Study on the Remote Sensing Assessment of Seismic Intensity of the Yushu Earthquake Based on the Synthetic Seismic Damage Index

This paper provides an overview of the ideas and methods of the assessment of seismic intensity based on remote sensing and describes the models used to assess the remote sensing based synthetic seismic damage index and seismic intensity. With the data of damage information extracted from the high-resolution aerial images in the earthquake-stricken areas( Jiegu town,Yushu city,Qinghai) of the 2010 MS7. 1 Yushu earthquake,and the data obtained through post-earthquake field investigation,the seismic damage degree and seismic intensity have been estimated. The analysis of the results shows that the seismic intensity in Yushu city is estimated as IX through the RS assessment method,which is consistent with the result estimated according to the ground surveys. The results are discussed in the last part of the paper and indicate that the RS techniques are expected to be one of the main methods used to estimate the seismic intensity values in the emergency stage.

Primary Quantitative Study on Earthquake Damage Extracted from Remote Sensing Imagery——A Case Study of Seismic Damage in the Urban Area of Dujiangyan due to the M_S8.0 Wenchuan Earthquake

The fast developing remote sensing techniques play an increasingly important role in earthquake emergency response, disaster survey and loss estimation. As there is a lack of quantitative studies on seismic damage based on remote sensing, its practicality in seismic disaster management has usually been questioned. The paper introduces the essential quantitative study idea, the concept of the remote sensing seismic damage index （D1RS） and analysis models, demonstrates the seismic damage indices （ D1G ） of buildings obtained from ground surveying and its quantitative relation to D1RS in Dujiangyan city, Sichuan Province, which was destroyed by the 2008 Wenchuan earthquake with Ms8.0. The primary results show that an obvious relationship exists between the D1RS of buildings obtained from the high resolution satellite or aerial remote sensing images and D1G or the building collapse ratio obtained through ground survey, which suggests that the quantitative study on seismic damage based on remote sensing will provide an effective method for seismic damage survey and loss estimation.

Post-earthquake building damage assessment in Yushu using airborne SAR imagery

The synthetic aperture radar （SAR） plays an important role in earthquake emergency response because of its all-time and all-weather imaging capabilities. On April 14, 2010, an Ms7.1 earthquake occurred in Yushu county, Qinghai province of China, causing a lot of buildings collapsed. In this paper, the building damage in Yushu city due to the earthquake was assessed quantitatively using high-resolution X-band airborne SAR image. The features of the buildings with different damage levels （collapsed, partial collapsed, non-collapsed） in the SAR image were analyzed first. Based on these building features, we interpreted the individual building damage in Yushu city block by block and got the numbers of the collapsed, partial collapsed and non-collapsed buildings separately for each block, referring to pre-earthquake QuickBird image when necessary. Let the damage index of individual collapsed, partial collapsed, non-collapsed building be 1, 0.5, 0 respectively, the remote sensing damage index of each block was then calculated through remote sensing damage index equation. Finally, the preliminary quantitative relationship between the remote sensing damage index interpreted from the SAR image and that interpreted from the optical image was built up. It can be concluded that a desirable damage assessment result can be derived from high-resolution airborne SAR imagery.