Earthquake is one of most serious natural disasters in the world.It has wide geographic coverage

huge damage

and long time influence for recovery.The earthquake happened in Wenchuan on May 12

2008 caused great damage in 42 counties in Sichuan province

23 counties in Gansu province

and 19 counties in Shaanxi province.In addition

it also has much influence on Chongqing

Yunnan

Shanxi

Guizhou

and Hubei provinces.Because of the severely destroyed infrastructures

complicated topography and bad weather condition after the earthquake

the disaster situation assessment from ground investigation is very difficult to undertake.In this situation

feasible approaches should be investigated.In this paper

we take the remote sensing monitoring and assessment of the Wenchuan Earthquake disaster situation as a case study and discuss the technical approaches and methods on application of space and airborne remote sensing technology for earthquake disaster situation monitoring and assessment.Firstly

by integrating multi-platform multi-sensor data

we defined the earthquake disaster situation monitoring indexes according to two different disaster severity levels.For areas with high-level disaster loss

aerial photos and high-resolution satellite images with less than 1 meter resolution are used as the major data sources

where four major categories with detailed subclasses are classified

i.e.

1) urban and rural residential areas;2) urban and rural infrastructures such as industrial and mining lands

highways

railways

bridges

tunnels

electric facilities

telecommunication facilities

channels

dikes

reservoirs

and dams;3) geological and environmental change information such as earthquake lakes

rock slumps

landslides

and turbidities;and 4) destroyed farmlands such as croplands and forest lands.For areas with low-level disaster loss

high and medium resolution optical and SAR satellite images before and after the earthquake are used as the major data sources

where four major categories with less detailed subclasses are classified

i.e.

1) urban and rural residential areas;2) urban and rural infrastructures such as industrial and mining lands

highways

railways

and large reservoirs;3) geological and environmental change information such as earthquake lakes

rock slumps

landslides

and turbidities;and 4) destroyed farmlands such as croplands and forest lands.By combining the multi-temporal

multi-source data before and after the earthquake

we establish the technical flows for quick geometric processing

quick data quality analysis and assessment

quick change detection

quick target interpretation

quick spatial risk assessment for landslides induced by earthquake

and the synthesis of these methods for disaster monitoring.For geometric processing

the ImageInfo software module PixelGrid is used.For image fusion

the data fusion module of ImageInfo is used.For interpretation of different area of images

the ArcGIS software is used.Additionally

the SINMAP module under ArcGIS software is also used for the validation of the extracted geological risk areas.The approach has been successfully applied in monitoring

mapping

and statistical assessment of the earthquake disaster situation.In addition

we also develope an application system which could provide functionalities for disaster information management

visualization

and statistical analysis.It utilize 2D WebGIS user interface and 3D virtual simulation environment to manage the disaster database and visualize the monitored results as 2D maps

statistic tables

graphs

and 3D models

and provide functionalities for measure and analysis.Finally

we also addressed and discussed some practical problems when applying this approach that should be well justified in the future

including the development of new geometric correction algorithm without control points

and the standardization of the workflow described in this paper for better accuracy.