丸山 喜久

The 2011 off the Pacific coast of Tohoku Earthquake triggered an extremely large tsunami. The authors conducted a field survey in Asahi City, Chiba Prefecture, after the occurrence of the earthquake. Tsunami-inundated areas in Asahi City were identified from the map developed by disaster relief volunteers and the satellite images captured after the event. Polygons to demonstrate the tsunami-inundated areas were developed in the geographic information system. The authors compared the identified affected areas with the existing tsunami hazard map of Asahi City. The relationship between the tsunami-inundated areas and the locations of seawalls and tide prevention forests was evaluated. In addition, a numerical simulation of tsunami propagation was performed and the ratio of damaged buildings to the total number of buildings, i.e., damage ratio, in terms of the estimated inundation depths was evaluated.

This study investigated the damage distribution of buried pipes due to the 2007 Niigata Chuetsu-Oki earthquake in Japan. Various damage datasets - e.g. water pipes, low-pressure gas pipes, mid-pressure gas pipes, sewage lines, collapsed houses, and liquefaction occurrences - were integrated into a geographic information system. Using the datasets, the spatial distribution of damage was investigated with respect to geomorphological land classification and altitude. The minimum distances between the damaged locations were measured, and the spatial correlations of damage incidents to lifeline systems were evaluated. In addition, the damage ratios of water distribution pipes were compared with different fragility curves constructed from the damage datasets for the 1995 Kobe earthquake and other recent earthquakes in Japan.

Using QuickBird satellite images of Boumerdes city obtained following the 21 May 2003 Algeria earthquake, our study examined the applicability of high-resolution optical imagery for the visual detection of building damage grade based on the ground-truth data on the urban nature, typology of a total of 2,794 buildings, and the real damage observed. The results are presented as geographical information system (GIS) damage mapping of buildings obtained from field surveys and QuickBird images. In general, totally collapsed buildings, partially collapsed buildings, and buildings surrounded by debris can be identified by using only post-event pan-sharpened images. However, due to the nature of the damage observed, some buildings may be judged incorrectly even if preevent images are employed as a reference to evaluate the damage status. Hence, in this study, we clarify the limitations regarding the applicability of high-resolution optical satellite imagery in building damage-level mapping.

The evaluation of strong motion with high accuracy is very important to clarify the mechanism of earthquake damage. The strong motion estimation methods which correct the difference of site effects between the reference site and its neighboring sites based on seismic observations are easy to be applied in Japan. In this article, the estimation methods were applied to the Horinouchi interchange of the Kan-etsu expressway and that circumferential strong motion station in the 2004 Mid Niigata Earthquake. We confirmed that not only the consideration of the site amplification factors but also the consideration of the site phase effects are very important.

This study investigates the relationship between damage ratios of water pipes and seismic motion intensity after the 2007 Niigata-ken Chuetsu-oki, Japan, earthquake. The damage ratios of water distribution pipelines within a 2 km radius from the seismic observation stations are calculated in Kashiwazaki City, Niigata Prefecture. The damage ratios are compared with the fragility curves that were empirically obtained after the 1995 Kobe earthquake. On the other hand, the damage ratios for the greater area are obtained with respect to the estimated seismic motion intensities. Based on the results, regression analyses are performed to reveal the characteristics of damage incidents to water pipes during the event.

The distribution of earthquake damage plays an important role in the rescue operation and the restoration work in the aftermath of a seismic event. Immediately after an earthquake, the building damage ratios are estimated using ground motion indices and fragility curves constructed from the prior earthquake damage information. However, it should be noted that the fragility curves may sometimes provide less accurate estimations for recent earthquakes. On the other hand, some researchers are focusing efforts on collecting the actual damage information efficiently soon after an earthquake has occurred. The increased attention to collecting the actual damage information is expected to improve the efficiency in the near future and become increasingly helpful for a rapid disaster assessment. In this study, a method for data synthesis to restructure fragility curves is proposed, with respect to the actual gathered damage information. Either the mean or the standard deviation of the prior fragility curve is updated based on collected building damage datasets after recent earthquakes. As a result, the restructured fragility curves with the updated mean values show better estimations than the original ones. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer]

The collapsed buildings during the 2007 Niigata Chuetsu-oki earthquake are detected based on aerial photogrammetry using digital aerial images. The digital surface models in the area where severe damage incidents were observed after the earthquake are constructed using digital aerial camera images. The pre- and post-event aerial images are employed to obtain the digital surface models in this study. The differences of building heights between pre- and post-event models are considered to detect collapsed buildings and the accuracy of the method is discussed in this paper. (C) 2011 Published by Elsevier Ltd.

