 26 6 6 36 41 20 24 21
0.009 0.741 0.732 0.377 0.645 0.424 0.582
(*)(*) (°) (0)(0) (*1 (%) (#) 65 312 283 209 33 221 100 271 243 248 97 158 105 200 209 249 196
82 -6 43 -60 87 0 44 17 71 165 41 120 10 -110 24-120 30 -18 45 19 74 0 47 69 36 -118 9 85 18 98 12 142 48 152
150 93 193 107 128 335 22 130 340 144 7 8 39 20 21 16 300
0.300 0.396 0.295 0.191 0.797 0.427 0.357 0.200 0.327 0.270
and maintaining the global networks and data centers. References Aki, K. And Richards, P.G., 1980. Quantitative Seismology, Vol. 1. W.H. Freeman, San Francisco, CA, 557 pp.
146
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Knopoff, L. and Randall, M.J., 1970. The compensated linear-vector dipole: a possible mechanism for deep earthquakes. J. Geophys. Res., 75: 4957-4963. Sipkin, S.A., 1982. Estimation of earthquake source parameters by the inversion of waveform data: synthetic waveforms. Phys. Earth Planet. Inter., 30: 242-259. Sipkin, S.A., 1986a. Interpretation of non-double-couple earthquake source mechanisms derived from moment tensor inversion. J. Geophys. Res., 91: 531-547. Sipkin, S.A., 1986b. Estimation of earthquake source parameters by the inversion of waveform data: global seismicity, 1981-1983. Bull. Seismol. Soc. Am., 76: 1515-1541. Sipkin, S.A. and Needham, R.E., 1989. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1984-1987. Phys. Earth Planet. Inter., 57: 233-259.
Sipkin, S.A. and Needham, R.E., 1991. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1988-1989. Phys. Earth Planet. Inter., 67: 221-230. Sipkin, S.A. and Needham, R.E., 1992. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1990. Phys. Earth Planet. Inter., 70: 16-21. Sipkin, S.A. and Needham, R.E., 1993. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1991. Phys. Earth Planet. Inter., 75: 199-204. Sipkin, S.A. and Needham, R.E., 1994a. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1992. Phys. Earth Planet. Inter., 82: 1-7. Sipkin, S.A. and Needham, R.E., 1994b. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1993. Phys. Earth Planet. Inter., 86: 245-252.
.
=
..
PHYSICS OFTHE EARTH A N D PLANETARY INTERIORS
-
ELSEVIER
Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Letter section
Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1994 Stuart A. Sipkin *, Madeleine D. Zirbes US Geological Survey, MS 967, Box 25046, DFC, Denver, CO 80225, USA Received 25 August 1995; accepted 16 October 1995
Abstract
Moment-tensor solutions, estimated using optimal filter theory, are listed for 177 moderate-to-large size earthquakes occurring during 1994.
1. Introduction
This paper is the fifth in a series published yearly containing moment-tensor solutions computed at the US Geological Survey using an algorithm based on the theory of optimal filter design (Sipkin, 1982, 1986b). An inversion has been attempted for all earthquakes With an mb of 5.8 or greater (5.7 for intermediate- and deep-focus events), as well as several smaller events of particular interest. Previous listings include solutions for earthquakes that occurred from 1981 through 1983 (Sipkin, 1986b), from 1984 through 1987 (Sipkin and Needham, 1989), from 1988 through 1989 (Sipkin and Needham, 1991), in 1990 (Sipkin and Needham, 1992), in 1991 (Sipkin and Needham, 1993), in 1992 (Sipkin and Needham, 1994a),
* Corresponding author. Elsevier Science B.V.
SSDI 0 0 3 1 - 9 2 0 1 ( 9 5 ) 0 3 1 1 6 - 2
and earthquakes that occurred in 1993 (Sipkin and Needham, 1994b).
2. Moment-tensor solutions
The hypocentral parameters, as determined by the National Earthquake Information Service (NEIS), are listed in Table 1. The epicenters listed were fixed in the inversions and the depths were used as starting depths. The moment-tensor solutions are also listed in Table 1, and their equal-area projections are shown in Fig. 1. The moment-tensor depths are those that minimize the misfit between the synthetic seismograms and the long-period P-wave data. The waveforms inverted contain both the direct P wave and the surface reflected phases, so the depth is well constrained, usually to within + 5 km (Sipkin, 1986a).
140
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
T h e s o u r c e g e o m e t r y is listed as the p r i n c i p a l axes o f the m o m e n t tensor, along with t h e i r assoc i a t e d eigenvalues. This is fully e q u i v a l e n t to listing the e l e m e n t s of t h e m o m e n t tensors. T h e
2
I
3
individual e l e m e n t s of the m o m e n t t e n s o r s a r e given in t h e Preliminary Determination of Epicenters Monthly Listings. T h e m o m e n t ( M 0) a n d strike (~bs), dip (6), a n d r a k e (A) of t h e n o d a l p l a n e s of
4
6
6
7
8
@@@@@@®© 9
I0
11
12
13
14
16
115
17
18
19
20
21
22
23
24
26
~
37
~
28
30
31
32
33
34
36
36
37
30
30
40
41
42
43
44
46
48
47
48
49
O0
8~
63
63
64
B8
88
B7
B8
Bii
80
81
03
83
84
88
88
67
1t8
S
70
71
73
73
74
715
78
77
78
79
80
0@@@@@@@ Fig. 1. Equal-area projections of the moment-tensor solutions listed in Table 1. Continuous lines are the projections of the nodal surfaces of the moment tensors; dashed lines are the projections of the nodal planes of the best double-couples. The principal axes are indicated by P and T.
S.A. Sipkin, M.D. Zirbes/ Physics of the Earth and Planetary Interiors 93 (1996) 139-146 N
O7
M
81
. I~
83
14
Im
07
R
W
1(30
1(31
t~
I03
104
~
107
108
108
110
11|
112
113
114
116
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117
llg
I10
130
lift
I~
123
I~I
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126
1~7
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ta9
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IX
140
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144
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1710
171
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177
Fig. 1 (continued).
