A spokesman of the National Polytechnic School Geophysical Institute said the first of a series of eruptions occurred at 07: 43 local time (12:43 GMT).
Water steam and volcanic material rose some 12 kilometers above the volcano, which is 4,794 meters above the sea level, said the spokesman.
Quito's international airport was closed again Friday due to the ash fallout caused by more eruptions of the Guagua Pichincha volcano.
The Mariscal Sucre airport of the Ecuadorian capital decided to suspend its operations until the situation becomes normal, said civil aviation authorities.
Many national and international flights were delayed or canceled as volcanic ash kept on falling.
The National Polytechnic School Geophysical Institute (IGEPN) said that after early Friday morning there had been more than 10 explosions in Guagua Pichincha.
IGEPN technicians said that the volcanic eruption contained 60 percent of ashes and 40 percent of water.
School students were seen covering their nose and mouth with gauze to filter out the ash and protecting their eyes with goggles.
Guagua Pichincha registered its biggest eruption on November 25 when it spewed 2 million tons of ashes, half of which fell onto Quito's urban areas and the rest on the mountains.
IGEPN volcanologists said that Guagua Pichincha's explosions could continue for months and even for years. Enditem 18/12/99 01:38 GMT
Copyright (c) 1999 Comtex Scientific
Received by NewsEdge Insight: 12/17/1999 21:25:36