From W.J.F.Simons at tudelft.nl Sun Mar 13 19:49:06 2011 From: W.J.F.Simons at tudelft.nl (Wim Simons) Date: Mon, 14 Mar 2011 03:49:06 +0100 Subject: [IGSMAIL-6362] DEOS/DUT IGS Network Co-seismic Displacements from the March 11, 2011 M8.9 Earthquake in Japan Message-ID: Dear colleagues, Following the Mw 8.9 earthquake in Japan last Friday, we made a first detailed GPS analysis over the weekend at DEOS/DUT (related to our ongoing co- and post-seismic GPS modelling research of the 2004 Mw 9.2 Sumatra-Andaman earthquake) that includes all operational IGS stations in Asia. The presented results use a combination of both static and kinematic mode in the JPL GIPSY-OASIS software. In static (bias-fixed) mode we analyzed an IGS network subset (57 stations) 10 days prior to the earthquake (GPS days 60-69) to get a good co-seismic deformation reference solution, followed by the 2 days after the earthquake (GPS days 70-71). These 2 post-quake solutions were averaged whereby station solutions with significant post-seismic motions on the second day were omitted. This averaged post-quake solution was then projected onto the pre-quake 10-day averaged solution using all (regional/global)IGS stations (38 in total) that were not affected by the earthquake. Finally the resulting (far-field) co-seismic displacements were reduced by 7% to remove the accumulated post-seismic deformation in the first 24 hours (percentage based on our recent revisit of the Mw 8.5 Bengkulu 2007 earthquake near Sumatra, Indonesia) In kinematic (bias-free) mode we analyzed GPS day 070 for the IGS stations located most close to the epicentre (MIZU, TSKB, TSK2, MTKA and USUD). For days 65-71 the JPL Rapid GPS orbit and clock products were used. As already explained by Susan Owen in her IGS mail the resulting co-seismic displacements are computed by GIPSY as absolute values. The kinematic mode (whereby typically five 5-minute position estimates before and after the earthquake were averaged and subsequently differenced) was extremely useful to determine the "pure" near-field co-seismic displacements caused by the Mw 8.9 earthquake. In static mode the daily (post-quake) averaged positions are already significantly polluted by post-seismic motions and an additional co-seismic jump on day 070 at TSKB/TSK2 (-3.5/18.5/-2.5 cm N/E/U) and MTKA (0/7.5/-1.5 cm N/E/U) from the Mw 6.8 quake that followed about 30 minutes later. Also MIZU apparently ceased to operate on day 070 at 06:00 UTC, about 15 minutes after the earthquake. Below our first co-seismic displacement table is included. For the co-seismic displacements estimated in static mode the errors (at 95% C.L.) should be within 1 and 2.5 cm for respectively the horizontal and vertical displacements. In kinematic mode errors up to a couple cm are still possible. IGS stations up to a distance of 5000 km have been