174
1715
1715
141
142
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
the best double-couple are given following the conventions of Aki and Richards (1980). The deviatoric moment tensor can be decomposed into a double-couple and a remainder term in an infinite number of ways. We prefer the decomposition suggested by Knopoff and Randall (1970) in which the moment tensor is decomposed into a 'best' double-couple and a compensated linear-vector dipole (CLVD). This decomposition is preferred to decomposing the moment tensor into a major and minor double-couple because it is unique, whereas there are an infinite number of major and minor double-couple combinations. In addition, the 'best' double-couple and CLVD share the same principal axes; the major and minor double-couples will, in general,
have equivalent force systems with differing directions. Using the preferred decomposition, the moment of the 'best' double-couple, M 0, is 1 (e I - e 3) where e 1 is the largest positive eigenvalue, corresponding to the T-axis, and e 3 is the largest negative eigenvalue, corresponding to the P-axis. The contribution of the CLVD component to the normalized total moment, MCLVD, is 2 I emin I//1 emax I, where emin is the eigenvalue with the smallest absolute value and emax is the eigenvalue with the largest absolute value. The per cent double-couple is then 100 × (1 - It4CLVD). The normalized mean square error (NMSE) is the residual sum of squares divided by the number of degrees-of-freedom. This number gives a relative measure of the goodness of fit.
Table I Hypocentral parameters and moment-tensor solutions PDE Time and Hypocenter
Principal Axes I axis
T axis
No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 33 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Date (Yr Mo Dy) 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 04 04 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4
3 3 3 4 5 7 9 10 11 17 17 19 20 21 21 3 5 11 12 12 15 15 15 16 16 16 18 23 24 26 1 9 14 14 15 30 31 4 5 6
Time IUTCI 1:20:11,4 5:92:27,6 13:24:13.9 19:31:59.9 13:24:9.9 3:42:42.9 21:29:1.9 15:53:50.1 0%1:56.4 12:30:55.4 23:33:30.7 1:53:34.9 9:6:52.8 2:24:30.0 18:0:17.7 9: 5 : 4 . 2 23:34:10.0 21:17:31.1 4:16:26.9 17:58:24.0 15:8:17.8 17:7:43.8 21:11.:56.4 6:46:57.0 6:48:58.0 22: 3 : 8 . 9 13:41:27.8 8: 2 : 4 . 7 0:11:12.3 2:31:11.1 3:49:0.8 23:28:6.8 4:30:15.8 20:51;25.0 3:36:19.9 13:29:11.3 22:40:52.2 1:37:2.8 9:35:44.9 12:13:45.0
Lat (o) 40.72 30.03 -40.28 -4.30 39.08 52.03 48.48 -13.34 25.23 34.21 34.33 -3.18 -6.00 1.01 -4.86 42.76 0.59 -18.77 -10.79 -20.55 -20.58 -4.97 -20.40 -20.09 -18.99 -20.23 -20.49 30.85 30.77 30.90 29.10 -18.04 -1.28 15.99 11.11 9.00 -22.06 -15.47 51.30 -17.37
Lon (o) -126.77 I00.I0 164.22 135.15 15.15 159.02 154.49 -60.45 97.20 -118.54 -118.70 135.07 -77.05 127.73 103.66 -110.98 30.04 109.17 -128.80 169.36 189.39 104.30 168.87 168.91 168.13 168.93 169.07 60.60 60.49 60.55 52.62 -178.41 -23.57 -92.43 -88.08 126.25 -179.53 -173.01 -178.15 167.82
P axis
Depth Depth Scale Val PI As Val PI As Val PI As Mo (kin) (kin) (1O") (Si n ) (o) (o) (Nm) (o) (o) (e,l'm)f')(°) (~m) 19 8 15 11 272 54 85 596 9 18 9 23 122 19 89 7 14 205 15 27 30 23 19 12 13 10 12 0 9 9 12 562 10 164 14 40 579 24 10 17
19 8 11 15 272 34 56 607 14 21 9 29 126 22 101 19 14 219 11 41 38 21 22 19 18 29 19 22 20 22 19 571 18 109 3 44 587 6 35 22
17 17 18 18 17 17 17 19 17 19 17 19 17 19 17 17 18 19 19 19 18 19 18 18 18 18 18 18 18 17 18 20 19 19 18 17 18 17 18 18
3.70 3.50 1.05 1.01 6.09 4.04 1.08 2.65 9.42 1.15 6.77 1.38 5.25 3.34 8.78 2.74 1.95 2.70 0.99 3.57 1.33 1.01 3.90 1.35 3.81 1.37 1.33 1.16 1.84 9.97 1.12 2.33 3.72 2.30 4.86 8.22 7.67 3,85 2.41 1.76
