This landslide took place due to climatological factors. Rainwater seeped through the joints and pores which got dammed up later on causing this landslide. 

 A report on recent landslides in Thodupuzha, Udumbanchola and Devikulam taluks, Idukki district, Kerala by C. Muraleedharan, Geologist (Sr) and M. P. Muraleedharan, Director, Opn TNPK, Unit Kerala, Thiruvananthapuram (2007)

Periyar valley
Vathikkudi
Afforestation, awareness campaign, prohibition of construction on steep slopes.
Water percolated through thin soil cover and highly jointed bedrock due to heavy incessant rainfall. This water got channelized and seeped through the subhorizontal  joints. In due course of time this water may have got blocked creating enormous pore wat