四川汶川大地震震害遥感调查与评估

回顾了中国应用遥感技术调查评估地震灾害的历史及其进展,经过综合论证,给出了汶川地震5种震害的分类划分标准和灾害遥感调查评估总体技术流程,总结了灾害遥感调查评估各个不同阶段,采用不同遥感信息源和不同遥感技术方法识别不同震害的效果,为汶川特大地震灾中救援和灾后重建提供了决策依据;结合遥感技术发展的趋势和地震灾害的特点,提出了震害遥感调查评估的发展趋势。

多尺度下的遥感震害异常区快速提取方法

地震灾害发生后的不同时期对震害信息提取速度和精度的要求有所不同,采用多尺度下的遥感震害异常区快速提取技术,针对灾害发生后的不同时期采用不同分辨率遥感影像和方法提取震害信息。选取北川县Modis,TM,航飞低、中、高分辨率数据,采用多时相变化监测,单时相多尺度分割和面向对象分类方法对遥感震害异常区提取。结果表明,多尺度下的遥感震害异常区快速提取技术能够有效解决该问题。

基于遥感震害指数的尼泊尔地震综合烈度评估研究

2015年4月25日在尼泊尔廓尔喀县发生的8.1级地震及后续强烈余震,造成尼泊尔北部严重的人员伤亡和财产损失,灾区建筑物倒塌损失严重。本文利用现场震害调查资料和高分卫星遥感影像,开展建筑物震害遥感解译,得到各个遥感解译点的遥感震害指数,结合现场调查点评估的烈度拟合了遥感震害指数-实际震害指数转换关系,再根据遥感震害指数估计了全部解译点的震害指数及地震烈度。估计的烈度与现场调查结果对比显示出较好的一致性,研究结果为该地区今后发生地震提供了可借鉴的遥感评估震害指数转换模型。

遥感震害快速评估技术在震后的有效应用

地震作为一种突发的,具有不确定必因素的地质运动,受到了越来越多专业人士与学者的关注和重视。并且,其特性复杂,震源、震中距和实际场所环境或地质条件等影响而产生不同程度的损失。在此期间,长周期成分的地震活动会对国民财产安全,社会以及国家的稳定均造成严重的影响。并且,如何在震后第一时间对其灾害程度进行评估也成为了我国目前所关注的重要问题。对此,本次研究则主要针对遥感震害快速评估技术在震后的有效应用展开了调查分析,旨在能够为相关研究人员后续工作的开展提供一些理论依据。

Characteristics and triggering mechanism of Xinmo landslide on 24 June 2017 in Sichuan, China

At 5: 39 AM on 24 June 2017, a huge landslide-debris avalanche occurred on Fugui Mountain at Xinmo village, Diexi town, Maoxian county, Sichuan province, China. The debris blocked the Songpinggou River for about 2 km, resulting in a heavy loss of both human lives and properties(10 deaths, 3 injuries, 73 missing, and 103 houses completely destroyed). The objectives of this paper are to understand the overall process and triggering factors of this landslide and to explore the affecting factors for its long term evolution before failure. Post event surveys were carried out the day after the landslide occurrence. Information was gathered from literature and on-site investigation and measurement. Topography, landforms, lithology, geological setting, earthquake history, meteorological and hydrological data of the area were analysed. Aerial photographs and other remote sensing information were used for evaluation and discussion. Eye witnesses also provided a lot of helpful information for us to understand the process of initiation, development and deposition. The depositional characteristics of the moving material as well as the traces of the movement,the structural features of the main scarp and the seismic waves induced by the slide are presented and discussed in detail in this paper. The results show that the mechanism of the landslide is a sudden rupture of the main block caused by the instability of a secondary block at a higher position. After the initiation, the failed rock mass at higher position overloaded the main block at the lower elevation and collapsed in tandem. Fragmentation of the rock mass occurred later, thus forming a debris avalanche with high mobility. This landslide case indicates that such seismic events could influence geological hazards for over 80 years and this study provides reference to the long term susceptibility and risk assessment of secondary geological hazards from earthquake.

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.

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.

地震灾害应急遥感合作与共享现状

地震灾害是危害人类社会最大的自然灾害之一,由于目前科技尚不可预知地震,地震灾后应急至关重要。遥感是目前震害应急最快速便捷的手段,本文总结了遥感震害应急信息四个方面的现状:数据共享、遥感震害评估技术、遥感震害评估系统、信息集成发布平台。遥感震害信息从数据、软硬件、产品等各个方面都已形成良好的合作交流,但是未能将整个遥感震害应急流程统筹规划,形成宏观的遥感震害应急共享机制。下一步应该从健全数据分享链、建立并开放共享专家知识库、建立实时协同判读平台、制定产品共享规范,创建并推广产品发布平台,相关软硬件技术支持等方面充分考虑,协同遥感震害应急的每一步流程,建立起一套针对数据、处理、软硬件、产品规范等遥感震害应急全面而又健全的合作机制。遥感震害应急正朝着全球遥感数据系统化、遥感震害应急业务平台化、遥感震害应急产品网络化的方向发展,保证遥感应急合作的全方位可行性是大势所趋。