DOI QR코드

DOI QR Code

복합재해 영향을 고려한 산불 후 산사태 잠재적 피해 위험도 분석

Analysis of the potential landslide hazard after wildfire considering compound disaster effect

  • 이종욱 (서울대학교 환경대학원 협동과정 조경학) ;
  • 이동근 (서울대학교 조경.지역시스템공학부) ;
  • 송영일 (환경정책평가연구원 국가기후변화적응센터)
  • Lee, Jong-Ook (Interdisciplinary Program in Landscape Architecture, Seoul National University) ;
  • Lee, Dong-Kun (Department of Landscape Architecture and Rural system Engineering, Seoul National University) ;
  • Song, Young-Il (Korea Environment Institute, Korea Adaptation Center for Climate Change)
  • 투고 : 2018.09.28
  • 심사 : 2018.12.17
  • 발행 : 2019.02.28

초록

Compound disaster is the type that increases the impact affected by two or more hazard events, and attention to compound disaster and multi-hazards risk is growing due to potential damages which are difficult to predict. The objective of this study is to analyze the possible impacts of post-fire landslide scenario quantitatively by using TRIGRS (Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis), a physics-based landslide model. In the case of wildfire, soil organic material and density are altered, and saturated hydraulic conductivity decrease because of soil exposed to high temperature. We have included the change of soil saturated hydraulic conductivity into the TRIGRS model through literature review. For a case study, we selected the area of $8km^2$ in Pyeongchang County. The landslide modeling process was calibrated before simulate the post-wildfire impact based on landslide inventory data to reduce uncertainty. As a result, the mean of the total factor of safety values in the case of landslide was 2.641 when rainfall duration is 1 hour with rainfall intensity of 100mm per day, while the mean value for the case of post-wildfire landslide was lower to 2.579, showing potential landslide occurrence areas appear more quickly in the compound disaster scenario. This study can be used to prevent potential losses caused by the compound disaster such as post-wildfire debris flow or landslides.

키워드

HKBOB5_2019_v22n1_33_f0001.png 이미지

Figure 1. Relation of multi-hazard risk causing compound disaster

HKBOB5_2019_v22n1_33_f0002.png 이미지

Figure 2. Location and topography of the study area, (a) Key map and satellite image (from Google map), (b) Digital elevation map (meter) (c) Slope map (degree,°)

HKBOB5_2019_v22n1_33_f0003.png 이미지

Figure 3. ROC graph (IZLT =1.0×10-7))

HKBOB5_2019_v22n1_33_f0004.png 이미지

Figure 4. TRIGRS modeling result maps of post-wildfire landslide compound disaster case compared to landslide single disaster case (rainfall intensity of 100mm/day), (a) Landslide single disaster case (rainfall duration-1h), (b)Landslide single disaster case (rainfall duration-4h), (c) Post-wildfire landslide compound disaster case (rainfall duration-1h), (d) Post-wildfire landslide compound disaster case(rainfall duration-4h)

HKBOB5_2019_v22n1_33_f0005.png 이미지

Figure 5. TRIGRS modeling result graphs of post-wildfire landslide compound disaster case compared to landslide single disaster case (rainfall intensity of 100mm/day), (a) Changes of factor of safety (FS) at different rainfall duration, (b) Changes of total area of FS less than 1 at different rainfall duration

