Landslide In Malaysia

 The 2003 Bukit Lanjan landslide in Malaysia:

Although Malaysia is not a mountainous country (mountains and hills are less than 25% of the territory), slope failures are a common phenomenon there. According to The Sun OnLine, there have already been a number of landslides only this year. So, why is this natural disaster so common in the country? We have come up with some answer, that is, a list of major landslide causes. You can correct us or add some causes to the list. Here it is:

1. Weathering. In tropical countries like Malaysia, weathering is always a cause. The weathering agents are: 1) changes in the daily temperature from 23 degrees (C) to 35 degrees. 2) Rainfall, which is also the major trigger. There are two rainy seasons in Malaysia: from April to October (the south-west monsoons), and from October to February (the north-east monsoons). The average annual rainfall is more than 250 cm.

2. Soil Properties. Due to the tropical climate and rainfalls, bed rocks are heavily weathered, resulting in residual soils. This type of soil, which is considered weak from the geotechnical point of view, is commonly found on hillsides and slopes. When unsaturated, residual soil has a cohesion due to suction, however, during rainfall the suction typically drops to zero, a process that is followed by buildup of excess pore pressures. As a rainfall continues, the excess pore pressure exceeds a certain threshold, the strength of soil dramatically drops, and a landslide is triggered.

3. Human Activities. This seems to be the major cause of landslides in big cities. Unfortunately, there is no geotechnical control over slope development works all the time, and some construction firms don't seem to observe safety standards for slope engineering practice. As a result, a strong rainfall can trigger a landslide on such slopes. There are a few pictures to illustrate the point. I found them in Here’s why Penang should ban hill-slope development.

Trail of destruction: Since the Bukit Antarabangsa landslide tragedy, residents in such areas have been up in arms against possible recurrences of a similar tragedy if nothing is done to halt further developments