This paper presents a new high-density structural health monitoring system and its application to earthquake recording in a high-rise seismic isolated building. The monitoring system consists of many smart sensors that have automated data acquisition and data communication functions. The smart sensors are e precisely synchronized with a time server by using Network Time Protocol. The system shows its accuracy of time synchronization meets the requirement for synchronized multipoint measurement; time lag between the sensors verified less than 1 millisecond on standalone use, and about 4 milliseconds in multilayer network equal to actual network of the target building. The system observed greater than 90 earthquakes during two years from October 2011. Due to precise synchronization and dense placement of seismometers, relative story displacements among each level can be estimated from a series of acceleration record and show the good agreement with the records obtained by contact displacement meters.

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A probabilistic fault displacement hazard analysis(PFDHA) is a methodology that assesses an annual rate/probability of exceedance that an amount of displacement of a surface earthquake fault exceeds a certain quantity. To perform the analysis, displacements due to a principal fault and distributed faults are indispensable to evaluate in a probabilistic manner. For principal faults, an abundance of data are accumulated by making use of the past surface earthquake faults in Japan, while for distributed faults, the data are not necessarily sufficient in reality.Although a past study shows that an occurrence probability of distributed fault depends on a grid size employed in the analysis, no study using the Japanese domestic data for distributed faults has been reported.Taking this into account, the present study tried to improve the reliability of evaluation formula by analyzing the dependency of the grid size. In addition, model experiments and numerical analyses based on the discrete element method were applied to compensate the lack of data of the distributed faults. Furthermore, we adopted a logic tree methodology that can consider epistemic uncertainties and demonstrated its application example.

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The authors investigate various influential factors (tsunami wave related and evacuation related factors) on the fatality rate in the 2011 disaster. The tsunami wave related factors were the maximum inundation height and its arrival time in each target area, and the evacuation related factors were evacuation starting time and the distance to evacuation areas. Results indicate that the fatality rate increases with elevated tsunami height and its faster arrival time along with longer distance for evacuation, despite little influence of slower evacuation starting time.

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We studied the spatial distribution characteristics of seismic motion intensities on the engineering bedrock around the southeastern Mt. Fuji region by using the seismic records. We used the ratios of response spectra between the observed record and calculated values by the existing attenuation relations as the index of seismic motion intensities. We compared the spatial distribution characteristics with topographical maps and geological maps. As a result of the zoning, the region was classified into five groups. Based on the zoning, we calculated the factors to correct the attenuation relation. The factors reflect the spatial distribution characteristics of each zoning group. We propose a new method to estimate acceleration response spectra on the engineering bedrock spread over a wide area.

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The objective of this study is to investigate the characteristics of strong ground motions separated from Fourier and response spectra based on a generalize spectral inversion method applied to the observed data by K-NET, KiK-net, and JMA Shindokei Network in Japan. The separation method that we used here is the same method proposed by Kawase and Matsuo (2004). We include all sources larger than M_JMA4.5 observed from 1996 to 2011. Our results are in good agreement with the results by Kawase and Matsuo (2004) on the characteristics estimated from Fourier spectra, but ours show higher stability. By using the same method, we also separated the strong motion characteristics based on the acceleration response spectra successfully. However, the separated characteristics of strong ground motions of both results are different, especially in the lower frequency range less than 1Hz. These differences comes from the difference between Fourier spectra and response spectra found in the observed data; that is, predominant components in high frequency range of Fourier spectra contribute to increase the response in lower frequency range with small Fourier amplitude because strong high frequency component acts as an impulse to a Single-Degree-of-Freedom system.

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In the Great East Japan Earthquake, the business activity was very influenced by disruption of supply chain. In this paper, the methods of the functional damage prediction of road and the evaluation of its influences on business continuity of supply chain were studied to contribute to the development of the reasonable BCP for the companies that compose supply chain. The example analysis which simulated transportation was conducted using actual road network data. The result showed that the methods were effective at developing BCP of supply chain.

