This paper reviews the development of reconstruction designs of the lost Zhang Heng's seismoscope. Historical background of Zhang Heng's seismoscope including the biography of Zhang Heng and existing historical archives is presented. Available reconstruction designs, which are classified into external shape, suspended pendulum, direct contact, inverted pendulum, and authors' approach, are presented. Based on the proposed approach, all feasible design concepts that meet the science theories and techniques of the subject's time period can be recreated. And, this provides a logical foundation for the reconstruction designs of Zhang Heng's seismoscope before new evidences are found.
This study aims to estimate the spectral amplification factor for all of Japan. The spectral amplification factor for each geomorphology is calculated from the H/V spectral ratio of the microtremor with the modification factors by Senna et al.(2008). For some geomorphologies, the subdivided units are used. The spectral amplification factor is modeled for each geomorphology. For the 2007 Niigata-ken-chuetsu-oki earthquake, the proposed method is applied. The estimated spectra show good agreements with the observed ones, and the effectiveness of the method is confirmed.
In a large-scale earthquake, it is important to understand road conditions over a wide area to establish vehicular and evacuation routes. This will allow us to carry out rescue and support activities rapidly. We propose a method of detecting road-blockage areas in mountainous districts. We use satellite images taken before the disaster and aerial images taken after the disaster. Since we can rapidly obtain information on a wide area from aerial images, we can use the images effectively to understand road conditions. We detect damaged areas by comparing the two images and using the digital elevation model (DEM). Then, we detect road-blockage areas using connectivity relationships between the damaged areas. Finally, we project the results obtained onto the digital map. We developed relevant software on the computer, and we analyzed actual images to evaluate the effectiveness of our method.
This study presents comparison of the results calculated from time history analysis and shaking table test of wood houses. Wood houses consist of timber frame with moment resisting joint, post and beam construction with shear walls and their composite structure. As the result, maximum displacement by numerical model corresponds to the result of shaking table test. Based on the confirmation of the capability of numerical model, some analytical parametric study were conducted. Main result obtained from the studies is that timber frame with moment resisting joint should be evaluated and be structural designed using horizontal load-carrying capacity in addition to allowable stress design.
A generic vibration model for analyzing the design of a mechanical continuous unloader of the harbor facilities was constructed. It optimizes the design on the basis of vibration measurements to obtain rigidity of the main portion of the unloader. The objective is to design an aseismatic device that is immune to damage or collapse during a major earthquake. This analytical approach was demonstrated to be an efficient way to optimize the specifications of an aseismatic device and to verify its effectiveness.