II 50 45 6 17 76 54 32 4 76 73 65 9 15 70 6 15 53 18 75 71 1 02 40 39 62 43 72 68 71 1 18 4 40 4 60 35 30 52 66
129 315 8 138 117 347 103 223 179 125 335 234 264 33 65 296 35 32 161 112 125 263 14 30 32 84 28 210 168 188 95 122 36 94 197 334 91 348 298 102
1.25 52 1.20 32 -0.20 44 -0.10 84 -1.36 27 0.00 7 -0.10 27 -0.03 28 -0.57 18 0.04 13 -0.10 12 0.03 24 0.34 11 -0.19 69 -0.36 17 0.23 17 0.01 20 0,27 35 0.00 12 0.06 13 0.03 19 0.03 83 -0.01 28 -0.22 49 -0.01 49 0.01 1 -0.30 42 0.11 1 0.03 20 -1.78 12 -0.17 83 0.01 17 -0.02 84 O.O0 41 -0.35 22 0.16 25 -0.90 18 0.07 20 -0.02 31 0.16 0
20 113 175 313 216 225 236 114 88 284 108 74 172 166 213 204 131 188 67 327 323 170 180 192 190 352 176 302 323 317 322 26 268 316 105 192 193 246 78 350
-5.00 -4.78 -1.66 -0.91 i -4.73 -4.04 -0.99 -2.61 -8.35 -1.19 -6.67 -1.42 -5.60 -3.15 -0.42 -2.97 -1.96 -2.96 -1.00 -3.63 -1.38 -1.04 -3.89 -1.13 -3.81 -1.38 -1.03 -1.27 -1.87 -0.20 -0.95 -2.34 -3.70 -2.36 -4.32 -8.37 -6.78 -3.92 -2.40 -1.92
36 10 6 0 57 12 23 43 72 5 12 7 76 15 10 72 64 12 69 9 5 7 6 9 11 28 17 18 9 14 1 64 5 23 68 16 51 53 20 22
228 210 271 46 338 134 338 332 282 15 200 340 30 299 306 44 270 286 305 235 231 355 273 292 293 262 281 32 56 50 183 256 126 205 296 94 303 127 180 256
4.4 4.2 1.8 0.9 5.4 4.0 1.0 2.6 9.1 1.2 6.7 1.4 5.4 3.2 8.6 2.9 2.0 2.8 1.0 3.6 1.3 1.0 3.9 1.2 3.8 1.4 1.2 1.2 1.9 9.1 1.0 2.3 3.7 2.4 4.5 8.3 7.2 3.9 2.4 1.8
Best Doub|e-Couple Plane I Plane 2 4), 6 A 4', 6 ~
(°)(°) 262 333 39 181 172 214 108 7 287 119 306 45 7 76 56 45 99 52 269 310 303 40 30 63 65 349 54 123 168 156 230 237 171 247 309 153 131 122 310 320
(°1 (°)(°)
57 -29 45 139 54 148 86 178 36 -140 34 77 33 147 29 -15 44 -64 42 110 34 111 43 53 38 -71 69-180 38 119 42 -63 34-127 45 143 20 -65 38 69 43 83 35 - 4 46 130 56 136 55 158 17 87 46 157 27 91 40 121 33 113 89 0 31 -55 84 -1 43 15 46 -$0 38 45 18 -153 24 -32 37 148 25 67
3 94 148 271 48 50 227 110 73 274 100 271 164 346 202 191 322 170 61 156 157 130 160 167 168 173 160 301 309 310 320 18 261 148 87 24 15 242 67 174
DC
StaiNMSE
(°) (%) (#)
73-145 60 63 5 3 50 68 40 78 86 4:80 68 -00 55 57 99 100 73 62 81 83-118 98 52-113 88 51 73 93 58 76 97 57 119 96 55-104 88 90 -21 89 57 69 92 53-112 85 63 -68 99 66 51 82 6 4 - 1 0 3 100 55 106 97 33 113 96 86-175 94 57 56 90 70 37 67 72 37 99 73 91 99 73 40 55 63 89 83 56 66 97 60 76 64 90 -179 70 65-109 99 69-174 99 80 132 100 52-118 85 68 117 96 82 -74 77 78-110 96 71 57 98 67 100 63
15 5 12 9 23 23 4 20 8 17 16 9 10 6 10 5 13 14 34 15 10 12 18 22 21 24 4 18 13 14 9 31 21 29 33 16 25 8 39 27
0.314 0.416 0.536 0.766 0.553 0.532 0.622 0.431 0.349 0.260 0.357 0.304 0.407 0.954 0.692 0.322 0.232 0.185 0.109 0.070 0.121 0.939 0.502 0.506 0.390 0.481 0.393 0.882 0.425 0.586 0.544 0.314 0.265 0.324 0.492 0.313 0.260 0.808 0.471 0.472
S.4. Sipkin, M.D. Zirbes/ Physics of the Earth and Planetary Interiors 93 (1996) 139-146
143
Table 1 (continued) PDE Time and Hypocenter
No 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79
80
Date
Time
Lat
Lon
Depth
Depth
(YrMoDy)
(UTC)
(o)
(o)
(km)
(kin) (I0")
94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94 94
4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
8 1:10:40.8 10 23:45:55.8 13 4:0:47,3 13 22:22:29.9 14 3:28:26.6 18 17:29:54.1 21 3:51:44.6 23 15:0:52.8 27 9:23:26.3 27 14:11:45.2 29 7:11:29.7 1 12:0:35.8 2 17:14:0.9 3 16:36:43,7 4 0:37:36,1 6 22:39:26.6 9 12:36:37.3 10 1:49:3.5 10 6:38:28,4 11 8:18:15.7 11 21:14:33.8 18 3:54:0.6 23 1:41:42,3 23 5:36:1,6 23 15:16:57.2 24 4:0:42.2 24 21:13:19.3 25 4:3:41.3 5 26 8:26:52.4 5 29 14:11:51.0