The objectives and methodologies to perform seismic microzonation are described and some examples are presented. The three major methods introduced to achieve seismic microzonation are the uses of geomorphological classification maps, dense borehole datasets, and microtremor measurements. The results of seismic microzonation are compiled for a GIS to draft microzonation maps and they can be used to predict ground motions during disastrous earthquakes and thus can assist in the mitigation of earthquake-induced damage.

The collapsed buildings in Kashiwazaki city due to the 2007 Niigata Chuetsu-oki earthquake are detected based on aerial photogrammetry using digital aerial images. The digital surface models in the area where severe damage incidents were observed after the earthquake are constructed using the digital aerial images. The pre- and post-event aerial images are employed to develop digital surface models in this study. The differences of building heights between the pre- and post-event 3D models are considered to detect collapsed buildings and the accuracy of the method is discussed.

The seismometer network of the Japanese expressway system was enhanced following the 1995 Kobe earthquake. Based on earthquake information from the instruments of the seismometer network, a traffic control is performed directly after the event because of the potential for damage to expressway structures. Expressways serve as vital trunk lines of transportation and are important for the restoration of damage-stricken areas Therefore, earthquake-induced damage to expressway structures should be estimated as soon as possible Expressway embankments were seriously damaged during recent earthquakes, such as the 2004 Niigata Chuetsu earthquake The present study constructs the fragility curves of expressway embankments in Japan in order to estimate the damage distribution immediately after an earthquake Damage datasets for expressways are compiled for the 2003 Northern-Miyagi earthquake, the 2003 Tokachi-oki earthquake, the 2004 Niigata Chuetsu earthquake, and the 2007 Niigata Chuetsu-oki earthquake The spatial distributions of the peak ground velocity (PGV) are estimated for these four earthquakes in order to evaluate the relationship between the damage ratio of expressway embankments and the PGV. Statistical analysis is then conducted in order to draw the fragility curves for expressway embankments. Based on the fragility curves, major damage that disrupts ordinary expressway traffic may occur when the peak ground velocity exceeds approximately 35.0 cm/s The fragility curves constructed in the present study are helpful for predicting the damage distribution on expressways soon after an earthquake, which enables efficient traffic control and rapid disaster response. (C) 2010 Elsevier Ltd All rights reserved.

Site response characteristics at seismic stations were investigated using horizontal-to-vertical (H/V) spectral ratios calculated from a seismic-motion dataset of the 2003 Boumerdes earthquake, and transfer functions were evaluated from soil profile data. Although high peak ground acceleration (PGA) values were recorded at some sites, the nonlinear effect at these stations was not clear. The H/V spectral ratios calculated from weak and strong motion events did not show a clear difference in the predominant period and amplitudes, and the shapes of the H/V ratios were flat for some stations. These observations are characteristic of the presence of firm to hard layers under the stations; however, one station was located on Quaternary deposits showed a remarkable amplification at the predominant period and a high PGA value. [DOI: 10.1193/1.3459158]

筆者らは，地球規模課題対応国際科学技術協力事業「ペルーにおける地震・津波減災技術の向上に関する研究」の一環としてJSTからの援助を受け，2010年2月27日に発生したチリ地震の被害調査を実施した．調査は地震から約1ヶ月後の4月2～8日にかけて実施した．本論では被害調査の概要と調査結果および地理情報システム（GIS）を用いた分析を行い地震，津波被害の特徴について述べる．具体的には，被災地域における衛星画像と現地調査写真を比較し，地震による建物被害がどの程度把握できるか検討を行う．また，標高データ（DEM）を利用し，津波被害が生じている地域の地形的特徴を分析する．

