Abstract
Using remote sensing data from 1992 to 1996, the expansions of lahar deposition and vegetation recovery situation were monitored. The lahar deposition area in Bamban river basin had spread from lower stream to upper and side ways from 1992 to 1996. Vegetation recovery had started from lower stream portions from 1993, where there was no new lahar deposition. Of the total 12,000 ha affected by lahar deposition from 1991 to 1996, vegetation recovery area was 6,200 ha in 1996. The spectral reflectance of 1,550-1,750nm wavelength (corresponding to Landsat TM band 5) determined by Spectral Radiometer had significant correlation with lahar surface moistures in the field. Area with band 5 DN range of 87 to 103 in 1992 and 92 to 110 in 1995, respectively, showed suitable moisture condition for high vegetation recovery for the following year. Vegetation recovery had started from lower stream portions of Bamban river basin from 1992 to 1996. Smaller particle size lahar materials were accumulated in the lower stream portion and water retentivity in this area was high, which could lead to fast vegetation recovery. The Landsat TM band 5 DN was estimated to be useful in identifying the suitable moisture condition for vegetation recovery in lahar affected area.