The authors thank Dr. Hiroshi Kawase for his discussion and the answers are as follows. (1) The 'focusing effect' used in a wide meaning in the original paper has the same meaning as the 'edge effect'. Although the ground motion amplification near the basin edge is due to the superposition of the directly propagating body wave and the defracted surface waves rather than the refracted body wave, the authors used the terminology 'focusing effect', because the superposition at a basin edge lead to almost the same amplification characteristics at the concave underground structure where the terminology is commonly accepted, as example analyses are shown in this answer. (2) Although the references which the discusser suggested should have been added in the reviewing process, the referred literature are selected based on the earlier stage research activities taking account of priority of the idea focused on the effect of deep irregular underground structure with exception of some references indicated in the reviewing stage. (3) As for the relation between PGA distribution and damage distribution, the authors referred the damage distribution which is best coincident with the analytically obtained PGA distribution among the some other damage distributions near the analyzed section. Although the PGA may not be good index to discuss structural damage, the calculated PGA distribution is coincidence well with the damage distribution. This reason seems to be that the PGAs are determined from the relatively longer period contents than 0.5s in Kobe case.
