To: Colleagues/Open Distribution From: Ken Hudnut and collaborators Date: Jan. 18, 1995 The following is a set of 61 displacement vectors that have been derived from GPS measurements before and after the Northridge earthquake. We ask that if you use these results or a future release of improved/added estimates that you refer to our submitted paper (Hudnut, K., Z-K. Shen, M. Murray, S. McClusky, R. King, T. Herring, B. Hager, Y. Feng, P. Fang, A. Donnellan, and Y. Bock, Co-seismic displacements of the 1994 Northridge, Calif., earthquake; submitted to Bulletin of the Seismological Society of America on January 17, 1995). The paper documents recognized problems with the measurements presented below that in some cases indicate errors larger than the one-sigma errors stated here. For example, we suspect monument instability at station LOVE, and a likely measurement error in the vertical component at station CATO. The vector stated for station JPLM also appears to contain unmodeled error, possibly due to antenna phase center mis-modeling. If you intend to use these data, we hope that you will obtain a preprint of our paper as a guide to the data. Please e-mail any questions regarding these data to hudnut@seismo.gps.caltech.edu Preprints are available from any of the co-authors. --------------- DISCLAIMER: These results are preliminary and the coordinates listed are in a reference frame not suitable to use in any land surveying applications. ___________________________________________________________________________________________ PRELIMINARY DISPLACEMENTS AT A SUBSET OF STATIONS (displ. and uncertainties in millimeters): ___________________________________________________________________________________________ long lat stn dE dN sigE sigN cor NE dU sigU ---------------------------------------------------------------------------- -117.4368 33.8567 MATH -7.4 2.2 3.01 3.01 0.068 1.2 3.40 -117.4511 34.3472 CAJO -4.8 16.3 3.91 4.24 -0.093 67.8 21.41 -117.7651 34.4927 0705 4.9 -8.4 6.18 5.00 0.158 0.1 26.57 -117.9224 34.5121 PEAR -5.1 -4.0 3.61 3.66 0.148 30.5 12.86 -118.0883 33.7375 1201 1.0 -5.5 4.92 5.33 -0.069 24.1 24.48 -118.1092 34.5436 ALPN -7.6 -8.4 34.33 19.83 0.554 -5.0 74.06 -118.1362 34.3794 07FI 3.4 -5.1 5.00 5.08 -0.283 7.8 24.19 -118.1539 34.2856 JSPH 2.7 -7.6 3.78 3.78 0.010 -29.5 16.57 -118.1572 35.0871 PORT -1.1 2.8 4.10 4.46 -0.056 22.6 22.50 -118.1711 34.0632 07DI 12.2 4.1 18.74 7.98 0.501 12.1 45.50 -118.1732 34.2048 JPLB 9.8 -9.1 3.01 3.01 -0.064 18.5 3.35 -118.1798 33.9513 07CI 9.8 6.8 20.03 9.49 0.412 -54.1 53.78 -118.2158 34.2107 07EH -4.2 2.6 31.05 19.33 0.617 -75.2 69.76 -118.2160 33.8682 56_Z -0.9 -7.3 29.45 15.20 0.158 71.3 83.25 -118.2853 34.0203 USC2 12.1 16.3 4.84 5.75 -0.083 -27.2 32.64 -118.3258 34.1370 CAHA 14.9 9.9 4.17 4.46 0.007 -5.9 22.40 -118.3309 34.1479 BURB 13.9 1.5 3.97 4.31 -0.097 -59.0 20.03 -118.3525 33.7968 SPHI -1.9 16.8 3.84 4.10 -0.079 -25.0 17.95 -118.3561 34.5610 PELN -7.5 -34.7 