Abstract:
Objectives The quantification of debris flow material sources is the basis of scientific evaluation of debris flow scale, degree of disaster and comprehensive management. It is difficult to identify debris flow source under dense vegetation by traditional ground survey and optical remote sensing in lush mountainous areas of southwest China.
Methods Comparatively, airborne light detection and ranging(LiDAR) technology can effectively remove vegetation to obtain high resolution digital elevation model, providing a new solution for debris flow source identification. Taking the Rize basin debris flow in Jiuzhaigou earthquake area as a case study, we propose a new methodology for interpretation debris flow source based on high-resolution LiDAR data. The material sources are divided into slump-mass source, gully sediments source and slope wash source, and we propose geomorphologic identification masks and remote sensing interpretation to regard different types of debris flow source.
Results A total of 155 debris flow material sources in Rize basin debris flow are interpreted, covering an area of 1.06 km2, accounting for 31.56% of the total basin. On this basis, the characteristics and distribution law of various types of material sources are analyzed.
Conclusions The results provides theoretical reference and data support for the quantification of debris flow source and debris flow prevention and risk assessment of the earthquake area in Jiuzhaigou.
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