40.61 143.68 23.71 126.85 22.77 123.63 -3.14 135.97 -6.59 129.77 -6.47 154.93 -5.70 154.12 -14.18 167.54 -21.51 -173.67 13.07 119.54 -28.30 -63.25 30.90 67.16 -1.12 97.49 10.24 -60.76 -17.05 168.28 -4.68 153.10 -2,06 99.73 -19.61 -69.79 -28.50 -63,10 -2.01 99.77 -2.06 98.67 44.73 149.40 18,17 -100,53 24,17 122.54 24.07 122,56 23.96 122.45 56.17 101.17 -4.20 135.49 35.31 -4.10 20,56 94.16
5 31
17:41:55.6
6 6 6 6 6 6 6 6
2 3 3 4 5 6 6 9
18:17:34.0 11:25:6.7 21:6:59.9 0:57:50.7 1:0:30.1 9: 3:0.5 20:47:40,5 0:33:16.2
-10.48 3.52 -10.36 -10.78 24.51 28.60 2.92 -13.84
7.41 -72.03
94 6 13
21:15:2.7
5.47
112.83 -78.78 112.89 113.37 121.90 129.10 -76,06 -67,55
151.84
13 10 9 28 166 26 28 10 28 I 9 561 18 15 36 206 48 27 52 600 20 28 26 55 19 25 16 95 33 9 35
16 7 21 20 189 37 56 2 38 21 568 22 9 39 203 46 38 48 602 23 23 32 08 22 22 5 89 15 19 69
Ii
12
18 9 25 11 11 60 12 631
6 19 29 18 12 66 20 631
17
25
Scale
T ~xis Val PI As
Principal Axes I axis P axis Val P] As Val P1 As
(Nrn) (o) (o) (Nm)(0)(o) 46 320 0.34 28 197 5 345 0.08 11 254 5 152 -0.06 26 60 19 261 0.06 43 153 35 273 -0.15 9 9 80 159 0.00 8 308 85 210 -0.06 3 330 76 266 -0.07 12 138 74 120 1.43 4 15 57 211 0.91 33 35 23 264 O.O0 7 171 66 115 0.04 22 270 8 255 -0.12 1 345 18 334 -0.26 25 72 64 281 0.04 24 76 11 314 -0.09 10 48 44 348 -0.02 43 142 70 64 0.22 1 156 40 274 0.90 8 177 50 27 ; -0.11 2 120 54 34 0.05 7 295 53 338 -6.01 23 213 7 41 -6.37 15 133 52 332 -0,02 6 69 53 321 0.94 11 67 39 348 0.17 6 253 22 306 -0.04 2 215 5 315 0.68 74 64 3 47 0.11 78 152 35 75 -0.72 31 320 80 353 -0.06 10 165 43 356 -0.93 11 96 14 322 -0.19 5 53 3 185 0.03 16 94
(Nm)(o)(r) -4.74 -1.31 -3.87 -3.11 -2.85 -1,41 -1.11 -2.22 -3.93 -8.52 -2.53 -1.67 -1.46 -2.26 -2.34 -7.09 -2.79 -8.81 -3.32 -5.00 -1.63 -1,72 -3.45 -1,96 -8.70 -7.90 -5.01 -7.70 -9.80 -3.88 -9.04 -4.75 -5.47 -3.46
Mo
(Nm)
18 18 17 18 17 19 19 18 18 17 19 18 18 18 18 17 17 17 19 18 18 18 18 18 17 18 17 18 17 18 17 20 17 18
4.40 1.24 3.93 3.05 3.00 1.41 1.17 2.28 2,51 7.61 2,53 1.62 1.58 2.52 2.30 7.18 2.81 8.59 2.42 5.71 1.59 1.72 3.82 1,98 7.76 7.73 5,05 7.02 9.70 4.60 9,11 5.68 5.66 3.43
31 89 78 98 64 251 41 8 54 111 5 39 5 60 7 46 15 284 2 303 66 64 9 4 82 79 58 211 9 171 75 178 13 244 20 246 48 77 40 211 35 200 27 110 74 286 38 163 34 165 51 156 68 119 15 223 11 317 40 200 1 255 45 198 75 161 74 286
4.6 1.3 3.9 3.1 2.9 1.4 1,1 2.2 3.2 8.1 2.5 1.6 1.5 2.4 2.3 7.1 2.8 8.7 2.9 5.7 1.6 1.7 3.6 2.0 8.2 7.8 5,0 7.4 9.7 4.2 9.1 5.2 5.6 3.4
18
2.14 4 14 -0.01 24 I05 -2.14 65 274
2.1
18 17 19 21 18
3.07 23 132 -0.05 65 333 -3.92 2.94 1 22 0.08 35 291 -3.02 1.34 6 346 0.00 78 227 I -1.34 2.13 38 108 -0.17 14 96 I -1.96 1,32 66 309 -0.02 17 84 J -1,29
3.9 3.0 1.3 2.0 1.3
8 55 10 48 16
226 114 79 349 179
Be~t' Double-Couple Plane 1 Plane 2 ~b, 6 ~ ~b, 6 ,~
(o)(0) 127 86 268 36 328 138 153 123 7 5 8 118 345 30 286 31 15 338 60 320 261 158 114 287 296 116 40 0 93 224 356 11 45 291
Co) (o)Co)
29 17 41 -73 46 -53 46 -20 13 -131 41 103 40 94 39 71 30 81 52 47 23 -71 41 125 37 -91 35-138 41 127 35 -108 40 154 25 92 9 -27 6 110 12 55 28 32 40-113 9 128 15 140 8 -47 23 -84 76-173 80-174 31 -6 44 105 11 -175 31 -99 44 -67
80 46-125 271 142 123 345 292
22 245 40 140 190 301 327 327 197 241 168 255 166 263 61 233 123 156 176 120 116 39 324 68 65 253 214 268 2 319 155 276 236 81
DC
Sta
NMSE
(.) (%) (#)
82 118 88 42 51-104 88 20 55 -122 97 9 76 -134 96 13 80 -61 90 7 51 79 100 21 50 87 90 27 53 105 94 23 60 95 27 25 55 131 79 I 13 68 -98 100 30 58 64 95 20 53 -88 85 17 68 -63 79 26 58 62 97 21 57 -78 97 20 71 44 99 15 65 89 95 23 86 -98 46 28 85 88 96 19 80 97 94 17 76 114 99 19 54 -72 81 11 83 84 98 22 80 78 78 20 84 -96 96 26 67 -92 98 16 83 -14 82 9 84 -10 98 18 87 -121! 69 17 47 76 99 29 89 -79 67 31 59 -85 93 24 50 -111 98 22
