2008/02/21 23:57:52 41.053 -114.923 10.0 4.6 Nevada
USGS Felt map for this earthquake
SLU Moment Tensor Solution
2008/02/21 23:57:52 41.053 -114.923 10.0 4.6 Nevada
Best Fitting Double Couple
Mo = 1.04e+23 dyne-cm
Mw = 4.61
Z = 9 km
Plane Strike Dip Rake
NP1 19 68 -118
NP2 255 35 -40
Principal Axes:
Axis Value Plunge Azimuth
T 1.04e+23 19 130
N 0.00e+00 26 31
P -1.04e+23 57 251
Moment Tensor: (dyne-cm)
Component Value
Mxx 3.56e+22
Mxy -5.50e+22
Mxz -5.17e+21
Myy 2.69e+22
Myz 6.86e+22
Mzz -6.25e+22
##############
##################----
######################------
################----###-------
##########---------------####-----
########------------------#######---
######---------------------##########-
#####----------------------############-
####-----------------------#############
####------------------------##############
###------------------------###############
##--------- -------------###############
#---------- P ------------################
---------- -----------################
-----------------------#################
---------------------########## ####
-------------------########### T ###
-----------------############ ##
--------------################
-----------#################
-------###############
##############
Harvard Convention
Moment Tensor:
R T F
-6.25e+22 -5.17e+21 -6.86e+22
-5.17e+21 3.56e+22 5.50e+22
-6.86e+22 5.50e+22 2.69e+22
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20080221235752/index.html
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STK = 255
DIP = 35
RAKE = -40
MW = 4.61
HS = 9
The waveform inversion is preferred. The surface-wave solution is consistent.
The following compares this source inversion to others
SLU Moment Tensor Solution
2008/02/21 23:57:52 41.053 -114.923 10.0 4.6 Nevada
Best Fitting Double Couple
Mo = 1.04e+23 dyne-cm
Mw = 4.61
Z = 9 km
Plane Strike Dip Rake
NP1 19 68 -118
NP2 255 35 -40
Principal Axes:
Axis Value Plunge Azimuth
T 1.04e+23 19 130
N 0.00e+00 26 31
P -1.04e+23 57 251
Moment Tensor: (dyne-cm)
Component Value
Mxx 3.56e+22
Mxy -5.50e+22
Mxz -5.17e+21
Myy 2.69e+22
Myz 6.86e+22
Mzz -6.25e+22
##############
##################----
######################------
################----###-------
##########---------------####-----
########------------------#######---
######---------------------##########-
#####----------------------############-
####-----------------------#############
####------------------------##############
###------------------------###############
##--------- -------------###############
#---------- P ------------################
---------- -----------################
-----------------------#################
---------------------########## ####
-------------------########### T ###
-----------------############ ##
--------------################
-----------#################
-------###############
##############
Harvard Convention
Moment Tensor:
R T F
-6.25e+22 -5.17e+21 -6.86e+22
-5.17e+21 3.56e+22 5.50e+22
-6.86e+22 5.50e+22 2.69e+22
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20080221235752/index.html
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The focal mechanism was determined using broadband seismic waveforms. The location of the event and the and stations used for the waveform inversion are shown in the next figure.
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The program wvfgrd96 was used with good traces observed at short distance to determine the focal mechanism, depth and seismic moment. This technique requires a high quality signal and well determined velocity model for the Green functions. To the extent that these are the quality data, this type of mechanism should be preferred over the radiation pattern technique which requires the separate step of defining the pressure and tension quadrants and the correct strike.
