On the Tasikmalaya Earthquake Induced Landslide in Indonesia: Field Investigation

Abstract

On Wednesday September 2nd, 2009 at 14:55 pm the 7-magnitude earthquake struck the southern coast of the main island of Java near Tasikmalaya city in Indonesia. The earthquake and subsequent landslides resulted in at least 75 deaths, more than 900 injuries, and the displacement of more than 88,000 people from nine districts in Central and West Java which are near the epicenter as of September 7. Tremors damaged or destroyed more than 55,000 houses in 13 districts, including the most-affected areas of Tasikmalaya, Cianjur, Garut, and Bandung. The magnitude of this earthquake was strong enough to cause office blocks to sway and windows to shatter in Jakarta. Many houses and commercial buildings had collapsed in the worst-hit areas around the towns of Tasikmalaya and Sukabumi. The US Geological Survey reported that the quake occurred less than 200 km south of Jakarta at a depth of 49 km. The location of this earthquake was found in latitude 7.809° south and longitude 107.259° east. Site investigations were done to explore the hazards induced by the Cikangkareng landslide. Based on site investigations, it was found that there were various disasters and rock avalanches observed in the affected area. The run-out distance of rock avalanches was found approximately 600 m measured from the toe of mount. The profile of the rock avalanche, which was induced by landslide, consists of three segments with different inclination angles.