0.525 0.322 0.706 0.450 0,738 0.121 0,273 0.584 0.396 0.283 0.161 0.194 0,395 0,300 0.777 0.357 0.649 0.233 0.247 0.425 0.354 0.539 0,459 0.246 0.324 0,380 0.345 0.384 0.872 0.266 0,213 0.640 0.346 0.708
305 54 -60
99
25
0.825
68 11 177 80 157 53 -45 263 55 -134 79 -3 214 87 -169 15 -20 95 85 -104 33 123 74 63 71
97 95 100 84 97
34 20 36 25 23
0.494 0.380 0.605 0.193 0.335
144
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Table 1 (continued) PDE Time and Hypocenter No 81 82 83 84 85 86 87 88 89 90 91 92 03 04 95 00 97 98 99 lOO 101 102 103 104 105 100 107 108 109 110 111 112 113 114 115 116 117 118 119 120
Date (YrMoDy) 94 0 15 94 6 16 94 6 16 94 6 18 94 8 10 94 6 20 04 6 20 94 6 30 94 7 1 94 7 1 94 7 2 94 7 4 94 7 6 04 7 13 94 7 13 94 7 14 94 7 16 94 7 21 04 7 22 94 7 24 94 7 25 94 7 29 94 7 29 94 8 2 94 8 3 94 8 4 94 8 8 94 8 8 94 8 11 94 8 14 94 8 14 94 8 16 94 0 18 94 8 18 94 8 10 94 8 19 94 8 20 94 8 20 04 8 21 04 8 22
Time (UTC) 9:22:57,2 10:12:46.9 18:41:28.3 3:25:15.8 13:43:51.2 9: 9:2.9 18:22:33,6 9:23:21.4 10:12:41.2 19:50:4.4 9:14:43.0 21:36:42.0 9:13:10.2 2:35:56.0 11:45:23,4 O: 0:24.7 18: 5 : 5 . 6 18:36:3i.7 16:57:48.4 17:55:40.4 22:0:23.0 0:17:45.4 7:53:28,5 14:17:52.2 14:50:57.6 22:15:37.8 7:55:39.2 21:8:31.7 20:42:9.0 0:46:20.4 1:31:12.9 10:9:32.8 0:45:47.2 4:42:57.4 10:2:51.8 21:2:45.6 2:21:11.1 4:38:50,6 15:55:50,2 17:26:37.0
Lat Lon Depth Depth (o) (o) (km) (kin) -10.34 113.66 lg 5 -7.39 128,12 108 141 -15.25 -70.29 199 199 -42,98 171.66 13 24 -43.27 171,61 10 14 28,97 52.61 8 7 32.57 93.67 9 8 36.33 71.13 226 242 40.23 53.38 40 43 40.22 53.39 44 44 -5.78 131.10 87 101 14.89 -97.32 14 13 5.08 125.93 151 144 -16.62 167,52 33 34 -7.53 127.77 158 169 -16.58 167.45 10 24 -4.62 125.61 442 452 42.34 132.87 471 489 -7.78 158.42 19 20 -18.97 167.57 20 18 -58.36 -27.36 81 73 52.40 -168,33 11 21 -16.98 167.74 13 28 52.43 158.04 144 152 21.51 93.98 34 41 -6.34 131.57 33 76 -13.82 -68,37 507 002 24.72 95.20 121 123 -21.00 -173.77 31 24 44.71 150.10 16 28 44.00 150.01 19 21 37.84 142.46 19 21 -7.43 31.75 25 29 44,?7 150.16 14 18 -20.64 --63.42 563 503 17.97 96.42 12 14 44.61 140.32 22 26 44.66 149.18 24 34 56,76 117.90 12 11 -11.51 166.45 142 151
T ~tis Scale Val PI As (10") (Nm)(°)(0) 18 2.09 41 20 17 8.55 71 341 18 1.20 24 353 19 1.28 04 144 18 1.08 19 41 17 5.80 20 314 17 5,74 0 289 18 3.34 88 256 17 3.33 65 351 16 7.19 72 349 17 5.09 75 106 18 1.29 16 41 17 7.16 22 210 10 5.42 21 125 18 5,78 67 313 18 0,81 31 70 17 3.91 31 28 19 8.57 34 38 17 6.30 85 261 18 3.27 40 116 18 8.39 32 162 17 5.87 48 6 17 6,84 71 152 17 6.81 53 302 17 5.21 4 76 18 1.54 18 298 17 2.84 36 233 18 1.76 67 117 17 5.48 53 48 17 9.15 60 324 18 2.88 35 357 17 4.81 89 287 17 7.67 17 241 18 4.68 53 309 18 5.38 23 261 17 4.82 19 153 17 2.21 02 208 18 1.73 50 205 17 9.30 I 313 18 1,08 70 315
Principal Axes I axis Val PI Az (Nm) (o) (o) 0.11 7 116 0,71 15 121 0.03 62 208 0.07 16 17 -0.13 65 181 0.01 60 83 0.00 6 19 0.00 2 29 -0.47 3 87 -0.01 1 257 -0.03 15 286 0.00 ? 133 0.28 50 328 -0.62 59 353 -0.87 21 106 0.19 0 160 0.00 1 208 0.82 35 158 -0.29 3 132 0.01 28 380 0.06 54 312 -0.21 28 239 -0.37 18 353 -0.11 10 199 0,04 86 246 0,06 72 107 0.00 O 143 0.16 17 255 2.26 26 179 0,44 3 230 0.55 27 245 -0.17 1 194 0.00 2 151 0.06 4 215 -0.01 15 165 -0.04 66 294 -0.20 4 36 -0.01 13 48 0.01 13 43 -0.02 .9 174
P axis Val P1 Az Mo (Nm) (o) (o) (Nm) -2.20 49 213 2.1 -9.26 12 214 8.9 -1.33 14 90 1.3 -1.34 19 281 1.3 -0.95 15 306 1.0 -5.86 21 216 5.9 -5.74 84 107 5.7 -3.34 2 119 3.3 -2.86 25 1?8 3.1 -7,18 18 167 7.2 -5.07 0 16 5.1 -1,38 72 245 1,3 -7.44 32 105 7.3 -4.80 21 223 5,1 -4.92 10 200 5.3 -1,00 59 251 0.9 -3,91 50 205 3,9 -9.39 37 278 9.0 -6.01 4 42 6.2 -3,28 37 246 3,3 -8.45 15 62 8.4 -5,67 28 133 5.8 -0.47 6 261 6.7 -6.70 35 102 6.8 -5.25 1 346 5.2 -1,60 3 207 1.6 -2.84 54 53 2.8 -1.92 14 350 1,8 -7.?4 24 281 6.6 -9.59 30 138 9.4 -3.44 42 127 3.2 -4.64 21 104 4,7 -7.67 73 56 " 7.7 -4.74 37 122 4.7 -5.37 02 44 5.4 -4.79 14 58 4.8 -1.93 28 128 2.1 -1.72 27 145 1.7 -9.39 76 218 9.4 -1,96 7 63 2,0
