[IGSMAIL-6362] DEOS/DUT IGS Network Co-seismic Displacements from the March 11, 2011 M8.9 Earthquake in Japan
Wim Simons
W.J.F.Simons at tudelft.nl
Sun Mar 13 19:49:06 PDT 2011
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
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