readme

RTOKADA - README , otherwise good luck.

Diego Melgar & Brendan Crowell 
06/2013 
dmelgarm[at]ucsd.edu

This code computes static slip inversions with Laplacian (second order Tikhonov)
regularization using coseismic offsets and off-shore wave gauge measurements.
The inversion can be eprformed with just coseismic offsets, just wave gauges or
the joint data set. If you want to know more about the code I suggest you take a
look at the references.

This code is perenially in research so you should always do your due dilligence
and double check and validate results.  I've put a little effort into making it
user friendly but my main goal is my own research not making your life easier.
That being said I think the code works fine and has been used for multiple
publications. I am glad to help and do often respond to email.

I have included a folder with sample input files so that you may know how to
format your own data.

The program flow is as follows:

1) Get your coseismic offset data into the "neu" format, there's an example file
'157.neu' in the samples folder. It's a one column file: 
-column 1 is a token
integer, any integer (yes this is dumb i'll get rid of it someday) 
-column 2 is north offset in metres 
-column 3 is east offset in metres
-column 4 is vertical offset (up is +)  in metres 
-column 5 is north data weight (I use the std. deviation of the pre-event noise) 
-column 6 is east data weight 
-column 7 is vertical data weight

2) Make a file 'stations.xy' (also in the samples folder) with the stationc
oordinates, it's a 3 column file 
-column 1 is station name (make sure it's consistent with the neu file name) 
-column 2 is station longitude 
-column 3 is station latitude

3) Make a file with coordinates at which you require output on the deformation
fo the seafloor. Theres a file 'seafloor.xy' in the samples folder. It's a 2
column folder. 
-column 1 is latitude 
-column 2 is longitude

4) Make your fault. I suggest starting from Slab 1.0 (Hayes et al, 2012) and
then following the method in Romano et al. (2009) to make the subfaults, you
might have another way. In any case, you should make two files, the first is
'faultdef.txt' (also in samples folder) there should be 2 numbers in this file
the first is the # of along strike subfaults, the second one is the # of along
dip subfaults

The second file is the subfault informaiton, 'fault.txt' in the samples folder.
It's a 20 column file
** Coordiantes of the centre of the patch 
- column 1 is longitude 
- column 2 is latitude 
- column 3 is depth (should be negative) 
** Coordinates of the 4 corners 
- column 4 is longitude of 1st corner 
- column 5 is longitude of 2nd corner 
- column 6 is longitude of 3rd corner 
- column 7 is longitude of 4th corner 
- column 8 is latitude of 1st corner 
- column 9 is latitude of 2nd corner 
- column 10 is latitude of 3rd corner 
- column 11 is latitude of 4th corner 
- column 12 is depth of 1st corner 
- column 13 is depth of 2nd corner 
- column 14 is depth of 3rd corner 
- column 15 is depth of 4th corner 
** Subfault geometry 
- column 16 is strike 
- column 17 is dip 
- column 18 is along strike length 
- column 19 is along dip length 
-column 20 is total area

5) Prepare your wave gauge data, make a file like "gauges.dat" in the samples
folder it's a 5 column file 
-Column 1 is an integer used as staton identifier
-Column 2 is station longitude 
-Column 3 is station latitude 
-Column 4 is a string with station name 
-Column 5 is a string witht he station description

Then assemble your data in individual 2 column files like the file 'OB.TM1' in
the samples folder. It's a 7 column file 
-Column 1 is month 
-Column 2 is day
-Column 3 is year 
-Column 4 is hour 
-Column 5 is minute 
-Column 6 is second
-Column 7 is sea surface elveation measurement

6) Now prepare your green functions, you need 3 sets of GFs, one for the
coseismic offsets, one for the points where you require seafloor deformation and
one for the wave gauges. Run the following 2 functions: 
-coseisgreen() will make the coseismic and seafloor GFs assuming you have prepared
	all the files succesfully. 
-wavegreen() will make the wavegauge GFs, again assuming all files are kosher

7) Run the inversion. To do so you run batch_rtokada(), the parameters that need
to be set are in the comments

8) Look at output, each inversion will make 7 output files; samples of all of
these are in the samples folder: 
	.log file with information ont he run 
	.slip file with the slip inversion results 
		-column 1 is amount of strike-slip motion (in mm) 
		-column 2 is amount of dip-slip motion (in mm) 
		-column 3 is moment magnitude of the whole inversion 
		-column 4 is subfault longitude 
		-column 5 is subfault latitiude 
		-column 6 is subfault depth 
	.disp file with the observed and synthetic coseismic offsets 
		-column 1 is station name 
		-column 2 is one of those stray integers, ignore it 
		-column 3 is station latitude 
		-column 4 is station longitude 
		-column 5 is north observed coseismic offset 
		-column 6 is east observed coseismic offset 
		-column 7 is vertical observed coseismic offset
		-column 8 is north synthetic coseismic offset 
		-column 9 is east synthetic coseismic offset 
		-column 10 is vertical synthetic coseismic offset 
	.rake file with the rake angle at each subfault (this is used for plotting with psvelo 
			in GMT) 
	.sflr file with neu motions of the requested points in the seafloor 
	.dtopo file is initial condition file (dtopo) for GeoClaw tsunami simulations 
			(topotype 3) 
	.wave is synthetic wave gauge calculations at all stations

9) Plot output. I also include a GMT script RTO_tohoku.gmt  that uses these
files as input for plotting. I don't include the topography grids used in the
plots, so you'll have to make your own.

Happy hunting!




If you use this please reference:

1) Crowell, B.W., Y. Bock, and D. Melgar (2012), Real-time inversion of GPS data
for finite fault modeling and rapid hazard assessment, Geophys. Res. Lett., 39,
L09305, doi:10.1029/2012GL051318.

2)Melgar, D., B.W. Crowell, Y. Bock, and J.S. Haase (2013), Rapid modeling of
the 2011 Mw 9.0 Tohoku-oki earthquake with seismogeodesy, Geophys. Res. Lett.,
doi:10.1002/grl.50590.

3)Melgar, D. and Y.Bock (in prep), Near-Field Tsunami Models with Rapid
Earthquake Source Inversions from Land and Ocean Based Observations: The
Potential for Forecast and Warning.

Acknowledgments: 
- okada_green is modified from Francois Beauducel's okada85
fucntion available on the mathworks file exchange. 
- DM has done most of the development of the code found in this repo but I started
from BC's kernel of code which allowed me to hit the ground running and without 
which this would have been tedious. 
- The idea and development of this code has benefited from fruitful discussions 
with Randy LeVeque.

References: 
- Hayes, G. P., D. J. Wald, and R. L. Johnson (2012), Slab1.0: A
three-dimensional model of global subduction zone geometries, J. Geophys. Res. ,
117, B01302, doi:10.1029/2011JB008524. 
- Romano, F., et al (2012), Clues from
joint inversion of tsunami an geodetic data of the 2011 Tohoku-oki earthquake,
Sci. Rep. 2(385), doi:10.1038/srep00385.