Vol.9 No.2 2016
Research paper : Three-dimensional urban geological map (T. NAKAZAWA et al.)−86−Synthesiology - English edition Vol.9 No.2 (2016) integration of six elemental technologies in the preface of Chapter 3, and we also added that we are working on the trial creation of a 3D geological map by integrating the six elemental technologies at the beginning of Chapter 4.4 Standard borehole data and borehole data of public worksComment (Akira Kageyama)You explain the differences between the two in Subchapter 3.2 and I think this is important. Therefore, how about showing the differences between the two data in a table? By directly comparing the objective and measurement data, I think it will make the scenario for the whole research easier to understand, that is, although borehole data for public works and others are useful, they are not sufficient as they are.It is the understanding of the Reviewer that the process of comparing, contrasting, and refining the borehole data possessed by the local governments against the results of the standard boring survey is the comparison of the strata in Subchapter 3.3. If so, I think the standard boring survey has the “hub function” while the local governments’ borehole data have the “satellite function.” Do you agree?Answer (Tsutomu Nakazawa)We newly created Table 1 that compares the characteristics of the standard borehole data and the borehole data of public works. The two data are in the relation of hub to satellite, as you indicated, and we added the explanation that the reliability of geoinformation can be increased by using the two data.5 3D modeling technologyQuestion & Comment (Akira Kageyama, Chikao Kurimoto)I think the terminology should be unified for the discussion in Subchapter 3.3 and Fig. 5. For example, the terms, “3D geological model,” “3D geological ground model,” “landform classification diagram,” and “landform categorization diagram” are mentioned.In Paragraph 2, Subchapter 3.5, it is described that there is a possibility that a completely different 3D model may be produced depending on the person in charge of manual work. Isn’t there need for making some sort of guideline that can produce a uniform model or interpretation? For example, the computer modeling method that you developed can be set as a common base, and then a gradual shift can be made to the system of adding on knowledge and experience of the experts as metadata.Answer (Tsutomu Nakazawa, Susumu Nonogaki)For terminology, we reviewed the descriptions, and call the 3D model for subsurface geology only as the “3D subsurface geological model,” and the model integrated with surface information as the “3D geological model.” The “landform classification” and “landform categorization” were unified into “landform classification map.”As you indicated, at this point, we are not working on obtaining a uniform model and interpretation, but we think it is important. The fact that the 3D model by computer processing is useful in sharing common awareness among experts was added to the paper.6 Discussion in Chapter 4Question (Akira Kageyama)(1) How many drilling surveys did you do for the establishment of reference data (standard borehole data) at Noda and Kashiwa? To obtain a certain level of reliability, how many drilling surveys are necessary? Also, while this may depend on the content of the local governments’ borehole data, how much supplementary effect can be expected in constructing the total system? If you would provide some information on these, I think it will be a rough guide (including costs) when expanding the project to various regions of Japan in the future.(2) For the utilization in real estate transactions, it is expected that there will be requests for not disclosing 3D geological maps because it may reduce the appraisal value of real estate. In the case of landslide damage that occurred in Asa-minami, Hiroshima Prefecture, it has been reported that the disaster increased because the disclosure of the hazard map was withheld. In such situations, from the viewpoint of increasing the risk response capability of society (community) by raising the understanding among interested parties, what are the authors’ thoughts on this (of course, the authors or AIST cannot undertake responsibility)?Answer (Tsutomu Nakazawa)(1) In the northern Chiba area that is the testing area, we ultimately plan to conduct about 20 sites of drilling surveys for establishing reference borehole data and use about 20,000 existing borehole data from public works. By doing so, we aim for geological maps of 1:25,000 that surpasses the 1:50,000 which is the basic scale of the conventional geological maps. We believe the goal can be achieved. We added this point to Subchapter 5.3. About half of the standard drilling survey sites in this research mainly target the irregularly distributed valley fill deposits. While it is desirable to have as many standard borehole data as possible, the geological structure can be estimated with surveys at lesser density in areas where the strata are distributed flatly and evenly. In contrast, in areas with complex strata, more surveys will be necessary. This means that the density of the drilling survey differs greatly according to the geological characteristics of that region.(2) As you indicate, I think there are concerns for the shift in appraisal value of a real estate if the geoinformation is added to real estate transactions. There may be both increase and decrease of the appraisal value. In either case, it is important for society to work on constructing a safe city by understanding the real geological and ground characteristics, and I think it is important to have people share the awareness that geoinformation is an important public asset for taking measures against disaster risks. We added this point to the paper, along with the citation of the proposal by the Science Council of Japan.7 Creation of the 3D geological map, future prospect, and ripple effectComment (Chikao Kurimoto)You cite Fig. 6 and explain the results of the prototype of the 3D geological map. I understand that this will lead to a “new style of geoinformation for urban areas” in future research. I think the readers will gain better understanding if you summarize the prospect of future research and its ripple effect.Answer (Tsutomu Nakazawa)The prototype of the 3D geological map is expected to increase the precision of geological disaster risk evaluation, and we believe the ripple effect on society is great. This point was added. Also, to clarify the future research prospect and the expected ripple effect, we summarized in Chapter 6 that we shall aim for the establishment of a new style of geoinformation for urban areas and the construction of 3D geological maps in the model region.