Relationship between Remotely Sensed Vegetation Change and Fracture Zones Induced by the 2008 Wenchuan Earthquake, China

• Published in: Journal of earth science (Wuhan, China) China), 2013-04, Vol.24 (2), p.282-296
• Main Authors: Wang, Ling, Tian, Bingwei, Masoud, Alaa, Koike, Katsuaki
• Format: Article
• Language: English
• Subjects: Agricultural land; Biogeosciences; Coniferous forests; Debris flow; Distribution patterns; Earth and Environmental Science; Earth science; Earth Sciences; Earthquakes; Geochemistry; Geographic information systems; Geology; Geostatistics; Geotechnical Engineering & Applied Earth Sciences; Heterogeneity; Landsat; Landslides; Meadows; Mixed forests; Plate tectonics; Remote sensing; Seismic activity; Vegetation changes; Vegetation mapping; Vegetation patterns; 半方差分析; 地理信息系统技术; 大地震; 断裂带; 植被变化; 汶川; 落叶阔叶林; 遥感
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-013-0329-y

The Wenchuan earthquake triggered cascading disasters of landslides and debris flows that caused severe vegetation damage. Fracture zones can affect geodynamics and spatial pattern of vegetation damage. A segment tracing algorithm method was applied for identifying the regional fracture system through lineament extractions from a shaded digital elevation model with 25 m mesh for southern Wenchuan. Remote sensing and geographic information system techniques were used to analyze the spatiotemporal vegetation pattern. The relationship between vegetation type identified from satellite images and lineament density was used to characterize the distribution patterns of each vegetation type according to fracture zones. Broad-leaved forest, mixed forest, and farmland persist in areas with moderate lineament density. Deciduous broad-leaved and coniferous forest persists in less frac- tured areas. Shrub and meadow seem to be relatively evenly distributed across all lineament densities.Meadow, farmland, and shrub persist in the fractured areas. Changes of spatial structure and correlation between vegetation patterns before and after the earthquake were examined using semivariogram analysis of normalized difference vegetation indices derived from Landsat enhanced thematic mapper images. The sill values of the semivariograms show that the spatial heterogeneity of vegetation covers increased after the earthquake. Moreover, the anisotropic behaviors of the semivariograms coincide with the vegetation changes due to the strikes of fracture zones.