The Tinguiririca lahar is an example of many similar landforms, which coverlarge surfaces 60th in andine valleys and the Chilean longitudinal depression.I t is smaller than other ones in Chile, but - at the same time - better conserved,offering good conditions for genetic, kinematic and geochronologic studies,respecting volcanic mudflows.From the genetic and kinematic point of view, the longitudinal lahar profile maybe in two parts: a) An upper and middle accumulative area, with concavetransverse profile; b) A low accumulative area; whose transverse profile is convexe.These two profiles could be explained by means of braking process inlateral parts, related to central parts, as a function of longitudinal distoncesfrom the origin.From the geochronologic point of view, the lahar was between theLast Glaciation and Late Glacial times. Therefore, i t is more recent than otherones.