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It is essential to evaluate the subsurface structure properly and validate previously proposed ground structure models based on the geological data and boring exploration data with the observation of ground shaking for extensive and highly precise estimation of strong ground motions in urban areas. In this study, we observed microtremors in the southern part of the Osaka Plain in Japan where detailed geological information are comparatively less than the other areas of the Osaka Plain. We calculated H/V spectral ratios from observed microtremors data and compared predominant peak frequencies and amplitudes at these frequencies of the H/V spectral ratio with those calculated theoretically from our initial model. We searched for the 1-D structures at each site based on these predominant frequencies and amplitudes calculated from the recently proposed diffuse-field theory. As a result we identified the modified subsurface structures for each observation point along the two east-west lines in the southern part of the Osaka Plain. We also constructed a two-dimensional velocity structure for future strong motion prediction purposes.

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This paper summarizes liquefaction-induced damage in the Tohoku region during the M_w 9.0 destructive earthquake that occurred March 11, 2011, focusing on land and geomorphologic conditions of affected areas.Based on this study the following conclusions were reached: liquefaction was observed at a total of 63 cities, towns and villages in all six prefectures in Tohoku regions, whose numbers of 7.5-arc-second grid cells are 561; most of the liquefaction occurred in the areas where the instrumental seismic intensity exceeded 5.0; liquefaction caused damage to road, levees and residential houses, the lifelines as well as farmlands; liquefaction took placed in paddy field and mulberry plantation along the meandering rivers and valleys between terraces and hills during the Meiji and Taisho eras; and liquefaction occurrence rate for each geomorphologic unit within the areas of the instrumental seismic intensity exceeded 5.0 is the highest for natural levee (6.6%) among 22 geomorphologic classification units; the rate for reclaimed land and filled land is fairly low, which correspond to less than 1%, respectively.

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The maximum accelerations of upper floors of the 29-stories building (Kogakuin University) in Tokyo were 150 - 350 cm/sec2 during the 2011 Great Tohoku Earthquake, and consequently, several ceiling boards of an integrated ceiling system fell. In order to investigate the mechanism of the fall, we carried out the full-scale shaking table tests and found that it was caused by not only the lateral movement of the ceiling boards due to the high accelerations, but also the deformation of the flexible bearing members by the inertial force of the boards

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The objective of this study is to clarify the damage tendency of the public school buildings in Ibaraki Prefecture.The database of damages and the results of seismic inspections is made out through the questionnaire survey for 45 governing bodies, and data of 3,148 buildings has been collected. The distribution of seismic capacity index I_S of RC and S buildings designed under the fomer laws is close to the form of log-normal distribution. The damage data of 2,834 buildings which were received from the governing bodies, these damage summaries show that the damage ratio of glass, ceiling, wall and EXP.J is larger in the 1st period (constructed before and in 1971) buildings.Meanwhile, the buildings of the 3rd period (constructed after1981) have slighter damage ratio. According to the damage evaluation results of 287 old standard buildings, for the RC buildings which values of I_S are bigger than 0.6, the mid-damage is almost not observed. The lower limit of the residual ratio R decreases as the values of JMA seismic intensity, PGV and SI increase.

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During the 2011 off the Pacific coast of Tohoku Earthquake, Minamidai Residential Area, Tokai Village, Ibaraki Prefecture, Japan, suffered significant damage including a large-scale landslide. In this study, to evaluate ground motions at the damage site, microtremor measurements and temporary aftershock observation were conducted at the site. The evaluated site amplification and phase effects between the damage site and SK-net Tokai site are very similar. It indicates that the observed ground motions at SK-net Tokai site during the 2011 main shock can be regarded as the ground motion at the damage site.

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Ground-motion prediction equations (GMPEs) are developed by regression analysis based on datasets of recorded ground-motion parameters at multiple stations during different earthquakes and in various source regions. The variability of the GMPE is considerable and its influence on probabilistic seismic hazard analysis is paramount.Much recent work has examined the distance-dependent variance of PGA and PGV and estimated the standard deviation increases with decreasing distance. In contrast, some studies have estimated the standard deviation decreases with decreasing distance. A possible reason of this distance-dependence is the heavy weight for short distances in regression analysis. In this paper, the influence of weighted regression analysis and a diverse set of strong motion data (data consisting of only strike-slip earthquakes and mixed data of reverse and strike-slip earthquakes) on distance-dependent variance of PGA and PGV is examined. When we do not apply weights during the regression analysis, the standard deviations does not clearly show the distance dependent variance. Added to this, the distance-dependent variance can't be clearly seen when we use the mixed data set.

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