多時序衛星影像在崩塌研究之應用－以高雄縣荖濃溪為例

A Landslide Study by Using multi-temporal Satellite Images: An Example from Lao-Lung River Watershed

陳志豪(Chih-Hao Chen) ； 林慶偉(Ching-Weei Lin) ； 陳勉銘(Mien-Ming Chen) ； 張維恕(Wei-Shu Chang) ； 劉守恆(Shou-Heng Liu)

《中華防災學刊》 3卷1期 (2011/02) Pp. 25-38

https://doi.org/10.30052/JTDPS.201102.0003

摘要

本研究以高屏溪上游的荖濃溪流域為研究區域，利用SPOT與福衛二號衛星影像之崩塌判釋，結合地理資訊系統之空間分析功能，分析集集地震發生前後荖濃溪流域內崩塌發生趨勢及特性的變化。此外，同時採用氣象局全台雨量站之時雨量資料並利用克利金方法內插得到每個降雨事件的降雨資訊，並配合氣象局全台365個地震測站所量測的集集地震的水平PGA資料，進而將崩塌資料與降雨及地震相關資訊套疊，以了解崩塌發生與降雨及地震之關係。
本研究結果發現在集集地震前的降雨事件中，崩塌主要分佈在30°~40°之坡度區間，但在集集地震後、2000年的碧利斯颱風、2001年的桃芝颱風及2003年的0607豪雨事件，崩塌主要分佈上升到40°~50°之坡度區間，在2004年敏督利及艾利颱風後之各式件中，崩塌主要分佈又回復到地震前的30°~40°之坡度區間，推測本區受地震效應的影響在5~6年左右。

關鍵字

集集地震 ； 荖濃溪 ； 崩塌

並列摘要

The Lao-Nong River watershed in southern Taiwan which covered 1,367 Km^2 is chosen to study the characteristics of rainfall induced landslide and to evaluate the impact of the Chi-Chi earthquake on the occurrence of landslides. The landslides of the study area were identified through 8 SPOT and 8 FORMOSAT 2 images that covered 15 typhoons from 1996 to 2007. The corresponding rainfall information in places where landslides occurred is interpolated from one hour interval rainfall data by using Kriging method. In addition, the peak ground acceleration of the Chi-Chi earthquake is also used to know the impact of the earthquake on the occurrence of landslides.
The study results show the landslide intensity obtained from images is well correlate to the corresponding cumulative precipitation of typhoons except for those occurred in typhoon Billis in 2000, Toraji in 2001, and 0609 event in 2003. In Billis, Toraji, and 0609 events, in area with PGA over 150 gal, landslide intensity shows good correlation to the PGA of the Chi-Chi earthquake. In addition, most of landslides distributed in areas with slopes of 30°-40° which is typical for rainfall induced landslides except for those occurred in area with PGA over 150 gal during Billis, Toraji, and 0607 event which mainly distributed in places with slopes between 40°-50°. Therefore, we conclude that the influence of the Chi-Chi earthquake on rainfall induced landslides in the Laolung River watershed is only seen in area with PGA over 150 gal and it sustains only 5-6 years.

並列關鍵字

Chi-Chi earthquake ； landslide ； Lao-Lung River watershed