Best Double-Couple Plane 1 Plane 2 ~, 6 A ~, ~ ~ (°)(o) (o) (o)(o) (o) 57 8 -149 296 86 -83 322 36 116 111 58 73 133 63 7 40 84 153 346 29 56 204 66 108 83 66 177 174 87 25 355 6 0 - 1 7 9 265 89 -30 13 45 -08 205 46 -82 211 43 92 28 47 88 274 20 98 86 70 87 256 27 89 77 63 91 121 47 111 271 47 69 120 29-104 316 62 -82 251 50-172 155 84 -~.0 264 59 0 174 00 149 3t3 40 124 92 58 65 160 14 -90 340 76 -90 123 14 -84 207 76 -91 69 35 -177 337 89 -55 129 41 85 315 49 94 273 28 3 181 89 118 198 56 106 296 79 35 176 31 23 66 79 119 332 42 62 187 54 113 152 14 42 20 81 100 121 87 178 211 88 3 341 75 109 74 80 15 323 9 -90 143 81 -00 102 34 122 245 61 70 52 31 147 171 74 63 219 15 70 50 75 93 1'46 28 -8 243 86 -117 191 24 87 15 66 91 334 28" -87 150 62 -02 190 9 65 35 82 94 10 26 -53 159 70 -106 194 66 176 286 86 24 230 18 105 34 73 85 265 21 129 44 74 76 29 45 -109 235 48 -72 164 39 76 i 52 101
DC Sis (%)(#) 90 27 85 19 95 26 90 22 76 5 100 16 100 28 100 26 72 29 100 11 99 16 87 33 92 14 77 24 70 16 62 24 100 7 83 42 91 27 99 30 99 10 93 33 89 27 97 30 98 8 93 16 I 100 12 83 23 42 22 91 41 08 8 93 40 100 16 97 20 100 31 98 13 74 11 99 51 100 42 98 35
NMSE 0.392 0.229 0.536 0.671 0.344 0,497 0.274 0.431 0.299 0.027 0.866 0,550 0.388 0.378 0.309 0.291 0,570 0.366 0.377 0,249 0.284 0,425 0.156 0.413 0.578 0.769 0.452 0,282 0,380 0.420 0.306 0.224 0.149 0.620 0.271 0.491 0.249 0.581 0.213 0.427
145
SJt. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Table 1 (continued) Principsl Axes No 121 122 123 124 125 126 127 129 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 :148 149 150 151 152 153 154 155 156 157 150 159 160
Date (Yr M o Sy) 94 8 26 94 8 30 94 8 30 94 8 31 94 9 I 94 9 3 94 9 3 94 9 5 94 9 12 94 0 12 94 0 12 94 9 13 94 9 13 94 9 18 94 9 23 94 0 28 04 10 1 04 10 4 94 10 5 94 10 5 94 10 7 94 10 8 94 10 8 94 10 9 94 10 11 04 10 12 94 10 13 94 10 15 04 10 10 94 10 16 94 10 18 94 10 20 04 10 25 94 10 27 94 10 27 94 10 31 94 11 4 94 11 5 94 11 0 94 11 11
Time
(UTC) 16:37:20.7 6:13:36.8 10:42:46.5 9:7:25.9 15:15:53.1 9:2:53,7 17:40:41.6 22:13:47.9 0:29:54.9 12:23:43.2 22:43:50,8 4:28:1.0 10:1:32.1 6:20:18.7 7:59:38.9 16:30:51.7 10:35:20.8 13:22:55.8 20:37:29.3 20:39:40.4 2:30:9.3 9:54:34,3 21:44:7.2 7:55:39.1J 1:37:20.4 0:43:39.7 5:4:25,0 0:39:25.5 0:0:49.1 5:10:0.9 17:12:50.9 1:15:10.2 0:54:34,3 17:45:58.0 22:20:28.5 11:48:13.9 1:13:20.1 2:16:3.3 18:21:2,7 8:48:30.0
I~t
Ion
Depth Depth
Scale
(*) (*) (kin) (kin) (10") 44.78 160.08 18 13 18 50 25 17 44.74 150.12 505 612 18 -6.07 124.11 70 85 18 43.72 140,01 lO 15 19 40.40 -125.68 6 13 17 -31.42 -111.03 33 33 18 -21.21 173.04 12 20 17 46.78 135.23 40 46 18 -31.10 -71.71 14 6 18 38.02 -119.85 -15.45 -172.09 15 11 17 34 43 18 29.29 129.91 13 30 18 7.05 -76.08 13 8 19 22.53 118.71 33 19 18 -3.38 148.54 037 642 19 -5.70 110.35 16 17 18 -17.75 167.08 14 61 21 43.77 147.32 13 8 17 43.59 147.45 43.95 147.34 40 20 17 43.61 147.29 52 47 17 9 23 17 43,87 148.17 -1.26 127.98 18 20 19 33 43 19 43.90 147.02 -32.10 -71.45 47 57 17 15 20 18 13.77 124.53 10 12 18 -1,21 127.91 8 15 18 -3.80 152.15 -9.30 -75,78 128 126 17 116 112 10 45.75 149,17 60 61 17 43.58 147.10 101 168 17 -30.19 -70.81 30.36 70.06 238 242 18 20 16 18 43.51 -127.43 518 540 19 -25.78 179,34 29 24 18 3,02 00,19 591 587 18 -9.38 -71.33 -57.19 157.86 24 18 18 43.58 147.14 53 56 17 120 132 17 -15.63 -72.54
T axis Val PI As
I axis Val PI As
P axis Val PI As
Mo
