Satellite image analysis of a huge landslide at Yi Gong, Tibet, China

At about 8 pm in the evening of Sunday 9 April 2000, a huge landslide occurred in the Yi Gong district, Tibet, China (⇓Fig. 1). A gigantic volume of soil and rock slipped from the upper hillside at more than 5500 mPD (metres above the Principal Datum, i.e, the Yellow Sea Level) along the Zamu gully, down to the Yi Gong River at about 2000 mPD, as shown in the site photos, a & b in ⇓Figure 2 respectively. It travelled about 8 km and lasted about 10 minutes. The landslide debris was composed of snow, glacial ice, trees, soil and rock (marble, slate and granite). It destroyed a 2.5 km long section of the highway connecting Qinghai province to Tibet, blocked the Yi Gong River at the toe of the slope, and resulted in the flooding of several villages. This landslide is estimated to have a volume of 300 000 000 m3 and is thus one of the largest landslides recorded in the world. Fig. 1. Location plan of the Yi Gong Landslide of 9 April 2000, Yi Gong, Tibet, China. Fig. 2. Site photographs illustrating the Yi Gong Landslide: ( a ) The Zone I (Landslide back-scar) and ( b ) Zone III (the Zamu gully mouth and the landslide debris dam). Immediately after the landslide, the central and provincial governments and other relevant organizations carried out investigations of the landslide and urgent remedial works. This paper presents a satellite image analysis of the landslide and its consequences. Satellite images have been used in landslide investigation since the mid-70s when Landsat MSS was launched. Examples of using satellite images to investigate landslides and to identify ground movements can be found in the publications by ⇓McDonald & Grubbs (1975) and ⇓Manotvani et al . (1996). The satellite images and remote sensing data used in the present analysis include the TM …