included. The detectable co-seismic displacements extend more than 2000 km away in both NW (China/Russia) and SE (beyond the Bonin Islands (Ogasawara)) direction. At first look the far-field displacements appear to be only about half the size of the first predictions posted here by Jeff Freymueller. They also appear to extend not as far as those of the Mw 9.2 Sumatra-Andaman quake. This could indicate that the actual magnitude is smaller than the Mw 8.9-9.0 reported values. We release these results to the international community as especially the far-field co-seismic displacements can contribute to the already extensive near-field GPS solutions made possible by the GEONET GPS network in Japan. The far-field GPS solutions may provide additional good constraints to the already ongoing geophysical/seismological modelling (rupture length, slip distribution) of the earthquake. If you find these solutions useful please credit them accordingly as "GPS co-seismic displacements (version 1.0) in the IGS GNSS network from the March 11, 2011 Mw 8.9 earthquake provided by the GEO2TECDI team at DEOS, Delft University of Technology, the Netherlands". Site Date Type Lat Lon Height Dnorth Dn SD Deast De SD Dup Du SD #sol Distance NECorr (deg) (deg) (m) (mm) (mm) (mm) (mm) (mm) (mm) bef/aft (km) ---------------------------------------------------------------------------- ----------------------------------------- MIZU 11MAR11 CP 39.1352 141.1328 0.118 -1140.13 (15.81) 2077.35 (14.10) -101.76 (16.46) (k6/ 1) d: 231 -0.083 TSKB 11MAR11 CP 36.1057 140.0875 67.180 90.64 (10.46) 324.11 ( 6.26) -49.23 (11.64) (k6/ 5) d: 315 -0.087 TSK2 11MAR11 CP 36.1056 140.0871 69.860 89.76 ( 8.27) 326.14 ( 8.26) -60.60 ( 6.88) (k6/ 5) d: 315 -0.097 MTKA 11MAR11 CP 35.6795 139.5614 108.906 52.37 ( 8.52) 145.31 ( 8.43) -27.61 (21.19) (k6/ 5) d: 381 -0.118 USUD 11MAR11 CP 36.1331 138.3620 1508.588 48.36 ( 5.15) 173.68 ( 6.63) 20.79 (14.39) (k6/ 5) d: 449 -0.077 STK2 11MAR11 CP 43.5286 141.8448 118.559 -23.19 ( 1.74) 12.96 ( 1.91) -7.49 ( 9.15) (10/ 1) d: 656 -0.037 YSSK 11MAR11 CP 47.0297 142.7167 91.299 -1.21 ( 1.78) -0.23 ( 0.71) -7.14 ( 2.98) (10/ 2) d: 1037 -0.065 CCJ2 11MAR11 CP 27.0675 142.1950 104.217 0.43 ( 1.92) -5.51 ( 1.74) -13.87 ( 6.46) (10/ 2) d: 1177 -0.031 AIRA 11MAR11 CP 31.8241 130.5996 314.652 2.39 ( 3.81) 7.33 ( 6.00) -7.32 (13.28) (10/ 1) d: 1306 -0.072 KHAJ 11MAR11 CP 48.5215 135.0462 130.474 -9.71 ( 1.27) 5.24 ( 1.80) -5.00 ( 2.30) (10/ 2) d: 1364 -0.123 DAEJ 11MAR11 CP 36.3994 127.3745 116.844 1.88 ( 0.88) 18.37 ( 2.06) -2.87 ( 2.95) (10/ 2) d: 1395 -0.122 SUWN 11MAR11 CP 37.2755 127.0542 82.272 1.11 ( 1.30) 19.05 ( 2.42) -1.43 ( 3.16) (10/ 2) d: 1409 -0.299 CHAN 11MAR11 CP 43.7907 125.4442 273.267 -6.59 ( 0.98) 14.48 ( 1.49) 0.91 ( 2.10) (10/ 2) d: 1624 -0.114 MCIL 11MAR11 CP 24.2901 153.9787 35.660 6.89 ( 1.44) -11.09 ( 