Vegetation recovery assessment at the Jou-Jou Mountain landslide area caused by the 921 Earthquake in Central Taiwan

Abstract The catastrophic earthquake, 7.3 on the Richter scale, occurred on September 21, 1999. The 921 Earthquake was a terrifying disaster that caused numerous casualties in Central Taiwan. It is the severest earthquake in a recent hundred years. The land morphology and topography changed greatly with such features as land upheaval, river blockades and lakes dammed by debris in many locations. Severe disaster districts were found in the Jou-Jou Mountain landslide area in Nan-Tou County. A method was developed to assess the landslide characteristics and monitor the vegetation recovery at Jou-Jou Mountain. SPOT satellite imageries were used to analyze the Normalized Difference Vegetation Index (NDVI) derived from SPOT imagery before and after the earthquake for comparison. The vegetation recovery index ( C ) was proposed to calculate and evaluate the vegetation recovery rate. The results showed that the vegetation restoration rate has achieved 47.1% in natural plant succession one year after the earthquake. The poor and very poor locations were distributed mainly in mountain ridge, scoured slope base and acidic sulfate soil areas. Mountain ridges and acidic sulfate soil had lower recovery rates affected by the impacts of soil moisture and SO 4 2− . Scoured slope bases next to the concave banks might need foundation engineering first to establish a stable habitat for plants.

[1]  C. Justice,et al.  Analysis of the phenology of global vegetation using meteorological satellite data , 1985 .

[2]  C. Chung,et al.  Probabilistic prediction models for landslide hazard mapping , 1999 .

[3]  Yasushi Yamaguchi,et al.  Detection of Landslide Areas Using Satellite Radar Interferometry , 2000 .

[4]  J. McKean,et al.  REMOTE SENSING AND LANDSLIDE HAZARD ASSESSMENT , 1991 .

[5]  R. Westerman.  Soil testing and plant analysis , 1990 .

[6]  Thomas A. Spies,et al.  TEN YEARS OF VEGETATION SUCCESSION ON A DEBRIS‐FLOW DEPOSIT IN OREGON 1 , 2001 .

[7]  Wen-Chieh Chou,et al.  Soil erosion prediction and sediment yield estimation: the Taiwan experience , 2002 .

[8]  M. Strecker,et al.  Tephrochronologic Constraints on Temporal Distribution of Large Landslides in Northwest Argentina , 2000, The Journal of Geology.

[9]  William Philpot,et al.  A derivative-aided hyperspectral image analysis system for land-cover classification , 2002, IEEE Trans. Geosci. Remote. Sens..

[10]  R. Bartha,et al.  The Sulphate-Reducing Bacteria , 1979 .

[11]  G. W. Thomas.  Problems Encountered in Soil Testing Methods , 2015 .

[12]  G. Senay,et al.  Combining AVHRR-NDVI and landuse data to describe temporal and spatial dynamics of vegetation , 2000 .

[13]  Alicia K. Birky,et al.  NDVI and a simple model of deciduous forest seasonal dynamics , 2001 .

[14]  Thomas J. Schmugge,et al.  An interpretation of methodologies for indirect measurement of soil water content , 1995 .

[15]  J. Townshend,et al.  African Land-Cover Classification Using Satellite Data , 1985, Science.

[16]  M. Aniya,et al.  Landslide hazard mapping and its evaluation using GIS: an investigation of sampling schemes for a grid-cell based quantitative method. , 2000 .

[17]  Thomas P. Kersten,et al.  AEROTRIANGULATION AND DEM/ORTHOPHOTO GENERATION FROM HIGH-RESOLUTION STILL-VIDEO IMAGERY , 1997 .