HR: 08:15h
AN: H31L-02    [Abstracts]
TI: The use of remote sensing for landslide hazard management in the aftermath of the Kashmir earthquake
AU: * Petley, D N
EM: d.n.petley@durham.ac.uk
AF: International Landslide Centre, Department of Geography, Durham University, Durham, DH1 3LE, United Kingdom
AU: Dunning, S A
EM: stuart.dunning@unn.ac.uk
AF: Northumbria University, School of Applied Sciences Lipman Building, Newcastle upon Tyne, NE1 8ST, United Kingdom
AU: Rosser, N J
EM: n.j.rosser@durham.ac.uk
AF: International Landslide Centre, Department of Geography, Durham University, Durham, DH1 3LE, United Kingdom
AU: Kausar, A
EM: kausar_20001@yahoo.com
AF: Geological Survey of Pakistan, Plot No. 84, Islamabad, H-8/1, Pakistan
AB: The ML=7.6 Kashmir earthquake of 8th October 2005 triggered large numbers of landslides, with the distribution being concentrated on the hanging wall block in the vicinity of the fault rupture. These landslides were responsible for an estimated 25,500 deaths, but also caused serious problems for the distribution of aid in the immediate aftermath of the earthquake event. In the longer term period after the earthquake, slope instability represents a very major problem for the authorities in Pakistan, primarily because many slopes appear to have been left in a quasi-stable state. As the area affected by landslides is so large, remote sensing represents the only reasonable way to assess the occurrence of landslides and the threats posed by future events. In this study, satellite imagery has been used for two purposes. First, several epochs of imagery have been used to examine the Hattian Bala landslide, which is a 68 million m3 rock avalanche that destroyed three villages and killed around 1000 people. The landslide deposit has blocked two valleys to a depth of about 130 m. Until the completion of a spillway in 2007, an outburst flood threatened a major settlement 3 km downstream. The images have allowed analysis of the landslide deposit itself and of the lakes, permitting estimates of the magnitude of a potential outburst flood. Interestingly, the satellite images also revealed clusters of landslides in the source area of the landslide prior to the earthquake. Furthermore, the images have allowed identification of a creeping landslide on the slopes above the lake, which represents a serious ongoing threat. In the second application, mapping has been undertaken of the landslide distribution in general. This has demonstrated that, contrary to other reports, many of the landslides now observed in the landscape in fact predate the earthquake. For example, in the valley containing the Hattian Bala landslide, 94 landslides can now be mapped. However, 76% of these are observable on imagery collected before the earthquake, meaning that just 24% were first time failures triggered by the event. The data have allowed the construction of landslide magnitude-frequency distribution plots, providing the basis for the assessment of the contribution of seismically triggered events as compared to background rates of activity. The study uses a combination of remote sensing tools, including Landsat 5, Landsat 7, Quickbird and TOPSAT. The latter is a new micro-satellite system that has been designed and built by a consortium led by Qinetiq Ltd to provide low cost, high resolution images of the Earth. TOPSAT has four spectral bands, consisting of a pan band with a spatial resolution of 2.5 m and RGB bands with a spatial resolution of 5.0 m. The image size is 17 km x 17 km. A key feature of TOPSAT is the potential for the satellite to deliver data directly to a mobile ground station immediately after an has been obtained. As such it is potentially a useful tool for the determination of the impact of natural disasters such as floods, landslides and earthquakes. A brief analysis is presented of the strengths and weaknesses of TOPSAT in this application when compared to the other systems.
DE: 0468 Natural hazards
DE: 0480 Remote sensing
DE: 1810 Debris flow and landslides
DE: 9320 Asia
DE: 9345 Large bodies of water (e.g., lakes and inland seas) (0746)
SC: Hydrology [H]
MN: 2007 Fall Meeting