ANALYSIS OF SPATIAL DISTRIBUTION AND CONTROLLING PARAMETERS OF LANDSLIDES TRIGGERED BY THE APRIL 14, 2010 YUSHU EARTHQUAKE

On April 14, 2010at 07: 49(Beijing time),a catastrophic earthquake with Ms 7.1 occurred beneath the central of the Tibetan Plateau in Qinghai,China.With visual interpretation of remote sensing imageriesand verifications of field check,about 2036 landslides are found in a total area of 1.194 square kilometers.They are triggered by the ground motion of the earthquake.They are extensively mapped over a rectangle landslide limit area of about 1455.3 square kilometers.Using both landslide area(LA)and landslide number(LN)to carry out statistical analysis on 3 categories of controlling parameters for landslides triggered by earthquake: 1)earthquake parameters(distance from earthquake epicenter,distance from macroscopical epicenter,distance from the main surface rupture,and PGA), 2)topographic parameters(elevation,slope angle,slope aspect,topographic position,distance from drainages),and 3)road parameters(distance from roads).The results are as follows: ① both LA and LN have strong positive correlations with distance from main surface rupture,landslides often occurred at a distance of 1.5km from the main surface rupture.Macroscopical epicenter also has some influence on the landslide distribution.The region about at a distance of 22km from the macroscopical epicenter is landslide intensive region.Both distance from earthquake epicenter and PGA have no obvious effect on the earthquake triggered landslides; ② most of the Yushu earthquake triggered landslide occurred in the areas about the following topographic controlling parameters,elevation as 3800~4000m and 4200~4600m,slope angle as 20~35,slope aspect as NE and E,topographic position as middle slope and lower slope are landslide.Landslides have strong positive correlations with distance from drainages; ③ the closer to the roads,landslide more occurring.Most of the landslides occurred within 300m from the roads.