The observed and predicted traces are filtered using the following gsac commands:
hp c 0.02 n 3 lp c 0.06 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT
WVFGRD96 0.5 270 70 -15 4.25 0.3827
WVFGRD96 1.0 95 90 0 4.25 0.3904
WVFGRD96 2.0 90 75 -20 4.36 0.4446
WVFGRD96 3.0 265 45 -20 4.46 0.4670
WVFGRD96 4.0 265 35 -20 4.52 0.5287
WVFGRD96 5.0 265 35 -20 4.53 0.5785
WVFGRD96 6.0 260 35 -30 4.54 0.6116
WVFGRD96 7.0 260 40 -35 4.54 0.6306
WVFGRD96 8.0 255 35 -40 4.61 0.6517
WVFGRD96 9.0 255 35 -40 4.61 0.6550
WVFGRD96 10.0 260 40 -35 4.60 0.6491
WVFGRD96 11.0 260 40 -30 4.59 0.6358
WVFGRD96 12.0 265 45 -25 4.59 0.6223
WVFGRD96 13.0 270 50 -10 4.58 0.6077
WVFGRD96 14.0 270 50 -10 4.59 0.5932
WVFGRD96 15.0 270 50 -10 4.59 0.5767
WVFGRD96 16.0 275 55 5 4.60 0.5612
WVFGRD96 17.0 275 55 5 4.60 0.5457
WVFGRD96 18.0 275 55 5 4.60 0.5293
WVFGRD96 19.0 275 55 5 4.60 0.5125
WVFGRD96 20.0 275 55 5 4.61 0.4957
WVFGRD96 21.0 275 55 5 4.61 0.4790
WVFGRD96 22.0 275 55 5 4.62 0.4626
WVFGRD96 23.0 275 55 5 4.62 0.4466
WVFGRD96 24.0 275 55 5 4.62 0.4311
WVFGRD96 25.0 275 55 5 4.62 0.4161
WVFGRD96 26.0 275 55 5 4.63 0.4016
WVFGRD96 27.0 275 60 10 4.64 0.3881
WVFGRD96 28.0 275 60 10 4.64 0.3751
WVFGRD96 29.0 275 60 10 4.64 0.3626
The best solution is
WVFGRD96 9.0 255 35 -40 4.61 0.6550
The mechanism correspond to the best fit is
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The best fit as a function of depth is given in the following figure:
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The comparison of the observed and predicted waveforms is given in the next figure. The red traces are the observed and the blue are the predicted. Each observed-predicted componnet is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. The number in black at the rightr of each predicted traces it the time shift required for maximum correlation between the observed and predicted traces. This time shift is required because the synthetics are not computed at exactly the same distance as the observed and because the velocity model used in the predictions may not be perfect. A positive time shift indicates that the prediction is too fast and should be delayed to match the observed trace (shift to the right in this figure). A negative value indicates that the prediction is too slow. The bandpass filter used in the processing and for the display was
hp c 0.02 n 3 lp c 0.06 n 3
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| Focal mechanism sensitivity at the preferred depth. The red color indicates a very good fit to thewavefroms. Each solution is plotted as a vector at a given value of strike and dip with the angle of the vector representing the rake angle, measured, with respect to the upward vertical (N) in the figure. |
The following figure shows the stations used in the grid search for the best focal mechanism to fit the surface-wave spectral amplitudes of the Love and Rayleigh waves.
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The surface-wave determined focal mechanism is shown here.
NODAL PLANES
STK= 15.00
DIP= 74.99
RAKE= -125.00
OR
STK= 264.71
DIP= 37.70
RAKE= -25.05
DEPTH = 7.0 km
Mw = 4.62
Best Fit 0.9154 - P-T axis plot gives solutions with FIT greater than FIT90
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The P-wave first motion data for focal mechanism studies are as follow:
Sta Az(deg) Dist(km) First motion ELK 218 43 -12345 M13A 62 72 -12345 N11A 249 73 -12345 O11A 211 120 -12345 O13A 142 130 -12345 L13A 35 141 -12345 M14A 69 141 -12345 N14A 98 148 -12345 BGU 95 160 -12345 L10A 312 172 -12345 K12A 1 176 -12345 L14A 52 178 -12345 K13A 21 190 -12345 HVU 65 197 -12345 DUG 117 202 -12345 N15A 94 203 -12345 SPU 81 209 -12345 M15A 77 212 -12345 O15A 112 224 -12345 Q12A 178 224 -12345 P14A 135 226 -12345 L15A 63 237 -12345 NOQ 100 240 -12345 J12A 357 244 -12345 Q13A 161 245 -12345 K10A 321 251 -12345 L09A 296 253 -12345 Q11A 195 253 -12345 J13A 13 268 -12345 K15A 47 269 -12345 NLU 116 270 -12345 N08A 265 272 -12345 J11A 344 273 -12345 J14A 24 278 -12345 M16A 83 278 -12345 Q10A 208 278 -12345 P15A 125 279 -12345 HLID 8 282 -12345 O08A 254 286 -12345 M08A 280 293 -12345 N16A 92 294 -12345 TCU 87 295 -12345 K09A 309 296 -12345 MPU 111 302 -12345 J10A 331 304 -12345 R12A 175 304 -12345 L08A 295 312 -12345 Q09A 219 313 -12345 Q15A 136 315 -12345 P16A 119 320 -12345 I13A 12 325 -12345 I11A 345 329 -12345 R10A 202 329 -12345 J15A 37 332 -12345 I14A 20 342 -12345 N07B 266 342 -12345 N17A 91 344 -12345 WVOR 298 345 -12345 J09A 318 346 -12345 R14A 151 347 -12345 M07A 277 358 -12345 M17A 81 360 -12345 O17A 104 367 -12345 J16A 47 368 -12345 AHID 58 370 -12345 TMU 120 372 -12345 S10A 203 376 -12345 P07A 245 377 -12345 K17A 59 382 -12345 S12A 179 382 -12345 I15A 31 384 -12345 H12A 1 388 -12345 R15A 143 389 -12345 RRI2 48 392 -12345 S13A 166 396 -12345 S14A 157 396 -12345 P17A 115 397 -12345 I09A 325 399 -12345 Q16A 125 399 -12345 K07A 298 402 -12345 R08A 223 406 -12345 CCUT 160 411 -12345 N06A 267 415 -12345 DCID1 46 418 -12345 S09A 209 419 -12345 REDW 51 423 -12345 O18A 100 425 -12345 TPAW 49 425 -12345 O06A 258 427 -12345 P18A 110 428 -12345 J17A 52 432 -12345 SRU 118 433 -12345 SRU 118 433 -12345 S15A 149 435 -12345 SNOW 51 436 -12345 I08A 318 437 -12345 H15A 24 438 -12345 K18A 65 442 -12345 G12A 356 454 -12345 IMW 45 455 -12345 LOHW 50 455 -12345 T13A 169 456 -12345 BMO 336 465 -12345 T14A 160 471 -12345 L19A 74 478 -12345 BEK 256 479 -12345 R06C 236 479 -12345 G14A 14 480 -12345 O19A 98 497 -12345 MLAC 223 508 -12345 I18A 53 513 -12345 U12A 176 514 -12345 U11A 185 516 -12345 R18A 123 523 -12345 F13A 5 528 -12345 TIN 214 528 -12345 P19A 105 529 -12345 FUR 199 536 -12345 U14A 163 536 -12345 T16A 146 540 -12345 H07A 318 546 -12345 F15A 19 567 -12345 R19A 120 574 -12345 K20A 70 575 -12345 O20A 98 575 -12345 CMB 236 577 -12345 F10A 342 577 -12345 CWC 209 581 -12345 V11A 185 581 -12345 V13A 172 583 -12345 V12A 179 591 -12345 MPM 203 598 -12345 E14A 10 607 -12345 Q20A 110 612 -12345 S19A 125 619 -12345 V15A 157 629 -12345 L21A 78 638 -12345 W12A 180 638 -12345 F17A 31 640 -12345 R20A 117 645 -12345 WDC 268 645 -12345 RCT 217 647 -12345 GSC 195 659 -12345 E09A 338 660 -12345 E16A 22 662 -12345 W13A 172 667 -12345 W14A 165 668 -12345 ISA 209 674 -12345 Q21A 109 674 -12345 D14A 9 679 -12345 VES 213 683 -12345 E17A 27 684 -12345
Surface wave analysis was performed using codes from Computer Programs in Seismology, specifically the multiple filter analysis program do_mft and the surface-wave radiation pattern search program srfgrd96.
Digital data were collected, instrument response removed and traces converted
to Z, R an T components. Multiple filter analysis was applied to the Z and T traces to obtain the Rayleigh- and Love-wave spectral amplitudes, respectively.
These were input to the search program which examined all depths between 1 and 25 km
and all possible mechanisms.