1.04) -6.99 ( 3.86) (10/ 2) d: 1806 0.006 PETS 11MAR11 CP 53.0233 158.6501 102.079 1.59 ( 1.15) -2.03 ( 1.00) -5.27 ( 7.58) (10/ 2) d: 2079 0.164 SHAO 11MAR11 CP 31.0996 121.2004 22.056 1.09 ( 1.38) 2.27 ( 2.09) -1.92 ( 3.32) (10/ 2) d: 2120 -0.116 BJFS 11MAR11 CP 39.6086 115.8925 87.454 -0.94 ( 1.44) 4.29 ( 1.28) 4.90 ( 3.42) ( 8/ 2) d: 2349 -0.097 CNMR 11MAR11 CP 15.2297 145.7431 64.384 -0.75 ( 6.62) -0.46 ( 6.71) -6.17 (22.68) (10/ 1) d: 2485 0.089 TWTF 11MAR11 CP 24.9536 121.1645 201.531 -1.09 ( 1.25) -0.62 ( 1.72) -1.46 ( 4.95) (10/ 2) d: 2488 -0.110 TNML 11MAR11 CP 24.7980 120.9873 75.873 -1.43 ( 0.37) 0.15 ( 2.00) 0.65 ( 6.55) ( 9/ 2) d: 2512 -0.092 TCMS 11MAR11 CP 24.7980 120.9874 77.253 -1.04 ( 1.50) -0.31 ( 2.57) -2.17 ( 7.00) (10/ 2) d: 2512 -0.096 GUAM 11MAR11 CP 13.5893 144.8684 201.919 -0.05 ( 3.15) -4.15 ( 6.59) -0.27 (10.18) (10/ 1) d: 2655 -0.070 GUUG 11MAR11 CP 13.4332 144.8027 134.724 -1.36 ( 1.09) -2.93 ( 2.89) -10.26 (18.58) (10/ 2) d: 2671 0.021 WUHN 11MAR11 CP 30.5317 114.3573 25.882 0.96 ( 1.10) -0.55 ( 2.91) 4.80 ( 5.54) (10/ 2) d: 2728 -0.104 YAKT 11MAR11 CP 62.0310 129.6803 103.406 -0.43 ( 2.28) -1.42 ( 0.92) 12.23 (10.96) (10/ 2) d: 2836 -0.152 ULAB 11MAR11 CP 47.8651 107.0523 1575.543 0.87 ( 2.88) 0.06 ( 1.84) 4.35 (11.83) (10/ 2) d: 3089 -0.042 PIMO 11MAR11 CP 14.6357 121.0777 95.535 -0.83 ( 3.62) -2.06 ( 4.75) -8.58 (12.79) (10/ 1) d: 3309 -0.092 IRKJ 11MAR11 CP 52.2190 104.3162 502.042 0.06 ( 1.60) 1.08 ( 1.89) 0.14 (12.15) (10/ 2) d: 3360 -0.032 IRKT 11MAR11 CP 52.2190 104.3162 502.352 -1.45 ( 1.00) 0.85 ( 2.98) 2.01 (12.42) (10/ 2) d: 3360 -0.024 KUNM 11MAR11 CP 25.0295 102.7972 1986.211 0.89 ( 4.60) -0.27 ( 5.92) -6.68 (21.92) (10/ 1) d: 3974 -0.078 URUM 11MAR11 CP 43.8079 87.6007 858.862 1.53 ( 2.08) 0.42 ( 1.20) -0.80 (11.79) (10/ 2) d: 4541 0.024 LHAZ 11MAR11 CP 29.6573 91.1040 3624.610 1.84 ( 1.11) -0.47 ( 1.30) -0.70 (12.23) (10/ 2) d: 4721 0.074 CUSV 11MAR11 CP 13.7359 100.5339 74.294 -0.63 ( 3.17) -1.91 ( 4.16) 1.52 ( 5.63) (10/ 2) d: 4836 -0.054 ---------------------------------------------------------------------------- ----------------------------------------- CP: "pure" co-seismic displacements / k: kinematic solution, # 5-min epochs or daily solutions before and after quake I hope you will appreciate our efforts. Please don't hesitate to contact me if you require additional information regarding this analysis. Sincerely, Wim Simons ---- Wim J.F. Simons - Research Associate phone: +31 15 2782043 DEOS, Faculty of Aerospace Engineering fax: +31 15 2785322 Delft University of Technology E-mail: W.J.F.Simons at tudelft.nl Kluyverweg 1 www: http://www.deos.tudelft.nl NL-2629 HS Delft, The Netherlands -------------- next part -------------- An HTML attachment was scrubbed... URL: http://igscb.jpl.nasa.gov/pipermail/igsmail/attachments/20110314/354e0f72/attachment-0001.html