本論は，リモートセンシング技術を防災分野に利用し，大地震発生後の早期被害把握を行なうことを目的としている．近年では，自然災害発生時の緊急撮影に従来からのアナログ航空カメラだけではなく，デジタル航空カメラが使用されている．デジタル航空画像は高い輝度分解能や近赤外波長帯を有するため，衛星画像やアナログ航空画像よりも詳細な被害把握が可能となる．これらのデジタル航空画像の利点を活かし，2007年新潟県中越沖地震で瓦礫と化した倒壊建物を画像解析によって自動的に抽出する方法を提案した．

Lagoons as one of the water resources play a basic role in microclimates and ecosystems of their regions. Depending on climatic and geographic conditions of regions, the water level of lagoons has permanent fluctuations and perhaps in most dry seasons completely drains and sometimes causes to irreparable environmental and economic effects. "Hamun-e-Saberi" Lagoon is no exception. It, as the seventh lagoon in the world and one of the largest lagoons in the eastern part of Iran (Sistan Province) located between Iran and Afghanistan and has main level changes during different years and sometimes dried and again found resurgence. This caused to the serious damages to ecosystem and loss of vegetation around as well as destruction of aquaculture in this lagoon. Dependency of "Hamun-e-Sabri" lagoon to "Hirmand" river, 120-day "Sistan" monsoon wind and recent years droughts can be mentioned as the most important reasons of fluctuations of the lagoon's water level. This paper examines the lagoon in the period of 1976-2008 using LANDSAT and MODIS satellite images and analyzes them with utilizing the Normalized Difference Water Index (NDWI) during the August months, to assess and evaluate its spatial variations. The result of this research shows that the water level in August 1976 was highest water level and during the next years, this lagoon had many fluctuations and its level decreased gradually and eventually was completely dried in August 2008.

This study investigates damage distribution characteristics after the 2007 Niigataken Chuetsu-oki, Japan, earthquake. First, various damage datasets, e.g. water pipes, low-pressure gas pipes, mid-pressure gas pipes, sewage lines, collapsed houses, liquefaction occurrences, are integrated on Geographic Information System (GIS). Using the datasets, spatial distribution of damages is investigated with respect to geomorphological land classification and altitude. Then, the damage ratios of lifeline systems are compared under various conditions. Finally, the minimum distances among the damaged locations are measured and the spatial correlations of damages to the lifeline systems are evaluated. The results of this study suggest that the damage incidents to low-pressure gas pipes are often found near those to water distribution pipes. Hence, the interactions among functional losses of lifeline systems are expected to be taken into consideration in the restoration process after urban earthquakes.

In this study, fragility curves for water distribution pipes are constructed and used to simulate the distribution of water pipe damage from the 2007 Niigata Chuetsuoki earthquake and from the Tokyo Metropolitan scenario earthquake in Chiba Prefecture. The damage ratio of water distribution pipes is assumed to follow the log-normal distribution, which is evaluated using the weighted least squares method. The results of this study suggest that the relationship, obtained only from the dataset after the Kobe earthquake, between the peak ground velocity and the damage ratio of water distribution pipes can overestimate the damage ratio.

Earthquake motion indices play an important role in estimating damages due to ground shaking, and they are expected to be highly correlated with actual earthquake damages. However, there are some cases when building damages cannot be explained only by earthquake motion indices as in recent earthquakes. Therefore, this study evaluates the correlations between earthquake motion indices and building damage ratios performing seismic response analyses using numerical models of typical Japanese wooden houses. To obtain higher correlations, the spectrum intensity (SI) is recalculated by changing the damping ratio and the range of periods for an integration process. As a result, the period range to calculate a SI value should be selected properly to obtain higher correlation with wooden houses damage in Japan.

