|Again sorry for the quality, but equipment and handling took a toll on the picures ;-).|
After eruptions ended, a crater lake formed in the 1991 caldera, with the 1992 lava dome forming an island. At first, the lake was small, hot and highly acidic, with a minimum pH of 2 and a temperature of about 40°C. Abundant rainfall cooled and diluted the lake, lowering the temperature to 26°C and raising the pH to 5.5 by 2003.
The lake increased in depth by about 1 metre per month on average, until September 2001, when fears that the walls of the crater might be unstable prompted the Philippine government to order a controlled draining of the lake. 9,000 people were once again evacuated from surrounding areas in case a large flood was accidentally triggered. Workers cut a 5 m notch in the crater rim, and successfully drained about a quarter of the lake's volume.
this picture was taken before 2001.
No points please!