Mt. Unzen, located in Nagasaki Prefecture, erupted first in 17th November 1990, and has been active ever since. During its activity, pyro-clastic flows originated from growth and depression of lava domes and debris flows caused death and severe damage in the populated area.
In this study, since the surveying area is under dangerous condition, there is great difficulty to keep observation sites in the damaged area.
Thus, it is indeed valuable to use remote sensing method for monitoring of active volcanos.
The use of aerial photographs taken at eleven different stages of volcanic activity enabled the easy comparison of geomorphological characteristics and volume calculation of volcanic products.
Such continuous aerial surveying will be effective to estimate investigation of disaster prevention.
