1. Military trucks carrying engineering team to Mount Pinatubo volcano
2. More trucks carrying soldiers
3. Truck passes water stream
4. Team disembarking from truck
5. Pig for sacrifice being brought down from truck
6. Various team unloading supplies from truck
7. Pig being carried
8. Team starting trek
9. Various of team carrying digging equipment
10. SOUNDBITE (Tagalog) Rogelio Yap, Mayor of Botolan
"If we do not do this now, there is a possibility that the Maraunot notch will be breached at night time, so that is really dangerous. So we are doing this engineering intervention so that we are sure that the water flows at daytime."
Philippine Institute of Volcanology VNR
Mount Pinatubo - 10 August, 2001
11. Aerial of Pinatubo crater lake
12. Spot where they will dig notch
13. Hardened lava flow
Manila - 14 August 2001
14. SOUNDBITE (English) Raymundo Punongbayan, Director Philippine Institute of Volcanology and Seismology
"It's not dangerous yet, but there is always that possibility that you will have sudden breaching of the crater wall and if that happens, you may have a lot of water that may go down along the Maraunot river. That is the worst-case scenario".
16. SOUNDBITE (English) Raymundo Punongbayan, Director Philippine Institute of Volcanology and Seismology
"There is a lot of uncertainty about this, and if you want to protect people, you don't gamble, you just try to intervene".
Botolan - 15 August 2001
17. Evacuees riding carts pulled by water buffalos
18. Husband and wife Benny and Flor Tinsay
19. Young boy on cart with belongings
20. SOUNDBITE (Tagalog) Benny Tinsay, evacuee
"We are evacuating because we were told that water from Mount Pinatubo will overflow."
21. Tent with evacuated families
22. Evacuees inside tent
23. Children inside tent
24. SOUNDBITE (Tagalog) Sammy Ocampo, evacuee
"Of course I am afraid. I only have one life, and if the water overflows....especially the children, they will suffer so much."
A dozen tribesmen with picks and shovels started climbing the Mount Pinatubo volcano in the Philippines on Thursday, on a mission to drain a crater lake that threatens their villages with massive floods.
Tugging along a leashed pig to sacrifice to the mountain god, the Aeta tribesmen were to carve a notch in the volcano's crater to bleed water from the rising lake.
The workers, accompanied by a dozen porters, two engineers and others, were expected to chop five metres (16 feet) off the lowest point of Pinatubo's summit and drain the lake that has risen to within five metres (16 feet) of the crater's rim.
In 1991, an eruption that killed 800 people and spewed (B) billions of tons of debris blew off Pinatubo's top, leaving a hole with an area of four point 4 square kilometres (two point one square miles) in its summit.
The bowl that was formed has acted as a collecting pot for rainwater and the lake now contains some 200 (M) million cubic metres (seven (tr) trillion cubic feet) of water.
Government geologists, supervising and planning the work, ruled out the use of explosives or heavy equipment for fear it could cause a large breach in the crater wall, allowing the water to flood out uncontrollably.
Local officials said the men would start digging a canal on Thursday but as many as 200 men will be needed to complete the operation over the next two weeks or so.
Scientists hope the notch and gradual draining of the crater lake will permanently avert a crater collapse.
Botolan Mayor Rogelio Yap, whose town is in the path of flood water if the volcano overflows, says that it is important to start digging now.
He adds that about 800 families will be exposed to danger if this is not done.
Without the canal, the weight of the water that has been rising rapidly in the May-October rainy season, could shatter the upper walls of the one thousand and 445-metre (four thousand and 740-foot) volcano and endanger villagers nearby, geologists said.
But the crumbly crater, composed of loosely packed volcanic rock and ash, could also give way under the digging, they said.
Raymundo Punongbayan, director of the Philippine Institute of Volcanology and Seismology, said it is believed to be the first attempt in the world to drain water from a volcano lake in this way.
Residents living near the volcano have started evacuating after they were advised of the danger.
Riding water buffalos, they left their homes for the evacuation centre.
Pinatubo, 90 kilometres (55 miles) north of Manila, is sitting atop a massive magma lake.
It remains classified as one of the Philippines' 22 active volcanos.