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| Pressure-tension axis trends. Since the surface-wave spectra search does not distinguish between P and T axes and since there is a 180 ambiguity in strike, all possible P and T axes are plotted. First motion data and waveforms will be used to select the preferred mechanism. The purpose of this plot is to provide an idea of the possible range of solutions. The P and T-axes for all mechanisms with goodness of fit greater than 0.9 FITMAX (above) are plotted here. |
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| Focal mechanism sensitivity at the preferred depth. The red color indicates a very good fit to the Love and Rayleigh wave radiation patterns. Each solution is plotted as a vector at a given value of strike and dip with the angle of the vector representing the rake angle, measured, with respect to the upward vertical (N) in the figure. Because of the symmetry of the spectral amplitude rediation patterns, only strikes from 0-180 degrees are sampled. |
The distribution of broadband stations with azimuth and distance is
Sta Az(deg) Dist(km) O11A 212 120 O13A 142 130 L13A 35 141 M14A 69 141 N14A 98 148 BGU 95 160 L10A 312 172 K12A 0 176 L14A 52 178 K13A 21 190 HVU 65 197 DUG 117 202 N15A 94 203 SPU 81 209 M15A 77 212 O15A 112 224 Q12A 178 224 P14A 135 226 L15A 63 237 NOQ 100 240 J12A 357 244 Q13A 161 245 K10A 320 251 L09A 296 253 Q11A 194 253 J13A 13 268 K15A 47 269 CTU 98 270 NLU 116 270 N08A 265 272 J11A 344 273 J14A 24 278 M16A 83 278 Q10A 208 278 P15A 125 279 HLID 8 282 O08A 254 286 M08A 280 293 N16A 92 294 K09A 309 296 MPU 111 302 J10A 331 304 R12A 175 304 P08A 242 308 L08A 295 312 Q09A 219 313 Q15A 136 315 P16A 119 320 I13A 12 325 I11A 345 329 R10A 202 329 J15A 37 332 I14A 20 342 N07B 266 342 N17A 91 344 WVOR 298 345 J09A 318 346 R14A 151 347 K08A 303 350 M07A 277 358 M17A 81 360 O17A 104 367 J16A 47 368 AHID 58 370 I10A 336 371 TMU 120 372 S10A 203 376 P07A 245 377 K17A 59 382 S12A 179 382 I15A 31 384 S11A 191 385 H12A 1 388 R15A 143 389 RRI2 48 392 H13A 8 394 S13A 166 396 S14A 157 396 P17A 115 397 I09A 325 399 Q16A 125 399 K07A 298 402 Q07A 236 406 R08A 223 406 CCUT 160 411 H11A 348 415 N06A 267 415 DCID1 46 418 S09A 209 419 H10A 340 420 REDW 51 423 T11A 184 424 O18A 100 425 TPAW 49 425 R16A 135 426 O06A 258 427 P18A 110 428 J17A 52 432 SRU 118 433 S15A 149 435 SNOW 51 436 I08A 318 437 H15A 24 438 K18A 65 442 G12A 356 454 IMW 45 455 LOHW 50 455 WCN 246 455 MOOW 48 456 T13A 169 456 H09A 332 460 Q18A 116 462 R17A 128 465 J18A 58 471 T14A 160 471 L19A 74 478 BEK 256 479 I17A 47 479 R06C 236 479 G14A 14 480 T12A 178 481 M19A 82 486 J06A 301 496 O19A 98 497 G15A 23 498 GRA 206 498 T15A 153 499 G10A 340 504 H16A 35 504 I07A 313 505 MLAC 223 508 I18A 53 513 U12A 176 514 DLMT 21 515 U11A 185 516 S17A 136 520 U13A 170 522 F12A 357 523 R18A 123 523 G09A 335 524 F13A 5 528 TIN 214 528 G16A 28 529 K05A 292 529 P19A 105 529 U10A 194 529 FUR 199 536 Q19A 114 536 U14A 163 536 I06A 308 540 T16A 146 540 K19A 67 541 F14A 13 543 F11A 350 546 L20A 77 559 N20A 90 561 S18A 130 565 M20A 83 566 F15A 20 567 G08A 326 574 R19A 120 574 K20A 70 575 O20A 98 575 BOZ 26 576 CMB 236 577 F10A 342 577 CWC 209 581 V11A 184 581 P20A 105 582 G17A 34 583 V13A 172 583 SHO 192 