[IGSMAIL-6367] DEOS/DUT IGS Network Co-seismic Displacements fromthe March 11, 2011 M8.9 Earthquake in Japan - Version 1.1

[Wim Simons]

Dear colleagues,

Referring to IGSMAIL-6362 I hereby provide you with an update of the DEOS
IGS GNSS network solution.  The kinematic solutions remain unchanged (please
notice that static solutions for these 5 stations would result in
significantly higher (additional) co-seismic and post-seismic polluted
displacements), but the addition of 2 additional days (days 72-73) have
(mainly) improved some far-field co-seismic displacement error estimates.
Also I have now included IGS stations up to 6000 km away from the Mw 8.9
earthquake epicentre.

You can get the table here:

http://www.deos.tudelft.nl/~wims/DEOS_japanv1.1.txt

Also I made a figure with the DEOS GPS results:

http://www.deos.tudelft.nl/~wims/DEOS_japanv1.1.pdf

I have plotted the co-seismic deformation in 3 different scales, otherwise
the far field displacements would not be visible at all.  So the scales
change each time by a factor 5. The horizontal magnitude of each vector is
plotted (in mm) in the direction of the deformation. So also for small
vectors you can still see where they point to.  

I also have plotted (in black) the present-day plate motions (in cm/yr) in
the region (based on the MORVEL plate motion of DeMets et al (2010).  

Additionally I have plotted the shallow (<34 km) seismicity both 5-days
before (yellow dots) and 5-days after (red dots) as well as the actual Mw
8.9 quake (purple).  You probably already have noticed that there was an Mw
7.3 on 9 March (followed by aftershocks) at almost the same location the Mw
8.9 rupture started.  So (of course looking back) this could be related to
each other and probably signalled that the stress along the fault plane slip
interface had reached a critical value.

You can notice (as expected) that the bulk of the (near to mid field)
co-seismic deformations point towards the earthquake epicentre. Finally the
plot also shows the max/min topography of the region.

Credits on this also plot go to the IGS (all CGPS data), JPL (GIPSY-OASIS
software and GPS products), USGS (earthquake data), MORVEL (the latest
detailed plate motion model), ETOPO (plotted topography and bathymetry) and
finally the GMT plotting software. 

If you find these solutions useful please credit them accordingly as "GPS
co-seismic displacements (version 1.1) 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 (TU Delft), the Netherlands".

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