Land use and land cover changes due to human activities in a time sequence. Detection of such changes may help decision makers and planners to understand the factors in land use and land cover change in order to take effective and useful measures. Remote sensing and GIS techniques may be used as efficient tools to detect and assess land use change. In recent years, a considerable land use change has occurred in the greater Zanjan area. In order to understand the type and rate of changes in this area, Landsat TM, ETM+ images captured in 1989 and 2008 have been selected for comparison. The results of the present study disclose that about 35 percents of the total area changed their land use. In order to evaluate land use changes in this area, the Environmental Impact Index are established into four different categories as: Very high, High, Medium and Low impacts. The proposed index shows that the highest impact has been generated due to changing agricultural and bare lands into urban use.

To reduce casualties and troubles due to earthquakes, Japan Meteorological Agency introduced earthquake early warning (EEW) to general public on 1 October 2007. However, the possibility that EEW induces traffic accidents exists because EEW through car radio may not be transmitted to all the expressway drivers. Hence, the effects of EEW were investigated based on driving simulator experiments. Two kinds of experiments were performed in this study. First, single driving simulator was employed to reveal the effects of EEW on expressways. The reactions of drivers with/without warning are compared in avoiding an obstacle induced by seismic motion. Second, three synchronized driving simulators, simulating three cars running together on an expressway, were employed. When EEW was transmitted to only one car, some drivers reduced speed suddenly, and accidents occurred in two cases out of 14 tests. These experiments show the necessity of public education how to react an EEW on expressways. Turning on the hazard lights after receiving an EEW and then reducing speed gradually is suggested to avoid traffic accidents.

To reduce the casualties and impacts resulting from earthquakes, the Japan Meteorological Agency (JMA) introduced its earthquake early warning (EEW) system to the general public on 1 October 2007. Interestingly, a side effect of the system is an anticipated increase in traffic accidents that may occur because the EEW transmission will not be received by all drivers. Consequently, the effects of an EEW are investigated using three synchronized driving simulators to replicate the conditions of three cars traveling in close proximity on an expressway. When the EEW was received by all cars, the drivers behaved properly, and no problems occurred. When an EEW was received by just one car, however, some drivers reduced speed immediately, and accidents resulted in two out of 14 test cases. These experiments show the necessity of educating the public on how to respond if an EEW is received while driving on an expressway. In such situations, activating hazard lights and reducing speed gradually is suggested to avoid traffic accidents.

本論文では液状化発生地点の早期把握のために，液状化地点，液状化が疑わしい地点，非液状化地点の計112地点を選出し，加速度記録から算出するゼロクロス周期を用いた液状化判定手法を提案する．液状化地点の加速度記録において，水平方向の卓越周期は長周期化する傾向がある一方で，主要動時の上下方向の卓越周期はあまり変化しない傾向がある．この振動数特性を捉えるために，簡易で即時性が高いゼロクロス周期を利用して，周期の時刻歴変化を把握する．得られたゼロクロス周期の水平·上下方向に閾値を設定し液状化を判定するとともに，既往の手法と比較することで本手法の有効性を確認した．

本研究では，首都直下地震を対象としたライフライン施設の復旧シミュレーションや，各種提案されている埋設管被害予測式の高度化のための基礎資料の構築を目的とし，2007年新潟県中越沖地震におけるライフライン被害がどのような条件下で発生しているかを整理し，ライフライン被害の空間相関性を把握した．具体的には，地震被害，管路，地形の各種データを収集し，地理情報システム(GIS)で統合を行い，微地形，標高，地盤切盛り高さの各条件ごとにライフラインの被害率の算出を行った．また，被害箇所の空間的相互位置関係を明らかにするために，各種地震被害間の最近接距離の分析を行った．

地震動指標は地震の規模や被害を知る上で重要な役割を果たしており，実際の地震被害との相関が高いことが求められる．しかし近年の地震において，地震動指標値のみで建物被害を説明しきれないケースがあり，新しい指標が提案されるなど多くの研究がなされている．これを受け本研究では，計測震度，地動最大加速度(PGA)，地動最大速度(PGV)，SI値に関して，木造建物を対象とした地震応答解析を行い応答塑性率との相関性を検討した．解析結果からSI値に着目し，現行の減衰定数と積分周期帯について変更した修正SI値を提案した．この修正SI値と応答塑性率や実地震時の建物被害率との相関性を検討し，修正SI値の評価を行った．

