1. August 25, 2005 Kuo-Hsin Hsiao, Jin-King Liu, Ming-Fong Yu Speaker : Kuo-Hsin Hsiao Identification of Landslides with combined RS and GIS data

2. 1. Introduction 2. Landslide Detection 3. Results of landslide interpretation 4. Concluding Remarks List of Contents

3. 1. Introduction ◆ Geologic and terrain characteristics in TAIWAN ◆ Climate condition – typhoon, torrential rainfall ◆ R.S. data – spatial 、 temporal resolution resolution, data acquisition, time required for interpretation, combined information of GIS, etc. Highly fractured rock formations Variations of Geologic Conditions: A section across Taiwan Lithology- conglomerates

4. Requirement of A Monitoring and Early Warning System Both for Emergency Response and for Mitigation Policy Landslide Detection Using Satellite Images –High Frequency Periodic Observation and Measurements : Month~Year –Data : SPOT-5 or Formosat-2. Objectives of the study: Periodic landslide Monitoring for Sustainable Management using high resolution data (for detecting small landslides) Prevention of Illegal Land Use and Deterioration Disaster Damage Estimation Background Orbit of FORMOSAT-2 Sun-Synchronous Orbit Altitude = 891 km; Inclination = 99.10 deg; Period = 14 Rev/day Introduction

5. Research Area: Shihmen Reservoir Introduction SPOT image flight path (CSRSR)

6. Shihmen Reservoir Purpose of the Reservoir –General water supply –Irrigation –High-tech industry Watershed Area:764 KM 2 Capacity: 2.5 x 10 8 M 3 Terrain Variation : 252M~3,500 M Average Rain Fall : 2,500 mm/yr Land-Use Type –Coniferous Tree, Deciduous Tree –Orchard, Rice, Village, Farming, Foresting –Bare Soil, River, Mixed-Forest, Bamboo, Grass Land –Mixed Coniferous-Deciduous Tree, Others. Land-Use Coverage Introduction

7. Shihmen Reservoir Introduction DEM slope forest type Soil map

8. Disaster – Typhoon AERE Duration : –Aug. 23 ~ Aug. 25, 2004 Maximum total accumulative rain fall -1,600 mm Maximum rain fall –146 mm / hr Contour of Total Accumulative Rain Fall 2004-08-24-09:232004-08-25-09:23 Introduction CWB

9. Water Quality after Typhoon Introduction 2004/8/26 FORMOSAT-2 Satellite IR Typhoon Road of AERE High turbidity Satellite Radar NSPO CWB

10. 2. Landslides Detection SPOT-5 2004/08/16 Resolution ： 10m SPOT5 2005/03/16 Resolution ： 2.5m & 10m Formosa-II 2005/04/04 Resolution ： 2m & 8m Data Acquisition

11. Disaster Estimation & Analysis Processes Disaster Estimation Disaster Areas DTM + Image (3D Visualization) Overlay Analysis Day-1 Image Day-2 Image NDVI/CVA Change Detection Landslide C overage Change ? YES NO Stop On-Site Photography Landslides Detection Classification overlay

12. Various Types of Landcover and Landuses Landslides Detection (a)River-bank landslides (b)Slope landslides (c)Upstream landslides (d) snow on tops (e)Grass lands (f)Excavated lands (g)Cultivated lands (h)Mountain village (i)Plain villages (j) Cemetery (k)Roads (l)Rivers

13. SPOT-5 data acquisition (before & after AERE) Landslides Spatial resolution Total No.Area (ha) Before typhoon (2004/08/16) 215225.8510m*10m Afetr typhoon (2005/03/16) 379629.2510m*10m 3. Results of landslide interpretation

14. Results Landslide interpreted from SPOT5 10m & 2.5m Acquisition date Landslide Spatial resolution Total No.Area (ha) SPOT5(2005/03/16) 379629.2510m*10m 477693.332.5m*2.5m Spatial resolution : 10mSpatial resolution : 2.5m

15. Results Landslide interpreted from formosat2 8m & 2m Acquisition date Landslide Spatial resolution Total No.Area (ha) Formosat-2(2005/04/04) 424689.568m*8m 473723.742m*2m Spatial resolution : 8mSpatial resolution : 2m

16. Results Landslide interpreted from Spot 10m & formosat2 8m Acquisition date Landslide Spatial resolution Total No.Area (ha) SPOT5(2005/03/16)379629.2510m*10m Formosat2 (2005/04/04) 424689.568m*8m Spatial resolution : 10mSpatial resolution : 8m

17. Results Landslide interpreted from Spot 2.5m & formosat2 2m Acquisition date landslide Spatial resolution Total No.Area (ha) SPOT5(2005/03/16)477693.332.5m*2.5m Formosat2 (2005/04/04) 473723.742m*2m Spatial resolution : 2.5mSpatial resolution :2m

18. Statistical analysis Results

19. 3D Visualization of Detected Landslides Red regions denote the detected landslides of Formosat-2 test data. Landslide induced by typhoon AERE Results SPOT-5(2004/08/16) SPOT-5(2005/03/16) On-Site Photography SPOT-5(2004/08/16) SPOT-5(2005/03/16) On-Site Photography CSRSR

20. SPOT-5(2004/08/16)SPOT-5(2005/03/16) On-Site Photography SPOT-5(2004/08/16)SPOT-5(2005/03/16) Helicopter Photography Landslide induced by typhoon AERE Results CSRSR

21. Formosat-2 image SPOT image Flight Simulation after NERE Typhoon 2004/8/31 (NSPO) After typhoon NERE 2003/11/14 Before typhoon NERE

22. Comparison with Existing Landslides in GIS database also with Cadastral Informations

23. Conclusions Requirements of A Monitoring and Early Warning System –Bottleneck--Data Acquisition High frequency data acquisition of remote sensing. Near Real-time Dynamic Monitoring… Typhoon AERE –Statistics 477 & 473 places, total areas of 693.33 & 723.74 hectares of landslides were detected using SPOT-5 and Formosat-2 fusion data The reliability of landslide detection is high when comparing with on-site photography.

24. Conclusions –With Formosat-2, A Possibility of Near real- time disaster estimation Provide disaster information in a short time. Historical data collection is important. A comparison can be made by GIS database. Construction of GIS database infrastructure is critical for post-disaster analysis.

25. Thanks for your attention