Yasuko Kuwata

Updated PGA, PGV, and Spectral Acceleration Attenuation Relations for Iran

We have developed updated attenuation relations for peak ground acceleration (PGA), peak ground velocity (PGV), and acceleration response spectra with 5% damping on the basis of the data (78 earthquakes and 351 records) pertaining to strong ground motion in Iran. Moment magnitude, distance, fault mechanism, site class, and zone were the model parameters considered. A term for the saturation of the acceleration amplitude was also used in the model in order to improve the estimations in near-source regions. A nonlinear regression analysis was performed to obtain the coefficients. A comparison between the data set used in the current study for Iran and two next generation attenuation (NGA) models showed good correlation between our model and the Campbell-Bozorgnia NGA model. The model described is applicable for moment magnitudes from 5.0 to 7.3, distances from 15 to 135 km, and site classes with an average shear-wave velocity at a subsurface depth of 30 m (AVS30) of more than 175 m/s.

Effective Emergency Transportation for Saving Human Lives

To save lives immediately after a catastrophic earthquake occurs, it is essential for an urban transportation system to retain its functional performance in order to carry injured people to hospitals. Recent seismic assessment studies have mostly been based on cost-benefit analyses, carried out in monetary terms that are reasonable for long-term considerations. However, many problems of seismic risk management still remain. For example, attributing a monetary value to a human life is considered impossible. Also, requirements for functioning of a transportation system are different in the period immediately after an earthquake. This paper concentrates on how to assess the importance of an urban transportation system as it relates to saving human life, and what system enhancements should be made to improve performance.This paper proposes a risk assessment method for the functional reliability of a transportation system immediately after an earthquake. In that period, system malfunction adversely affects the saving of lives as a result of time delays when moving injured people to medical facilities. A system dynamics simulation of transporting injured people is incorporated in the method, which uses two assessment approaches to evaluate the differences of cumulative injured people who receive medical care. In deciding on the destination of medical facility in the simulation, two ways of deciding are addressed; one uses information only on the road network, and the other uses information on both road network and hospital availability. Results of an application to an actual target area show the most vulnerable road links and differences of the two decision-making processes. A way to mitigate the loss due to damage to road links is examined. The paper also summarizes future developments in advanced information technology for emergency transportation systems.

BUSINESS RESTORATION RELATED TO LIFELINE AFTER TSUNAMI DISASTER

This paper proposes a method to evaluate functionality of a business after a tsunami disaster. This method has several modules such as damage estimation of business base (building, equipments, and lifeline) caused by tsunami hazard, restoration ratio-to-time model for business base, and the functionality of the business introduced by facility restoration and its influence to the business. As a case study, the tsunami impact to industries and its subsequent restoration process were studied based on an interview survey in southern Sri Lanka after the 2004 Indian Ocean earthquake and tsunami, and the survey results were applied to the proposed model. Results of application showed that buildings and equipments were slowly restored when they were extensively damaged or flooded. Further, the business restoration depends more heavily on the business facilities restoration than the lifeline restoration, when the business facilities are flooded with tsunami inundation higher than 1 m.

DAMAGE AND RECONSTRUCTION OF LIFELINES IN PHANG NGA PROVINCE, THAILAND AFTER THE 2004 INDIAN OCEAN EARTHQUAKE AND TSUNAMI

The Indian Ocean earthquake and tsunami occurred in December 2004 caused destructive damage to Phang Nga Province, Thailand. We carried out two times of interview surveys about 1 and 3 years after the event to administrative bodies and lifeline companies for getting the information on lifeline damage, restoration and reconstruction situation, and summarized the basic concept of reconstruction plan of tsunami suffered towns considering lifeline restoration. On the other hand, as for the comparison of reconstruction problems, the lifelines recovery is reviewed at Aonae district in Okushiri Island after the 1993 Hokkaido-Nansei-oki earthquake. As the result, the difference of the process of reconstruction of town and lifelines has been revealed and the importance of preparing of the reconstruction plan before the event under the consideration of a long-term city planning is pointed out.

Site Amplification of Iran’s Major Seismic Zones Using Attenuation Relationship

ABSTRACT This study deals with attenuation relation for Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), and spectral acceleration of Iran’s major seismic zones (the Central Iran and Zagros zones) considering ground amplification of site classes. The main development of attenuation relationship in terms of site classes has already been published by the authors. This study discusses site amplification in spectral acceleration compared to the seismic design codes of Iran (Standard 2800, 2014) and FEMA368 limits of amplification. Moreover, the relationships between the PGA or PGV and average shear wave velocity at 30-m depth (AVs30) are presented. This helps to predict appropriate PGA or PGV for each site corresponding to its AVs30.

DECISION OF OPTIMUM RENEWAL TIME AND METHOD OF SEWAGE CONCRETE PIPES CONSIDERING COST BENEFIT

下水道管きょの改築・修繕については，今後その需要増大が見込まれることから，効率的・効果的に行われることが必要である．そこで，下水道管きょの効率的な管理を行うため，下水道管路施設の最適更生時期を決定する方法を提案した．下水道施設の酸による劣化速度を定量的に評価し，下水道管路の耐久性の検討を行った．さらに，酸による下水道管路の劣化状況により腐食レベル分類し，それぞれの腐食レベルに到達する年数を推定した．到達する年数から耐用年数投資効果分析を行うことで，最適な管更生の工法とタイミングを選定する手法を提案した．