(Nm)(0) (o) (Nm)(0) (0) (Nm)(0) (0) (Nm) 8.00 55 288 -6.11 14 39 -7.09 4.33 32 349 -6.04 37 231 -4.29 2.16 9 113 -6.02 18 205 -2.14 2,11 20 35 0.04 20 132 -2.15 4.32 1 50 0.23 85 302 -4.55
4.40 3.45 3.08 0.97 1.45 6.97 1.48 1.38 1.46 1,10 1.03 4.60 1.81 9.00 9.43 3.07 1.52 1.70 5.70
I 297 4 25 57 16 57 60 8 11 13 7 55 44 0 28 44 65 0 63
76 355 100 03 296 302 229 186 333 34 45 5 182 39 34 198 317 293
5.25 47 125 3.84 4.02 1.70 2.03 1.31 0.37 9.97 1.00 3.13 1.00 1.80 1.53 6.58 5.01 5.89
58 284 11 134 5 168 0 53 31 23 47 328 46 233 81 267 22 61 47 81 50 37 2 245 1 183 57 336 22 88
7.0 4.3 2.1 2.1 4.4
0.00 77 204 -4.46 13 27
4.5
72
3.8 3.1 1.1 1.4 7.0 1.4 1.3 1.5 1,1 1.0 4.6 2.0 8.9 8.1 2.8 1.5 1.9 5.8
121 110 280 135 220 210 4 271 17 104 351 163 251 76 200 185 92 215
3.3
275
4,1 4,6 1.8 2.5 1.3 6.4 9.7 1.0 3.3 1.0 1.8 1.4 6,9 5.1 5,8
128 270 303 117 57 147 241 85 201 91 301 340 228 162 130
83 13 20 63 4 2 08 4 76 17 13 37 20 47 24 19 82 2
198 250 336 217 32 36 117 277 147 126 296 229 274 164 278 334 227 28
-3.72 -3.14 -1.31 -1.20 -6,95 -1.40 -1.27 -1.52 -1.19 -1.00 -4.60 -2.20 -6.76 -6.00 -2.63 -1,42 -2.03 -5.95
0 62 25 21 33 21 20 78 1 71 32 23 09 29 36 17 8 27
345 144 236 350 125 126 323 28 243 281 108 120 78 291
170 70 47 119
0.06 42 315 -5.31 5 220 0,47 -0,02 0,13 -0.91 -0.09 0.04 -0.00 0.03 0,40 0,02 -6.01 -0.19 0.63 0.08 -0.16
0 159 78 335 82 37 30 144 48 154 16 221 20 346 9 04 52 299 36 303 1 305 4 155 87 300 22 208 67 249
-4.31 -4.00 -1.83 -2.02 -1.22 -6.41 -9.36 -1.03 -3.53 -1,02 -],80 -1.33 -7.21 -5.09 -5.73
30 4 0 60 26 39 37 1 29 31 31 85 3 23 7
64 225 259 323 276 118 92 4 164 310 215 4 93 108 356
DC
Sts N M S E
c*)(*) (*) (*)(*) c * ) ( % ) ( # )
203 135 182 95 185
137 107 358 264 140
0.27 0.06 0.35 -6.16 -6,02 -0.06 0.00 0.07 0.09 -0.03 0.00 0.39 -0.33 -2.57 -0.44 -0.10 0.26 0.24
31 37 70 81 5
Best Double-Couple Plane 1 Plane 2 ~, 6 A ~, 6 A 10 138 30 37 -5 229 40-119 38 3 1 - 1 3 2 321 86 -2 275 80 -9 103 83 -176 30 23 -50 254 27 40 162 03-170 43 13 107 31 24 94 35 70 -8 97 34 -98 100 79 171 109 4 1 - 1 1 8 319 18 44 119 39 19 58 43-121 110 47 -179 i 345 24 11 100 33 126 324 84 -6 103 18 98 27 54 34 163 17 58 342 79 5 179 82 0 ! 34 5 2 - 1 2 0 350 48 170 150 16 15 42 21 167 344 45 77 282 53 -5 294 28 160 108 14 85 126 43 -84 151 8 7 - 1 7 9 138 29 40 36 70 169 224
78 70 07 87-127 98 56 -68 98 07 -68! 96 88 -176 90 8 1 - 1 7 0 100 86 -7 J 85 71-104 90 73 111 47 87 -27 78 78 86 99 66 08 92 82-160 100 56 -83 91 82 11 85 55 -68 94 76 103 100 78 128 65 54 -64 03 00 -43 45 86 114 71 64 09 87 84-174 74 72 87 92 63 139 98 70 00 78 85 169 99 00 -172 80 52 -51 38 87 42 66 86 106 99 85 70 88 47 102 04 86-142 77 81 64 96 76 91 99 48 -96 75 89 -3 83 72 113 97 80 21 95
43 0.470 27 !0.406 16 0.572 41 0.017 13 0,810 20 0.354 10 0.450 24 0.591 13 0.220 14 0.591 24 0.235 38 0.538 32 0.345 31 0.233 14 0.656 21 0.014 31 0.333 41 0.310 33 0,449 12 0.401 15 0,325 8 0.456 24 0.900 18 0,701 19 0.337 10 0.380 16 0.807 26 0.631 14 0.351 45 0.252 34 0.387 18 0.543 23 0.597 7 0.357 43 0.530 26 0.259 28 0,606 13 0,101 21 0.310 4 0.073
Table 1 (continued) Principal Axes
P D E Time and Ilypocenter
161 102
Lon Depth Depth Lat (UTC) (0) (*) (kin) (kin) 31 14 04 11 14 19:13:30.7 13.32 121.07 560 585 04 11 15 20:10:11.3 -5.30 110.19
163 104 165 166 167 108 160 170 171 172 173 174 175 176 177
94 04 94 04 04 04 94 94 94 94 04 04 94 94 04
No
Date (Yr Mo Dy)
11 11 11 11 12 12 12 12 12 12 12 12 12 12 12
20 20 21 22 7 10 12 14 15 18 27 28 28 28 30
Time
16:59:5.6 18:34:34.5 8:10:34,1 11:11:37.8 5:37:54.8 16:17:38.5 7:41:55.4 7:28:53.2 11:20:22.1 20:38:32,1 17:32:50.8 12:19:23.0 20:52:25.8 22:37:46.3 15:12:25.3
