^aFaculty of Marine Science and Technology, Tokai University, Shimizu, Shizuoka 424 Japan

^bKensetsu Kiso Chosa Sekkei Co., Ltd., Kusunoki-shinden 241-7, Shimizu 424 Japan

The aftershock zone shifted westward to the interior of the peninsula. The largest aftershock (M = 5.8) struck the central to western part of the peninsula on 15 January, causing severe damage in its mountainous terrain.

Most of the hazards related to slope failures of sea cliffs, river cliffs and road cuttings of convex vertical section with the upper parts sloping gently and the lower parts steeply.

Large slope failures occurred close to the activated faults, indicating that the shocks and displacement were locally amplified along the activated faults.

In the meizoseismal zone, high embankments of roads and housing sites on natural slopes were damaged by slides and tension cracks between the embankment and natural ground.

Subsidence and tilting of retaining structures were generally observed. Damage to high concrete retaining walls of gravity type was due to the insufficient bearing capacity of the foundation soil. Any type of retaining structure, even if seismic-resistant, would be considered ineffective in case of failure of the back slope.

Buildings in the meizoseismal zone were damaged due to sliding of the underlying embankments and ground displacement due to the activated faults.

Falling rock blocks and sliding soil masses struck cars and houses close to the foot of cliffs and steep slopes, causing many deaths and injuries.

A number of tension cracks in the middle to upper parts of steep slopes and on the shoulders of road embankments threatened to cause secondary failures, rockfalls and avalanches during heavy rain.

At a gold and silver mine, the tailings dam of a concentration plant failed due to liquefaction of the tailings.

The above experience may throw some light on the possibility of seismic failures in mountainous countries in seismically active regions of the world.