Yoshimitsu TAJIMA

Japan Society of Civil Engineers (JSCE) and Philippine Institute of Civil Engineers (PICE) jointly collaborated to carry out the field survey on severe storm surge disasters caused by Typhoon Haiyan/Yolanda from 12 December to 16 December, 2013 in Leyte and Samar. Based on interviews with local residents, the joint survey team obtained measured inundation and run-up heights at almost 80 different locations along the coast and also at more than 70 locations inside the cities of Tacloban and Palo.

This paper presents a theoretical model for the prediction of near-shore hydrodynamics in the surf zone along long straight beaches. The waves may be periodic or narrow-banded random waves, and the beach profile may be plane or barred. The theoretical model consists of three components: wave model, surface roller model, and near-shore mean current model. Both wave and surface roller models are based on simple energy balance equations and all the variables applied for the current model are determ

In 1972 Konishi proposed a unique waveguide filter of sandwich-like construction that was attractive because of its simplicity. This short paper presents an analysis of the sandwich filter that has a conductive sheet with finite thickness sandwiched between waveguide shells. An equivalent circuit is derived, design charts are proposed, and Young's technique is applied to the design of an M-band waveguide filter. The experimental results were found to be in good agreement with the theory and anal

Monitoring shoreline change is one of the essential tasks for sustainable coastal zone management. Due to its wide coverage and relatively high spatiotemporal monitoring resolutions, satellite imagery based on synthetic aperture radar (SAR) is considered a promising data source for shoreline monitoring. In this study, we developed a robust shoreline detection method based on satellite SAR imagery using an artificial neural network (NN). The method uses the feedforward NN to classify the pixels o

This paper reports the post-disaster survey results of storm surge and waves due to Super Typhoon Meranti (local name: Ferdie), along the coastline of the province of Batanes, Philippines. The survey was conducted by a joint survey team of the University of Tokyo and University of the Philippines from 9 to 12 October 2016, about one month after the disaster. Water levels in the inundated area or runup heights were measured at 37 locations along the coast of the islands of Batan and Sabtang by in

This paper investigates characteristics of coastal damage caused by Super Typhoon Haiyan with special focuses on locally varying wave deformations along the coast of Eastern Samar fronted by shallow fringing reef. The paper first summarized the field survey results and indicated that the erosion depth of the beach had negative correlation with the width of fringing reef along the straight coastline while a drastic variation of the damage levels was observed around Matarinao Bay mouth. A phase-re

This paper investigates the characteristics of coastal damages caused by Super Typhoon Haiyan with special focuses on dynamic behavior of storm surge and waves around Sam Pedro Bay. Numerical experiments were carried out to investigate the sensitivity of storm surge characteristics to various conditions, such as typhoon tracks, forward speed, and bottom frictions. Computed characteristics of storm surge and waves were compared to the observed inundation characteristics. Primary findings of the s

The present study develops a SAR-based shoreline monitoring system which consists of: (i) selection of SAR scenes suitable for shoreline detection; (ii) extraction of shoreline from the selected scenes; and (iii) estimation of the shoreline at arbitrary water level. The first model focused on ALOS-2 SAR scenes and determined fitting formulae for estimation of the backscattering coefficients at a sea and a beach surfaces. To quantify the suitability of scenes for shoreline detection, a parameter,

The tsunami that was triggered by the 2024 Noto Peninsula Earthquake caused severe inundation along the coast on the northeastern tip of the peninsula, propagated over the sea with rough wind waves, and reached the coast and rivers located away from the peninsula. This manuscript presents the results of a field survey and a supplementary analysis for investigating the tsunami characteristics away from the peninsula where rough wind waves had a significant influence on the tsunami behavior. Video

This study presents a theoretical model for predictions of nearshore hydrodynamic characteristics and the local sediment transport rate along long, straight beaches. The wave may be periodic or random, the beach may be plane or barred, and the bed may be concrete or covered with movable natural sand grains. The present model must be efficient and flexible so that it can accommodate iterative computations for time-varying and, hence, arbitrary beach profiles. The nearshore hydrodynamics model con

Abstract Many urban flood models employ coarse grids to reduce the computational cost of real‐time forecasting. Such a coarse grid, however, may result in poor predictions of the discharge rate of surface water because of difficulties in representing the detailed features of drainage facilities. In the present study, an urban flood model that consists of a one‐dimensional (1D) river flow model, a two‐dimensional (2D) ground surface flow model, and a 1D sewer network model was developed. A coarse

This study focuses on the impact of morphological changes on storm surge disaster risks in coastal areas around the Meghna estuary of Bangladesh. Long term meso scale features of bathymetry change in the target area are first investigated through analysis of shoreline profiles extracted from satellite images. More than 40 shoreline profiles within the past 40 years are extracted from satellite images. Difference of the tidal phaseduring the period when satellite image was acquired is taken into