日本水道協会により提案されている配水管の標準被害率曲線は，1995年兵庫県南部地震における強震観測点から周辺2km四方の配水管被害率によって構築されている．国や自治体が行う地震被害想定調査では，標準被害率曲線が対象地域における配水管被害率，断水率などの推定に用いられている．しかし，日本水道協会が提案する標準被害率曲線に加えて，その変形式が使用される場合もあるなど，地震被害想定調査の実施主体によって様々である．これには，一地震の被害データのみから標準被害率曲線が構築されており，ときに過大な被害率が見込まれてしまうということも多分に影響していると考えられる．そこで，本研究では近年の地震被害データも考慮に入れた新たな標準被害率曲線を提案する．

<p>It is anticipated that traffic accidents may occur because of the Earthquake Early Warning (EEW). The present authors introduced two driving simulators synchronized by server to perform virtual driving tests when the EEW is transmitted. To consider more realistic driving conditions, the agent-based model simulation was employed in this study. The behaviors of agents (drivers) were modeled based on the results of the driving simulator experiments. According to the numerical simulation of three moving vehicles under the EEW, a lower accident rate was observed on condition that more drivers turned on hazard lights after receiving the EEW. Hence, it is important to instruct drivers to turn on the hazard light before reducing moving speed if an EEW is transmitted on an expressway.</p>

<p>The number of traffic accidents associated with drunken-driving is reducing because the punishment for drunken-driving becomes heavier than before. However, the mortality rate due to drunken-driving is higher than any other cause of traffic accident. In this study, a series of driving simulator experiments were conducted to reveal the driving characteristics under the influence of alcohol. The reaction delay to signals, mistake rate of the reactions, driving performance under various circumstances and so forth were compared with respect to the alcoholic density in breath and the elapsed time after drinking.</p>

東京ガス(株)では2001年からSUPREMEと呼ばれる新防災システムを導入し，大きな地震動が観測されると地区ガバナ単位でガス供給を自動遮断および遠隔遮断する．さらに，各需要家に配備されているマイコンメーターは，地震動を感知するとガスの供給を自動遮断する仕組みを有している．しかし，マイコンメーターの地震時遮断特性に関してはまだ不明瞭な部分が残っている．本研究では，マイコンメーターの地震時遮断特性を評価するための振動台実験を行うとともに，実地震時におけるマイコンメーターの遮断データを収集し分析を行った．さらに，地震動強さとマイコンメーター遮断率の関係を評価し，対数正規分布を用いた遮断率推定曲線を構築した．

2004年10月23日に発生した新潟県中越地震では，関越自動車道と北陸自動車道の一部区間でとくに盛土部に震動が原因となった被害が多数発生した．そこで，本研究では，詳細な高速道路被害データと250mメッシュ単位で細密に推定した地震動強度分布をもとに，盛土部の被害程度と地震動強さの関係について統計的な分析を行い高速道路盛土部の被害関数を構築した．その結果，車両の走行に支障のある被害は，計測震度が5.1&amp;sim;5.2のとき0.05&amp;sim;0.1件/kmの被害率を示すと推定された．走行に支障のない軽微な被害も含めると，計測震度4.5&amp;sim;4.6のとき0.05&amp;sim;0.1件/kmの被害率を示した．

To prevent secondary disasters due to strong earthquakes, Tokyo Gas Co., Ltd. has introduced an earthquake monitoring and rapid damage assessment system called SUPREME, which has a subsystem to estimate the number of gas meters' shutoff. In a previous research, a shutoff rate estimation model of gas meters for wooden houses was constructed. The effect of seismic response of multistory buildings were not considered in the study. Hence, the estimation method of shutoff rate of gas meters in multistory buildings is considered in this research based on the actual earthquake data of the 2005 North-western Chiba Earthquake. First, the response acceleration at each floor of a multistory building is estimated using ground motion records and a simplified response model. Second, the height of building is obtained from a 3D GIS data. Then, the relationship between the estimated response accelerations and the actual shutoff rate is compared to demonstrate the accuracy of the proposed method. The result shows the possibility of grasping the shutoff rate of gas meters in various buildings from the earthquake ground motion recorded at a nearby district regulator.