Table 1. Type of compound disaster and description

HKBOB5_2019_v22n1_33_t0001.png 이미지

Table 2. Summary of soil property values used for modelling

HKBOB5_2019_v22n1_33_t0002.png 이미지

Table 3. Result of ROC analysis

HKBOB5_2019_v22n1_33_t0003.png 이미지

참고문헌

  1. AghaKouchak, A., Huning, L. S., Chiang, F., Sadegh, M., Vahedifard, F., Mazdiyasni, O., ... & Mallakpour, I. 2018. How do natural hazards cascade to cause disasters?. Nature, 561, 458-460.(Proceeding, Nature comment) https://doi.org/10.1038/d41586-018-06783-6
  2. Baum, R. L., Savage, W. Z., & Godt, J. W. 2008. TRIGRS - A FORTRAN program for transient rainfall infiltration and grid-based regional slope stability analysis version 2.0, US Geological Survey Open-File Report, 2008-1159.
  3. Cannon, S. H., Gartner, J. E., Wilson, R. C., Bowers, J. C. & Laber, J. L. 2008. Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California. Geomorphology, 96, 250-269. https://doi.org/10.1016/j.geomorph.2007.03.019
  4. Caribbean Handbook on Risk Management (CHARIM) : Multi-hazard risk assessment, http://www.charim.net/methodology/54, lastaccess : Oct30, 2018.
  5. Cawson, J. G., Sheridan, G. J., Smith, H. G. & Lane, P. N. J. 2013. Effects of fire severity and burn patchiness on hillslope-scale surface runoff, erosion and hydrologic connectivity in a prescribed burn. Forest Ecology and Management, 310, 219-233. https://doi.org/10.1016/j.foreco.2013.08.016
  6. Fernandez, C., Fontürbel, T. & Vega, J. A. 2019. Effects of pre-fire site preparation and postfire erosion barriers on soil erosion after a wildfire in NW Spain. Catena, 172, 691-698. https://doi.org/10.1016/j.catena.2018.09.038
  7. Iverson, R.M. 2000. Landslide triggering by rain infiltration, Water Resources Research, 36-7, 1897-1910 https://doi.org/10.1029/2000WR900090
  8. Jordan, P. 2016. Post-wildfire debris flows in southern British Columbia, Canada. International Journal of Wildland Fire, 25, 322-336. https://doi.org/10.1071/WF14070
  9. Jun, K. , Lee, S. & Yune, C. 2009. Analysis on the effect of the forest fire and rainfall on Landslide in Gangwon area. Korean Geotechnical Society conference proceedings, 1020-1025. (Proceeding in Korean)
  10. Kappes, M. S., Keiler, M., Von Elverfeldt, K. & Glade, T. 2012. Challenges of analyzing multi- hazard risk: A review. Natural Hazards, 64, 1925-1958. https://doi.org/10.1007/s11069-012-0294-2
  11. Kim, D., Im, S., Lee, C. & Woo, C. 2013. Modeling the contribution of trees to shallow landslide development in a steep, forested watershed. Ecological Engineering, 61, 658-668. https://doi.org/10.1016/j.ecoleng.2013.05.003
  12. Kim, W. Y., and Chae, B. G. 2009. Characteristics of Rainfall, Geology and failure Geometry of the Landslide Areas on Natural Terrains in Korea, The Journal of Engineering Geology, 19, 331-344. (in Korean)
  13. Kim, W. Y. 2014. Landslide vulnerability in wildfire area. The Journal of Engineering Geology conference proceedings, 377-378. (Proceeding in Korean)
  14. Korea Environment Institute 2015. 2nd study on the establishment of national climate change adaptation, Korea Environment Institute
  15. Lainas, S., Sabatakakis, N. & Koukis, G. 2016. Rainfall thresholds for possible landslide initiation in wildfire-affected areas of western Greece. Bulletin of Engineering Geology and the Environment, 75, 883-896. https://doi.org/10.1007/s10064-015-0762-5
  16. Liu, C. N. & Wu, C. C. 2008. Mapping susceptibility of rainfall triggered shallow landslides using a probabilistic approach, Environ. Geol., 55, 907-915 https://doi.org/10.1007/s00254-007-1042-x
  17. Liu M., & Huang M. 2014. Compound Disasters and Compounding Processes: Implications for Disaster Risk Management, UNISDR
  18. Liu, B. Siu, Y.L. and Mitchell, G. 2016. Hazard interaction analysis for multi-hazard risk assessment: A systematic classification based on hazard-forming environment. Natural Hazards and Earth System Sciences, 16, 629-642. https://doi.org/10.5194/nhess-16-629-2016
  19. Moody, J.A. & Ebel, B.A. 2012. Hyper-dry conditions provide new insights into the cause of extreme floods after wildfire. Catena 93, 58-63. https://doi.org/10.1016/j.catena.2012.01.006
  20. Nyman, P., Sheridan, G. J., Smith, H. G. & Lane, P. N. J. 2011. Evidence of debris flow occurrence after wildfire in upland catchments of south-east Australia. Geomorphology, 125, 383-401. https://doi.org/10.1016/j.geomorph.2010.10.016
  21. Parise, M. & Cannon, S. H. 2012. Wildfire impacts on the processes that generate debris flows in burned watersheds. Natural Hazards, 61, 217-227. https://doi.org/10.1007/s11069-011-9769-9
  22. Oh, G., Kim, J. Jeong, W. & Min, J. 2001. The Changes of Forest Vegetation and Soil Environmental after Forest Fire. Journal of Korean Environmental Restoration And Revegetation Technology, 4, 19-29.
  23. Park, D., Shim, J. & Kim, Y. 2000. Landslide Hazards by Wildfires along the East Seacoast and Field .Survey of Landslide Damages Triggered by July 2000 Torrential Rain. Korean Society of Civil Engineers conference proceedings,159-162. (Proceeding in Korean)
  24. Park, D.W., Nikhil, N.V. & Lee, S.R. 2013. Landslide and debris flow susceptibility zonation using TRIGRS for the 2011 Seoul landslide event. Natural Hazards and Earth System Sciences, 13, 2833-2849. https://doi.org/10.5194/nhess-13-2833-2013
  25. Ren, D., Fu, R., Leslie, L. M. & Dickinson, R. E. 2011. Modeling the mudslide aftermath of the 2007 Southern California Wildfires. Natural Hazards, 57, 327-343. https://doi.org/10.1007/s11069-010-9615-5
  26. Shakesby, R. A. & Doerr, S. H. 2006. Wildfire as a hydrological and geomorphological agent. Earth-Science Reviews, 74, 269-307.
  27. Staley, D. M., Kean, J. W., Cannon, S. H., Schmidt, K. M. & Laber, J. L. 2013. Objective definition of rainfall intensity- duration thresholds for the initiation of post-fire debris flows in southern California. Landslides, 10, 547-562. https://doi.org/10.1007/s10346-012-0341-9
  28. United Nations Conference on Environment and Development. 1992. Agenda 21, Rio Declaration, Forest Principles. New York, United Nations.
  29. Wieting, C.; Ebel, B.A.; Singha, K. 2017. Quantifying the effects of wildfire on changes in soil properties by surface burning of soils from the boulder creek critical zone observatory. J. Hydrol. Reg. Stud, 13, 43-57. https://doi.org/10.1016/j.ejrh.2017.07.006