四川汶川地震地质灾害活动强度分析评价
|
摘要
为了探索区域群发地质灾害活动强度评价方法和指标体系,以汶川地震诱发地质灾害活动强度评价为例,在简单分析汶川地震地质灾害宏观特征的基础上,利用高精度遥感解译资料和GIS技术,计算汶川地震诱发地质灾害分布最大面密度,结合对近年来陕西宝鸡市地质灾害调查统计的历史资料分析,提出以地质灾害分布最大面密度为衡量区域地质灾害活动强度指标的基本思路和分级标准,初步建立了地质灾害活动强度指数8级划分标准,并计算出汶川地震诱发地质灾害活动强度指数最高为7级,属于极端强烈活动。其中,地质灾害活动最强地段(7级活动区)位于强震震中区映秀镇附近的岷江两岸和绵竹汉旺镇银厂沟上游发震断裂两侧;次强地段(6级活动区)位于北川县城湔河两岸和平武县南坝镇北东小流域两岸。初步揭示:地质灾害活动强度从发震断裂带向两侧具有明显衰减的趋势。最后,简要讨论了汶川地震引发地质灾害活动如此强烈的主要原因及其发展趋势。
In order to study the evaluation method and index system of regional group-occurring geohazard activities, take for example the evaluation of the intensity of geohazard activity induced by the Wenchuan earthquake, the authors calculated the maximum surface density of distribution of geohazards induced by the Wenchuan earthquake on the basis of a simple analysis of the macroscopic features of geohazards induced by the earthquake and by using high-precision remote sensing interpretation data and GIS data.In addition, in combination with the recent analysis of historic data got by geohazard survey of Baoji City, Shaanxi, the authors proposed the basic idea of taking the maximum surface density of geohazard distribution as the indices of the intensity of regional geohazard activity and classification standard.Eight classes of the indices of the intensity of geohazard activity were preliminarily established, of which the highest intensity of geohazard activity induced by the Wenchuan earthquake is class 7, belonging to extremely strong activi-ty.The area with the strongest geohazard activity(class 7 activity area) is located on both sides of the causative earthquake on both banks of the Minjiang River near Yingxiu Township and in the upper reaches of the Yinchang Gully, Hanwang Township, Mianzhu in the epicenter area of the strong earthquake.The area with the less strong geohazard activity(class 6 activity area) is situated on both bank of the Qianhe River in the seat of Beichuan County and on both banks of a small river northeast of Nanba Township, Pingwu County.It is revealed that the activity intensity of geohazards had a trend of significant decline from the causative fault zone towardboth sides.Finally, the paper briefly discusses the main cause for so strong geohazard activities deduced by the Wenchuan earthquake and their development trend.
In order to study the evaluation method and index system of regional group-occurring geohazard activities, take for example the evaluation of the intensity of geohazard activity induced by the Wenchuan earthquake, the authors calculated the maximum surface density of distribution of geohazards induced by the Wenchuan earthquake on the basis of a simple analysis of the macroscopic features of geohazards induced by the earthquake and by using high-precision remote sensing interpretation data and GIS data.In addition, in combination with the recent analysis of historic data got by geohazard survey of Baoji City, Shaanxi, the authors proposed the basic idea of taking the maximum surface density of geohazard distribution as the indices of the intensity of regional geohazard activity and classification standard.Eight classes of the indices of the intensity of geohazard activity were preliminarily established, of which the highest intensity of geohazard activity induced by the Wenchuan earthquake is class 7, belonging to extremely strong activi-ty.The area with the strongest geohazard activity(class 7 activity area) is located on both sides of the causative earthquake on both banks of the Minjiang River near Yingxiu Township and in the upper reaches of the Yinchang Gully, Hanwang Township, Mianzhu in the epicenter area of the strong earthquake.The area with the less strong geohazard activity(class 6 activity area) is situated on both bank of the Qianhe River in the seat of Beichuan County and on both banks of a small river northeast of Nanba Township, Pingwu County.It is revealed that the activity intensity of geohazards had a trend of significant decline from the causative fault zone towardboth sides.Finally, the paper briefly discusses the main cause for so strong geohazard activities deduced by the Wenchuan earthquake and their development trend.
引文
[1]Hungr O.Some methods of landslide hazard intensity mapping[C]//Cruden D M,Fell R.Landslide risk assessment.Proceedings Interna-tional Workshop on Landslide Risk Assessment,Honolulu,19-21February1997,Balkema,Rotterdam,1997:215-226.
[2]Cardinali M,Reichenbach P,Guzzetti F,et al.A geomorphological approach to the estimation of landslide hazards and risks in Umbria,Central Italy[J].Natural Hazards and Earth System Sciences,2002,2:57-72.
[3]王涛,马寅生,龙长兴,等.四川汶川地震断裂活动和次生地质灾害浅析[J].地质通报,2008,27(11):1913-1922.
[2]Cardinali M,Reichenbach P,Guzzetti F,et al.A geomorphological approach to the estimation of landslide hazards and risks in Umbria,Central Italy[J].Natural Hazards and Earth System Sciences,2002,2:57-72.
[3]王涛,马寅生,龙长兴,等.四川汶川地震断裂活动和次生地质灾害浅析[J].地质通报,2008,27(11):1913-1922.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心