When a large earthquake occurs, buried pipes and harbor structures often suffer from serious damages. These damages are mainly caused by large ground deformation due to soil liquefaction. Hence, it is important to detect liquefied sites at an early stage. Many seismometers have been deployed in Japan and acceleration records at liquefied sites were obtained in recent earthquakes. In this study, a method to detect soil liquefaction using acceleration records is proposed based on a dataset including records at liquefied and non-liquefied sites. As for the records at liquefied sites, the predominant period of the horizontal components tends to be longer. On the other hand, the predominant period of the vertical component is not lengthened even at a liquefied site. To reveal these characteristics, the change of the predominant frequency over the time was calculated from the Fourier spectra and the zero-crossing period. The occurrence of liquefaction is judged by setting threshold values for the JMA instrumental seismic intensity and the predominant frequencies for the horizontal and vertical components.

Many major and minor damages were caused to various structures in the recent earthquakes in Japan. Among them, the embankments of expressways were severely damaged. Using both the actual damage data and estimated spatial distribution of seismic intensity, this study conducts the statistical analysis on the relationship between the damage ratio of expressway embankment and seismic intensity. Based on the results, the fragility curves of expressway embankment are constructed. The actual damage datasets used in this study were compiled for the 2003 Northern-Miyagi earthquake and the 2003 Tokachi-oki earthquake. Based on the obtained results, major damages affecting the traffic are found to occur in the area where the JMA instrumental seismic intensity is larger than 5.3. Slight damages are also found to occur when JMA seismic intensity exceeds 4.8. The fragility curves constructed in this study may be helpful to predict the damage distribution in the expressway at an early stage of an earthquake occurrence so as to make an efficient traffic control and a rapid disaster response.

<p>In order to investigate driver's reactions to early warning of seismic motion, the present authors have conducted a series of virtual tests using driving simulators. Two driving simulators were employed in this study to consider the interaction between the drivers during an earthquake. When the early warning was given to the only one driver, traffic accidents sometimes occurred because of the disagreement of responses between the two drivers. Therefore, the instructions for drivers are necessary before the early warning is broadcasted to general public. Turning on the hazard lights after receiving the early warning, for example, may be effective to avoid accidents.</p>

2005年福岡県西方沖の地震における被災地域の地形情報, 地盤ボーリング情報を収集した. 地形分類およびボーリングデータのそれぞれから表層地盤の地震動増幅特性を評価できるが, ボーリングデータが密なところではボーリングデータに基づく評価に, 疎なところでは地形分類に基づく評価となるように両者の統合を行い, 地震動増幅特性の面的分布を求めた. この面的な増幅特性分布を考慮して福岡県西方沖の地震の観測地点地震動を空間補間することにより, 面的な地表面地震動分布を作成した.

2005年福岡県西方沖の地震の強震域にあたる福岡市中央区舞鶴の建物地下1階の観測点と地表の観測点において, 福岡県西方沖の地震本震の地震動を, その地点の余震記録と近傍観測点での本震・余震記録を用いて複数の方法で推定し, 本震観測記録との比較を行った.

A new object-based method is developed to extract moving vehicles and subsequently detect their speeds from two consecutive images automatically. Several global and local parameters of gray values and sizes are examined to classify the objects in the image. Vehicles and their associated shadows can be discriminated by removing big objects such as roads. To detect speed, firstly vehicles and shadows are extracted from two consecutive images. The corresponding vehicles from the two images are then linked based on the similarity in shape and size and on the distance within a threshold. Finally, using the distance between the corresponding vehicles and time lag between two images, we can detect the moving speed and azimuth angle. Our test shows promising results for detecting vehicles speeds. Further development will employ the proposed method to a pair of QuickBird panchromatic and multi-spectral images, which are at a coarser spatial resolution.

