PROGLACIAL DEBRIS FLOWS IN POPOCATEPETL NORTH FACE AND THEIR RELATIONTO 1995 ERUPTION

In April 1995, ash had covered the glacier located on the north face o f the volcano Popocatepetl (19 degrees 03'N, 98 degrees 35'W; 5450 m), which provoked rapid melting of the surface of the glacier. The incre ased availability of water triggered many debris flows on the bottom o f the proglacial gorges. This paper analyzes the sedimentary structure and origin of these flows. Research findings showed that the debris f lows originated in an area of frozen ground where in 1992, a snow aval anche had occurred. As ash fell from the walls of the gorge, it blanke ted the compacted snow layer and protected it from melting.