The Nojima seismic fault, appeared in the Awaji Island following the Hyogo-ken Nanbu Earthquake, it attracted the interest of many researchers from immediately after the occurrence, since it showed a large displacement crossing a farmland, road and a river embankment. Engineering geological surveyers and researchers energetically investigated and studied the scale and moving mode of the surface seismic faulting and the relation between the surface deformation around the fault and various other kinds of damage.
In contrast to the Nojima seismic fault, a seismic surface faulting in the Kobe district was not clear except in a part of the area. Although the presence of faulting particularly becomes of major interest as an expansion factor of damage in the earthquake disaster belt; the remarkable damaged zone from Kobe to Ashiya and Nishinomiya; the results of the surveying were confined to finding out the intermittent shear displacement in some places. However, the results of deep ground prospecting showed that the extended part of known faults and the unknown faults lay under the alluvium or dilluvium. The relations between the lying positions of these faults and the damage on ground surface, ground ruptures and ground deformation, are so important to the engineering geologist.
The engineering geological investigation practiced after the earthquake about the crustal movement, the surface seismic faulting and the ground deformation related to the faulting, was unprecedented in scale, and it was the first case that various kinds of investigation methods were applied to the ground after the earthquake. Therefore, this chapter was written from the standpoint that the results of the investigation should be left as a documentary record as much as possible. These records would be expected to become valid material when later evaluation on fault activities, or to estimate any damage during earthquake.