In expanding expressway networks in Japan, various types of structures have been constructed, e.g., long span bridges and bridges with high piers. The expressway structures are well designed for the external dynamic forces, e.g., earthquakes and strong winds. However, for further safety promotion of the expressway networks, it is important to evaluate the drivers' responses under strong dynamic disturbances. The present authors have investigated the moving stability of a vehicle under seismic motion based on both numerical simulation and virtual experiments using a driving simulator. Strong crosswind is considered as another factor that makes it difficult for drivers to control their vehicles. This study investigates the moving stability of a vehicle under strong crosswind based on numerical analyses and driving simulator experiments. To predict the future position of a moving vehicle including the reaction of a driver, the second-order predictable correction model is used in the numerical analyses. The results obtained from the numerical and experimental studies are compared and the validity of the driver model is discussed. It is expected that this research is helpful for the decision-making of expressway closure under strong wind and the design of wind barriers. (c) 2006 Elsevier Ltd. All rights reserved.

本研究では，気象庁87型地震計で観測された地震記録をもとに，減衰比1％，2％，5％，10％および20％の応答スペクトルの距離減衰式を構築し，5％減衰の応答スペクトルを基準とした各減衰の応答スペクトル比に，マグニチュード，震源距離，震源深さ，地盤条件が与える影響を検討した．さらに，距離減衰式から予測される応答スペクトル比と実地震記録を用いて算出した応答スペクトル比を比較し，その推定精度を検討した．以上の検討をふまえて，5％減衰の応答スペクトルを任意の減衰定数の応答スペクトルに換算する方法を示した．

Various organizations have deployed seismometer networks to gather the earthquake information. However, some ground motion records are sometimes missed because of electric power failure etc. This study proposes the estimation method of JMA (Japan Meteorological Agency) instrumental seismic intensity using neighboring ground motion records. First, the response spectra with 5% damping were estimated using the Fourier spectrum ratios between two neighboring seismic observation stations. Then, the peak ground acceleration (PGA) and the peak ground velocity (PGV) were calculated through the spectrum intensity. Finally, using the estimated PGA and PGV, the JMA instrumental seismic intensity was obtained.

高速道路で重大事故や大規模災害等が発生した場合，その負傷者が重傷である可能性が高く，ドクターヘリを活用することにより高い救命効果が期待できる．一方，ヘリコプターの離着陸に伴うダウンウォッシュと呼ばれる吹き下ろし風が原因となり，対向車線の走行車両が二次的な事故を起こしてしまうことが懸念されている．そこで，本研究では，建設中の第二東海自動車道（第二東名）においてドクターヘリのダウンウォッシュ風速の観測を行った．さらに，実車を用いた走行実験と数値解析により，ドクターヘリのダウンウォッシュが車両の走行安定性に与える影響について評価した．

The relationship between the seismic intensity and the reactions of expressways drivers was investigated based on the questionnaire survey conducted by Japan Highway Public Corporation after the 2003 Miyagi-ken Oki earthquake. Only 40 % of drivers were aware of the earthquake in the areas where the Japan Meteorological Agency (JMA) seismic intensity was smaller than 4.0. On the contrary, more than 80 % of drivers recognized the earthquake in the areas where the JMA seismic intensity was larger than 4.0. The abnormal vibration of the vehicle was indicated as the reason why the drivers recognized the earthquake. Hence, the seismic motion is considered to affect the safe and stable driving.

After the 1995 Kobe earthquake, countermeasures against earthquakes got higher priority than before. As one of such earthquake countermeasures, Tokyo Gas Co., Ltd. introduced an earthquake monitoring and rapid damage assessment system called SUPREME. This system has been under operation since 2001. The intelligent gas meters have been deployed for 9.8 million customers in the area where Tokyo Gas Co., Ltd. provides the service. The gas meter stops gas supply if earthquake motion exceeds a certain level. SUPREME has a subsystem to estimate the number of gas meters which stop gas supply because of an earthquake. However, the accuracy of estimation by this subsystem is not good because the characteristics of gas supply shutoff by intelligent gas meter are not very clear. In this study, to improve the accuracy of estimation, the characteristics of gas supply shutoff by intelligent gas meter are investigated based on shaking table tests and the questionnaire survey among employees of Tokyo Gas Co., Ltd.

