Sobre o deslizamento de lama turfosa ocorrido em Campos do Jordão, SP, em agosto de 1972

Abstract

This note describes a 70.000 cubic meters landslide of high rich water and organic mate- rial loam (80% water, 15% inorganic residue plns 'i'll organic material). The orj!anic material was formed by grass leaves, carbonized frag- ments amt humltied substances. Splcules ui sponges and diatoms fragrnents occur together, proving the existence of an ancient and small lake in the place of the loam accumulation. Humified material and the high water con- tend caused the decrease of the loam shear strength. The clay mineral of the loam belongs to the caulinite group, but gibbsite is also pre- sento The coarser mineraIs are quartz, baueriti- zed biotite and partially decomposed feldspar. The loam accumulated in 'an amphitheater of 13.000 square meters and 8 meters thick- ness. was liquefied due to the weight of a small fill. The vibration caused by the move- ment of a tractor was the possible start of the landslide, who runned more than 500 meters, covering 60 houses and killing 17 people.