Which of the following statements regarding landslides is/are correct? 1. They are sudden and sporadic. 2. They result when the slope is gentle. 3. Mining activity is also responsible for landslides. Select the correct answer using the code given below.

Landslides are defined as sudden, rapid, down-slope movements of rock or soil under the influence of gravity [3]. They are typically sporadic events triggered by natural factors like heavy rainfall, earthquakes, or volcanic disturbances [1]. Regarding slope, landslides usually occur on steep slopes, such as those found in mountainous areas or cliffs, rather than gentle slopes [3]. Human interference significantly contributes to these events; activities such as road or rail construction, which artificially steepen slopes, and mining activities that undercut slopes or set up vibrations, are major man-made causes [1]. While some lateral spreads can occur on gentler gradients, the general characteristic of a landslide is associated with steep topography [3]. Therefore, statements 1 and 3 are correct, while statement 2 is incorrect as landslides are primarily associated with steep, not gentle, slopes.

Sources

1. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 4: Weathering, Mass Movement and Groundwater > L.ANDSLIDES (SLUMPING OR SLIDING) > p. 40
2. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > Landslides (Landslips) > p. 4