In the seismic hazard assessment, the frequency of onshore blind earthquakes is evaluated from the seismic activities in the region where the characteristics of earthquake occurrence are similar. As a result, the modeling of the seismotectonic province map and the seismic activity based on the map are critical. The National Seismic Hazard Map in Japan averages three methods for estimating the frequency of the blind earthquakes, implying that the evaluation method has a high level of uncertainty. Furthermore, the boundary setting of the seismotectonic province map still includes based uncertainties on expert judgement. In this study, we have conducted principal component analysis and cluster analysis for six parameters which indicate seismotectonics. Furthermore, we have attempted to develop the quantitative modeling of the seismotectonic province map based on the statistic approach. The results can be interpreted as the seismotectonic province map and are based on three tectonic characteristics relating to different time scale: "geomorphological and seismological," "geodetic" and "geological and structural geological characteristics." The method of this study is considered to be useful for reflecting quantitative seismotectonic differences in the seismic hazard assessment.

From a seismogram recorded at Tokyo by a Ewing strong-motion seismograph during the 1923 Kanto earthquake, ground motion at Tokyo is restored by mending of off-scale parts and instrumental correction of the seismograph. The characteristics of the seismograph such as the rotation time of the recording disk, the natural period and damping are examined carefully, however the estimated constants of the seismograph include uncertainties. The velocity response spectrum (h = 0.05) of the restored record has peaks at a little less than ten seconds in the SW-NE direction and at 4 to 5 seconds and a little over ten seconds in the SE-NW direction, respectively. The spectrum amplitudes in 2 to 10 seconds are around 30 to 80 cm/s in the SW-NE direction and around 60 to 100 cm/s in the SE-NW direction, respectively. The amplitudes are larger than the results of the previous studies by Morioka (1980) and by Yokota et al. (1979). The restored record shows similarity in spectral characteristics with records observed at the same site during other large earthquakes and in time history of strong shaking with records of personal experiences during the Kanto earthquake.

This study proposed a method to simply predict the rise part of real-time seismic intensity time-series. First, we focused on the duration between the arrival of P-wave and 95% of the maximum value of real-time seismic intensity as the characteristic time of the rise part. We developed a prediction equation of it using hypocentral distance, moment magnitude, source depth, average S-wave velocity up to a 30 m depth, and top depth to the layer whose S-wave velocity is 1,400 m/s as explanatory variables by regression analysis based on strong-motion records of 41 earthquakes. In addition, an approximate function based on a logarithmic function was proposed to reproduce the time-series shape of the rise part. We validated this prediction approach with records of the 2016 Kumamoto earthquake and the 2011 Tohoku earthquake to investigate its effectiveness and limitation.

Injuries and deaths caused by liquefaction, as well as delays in escaping from tsunamis, have actually occurred in past earthquakes. After the 2011 off the Pacific Coast of Tohoku Earthquake, tsunami-related measures have been greatly improved in school disaster prevention. However, it is not clear to what extent the measures related to liquefaction have been taken and how many descriptions are available for liquefaction. The purpose of this study is to investigate disaster prevention manuals and pamphlets produced by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and prefectural boards of education, and to clarify the extent to which manuals and pamphlets are prepared to deal with liquefaction in school education.The results of the survey revealed the following three points. (1) Disaster prevention manuals are greatly influenced by recent disasters, and they are full of information about the most recent disaster that caused serious damage. Therefore, even in areas where disaster prevention education materials are abundant, liquefaction is not emphasized. (2) The data prepared by Chiba Prefecture, which suffered severe damage due to liquefaction caused by the Tohoku Earthquake, had the most extensive description of liquefaction among the 47 prefectures. (3) Only three prefectures (Chiba, Tokyo, and Aichi) have specific information on liquefaction, and there are few regions in Japan that have specific information on liquefaction.