Emergency medical care is very effective to save the lives of injured people in traffic accidents. The heliambulance has been under operation since 1999 in Japan, and it is expected to contribute for the emergency medical care. However, the heliambulance is allowed to land on the expressway under only some restricted conditions in Japan, because the heliambulance generates strong wind, called downwash. It is afraid that the drivers in the other lane of the expressway may feel the difficulties in controlling their vehicles because of the strong wind generated by the heliambulance. In this study, the moving stability of vehicles under crosswind generated by a helicopter is investigated based on field experiments and numerical simulation. In the numerical simulation, a driver-vehicle model is employed to obtain the moving trajectories of vehicles subjected to crosswind. Based on these results, the possibility of landing of a heliambulance on expressways is discussed. © 2006 by School of Engineering and Technology, Asian Institute of Technology.

日本道路公団の行った2003年5月26日宮城県沖の地震時に高速道路を走行していた運転者へのアンケート調査をもとに, Simple Kriging法により推定した高速道路沿線の地震動強さと自動車運転者の反応の関係について検討を行った. その結果, 計測震度4.0未満の地域を走行中の運転者のうち, 地震に気付いた運転者は4割に達していないが, 計測震度が4.0以上になると8割程度以上の運転者が地震を認識するようになることが分かった. 地震を認識した理由には, 車両の異常な振動が最も多くあげられており, 震動が車両の走行安定性に何らかの影響を与えることが推測できる.

2004年10月23日に発生した新潟県中越地震における高速道路被害と地震動強さの関係について検討を行った. 新潟県中越地震の地震動分布を推定し, 高速道路の被害データと推定された地震動強さとの関係を検討した結果, 高速道路に被害が発生している区間の平均計測震度はいずれも 5.0以上であり, 平均計測震度が6.0以上の堀之内インターチェンジ (IC) ～越後川口IC間, 越後川口IC～小千谷IC間に多くの被害が集中していることが明らかとなった. さらに, 航空写真から判読される高速道路の被害程度が, 実際の被害報告とどの程度一致するか検討を行い, 航空写真による早期被害把握が可能性を示した.

高速道路走行車両の横風安定性を定量的に評価することを目的に, 車両モデルを用いた数値解析とドライビングシミュレータを用いた走行模擬実験を行った. 運転者の反応と車両の運動の相互作用を考慮できる人間-自動車系操舵モデルを用いると, 走行模擬実験の結果が比較的精度良く再現されることが分かった. これより, 車両に依存するパラメータが適切に設定できれば, 実車走行試験やドライビングシミュレータによる走行実験を多数行わずとも, 従来まであまり定量的に評価されていなかった強風時の車両の走行安定性について, 系統立てた評価が可能になるものと期待される.

After the 1995 Kobe earthquake, the expressway structures in Japan were retrofitted and they will not now be Seriously damaged under a certain level of strong earthquake motion. However, the stability of a moving vehicle has not been investigated yet. It has been reported that drivers feel seismically induced vibrations, especially in the transverse direction of vehicles. Owing to this phenomenon, drivers have some difficulty in controlling the vehicles during strong shaking. For further safety promotion of the expressway networks, it is important to understand the drivers' reactions to seismic motion. The present authors have performed a series of seismic response analyses of a moving vehicle to investigate its response characteristics based on numerical simulation. However, the responses of the driver were not considered in the simulation process. In order to investigate the drivers' reactions during an earthquake. a series Of virtual tests were conducted using a driving simulator. This driving simulator has six servomotor-powered electric actuators that control its motions. Several types of tests were carried Out for different examinees to investigate drivers' responses while controlling the simulator under seismic motion. The results of this study showed that a larger response time lag to strong shaking and over turning of the steering wheel may shift the vehicle into the next lane. According to this finding, traffic accidents Could possibly Occur under strong ground shaking in the case of heavy traffic. Copyright (C) 2004 John Wiley Sons. Ltd.