584 F16A 26 589 V12A 179 591 E11A 350 598 MPM 203 598 E13A 5 602 H06A 315 602 G07A 322 606 E14A 10 607 SLA 200 609 Q20A 110 612 T18A 133 616 U17A 142 617 S19A 124 619 V14A 165 622 E15A 16 624 N21A 91 624 E10A 344 629 V15A 157 629 M21A 82 636 O21A 96 637 U16A 148 637 L21A 78 638 W12A 180 638 F17A 31 640 G18A 41 643 R20A 117 645 RLMT 44 645 WDC 268 645 MSO 7 647 RCT 217 647 RWWY 81 649 G06A 317 657 LDF 182 658 GSC 195 659 E09A 338 660 E16A 22 662 LRL 202 664 W13A 172 667 W14A 166 668 D13A 3 672 F07A 325 673 ISA 208 674 Q21A 109 674 D11A 351 676 U18A 138 676 D14A 9 679 VES 213 683 E17A 27 684 F18A 36 684 WUAZ 152 688 HUMO 287 689 E08A 332 690 W15A 160 692 D10A 345 693 D15A 15 693 T19A 131 693 G05A 314 698 NEE2 178 698 GMR 186 699 M22A 84 699 HAWA 330 700 MVCO 126 700 HEC 191 702 RRX 196 709 DAN 183 713 N22A 90 714 D16A 21 717 D09A 339 720 X13A 172 723 W16A 155 725 Q22A 107 726 E07A 329 729 E18A 32 733 EDW2 202 736 V18A 142 736 C13A 2 737 SAO 232 739 D08A 336 740 C12B 357 741 ARV 209 742 PDM 174 752 X14A 166 752 ADO 198 755 MCCM 247 755 D17A 25 758 W17A 150 759 IRM 182 766 X15A 161 766 G04A 309 768 R22A 112 768 C15A 13 769 BBR 194 774 C10A 347 775 SMM 216 776 E06A 323 780 VCS 202 781 BEL 187 788 COR 303 789 OSI 206 789 C16A 18 791 D07A 331 793 BFS 198 794 CHF 201 794 PHWY 85 794 SVD 195 794 C09A 342 796 D18A 29 796 PHL 220 796 X16A 156 798 W18A 144 800 ISCO 97 802 C17A 23 803 MWC 201 807 Y14A 167 808 Y13A 173 809 Y12C 177 811 DEC 203 812 F04A 314 813 B13A 2 814 PASC 202 816 C08A 338 817 W19A 142 819 NEW 348 820 Y15A 163 820 BC3 183 822 B10A 348 826 B12A 357 826 T22A 120 826 B11A 353 828 B15A 12 828 X17A 153 829 D06A 327 830 DJJ 203 832 USC 202 835 DGR 193 842 C07A 333 843 X18A 147 846 MUR 194 851 Y16A 158 852 B16A 16 856 B09A 344 858 W20A 137 866 FMP 201 867 SDD 197 867 B17A 21 868 RPV 202 868 Z14A 168 871 PLM 192 872 EGMT 26 876 A13A 2 877 A12A 356 878 B08A 338 883 D05A 323 885 A11A 353 886 A14A 7 888 GLA 179 888 SDCO 111 890 Y17A 155 893 Z15A 163 896 A15A 10 897 C06A 330 898 SWS 185 904 A10A 348 905 Z16A 159 910 B18A 25 911 A16A 16 916 W21A 134 917 B07A 335 920 D04A 320 922 E03A 314 924 113A 173 925 A09A 343 926 109C 193 927 Y19A 146 933 DVT 187 937 A17A 19 938 LAO 45 938 114A 168 939 A08A 340 942 BAR 190 942 112A 178 946 Z17A 154 947 RSSD 66 955 115A 165 957 SNCC 207 957 A18A 23 961 W22A 131 969 B06A 330 978 116A 162 985 Z18A 152 985 A07A 336 987 Z19A 148 997 NLWA 318 1002 ANMO 130 1005 X22A 134 1006 117A 157 1012 214A 169 1027 118A 153 1032 A06A 332 1032 TUC 158 1038 119A 150 1047 A05A 330 1047 Y22D 135 1047 216A 162 1051 OGNE 86 1084 217A 159 1093 120A 147 1098 218A 155 1098 219A 152 1125 318A 156 1155 122A 140 1164 DGMT 42 1181 319A 153 1187 CBKS 96 1320 AMTX 116 1348 ECSD 73 1533 KSU1 92 1574 WMOK 111 1580 AGMN 56 1706 JCT 126 1797 CIA 201 1811 SCIA 80 1811 MIAR 104 2007 JFWS 76 2048 CCM 247 2056 NATX 113 2082 UALR 102 2097 HKT 120 2116 SLM 89 2123 FVM 91 2127 COWI 66 2146 HDIL 83 2156 BMO 336 2169 PBMO 95 2169 SIUC 91 2237 PVMO 95 2244 MPH 99 2280 OLIL 88 2299 OXF 100 2352 USIN 89 2359 VBMS 106 2382 WVT 94 2412 BLO 86 2420 PLAL 97 2441 GLMI 70 2494 AAM 76 2592 ACSO 81 2688 BRAL 105 2723 TZTN 90 2756 ALLY 77 2891 ERPA 76 2895 GOGA 97 2899 MCWV 81 2964 BLA 87 2994 SSPA 78 3099 NHSC 95 3189 CBN 83 3214 BINY 75 3219 SDMD 81 3220 MVL 79 3244 DWPF 105 3364 ACCN 72 3381 PAL 76 3417 CPNY 77 3418 LBNH 70 3503
