Landers
EQ
Hector Mine
EQ
Lyons and Sandwell, JGR, 2003
http://topex.ucsd.edu/gmtsar
forming interferogram
Perpendicular baseline
MATTERS!
B = Bsin (q - a )
B^ = B cos (q - a )
¶f -4p B cos (q - a ) æ
rö
=
çè cosq - ÷ø
¶r
lr
sinq
b
(f - f e ) @
-4p re B cos (q - a )
(r - re )
lrbsin q
phase due to curved earth
phase due to topography
total phase
Phase from
curved Earth
total phase
Critical Baseline
Phase from
topography
phase minus spherical earth
How high is Toro Peak?
deformation and topography
Triggered
slip on
Southern
San
Andreas
Fault
Need for Precise Orbits
1.
proper focus
2.
transform from geographic radar coordinates
3.
image alignment
4.
flattening interferogram
Brute force algorithm given precise orbit subroutine
pick target point
fly satellite along orbit and identify point of closest approach
(This is inefficient but computers are fast so don’t waste time coding.)
GMTSAR
2-pass processing
no ground control
seamless abutment of frames along track
stacking for time series
one master and many slaves
primary, secondary, tertiary, image alignment
ScanSAR Interferometry
possible but not easy
code needs refinement