Around the Senbongi district of Shimabara City, there were 3 towns and more than 180 houses. They were devastated by the pyroclastic flows and fiery winds (pyroclastic surge) which occurred intermittently over 2 days on 23-24 June 1993. In this area, you can see the deposits of pyroclastic flows and the houses damaged by them. Although this area has been under the erosion control works to reduce the risk of debris flows, some sites are preserved in the condition when the deposits of pyroclastic flows were formed. It is one of the few places where the precise correspondence between the deposits and the time of their occurance is verified. Some of the damaged houses and other remains of disaster are also preserved here. At the Senbongi Observatory along the Shimabara Mayuyama Road, you can see the valley through which large-scale pyroclastic flows passed and the area devastated by them. Behind the remains of disaster among the trees, you can also see the tip of the Shin'yake lava that flowed down during the 1792 eruption.