Nobuoto Nojima

MEASURING POST-DISASTER TRANSPORTATION SYSTEM PERFORMANCE: THE 1995 KOBE EARTHQUAKE IN COMPARATIVE PERSPECTIVE

Recent earthquake disasters have caused major damage to transportation networks, leading to significant economic disruption. While this suggests the need to evaluate total system performance in transportation risk assessment, in addition to examining the vulnerability of individual components such as bridges, no appropriate measures currently exist. This paper develops post-disaster system performance measures and applies them to the urban rail and highway transportation systems in the Kobe, Japan, region devastated by the 1995 Hyogoken-Nanbu earthquake. Performance is evaluated in terms of network coverage and transport accessibility. Performance degradation was much more severe for highways and railways than for other lifeline infrastructure systems. Both transportation systems fared poorly in the disaster but service restoration proceeded much more rapidly for rail. The restoration of highway system performance correlated closely with the recovery of highway traffic volumes. The paper further develops a measure of subarea transport accessibility and applies this to Kobes constituent city wards. Results indicate substantial spatial disparity that is maintained throughout the restoration period. Comparisons with the 1989 Loma Prieta and 1994 Northridge earthquakes in the US show that although these disasters caused notable damage to highway bridges, system performance degradation was small in comparison with the Kobe experience. The paper argues that explicitly measuring transportation system performance can greatly facilitate both understanding the effects of historic disasters and preparing for future hazard events.

Building Damage Estimation by Integration of Seismic Intensity Information and Satellite L-band SAR Imagery

For a quick and stable estimation of earthquake damaged buildings worldwide, using Phased Array type L-band Synthetic Aperture Radar (PALSAR) loaded on the Advanced Land Observing Satellite (ALOS) satellite, a model combining the usage of satellite synthetic aperture radar (SAR) imagery and Japan Meteorological Agency (JMA)-scale seismic intensity is proposed. In order to expand the existing C-band SAR based damage estimation model into L-band SAR, this paper rebuilds a likelihood function for severe damage ratio, on the basis of dataset from Japanese Earth Resource Satellite-1 (JERS-1)/SAR (L-band SAR) images observed during the 1995 Kobe earthquake and its detailed ground truth data. The model which integrates the fragility functions of building damage in terms of seismic intensity and the proposed likelihood function is then applied to PALSAR images taken over the areas affected by the 2007 earthquake in Pisco, Peru. The accuracy of the proposed damage estimation model is examined by comparing the results of the analyses with field investigations and/or interpretation of high-resolution satellite images.

Estimation of building damage ratio due to earthquakes and tsunamis using satellite SAR imagery

In order to expand the existing C-band SAR based damage estimation model into L-band SAR, this paper introduces a likelihood function to estimate severe damage ratio by earthquakes on the basis of dataset from JERS-1/SAR (L-band SAR) images observed the 1995 Kobe earthquake and its detailed ground truth data. The model is applied to JERS-1/SAR images taken over the tsunami affected areas by the 1993 Hokkaido Nansei-oki, Japan earthquake.

Application of an Assessment Model of Post-Earthquake Lifeline Serviceability to Recent Earthquakes in Japan

An assessment model for post-earthquake serviceability of three utility lifeline systems was applied to seven recent earthquakes in Japan. First, using the “Quick estimation system for earthquake maps triggered by observation records (QuiQuake),” population exposures to shaking intensities were obtained for each earthquake. The assessment model was then applied, and preliminary results for the time histories of the number of people without lifeline service were obtained.

INTERACTION-RELATED DISASTER PROPAGATION BETWEEN WATER SUPPLY SYSTEM AND URBAN FUNCTIONS DURING THE GREAT HANSHIN EARTHQUAKE

1995年兵庫県南部地震は都市機能を支えるライフラインに多大な被害を与えた. ライフライン被害の相互連鎖は, 既往の震災事例をはるかに超え, 明らかに質の異なるものとなった. 本報告では, 断水が他のライフライン (電気, ガス, 下水道) や医療機関の機能および消火活動や廃棄物焼却施設などに及ぼした影響について述べる. 差し水によるガスの復旧の遅れ, 冷却水や工業用水道の供給停止による発電などへの影響や消火用水の多様な確保策がわかった. さらに, 意外に少なかった通電火災, 復電による通水の状況, 水道の回復が下水道の機能に与えた影響や医療に不可欠な水道の役割などが定量的に明らかになった.