Remote sensing analysis of the distribution and genetic mechanisms of transportation network damage caused by the Wenchuan earthquake

摘要

Transportation networks are among the most important lifelines for post-seismic relief and reconstruction. It is imperative to investigate, monitor, and analyze transportation network damage caused by earthquake disasters in near real-time. Herein, we present a method for the analysis of seismic hazards and the subsequent assessment of the impact of the Wenchuan earthquake on transportation networks employing remote sensing and geographical information systems. In this method, the locations, shapes, lengths, and areas of the main damaged segments of state and provincial highways are interpreted and surveyed based on airborne ADS40 data and diverse remotely sensed satellite images of varying resolutions before and after the disaster. Next, the spatial distributions of geological disasters such as landslides, land-collapses, mud-rock flows, bank-collapses, earthquake rifts, and faults, as well as barrier lakes, were analyzed. These types of geological disasters commonly cause transportation network blockage and damage. Finally, geographical factors, including geological structures, topography, and landscapes, were collected and integrated with the disaster statistics to quantitatively analyze the primary transportation seismic disaster indices, and evaluate the geographical characteristics and genetic mechanisms of seismic disasters. Our results indicate that transportation network blockage and damage occurred in 808 segments, with a total length of 170.2 km, and occupied 29.66percent of the total length of the state and provincial highways in the core disaster regions. The distribution of transportation network blockage and damage has obvious geographical characteristics. It is concentrated in regions near geological faults, folds, rock crushes, and breaks, especially near the Longmenshan-controlling fault, which played a decisive role in the Wenchuan earthquake. The remotely sensed images, maps, and analytical results on the geographical distribution and genetic mechanisms of the transportation network blockage and damage effectively guided the national department of transportation repair and reconstruction planning for the disaster areas.