30.15 19.14 0.588 15.3 71.06 -118.3734 34.2223 Z786 53.8 -2.0 17.16 5.66 0.161 36.4 25.97 -118.3945 33.8773 WBCH 6.8 15.0 3.97 4.24 -0.016 -54.5 20.82 -118.4033 33.9965 0701 6.6 22.7 3.84 4.17 -0.091 6.7 20.82 -118.4036 33.7438 PVER 7.3 15.1 3.35 3.50 0.044 27.2 12.27 -118.4042 33.7433 PVEP -0.2 8.4 3.01 3.01 0.117 -9.9 3.45 -118.4073 34.4654 0141 -14.4 -42.7 19.63 8.92 0.445 -41.1 48.09 -118.4083 34.2636 PACO 101.8 -10.6 3.40 3.55 -0.014 69.1 12.66 -118.4186 33.9722 VENI 9.0 26.5 4.04 4.24 -0.013 -31.7 20.62 -118.4264 34.2092 SATI 70.9 -26.8 4.76 5.24 -0.080 46.9 27.56 -118.4329 33.9282 07CG 1.6 22.9 4.92 5.83 -0.051 -21.6 34.33 -118.4410 34.0687 UCLA -0.3 49.4 3.35 3.35 -0.005 -17.7 11.02 -118.4769 34.1259 MLND 9.7 28.0 4.69 5.58 -0.023 2.7 31.14 -118.4882 34.2917 RESE 200.3 -6.7 3.40 3.31 -0.197 338.5 9.77 -118.5340 34.0343 N_49 21.4 54.4 37.32 24.58 0.676 -28.9 88.45 -118.5401 34.4071 0704 -33.4 -61.4 3.27 3.27 -0.075 9.5 9.20 -118.5552 34.2328 NORT 34.8 -59.9 3.45 3.45 -0.231 225.8 10.73 -118.5638 34.3742 NEWH -94.4 44.4 13.63 6.62 0.512 257.7 32.34 -118.6013 34.3306 PICO -126.7 159.9 3.50 3.50 -0.073 431.9 12.56 -118.6013 34.3304 SAFE -140.7 161.4 3.08 3.06 -0.119 408.6 5.41 -118.6014 34.3305 SAFR -133.8 159.0 4.53 4.53 -0.063 378.6 23.59 -118.6457 34.1401 CALA 52.2 83.0 3.31 3.35 -0.054 -12.1 10.54 -118.6517 34.5445 Z370 8.8 -38.6 30.15 19.24 0.558 -21.1 72.56 -118.6687 34.4963 LOVE -84.7 -48.3 3.08 3.08 -0.035 -68.8 5.58 -118.6702 34.2788 CHRN -91.7 46.0 4.04 4.46 -0.087 154.1 21.21 -118.6929 34.4059 U145 -54.3 10.3 4.39 4.53 -0.047 34.6 20.82 -118.7019 34.0332 MALI 37.9 59.3 4.46 5.16 -0.083 -21.8 31.05 -118.7428 34.5674 WHIT -17.9 -24.6 3.31 3.31 0.099 -11.3 9.11 -118.7518 34.2719 Y609 -27.7 44.1 4.46 4.84 -0.036 63.1 25.48 -118.7858 34.0858 CATO 37.1 48.0 3.20 3.16 0.058 34.6 7.52 -118.7903 34.6877 WARN 33.8 -10.3 41.11 20.52 0.315 -10.0 86.45 -118.8248 34.0176 DUMP 46.1 41.7 4.53 5.16 -0.045 -20.8 31.74 -118.8501 34.3580 HAPY -37.6 19.4 3.55 3.35 -0.057 69.0 9.77 -118.8655 34.4777 HOPP -14.0 3.1 3.27 3.31 0.069 59.5 8.92 -118.8681 34.8252 0618 3.6 -7.3 3.91 4.24 -0.117 2.7 19.53 -118.8771 34.3280 HAP2 -21.3 7.8 3.13 3.08 -0.293 14.1 6.35 -118.8858 34.1955 OAKS 3.5 24.7 43.10 21.71 0.224 12.4 124.14 -118.9234 34.2776 F113 17.0 34.8 70.86 37.02 0.743 -26.9 184.22 -118.9398 34.3938 0706 -6.5 2.8 5.33 5.66 0.173 21.8 29.15 -118.9627 34.0528 0703 34.2 21.3 4.17 4.04 0.008 4.4 18.15 -118.9988 34.3879 SNPA -10.7 2.9 3.35 3.31 0.150 5.2 8.92 -119.1233 34.3058 W304 2.3 17.3 5.00 6.80 -0.390 5.7 30.65 -119.2022 34.4399 OJAI -28.4 -12.7 46.00 24.39 0.717 37.2 73.86 ---------------------------------------------------------------------------------- Sites for which 95% conf. volume is approx. as large or larger than displacement, yet we include their measurements in the displacement table: OJAI WARN Z370 PELN ALPN 07EH 07DI 07CI 56_Z N_49 OAKS F113 ----------------------------------------------------------------------------------