SAR Data Applications for Disasters
- 1. Center for Research and Application for Satellite Remote Sensing Yamaguchi University SAR Data Utilizations for Disasters
- 2. • Floods • Japan flood in 2018 • Thailand flood in 2011 • Other floods in Laos, Myanmar, India in 2018 • Landslides o Landslides after heavy rain in Kyushu o Landslides after earthquake in Hokkaido • Earthquakes o Nepal earthquake in 2015 o Taiwan earthquake in 2016 o Kumamoto earthquake in 2016 o Hokkaido earthquake in 2018 o Indonesia earthqukae: Lombok and Sulawesi in 2018 2 Disasters
- 3. 3 A false color composite is created, with two of the RGB bands on the "during" image and one on the "before" Red : SAR Image before disaster Green : SAR Image during flood Blue : SAR Image during flood http://gsp.humboldt.edu/olm_2015/Courses/GSP_216_Online/images/sartable.png Before flood During flood Bright pixel Dark pixel Then, flood is red color Color composite for detecting disaster
- 4. • Roughly identify by backscattering coefficient of water • Automatic threshold methods (Ostu, clustering) 4 Flood thresholding
- 5. • ALOS-2 images • Image before disaster: 2016/04/29 • Image after disaster: 2017/07/07 Flood in Laos 5 Color composite for detecting disaster
- 6. Occurrence date: 23 July 2018 Input data: ALOS-2 ScanSAR on 29 July 2018 and 1 July 2018 ALOS-2 StripMap on 2 August 2018 Analysis method: • water detection by before- and during- flood images • water detection by during flood image Flood in Myanmar
- 7. Flood in Laos Occurrence date: 23 July 2018 Information: dam collapsed Input data: ALOS-2 StripMap (SM1) on 25 July 2018 Analysis method: water detection by during flood image Flood in Thailand Occurrence date: 29 July 2018 Input data: ALOS-2 StripMap (SM3) on 10 August and 6 April 2018 Analysis method: • water detection by before- and during- flood images Flood in Laos and Thailand
- 8. Occurrence date: 9 August 2018 Input data: Before ALOS-2 StripMap (SM3) on 7 April 2018 Before ALOS-2 ScanSAR (WD1) on 30 April 2018 After ALOS-2 ScanSAR (WD1) on 14 August 2018 After ALOS-2 StripMap (SM3) on 17 August 2018 Analysis method: • water detection by multi-temporal images Blue: permanent water Green: seasonal water Red: flood water Flood in India
- 9. Interferometry technique (Source: Soussa abd Bastos 2013) https://www.nat-hazards-earth-syst-sci.net/13/659/2013/nhess-13-659-2013.pdf Differential SAR Interferometry (DInSAR) uses two or more SAR images to generate maps of surface deformation, using differences in the phase of the waves returning to the satellite The need of InSAR technique ▪ Two SAR images are required. ▪ Both the images should have same frequency (X, C, S, L) and SAR geometry. 9
- 10. Nepal Earthquake — 7.8 Mw. on 25 April 2015 Pre-seismic Pre-seismic Damage assessment by Interferometric coherence Surface displacement by Interferogram Nepal Earthquake
- 11. Damage assessment by Interferometric coherence Surface displacement by Interferogram Kumamoto Earthquake (15 April 2016)
- 12. Occurrence date: 29 July 2018 Information: 6.4 Mw. Input data: ALOS-2 StripMap on 4 August and 12 May 2018 Analysis method: • Differential SAR interferometry (DInSAR) Occurrence date: 5 August 2018 Information: 6.9 Mw. Input data: ALOS-2 StripMap on 7 August 2018 and 29 December 2015 Analysis method: • Differential SAR interferometry (DInSAR) Earthquake in Lombok Island, Indonesia
- 13. Earthquake in Hokkaido, Japan Occurrence date: 5 September 2018 Information: 6.7 M Input data: ALOS-2 StripMap on 6 September and 23 August 2018 Analysis method: • Before and after-images color composite • Differential SAR interferometry (DInSAR) • Backscattering change detection
- 15. Occurrence date: 28 September 2018 Information: M7.5, induce tsunami and liquefaction Input data: ALOS-2 StripMap on 2018/10/01 ALOS-2 SCANSAR on 2018/10/02, 2018/08/21, 2018/07/10 ALOS-2 StripMap on 2018/10/12, 2018/08/17, 2018/05/11 Analysis method: • Change of backscattering pattern • Differential SAR interferometry (DInSAR) • Interferometric coherence change ScanSAR StripMap Earthquake and tsunami in Palu, Indonesia
- 16. Sentinel-2 ALOS-2 Damaged area by tsunami Liquefaction Damaged area by tsunami Liquefaction