摘要
降雨与地震是引发地质灾害的两个主要原因,尤其在地震区,地震导致了大量的滑坡松散堆积物与不稳定斜坡,在后续降雨条件下极易产生新的地质灾害。另一方面,高精度降雨数据的缺乏一直是由降雨导致的地质灾害预测预报的瓶颈。因此,该文尝试应用业内评价较好,精度较高的TRMM降雨数据来获取地质灾害发生前期降雨量。应用2000-2012年间的3h分辨率的TRMM3B42数据,结合2000-2012年间四川发生的重大滑坡泥石流灾害,提取出每次地质气象灾害发生前30d,15d,3d和当天的降雨数据。在此基础上,结合收集来的历次地质气象灾害的临界降雨过程雨量和历时数据,应用主成分分析法,将五组数据划分为两大主成分,并进行分析;绘制四川省地质气象灾害的降雨强度—历时阈值曲线,并以汶川地震为分界点,比较分析了地震前后的阈值变化情况。结果表明,在四川地区,滑坡泥石流灾害的发生同时受到降雨和汶川地震的影响。以灾害发生前30d,前15d,前3d有效降雨量因子组成的前期降雨这一主成分在滑坡泥石流灾害中贡献率较高,其次是以当天降雨和临界降雨过程组成的短历时降雨;通过对比地震前后的阈值曲线变化发现地震后的阈值更低,表明强地震后坡面稳定性降低,引发地质灾害的降雨条件降低。
Rainfall and earthquake are the two main triggers of geological disasters.In earthquake zones,earthquake could cause a lot of loose deposits and unstable slopes,which are prone to generate new geological disasters under the subsequent rainfall after earthquake.On the other hand,the lack of high resolution rainfall data is the bottleneck of rainfall induced geological disasters forecasting.Tropical Rainfall Measuring Mission（TRMM）data is accorded a high opinion due to its good accuracy.Therefore,the early rainfall data of geological disasters are attempted to be gotten by TRMM data.Based on the inventory of major geological disasters occurred in Sichuan Province since 2000,by using 3 hours resolution TRMM 3B42 data during 2000-2012,the rainfall data of each geological meteorological disasters before 30 days,15 days,3 days and the day are extracted.Then,combined with the critical rainfall and duration data included on the inventory,by applying the principal component analysis,the five data sets are divided into two main components.At last,the rainfall duration-threshold curves of geological meteorological disasters in Sichuan are drawn,and the threshold changes before and after Wenchuan earthquake are analyzed comparatively.Results show that in Sichuan Province,the occurrence and distribution of landslide disaster are affected by rainfall and Wenchuan earthquake.The effective rainfall data of 30 days,15 days and 3 days before disasters have a higher contribution rate on landslide,which composed the early rainfall factor and regarded as the first main ingredient.Followed by the second main ingredient,which is the short duration rainfall factor composes of the day＇s rainfall data and the critical rainfall data.By comparing the rainfall threshold curves before and after the earthquake,it reveals that the threshold is lower after earthquake,indicating an unstable state of slope after strong earthquakes which cause low rainfall condition to initiate geological disasters.
出处
《灾害学》
CSCD
2015年第2期220-227,共8页
Journal of Catastrophology
基金
国家科技支撑计划课题(2012BAK10B03)
