Geodesy and Earth Observation Systems Group (GEOS)
Cooperative Research Centre for Spatial Information (CRCSI)
School of Surveying & Spatial Information Systems (SSIS)
Faculty of Engineering (Engineering)
The University of New South Wales (UNSW)
NSW Department of Lands (Lands)
in Collaboration with
The Earth Remote Sensing Data Analysis Center (ERSDAC)
The International Association of Geodesy Sub-Commission
4.4 "Applications of Satellite & Airborne Imaging Systems"
The IAG Consortium for Mine Subsidence Monitoring
This webpage provides updates on mapping the 12 May 2008 Sichuan Earthquake in China with differential satellite radar interferometry (DInSAR). We show the preliminary results in order to demonstrate the performance of L-band ALOS/PALSAR for monitoring deformation over large area. We will continue to update them.
The given images are preliminary results and will be improved by more detailed analysis including future additional PALSAR data acquisitions and modeling. Please note that the fringe pattern in the southwestern part (Sichuan Basin) may change in the improved results. At this stage, there is certain ambiguity in the calculation of contribution from satellite orbit conditions.
Because the seismic fault is more than 300km in length as estimated from seismic data, it can be seen from the prelimary results below that the currently available imagery covers only a portion of the ruptured fault and it has not been possible to compute the "absolute" displacement.
Please refresh regularly to view our latest updates. A FAQ page has been prepared to help better understand the results here.
Too busy/ slow, please visit our backup server HERE. Please also see our Chinese web page .
Most Recent Release
18 June 2008
Please see our latest DInSAR result from Path 472 HERE.
13 June 2008
UNSW has announced today that it will provide AU$300,000 in postgraduate scholarships to students from the quake devastated Sichuan region of China. Further details, please see HERE. Note our research has been mentioned on page 2 of the UNSW Media Release. The China Central Television interviewed UNSW Vice-Chancellor Professor Fred Hilmer at the press conference.
11 June 2008
Please see our latest results below from Path 477 (the left most track)
Again we've tried to push the envelope a bit further. Unlike most of the earlier results which were produced using precise satellite orbit data, we use predicted orbit data again this time in order to produce and deliver the result in NEAR REAL-TIME: 17 hours and 46 minutes – yet to beat our last record of less than 17.5 hours from image capture to result on web!
The Japanese ALOS PALSAR sensor acquired the Path 477 image on 11 June 2008 1:37 Sydney Time AEST (10/06/2008 15:37:07 UTC; 10/06/2008 23:37 Bejing Time).
Image data were available to download from ERSDAC at 11:24AM.
Image data (using predicted orbit) were downloaded to UNSW on 11/06/2008 at
16:55. DInSAR results were generated on 11/06/2008 at 19:05. Post-processed
DInSAR results were uploaded on 11/06/2008 at 19:23.
ALOS PALSAR Path 477, DInSAR interferogram:
Milestone 1: ALOS PALSAR imagery from Path 473
21 May 2008 Co- and pre-seismic deformation (interferogram)
23 May 2008 Ground displacement map from DInSAR and interferogram in Google Earth
26 May 2008 Ground displacement map from pixel offset analysis - ALOS PALSAR Path 473 (17 Feburary 2008 and 19 May 2008)
27 May 2008 Quake damage assessment based on the difference of DInSAR coherence
Milestone 2: ALOS PALSAR imagery from Path 476 was added
29 May 2008 DInSAR results: Paths 473 and 476 combined
31 May 2008 Ground displacement map from pixel offset analysis - ALOS PALSAR Path 476 (8 April - 24 May)
01 June 2008 Ground displacement map from pixel offset analysis - ALOS PALSAR Path 476 (8 April - 24 May) and Path 473 (2 Jan - 19 May); Quake damage assessment from InSAR coherence difference - ALOS PALSAR Path 476: (22 Feb & 8 April) - (8 April & 24 May)
Milestone 3: ALOS PALSAR imagery from Path 471 was added
03 June 2008 Officials from the Chinese Consulate-General of the People's Republic of China in Sydney, Counsellor BAI Gang and Consul GUO Liang, visited the UNSW Image Analysis Lab to thank the Team for their joint efforts in supporting the earthquake rescue operation in China by working closely with ERSDAC and IAG. Prof Graham Davies, the Dean for the UNSW Faculty of Engineering, hosted their visit.
04 June 2008 DInSAR results: Paths 473, 476 and 471 combined
05 June 2008 Pixel offset analysis for Path 471 (29 Feb - 31 May)
Milestone 4: ALOS PALSAR imagery from Path 474 was added
06 June 2008 DInSAR results: Paths 473, 476, 471 and 474 combined
Milestone 5: ALOS PALSAR imagery from Path 477 was added
11 June 2008 DInSAR results: Paths 473, 476, 471, 474 and 477 combined
Over the last few years the Group has focused on monitoring ground subsidence due to underground mining. Below is an animation of accumulated mine subsidence mapped by the ALOS PALSAR sensor. Note that DInSAR result has been successfully derived from EVERY cycle of the image acquisition.
References related to this result (PDF files for full papers can be found here):
Ng, A.H., H. Chang, L. Ge, C. Rizos, and M. Omura, 2008. Radar interferometry
for ground subsidence monitoring using ALOS PALSAR data. The XXI Congress of
The International Society for Photogrammetry and Remote Sensing,
3-11 July, Beijing.
Ge, L., H-C Chang and C Rizos, 2007. Mine Subsidence Monitoring Using Multi-source Satellite SAR Images, Photogrammetric Engineering and Remote Sensing (PE & RS), 73(3), 259-266.
Ge, L., X. Li, C. Rizos, and M. Omura, 2004. GPS and GIS Assisted radar interferometry. Photogrammetric Engineering and Remote Sensing (PE & RS), 70(10), 1173-1178.
Ge, L., H.-C. Chang, C. Rizos and J. Trinder, 2004. Multi-pass Differential Radar Interferometry with the Aid of GIS. The International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (IAPRSSIS), Vol.34, Part XXX, Istanbul, Turkey, 861-867.
Acknowledgement
We wish to thank the Earth Remote Sensing Data Analysis Center (ERSDAC) for providing ALOS PALSAR data. We also acknowledge the strong support from the International Association of Geodesy Sub-Commission 4.4 "Applications of Satellite & Airborne Imaging Systems" and IAG Consortium for Mine Subsidence Monitoring.
METI and JAXA have the ownership of the ALOS PALSAR original data. The PALSAR Level-1.1 products were produced and distributed to CRC-IS/UNSW by ERSDAC, Japan.
Further readings
1. General information on radar interferometry click here
2. Up-to-date information about seismic activities related to the quake by Yuzo Ishikawa click here
For further details and comments, please contact:
Dr Linlin Ge
A/Professor
School of Surveying & Spatial Information Systems
The University of New South Wales (UNSW)
Project Leader and Senior Research Fellow
Cooperative Research Centre for Spatial Information (CRCSI)
Visiting Professor
New South Wales Department of Lands (NSW
Lands)
Deputy Director
CRCSI-CEODE Joint Centre for Spatial Information (JoCSI)
Sydney, NSW 2052
AUSTRALIA
Phone: +61-2-9385 4177
Fax: +61-2-9313 7493
Mobile: 0423 287 219
Email: l.ge@unsw.edu.au
http://www.gmat.unsw.edu.au/LinlinGe
No of visits since 27 May 2008