Differential
interferogram superimposed on a Landsat TM image
SAR
dates:
13-Aug-99
and 17-Sep-99
Separation:
35
days
Comments
The
image shows the differential interferogram of the Izmit
earthquake, Turkey (17-Aug-99, magnitude 7.4 on the Richter
scale), overlaid on a Landsat TM (bands 3-2-3, R-G-B)
background. The interferogram has been filtered to reduce
noise and enhance clarity.
Contours
of displacement superimposed on a Landsat TM image
SAR
dates:
13-Aug-99
and 17-Sep-99
Separation:
35
days
Comments
The
image shows estimated displacement contours derived from
the differential interferogram (shown on upper image)
overlaid on a Landsat TM (bands 3-2-3, R-G-B)
background. Each contour represents 28mm of displacement
in the line of sight of the satellite (~72mm purely horizontal
in range). Displacement amounts as labelled are relative
to the reference contours. The white arrows indicate
the overall direction of ground displacement north and
south of the fault.
Quantitatively the contour pattern indicates in excess
of 2m lateral movement at the fault in either direction,
with more than 4m of relative movement across the fault.
An exact measurement of lateral strain is not possible,
because coherence is lost approaching the fault, possibly
due to excessive surface disruption associated with the
earthquake, e.g. liquefaction.
