Atago, which is close to 70m above sea level, is made of sandstone from the Meinohama Formation, which is vulnerable to weathering and is fragile. Since most of the surrounding area is steep cliffs, there is a risk of landslides, and it is designated as a sediment-related disaster special caution area and sediment-related disaster caution area (see below).

In the photo on the left, a steep cliff is approaching the residence, but this cliff is the site of the "Meinohama stone" quarry. The photo on the lower left is the site of the collapse accident that occurred on March 1, 2015. Part of the cliff was peeled off all at once, and rocks over 1 m in diameter hit the fence and storeroom of the house directly. This photo is after the rock was removed.

At the condominium (Atagoyama High Living) on the south side of the mountain, there is a rock fall from the back cliff (because the wild boar caught bait and dug up), and it is sometimes asked to put up a danger prevention iron net. did.

Strong ground motion during an earthquake and flooding and infiltration due to rainwater are also risk factors that cause cliff collapse. During the torrential rain on July 29, 1980, a landslide caused a disaster in which the houses in Atago 3-chome were partially destroyed. In recent years, the risk of "bursts that have never been experienced" has increased due to the effects of global warming, and it has been pointed out that an earthquake may occur at the Kego fault. How to prevent the problem and protect the safety of the residents is an important issue. The photo on the left shows a blue sheet being urgently placed on the cliff of the quarry site just behind the house to prevent rainwater from penetrating. The photo on the lower right is a photo of Onnazaka from the east side. The steep slope is covered with a concrete retaining wall, and many houses are built there. A blue sheet to prevent rainwater infiltration can be seen in the center, but solid disaster prevention measures are desired. Even if you make a mistake, it is a problem that you should not be satisfied if you specify a dangerous place.