142
Figure 2-a. Differential interferogram
after modified Goldstein filtering(No.l)
Figure 2-b. Differential interferogram
after modified Goldstein filtering(No.5)
123700 123800 123900 124000 124100 124200 124300
Figure 3. The average annual subsidence rate map from 1993 to 2000-2000
41900
41800
41700
41600
Figure 4. Main mines distribution map of Fushun city (Zhao, 2003)
3.3 Result
Assuming that the deformation is linear, we then compute the
average deformation rate within 7 years from the former 5
vertical change maps. The annual elevation change of Funshun
city is overlaid on the shaded SAR image acquired on July 14,
1998, seen in Figure 3. The vertical and horizontal coordinate
represent latitude and longitude amplified 1000 times,
respectively.
Figure 4 shows several main mines of Fushun city. There are
three main large mine fileds, such as WOSM (Western Open-pet
Coal Mine), Shengli, Laohutai, and Longfeng mine fields and
EOSM (Eastern Open-pet Coal Mine) etc. Compared Figure2 and
Figure 4, we can see the two “holes” due to severe decoherence
shows the boundary of WOSM and Shengli, Laohutai and
Longfeng mine fields. In the “holes”, we can only compute the
range where dramatic deformation occurred, and can not provide
accurate amplitude of deformation. Except this, the amplitude and
range of deformation are both displayed in Figure 4. From Figure
4 we can find that the relative subsidence value of east part
around the WOSM and Shengli mine field are generally more
than that of west part around Laohutai and Longfeng mine field,
which coincide with the open report( Xu ,2005). 50% area of
eastern Fushun has the 6-8 cm/y velocity, and most of the
western Fushun has the velocity of more than 10 cm/y.
4 DISCUSSION
The above case studies have supplied much ground surface
displacement information, and verified the D-InSAR technique
can detect cm level motion effectively and rapidly with low cost.
Meanwhile, we can find that the interferogram suffers from
spatial and temporal decorrelation, which leads to the occurrence
of some resultless area in the change maps. Besides this, the
terrain of Fushun urban is rigorous, and high-precision
topographic information is lacked. All these disadvantages make
the two pass D-InSAR little difficult. Provided that more SAR
SLC images are obtained, the results will be improved a lot.
In addition, the D-InSAR technique provide relative motion of
land surface, in collaboration with precise leveling surveying,
GPS ,and GIS and professional subsidence model, we can
evaluate the accuracy of D-InSAR technique, which is what we
will do in the future.
REFERENCES
Ding, X. L., Li Z. W., 2006.Selection of Filtering Parameter for
the Goldstein Radar Interferogram Filter. IEEE Transactions on
Geoscience and Remote Sensing(submitted)
Zhao, G X., Li, L., Chang Y. G, 2003.Design scheme of
geological hazard monitoring system in Fushun urban, Liaoning
Province, The Chinese Journal of Geological Hazard and Control,
14(3), pp. 100-105
Ge, L., Rizos C., Han S.W., and Zebker, H., 2001. Mining
subsidence monitoring using the combined InSAR and GPS
approach. The 10th FIG international symposium on deformation
measurements, California: Orange
Ge, L. L., Chang, H. C., Rizos, C., and Omura, M., 2004, Mine