IGARSS_2011_ScanSAR_new.pptx

Extraction of Wide-ranging Crustal Movement Using ALOS/PALSAR

ScanSAR Interferometry

July 26, 2011 　 IGARSS 2011 Vancouver, Canada

Masanori Miyawaki (NEC Aerospace Systems)

Shino Yamaguchi (NEC Aerospace Systems)

Tsunekazu Kimura (NEC)

Page 2 © NEC Corporation 2011

Outline

▌1. Introduction

▌2. Comparison of stripmap-mode and ScanSAR-mode

▌3. Processing flow of ScanSAR-ScanSAR interferometry

▌4. Processing results of ScanSAR-ScanSAR interferometry

▌5. Conclusions


Introduction

▌Differential SAR interferometry is a very powerful tool to detect crustal movement. ▌Many excellent D-InSAR results are reported by ALOS/PALSAR stripmap-mode data.▌In recent years, huge earthquakes have occurred with wide-ranging crustal movement over hundred of kilometers.▌In such cases, the entire deformation area cannot be covered using stripmap-mode data.▌ScanSAR has very wide swath. So, ScanSAR-ScanSAR interferometry is suitable for extraction of wide-ranging crustal movement caused by huge earthquake.▌We tried ScanSAR-ScanSAR D-InSAR processing using a lot of pairs ALOS/PALSAR scanSAR mode data.

Earthquake Date Mw Rupture length

2004 Indonesia Sumatra Earthquake Dec.26,2004 9.1-9.3 1,300km

2008 China Wenchuan Earthquake May 12,2008 7.9 300km

2010 Chile Earthquake Feb.27,2010 8.8 700km

2011 Japan Tohoku Earthquake Mar.11,2011 9.0 500km


Comparison of Stripmap-mode and ScanSAR-mode (ALOS/PALSAR)

Mode Stripmap-mode (FBS) ScanSAR-mode (WB1)

Swath 70km 350km

Resolution 10m 100m

Interferometric Condition

Critical baseline about 13km Critical baseline about 5kmNeed the synchoronizing Burst timing

Strong point High resolutionHigh signal to noise ratio

Wide swath

Weak point Narrow swathWide ranging crustal movement

cannot be covered by one pass data

Low resolutionLow signal to noise ratioSevere the interferometric condition

Suitable use Detection of detail crustal movement - within 50km spread

Detection of widespread crustal movement – more than 100km spread


Example of Analysis result of Stripmap-mode data

2008 China Wenchuan Earthquake case

Analysis by GSI from ALOS raw data (c) JAXA, METI

（ http://cais.gsi.go.jp/Research/topics/topic080604/index.html ）

Illuminated direction

Flight direction


Comparison of Stripmap-mode and ScanSAR-mode (ALOS/PALSAR)

Mode Stripmap-mode (FBS) ScanSAR-mode (WB1)

Swath 70km 350km

Resolution 10m 100m

Interferometric Condition

Critical baseline about 13km Critical baseline about 5kmNeed the synchoronizing Burst timing

Strong point High resolutionHigh signal to noise ratio

Wide swath

Weak point Narrow swathWide ranging crustal movement

cannot be covered by one pass data

Low resolutionLow signal to noise ratioSevere the interferometric condition

Suitable use Detection of detail crustal movement - within 50km spread

Detection of widespread crustal movement – more than 100km spread


Burst Timing

Scan-1Scan-2

Scan-3Scan-4

Scan-5

Observation Geometry of ScanSAR-mode

Burst Footprint

Swath

SAR

Along-track direction


Burst Timing

Master

Slave

Interference No Interference

Burst overlap rate 100% 70% 30% 0% 0%

: Burst overlap time between master and slave : Burst duration time


Processing flow of ScanSAR-ScanSAR interferometry

MASTER

SLAVEDEM &

Orbit information

Processing at each scan data

SA

R im

age processing

Differential interferogramof each scan

SA

R im

age processing

Registration

Interferometry

Mosaic

Map projection

Rem

oval of topographic fringe

and orbital fringe


Processed data (2008 China Wenchuan Earthquake Case)

Path 124

Frame 2950 ， 3000

Orbit Direction Descending

Master data 2008/01/03

Slave data 2008/05/20

Perpendicular Baseline 477 - 556m (at swath center)

Burst overlap rate 78 - 79% (at swath center)

PRF / Burst duration time 1683.5Hz / 0.1467sec (scan #1)2358.5Hz / 0.1509sec (scan #2)1706.5Hz / 0.1606sec (scan #3)2150.5Hz / 0.1651sec (scan #4)1908.4Hz / 0.1713sec (scan #5)


Processing Result ( 2008 China Wenchuan Earthquake)


Processed data (2010 Chile Earthquake Case)

Path 422

Frame 4300, 4350, 4400




Perpendicular Baseline 1,480 – 1,565m (at swath center)


PRF / Burst duration time (Master data)

1689.2Hz / 0.1462sec (scan #1)2336.4Hz / 0.1524sec (scan #2)1712.3Hz / 0.1600sec (scan #3)2109.7Hz / 0.1683sec (scan #4)1915.7Hz→1862.2Hz / 0.1707sec→0.1756sec (scan #5)

PRF / Burst duration time (Slave data)

1686.3Hz / 0.1465sec (scan #1)2336.4Hz / 0.1524sec (scan #2)1709.4Hz / 0.1603sec (scan #3)2109.7Hz / 0.1683sec (scan #4)1912.0Hz→1858.7Hz / 0.1710sec→0.1759sec (scan #5)


Processing Result ( 2010 Chile Earthquake)


The differential fringe and burst overlap rate

Azimuth

0

20

40

60

80

100

Burs

t O

verlap R

ate

[%]

PRF change(master data)

PRF change(slave data)

Range

Bur

st O

verla

p R

ate

[%]


Processed data (2011 Japan Tohoku Earthquake Case)

Path 61

Frame 2800 ， 2850, 2900




Perpendicular Baseline 2,045 - 2,270 m (at swath center)


PRF / Burst duration time 1675.0Hz / 0.1475sec (scan #1)2375.3Hz / 0.1499sec (scan #2)1700.7Hz / 0.1611sec (scan #3)2141.3Hz / 0.1658sec (scan #4)1901.1Hz / 0.1720sec (scan #5)


Preliminary Result ( 2011 Japan Tohoku Earthquake)

ScanSAR D-InSAR fringe

Stripmap-mode D-InSAR fringe (analyzed by JAXA)


The conditions for ScanSAR-ScanSAR interferometry

2008 China Wenchuan 2010 Chile

2011 Japan Tohoku


Conclusions

▌We tried to detect the crustal movement deformation by ScanSAR-ScanSAR interferometry processing using the ALOS/PALSAR data.

▌We could get good interferograms without the phase discontinuity between scans. (2008 China Wenchuan Earthquake, 2010 Chile Earthquake)

▌It was confirmed to be able to detect crustal movement by ScanSAR-ScanSAR interferometry analysis.

▌It was shown that the ScanSAR-ScanSAR interferometry can be a very powerful tool of wide-ranging crustal movement analysis.

▌To utilize ScanSAR-ScanSAR Interferometry more effective, interferometric baseline and burst timing ought to be controlled.


Acknowledgement

▌In this study, PALSAR Level 1.0 data are provided from Earthquake Working Group under a cooperative research contract with JAXA.

▌The ownership of PALSAR data belongs to METI and JAXA.

▌We greatly appreciate supports by these groups.


Technology

IGARSS_2011_ScanSAR_new.pptx