Fig. 1 Landslide location map with hill shaded map of study area
Karang weather station provided by Malaysian Meteorological Services Department).
Tectonically, Selangor area forms a part of the Sunda Shield. Its fold-mountain system, the dominant regional trend of which is northerly to north-northwesterly, is a southerly continuation of that extending from eastern Burma through Thailand, peninsular Malaysia, the Banka and Billiton islands and eastwards into Indonesian Borneo. All the systems, ranging from the Cambrian to the Quaternary, are represented in Peninsular Malaysia. The pre-Triassic rocks are essentially marine origin, whereas the post-Triassic rocks are characteristically non-marine origin. The Triassic rocks themselves are both marine and non-marine origins but in general, the non-marine deposits where present, occur in the Upper Triassic. Within Selangor itself, it is probable that sedimentation was continuous throughout the Paleozoic and Mesozoic, but because of the instability of the basin, the sedimentary record is incomplete. Major breaks are apparent between the Paleozoic, Mesozoic and Cenozoic groups of rocks, whereas within and between the systems themselves minor breaks are also presented. Granitoids occupy almost half of the study area. These bodies commonly form topographic highs, the largest of which is the Main range situated on the eastern flank of the area. Although many of the granite bodies are aligned parallel to the structural trend, they do not always occupy the anticlinal ridges of the sedimentary covers and some of the smaller bodies are found to cut across