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| Titel |
Rainfall-induced landslides in Chenyulan River watershed, Central Taiwan: An example illustrates the impact of Chi-Chi earthquake on subsequent rainfall induced landslide |
| VerfasserIn |
S.-H. Liu, W.-S. Chang, C.-W. Lin |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025446
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| Zusammenfassung |
| Landslides of the Chenyulan River watershed in central Taiwan were used to illustrate how
the catastrophic Chi-Chi earthquake in 1999 influences the subsequent rainfall-induced
landslides in an intensively disturbed region. Landslides identified from 9 SPOT and 9
FORMOSAT 2 images that cover 14 typhoons from 1996–2008 are used to differentiate the
variations of landslide occurrence and intensity prior to and after the earthquake. The impact
of the Chi-Chi earthquake was evaluated by comparing the PGA of the earthquake with the
occurrence of landslides, the landslide intensity, and the corresponding rainfall
data of each typhoon. The rainfall information in places where landslides occurred
is interpolated from one hour interval rainfall data recording at by using Kriging
method.
Compared with the data obtained from images before the Ch-Chi earthquake, the
landslides intensity increased significantly after the earthquake and it gradually
decreases. Landslide intensity obtained from images taken after typhoon Kalmaegi in
2008 is still near twice of that obtained from typhoon Herb in1996 although the
cumulative precipitation of Herb is six times of the Kalmaegi. Besides, landslides before
the Chi-Chi earthquake were mainly distributed in mid-slope areas, with slopes of
30o–40o but they still shift to the places with slopes 40o-50o in the Kalmaegi. In
addition, after the Chi-Chi earthquake till the Typhoon Aere in 2004, it shows that
landslide intensity is always greater in area with larger PGA without regarding
to the cumulative rainfall and maximum rainfall intensity of typhoon. After the
Aere, for the same typhoon, landslide intensities in area with different PGA are
well correlated with rainfall intensity of Typhoon without regarding the suffered
PGA. Consequently, we conclude that the Chi-Chi earthquake still influence the
occurring of landslides in the Chenyulan river watershed at present. However, landslide
intensity is dominated by ground motion of the Chi-Chi earthquake till Typhoon
Aeae in 2004, and then it is dominated by rainfall intensity and cumulative rainfall |
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