Background

BackgroundEarthquake shaking commonly triggers landslides and induced huge disasters. Recent events like the Mw 7.9 Wenchuan, China earthquake of May 2008, shown that the death toll and destruction from seismicallyinduced landslides can be extremely high.

Ten years ago, during the Chi-Chi earthquake, 9,272 landslides (with each area of greater than 625 squared meters and a total area of 127.8 squared kilometers) were triggered in central Taiwan. The heavy rainfall brought by the subsequent typhoons caused further damage in central Taiwan with numerous landslides. For example, after the 1999 Chi-Chi earthquake, the total area of shallow landslides in the Chenyulan River watershed was increased by 20 times. The amount of suspended sediment in the Chenyulan River watershed is as much as four times higher than background values before the Chi-Chi earthquake.

According to the Japanese experience with the influence of the great Kando earthquake of 1923, the sediment supply in the river catchments lasted for about 40 years. The effect of the earthquake and subsequent heavy rainfall on the characteristics of landslides deserves more attention.

The purpose of this symposium is to provide a forum for discussion among researchers and other professionals involved in studies of landslides.

Area of Coverage

1. Post-earthquake inventories of landslides and related ground failures (remote sensing, field observations, and statistical analysis)

2. Earthquake-induced landsliding and ground failures in different tectonic/climatic environments (case histories)

3. Regional-scale seismic landslide hazard mapping and assessment (applications of physically-based models, statistical analyses, and GIS techniques to regional-scale slope instability zonation under dynamic conditions; statistical approach to model spatial and temporal variability of earthquake- induced landslides)

4. Mechanisms of seismically induced permanent deformations in slopes (physical and numerical modeling; shaking table modeling of seismically induced deformations in slopes; nonlinear seismic sliding analysis of earth structures; evaluation of different models to estimate co-seismic landslide displacements and to assess regional seismic slope performance)

5. Seismic site response (topographic and litho- stratigraphic factors of ground motion amplification with examples from instrumented sites; ground motion directivity and slope dynamic response; site response analysis using modeling and numerical simulations; empirical geotechnical seismic site response procedures)

6. Uncertainty in ground motion estimates and in analyses of slope stability (simplified methods for evaluating seismic stability of steep slopes; evaluation of seismic slope stability procedures through shaking table testing; seismic landslide hazard assessment in connection with site-specific ground-motion dynamics)

7. Impact of earthquakes on the evolution of mountain slopes and fluvial sediment yields (including enhanced landslide generation by precipitation events following earthquakes)

8. Next generation of research on earthquake- induced landslides (plenary discussion)