 As a result, this caused an abrasion to a volatile soil structure that is somewhat sandy.Slowly the hillside was unable to withstand the weight of the hill above it, causing a landslide that brought the hill down into the wallow of spring below the mountain until a small lake was formed.For the Pamona community, the event of the collapse of the mountain is often mentioned until they coined the word "Lake Poso" which is given as a name to the then newly formed lake.