-2,00 135.93 4.33 07.50 25,54 90,66 43.00 147.29 -23.42 -66.64 18.14 -101,38 -17.48 -69.60 -9.52 159.41 -37.28 177.52 -17.84 -178.70 -31.97 179,86 40.33 143.42 40.09 142.00 40,38 143.04 18.55 145.30
16 153 14 49 235 48 148 16 33 545 212 26 21 10 219
17 157 15 34 244 55 147 12 38 580 230 7 20
7 227
T axis Scale Val Pl As (10") (Nm)(*)(*) 19 2.66 1 201 18 8.62 6 201 18 3.64 2 148 18 1.39 41 56 17 5.84 24 352 17 2,50 64 210 18 1.02 23 100 18 5,28 24 208 10 2.86 30 102 18 1.37 42 95 18 6.24 12 321 17 3.08 75 353 18 3.99 12 116 20 4.27 54 297 18 1.97 63 286 18 4.57 52 275 18 3.24 40 1 7 0
Acknowledgments W e thank the staff of the U S G S Albuquerque Seismological Laboratory, the I D A program at the Scripps Institution of Oceanography, and the Incorporated Research Institutions for Seismology w h o make all of this possible by operating
I axis P axis Val PI As Val PI As M0 (Nm)(')(o) (Nm)(o)(0) (Nm) 0.57 60 193 -3.45 10 21 3.2 -0.06 20 109 -6.57 69 305 6.0 -6.01 87 9 -3.64 2 238 3.6 0.00 41 270 -1.39 22 160 1.4 -0,20 00 163 I -5,63 3 260 5.7 0.06 24 10 ; -2.55 10 105 2.5 0.00 6 200 -1,02 61 301 1,0 0,91 14 304 -6.19 62 62 5.7 -0.16 28 354 -2.70 46 220 2.8 -0,01 42 312 -1.35 20 203 1.4 -0.01 74 186 -6.23 11 53 6,2 0.75 15 173 -3.83 0 83 3.4 0.00 16 209 -3,98 70 351 4.0 0.10 1 205 -4.37 36 115 4.3 -0.11 3 21 -1.88 27 113 1.0 -0.03 10 18 -4.55 37 115 4.6 0.21 41 324 -3.46 13 66 3.4
Best Double-Couple Plane I ~, 6 A
Plane 2 ¢, 6 A
DC
Sis
NMSE
84-172 07 54 -115 08 90 177 99 78 133 100 70 19 93 50 62 95 73 -84 100 71 -75 71 01-119 89 77 133 99 90 104 100 47 111 01 59 -71 100 81 91 95 72 87 89 83 80 09 70 46 88
25 10 19 9 17 30 29 29 21 26 6 6 36 41 20 24 21
0.009 0.741 0.732 0.377 0.645 0.424 0.582
(*)(*) (°) (0)(0) (*1 (%) (#) 65 312 283 209 33 221 100 271 243 248 97 158 105 200 209 249 196
82 -6 43 -60 87 0 44 17 71 165 41 120 10 -110 24-120 30 -18 45 19 74 0 47 69 36 -118 9 85 18 98 12 142 48 152
150 93 193 107 128 335 22 130 340 144 7 8 39 20 21 16 300
0.300 0.396 0.295 0.191 0.797 0.427 0.357 0.200 0.327 0.270
and maintaining the global networks and data centers. References Aki, K. And Richards, P.G., 1980. Quantitative Seismology, Vol. 1. W.H. Freeman, San Francisco, CA, 557 pp.
146
S.A. Sipkin, M.D. Zirbes / Physics of the Earth and Planetary Interiors 93 (1996) 139-146
Knopoff, L. and Randall, M.J., 1970. The compensated linear-vector dipole: a possible mechanism for deep earthquakes. J. Geophys. Res., 75: 4957-4963. Sipkin, S.A., 1982. Estimation of earthquake source parameters by the inversion of waveform data: synthetic waveforms. Phys. Earth Planet. Inter., 30: 242-259. Sipkin, S.A., 1986a. Interpretation of non-double-couple earthquake source mechanisms derived from moment tensor inversion. J. Geophys. Res., 91: 531-547. Sipkin, S.A., 1986b. Estimation of earthquake source parameters by the inversion of waveform data: global seismicity, 1981-1983. Bull. Seismol. Soc. Am., 76: 1515-1541. Sipkin, S.A. and Needham, R.E., 1989. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1984-1987. Phys. Earth Planet. Inter., 57: 233-259.
Sipkin, S.A. and Needham, R.E., 1991. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1988-1989. Phys. Earth Planet. Inter., 67: 221-230. Sipkin, S.A. and Needham, R.E., 1992. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1990. Phys. Earth Planet. Inter., 70: 16-21. Sipkin, S.A. and Needham, R.E., 1993. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1991. Phys. Earth Planet. Inter., 75: 199-204. Sipkin, S.A. and Needham, R.E., 1994a. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1992. Phys. Earth Planet. Inter., 82: 1-7. Sipkin, S.A. and Needham, R.E., 1994b. Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1993. Phys. Earth Planet. Inter., 86: 245-252.