Vol.5 No.4 2013

Research paper : Reconstruction of the 869 Jogan tsunami and lessons from the 2011 Tohoku earthquake (Y. Okamura)−250−Synthesiology - English edition Vol.5 No.4 (2013) Discussions with Reviewers1 Overall comment 1Comment (Shigeko Togashi, AIST)This paper discusses the way in which science may contribute to society through the research of long-term earthquake prediction that may help disaster prevention, by thoroughly clarifying the geological evidences of tsunami deposit and then estimating the image of past earthquakes using the geophysical methods.Specifically, 1) the paper presents a scientific methodology in which the reconstruction model of past earthquake is created by integrating the data with differing time scale such as geological record of tsunami deposit, historical record, observation record, and others, then simulating a geophysical model, and improving the prediction accuracy by verifying the model against the earthquake that actually occurred. 2) It also discusses the method for realistically contributing to disaster prevention by quickly and accurately announcing the latest research results to society, even if it is in mid-research stage, including the areas that may be still uncertain.This paper raises important issues from the perspective of methodology for how science may contribute to society, and I think it is appropriate as a paper to be published in Synthesiology.Upon review, the paper was revised to clearly state the significance of the aforementioned methodology.2 Overall comment 2Comment (Akira Ono, AIST)I think the earthquake model construction method, in which the elemental research of geological survey of tsunami deposit and the geophysical method were combined to achieve the research objective of reconstructing paleo-earthquakes, is an excellent Type 2 Basic Research. I respect the fact that this research was perfected at a high level before the occurrence of the 2011 Tohoku-oki Earthquake.In this research, the Jogan Earthquake was reconstructed accurately. It is regretful that the results could not be announced before the tsunami of the Tohoku-oki Earthquake. On the other hand, while it was completely coincidental that the constructed earthquake model was verified immediately by the actual phenomenon, it was greatly significant in considering the measures against future large-scale earthquakes. I think the earthquake model that was constructed will be useful in reliably predicting large-scale earthquakes and accompanying tsunamis that are expected to occur in the future in the Tokai, Tonankai, and Nankai areas.3 Approaches in geology and geophysicsComment (Akira Ono)In this paper, you describe the role, mission, and position of the geology groups within AIST. Considering that Synthesiology is read by people of wide-ranging fields, can you expand the description to “seismology” or “earthquake studies” rather than keeping yourself within the geology of “AIST”?Answer (Yukinobu Okamura)The mainstream of “seismology” or “earthquake studies” is the research based on geophysics, and the research based on geology conducted at AIST is a minority. This minor research drew attention after the Tohoku-oki Earthquake. The mainstream researchers are working to figure out the reason why they were unable to issue preliminary warnings, and are discussing the direction of future research based on the lessons learned. The objective of this paper is to emphasize the importance of earthquake research based on geology and to discuss the various issues. Widening the discussion to the entire seismology will derail from the main topic, and I feel it is too much of a load for me. In the “Introduction,” I added some simple description of the difference between AIST and the mainstream earthquake researches.4 Presentation of a flowchart of the paleo-tsunami research as a scientific methodologyComment (Shigeko Togashi)I think it will help our understanding if you draw a generalized flowchart of the paleo-tsunami research as a scientific methodology.Answer (Yukinobu Okamura)I created my version of the flowchart in Fig. 2, based on the sample.5 Action for the “organization of a system for quick objective evaluation”Comment (Shigeko Togashi)What are the actions for the “organization of a system for quick objective evaluation” mentioned at the end of chapter 6?Answer (Yukinobu Okamura)The objective evaluation must be conducted by a national organization such as the Earthquake Research Committee, and I think it will be most efficient if the government’s evaluation process is accelerated, but it is not easy to do so. Another method is the publication as papers of the correct method for tsunami deposit research. If the researchers publish highly reliable results, I think highly reliable tsunami evaluation will spread quickly throughout society.


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