Since the analysis of the surface-wave radiation patterns uses only spectral amplitudes and because the surfave-wave radiation patterns have a 180 degree symmetry, each surface-wave solution consists of four possible focal mechanisms corresponding to the interchange of the P- and T-axes and a roation of the mechanism by 180 degrees. To select one mechanism, P-wave first motion can be used. This was not possible in this case because all the P-wave first motions were emergent ( a feature of the P-wave wave takeoff angle, the station location and the mechanism). The other way to select among the mechanisms is to compute forward synthetics and compare the observed and predicted waveforms.
The fits to the waveforms with the given mechanism are show below:
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This figure shows the fit to the three components of motion (Z - vertical, R-radial and T - transverse). For each station and component, the observed traces is shown in red and the model predicted trace in blue. The traces represent filtered ground velocity in units of meters/sec (the peak value is printed adjacent to each trace; each pair of traces to plotted to the same scale to emphasize the difference in levels). Both synthetic and observed traces have been filtered using the SAC commands:
hp c 0.02 n 3 lp c 0.06 n 3
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Should the national backbone of the USGS Advanced National Seismic System (ANSS) be implemented with an interstation separation of 300 km, it is very likely that an earthquake such as this would have been recorded at distances on the order of 100-200 km. This means that the closest station would have information on source depth and mechanism that was lacking here.
Dr. Harley Benz, USGS, provided the USGS USNSN digital data. The digital data used in this study were provided by Natural Resources Canada through their AUTODRM site http://www.seismo.nrcan.gc.ca/nwfa/autodrm/autodrm_req_e.php, and IRIS using their BUD interface.
Thanks also to the many seismic network operators whose dedication make this effort possible: University of Alaska, University of Washington, Oregon State University, University of Utah, Montana Bureas of Mines, UC Berkely, Caltech, UC San Diego, Saint L ouis University, Universityof Memphis, Lamont Doehrty Earth Observatory, Boston College, the Iris stations and the Transportable Array of EarthScope.
The WUS used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01
Model after 8 iterations
ISOTROPIC
KGS
FLAT EARTH
1-D
CONSTANT VELOCITY
LINE08
LINE09
LINE10
LINE11
H(KM) VP(KM/S) VS(KM/S) RHO(GM/CC) QP QS ETAP ETAS FREFP FREFS
1.9000 3.4065 2.0089 2.2150 0.302E-02 0.679E-02 0.00 0.00 1.00 1.00
6.1000 5.5445 3.2953 2.6089 0.349E-02 0.784E-02 0.00 0.00 1.00 1.00
13.0000 6.2708 3.7396 2.7812 0.212E-02 0.476E-02 0.00 0.00 1.00 1.00
19.0000 6.4075 3.7680 2.8223 0.111E-02 0.249E-02 0.00 0.00 1.00 1.00
0.0000 7.9000 4.6200 3.2760 0.164E-10 0.370E-10 0.00 0.00 1.00 1.00
Here we tabulate the reasons for not using certain digital data sets
The following stations did not have a valid response files:
DATE=Sun Feb 24 17:56:41 CST 2008