Tsunami Hazard Map Research Articles

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Historically, the Colombian Pacific Coast has witnessed six tsunamis in the past 130 years, two of which have caused complete community destruction and human loss. The present paper aims to provide a conceptual framework needed to approach palaeo-tsunami research in the area, verifying the state of the art of tsunami hazard characterization and identifying any future investigations. Any acceptable palaeo-tsunami investigation should be multi-disciplinary, and compile, acquire and analyze in much detail, geological, geomorphological, biological, anthropological, archaeological and historical information. So far, the only research done related to tsunami hazard has been for the coastal cities of Tumaco and Buenaventura, and it has been focused on quantification of tsunami flooding. However, no research has yet been done on the identification and characterization of tsunami sources, exploration and characterization of the physical evidence of past events (e.g. palaeo-tsunami deposits), seismic micro-zonation, regional changes in vegetation patterns resulting from extreme events, or changes related to indigenous peoples’ habitational patterns or settlement abandonment, among others. For an effective risk management, tsunami hazard maps have to be emplaced, but they should integrate all the proxies and disciplines that enhance the identification and characterization of this hazard. We propose herein, the steps to follow to develop adequate tsunamigenic research.Keywords: palaeo-tsunamis, tsunami Deposits, paleoseismology, Pacific Coast of Colombia, Nazca Subduction Zone.

津波被災した地域住民と津波被災が懸念される地域住民の津波防災意識の比較

In this study, similarities and differences of psychological processes were investigated based on the questionnaire survey which was carried out in 2 target area; Hirono town where it was affected by the Great East Japan Earthquake and Tosashimizu city where it will be further risk by the Nankai Trough Earthquake. The analysis was as follows: (i) Tsunami Disaster Prevention Awareness is unaffected real experience of large scale disaster, (ii) Tsunami hazard map is one of effective method for strengthen Disaster Prevention Awareness even though elder people, (iii) A rising “Behavior” directly connect to “Will for Evacuation” as countermeasure against next disaster.

ドライビングシミュレータ実験による津波避難のためのハザードマップ利用の有効性の検討

本研究では、津波が発生した際の自動車運転を体験できるドライビングシミュレータを用いて、自動車による避難実験を行った。このドライビングシミュレータには、神奈川県鎌倉市を想定した津波遡上CGが搭載されており、津波数値解析結果が3次元都市モデル内で生成される。避難実験は、カーナビによる経路案内や、津波ハザードマップを走行中に表示するシナリオを用いることとし、被験者の避難行動を、浸水情報の周知、経路案内の有無などに着目し、シナリオ間で比較した。さらに、運転者への情報提供が津波時の避難行動にもたらす効果および問題点を検討した。実験の結果から、自動車の津波避難成功率を高めるには周囲の交通状況に応じた推奨避難経路を提供することが最も望ましいと考えられるが、その実現は短期的には難しく、道路標識等を活用する、地域内で自動車避難の優先順位付けをする、防災教育を充実するなど、多角的な取り組みが重要と考えられる。

The validity of the tsunami hazard map system of the Naha City, Okinawa Prefecture

The validity of the tsunami hazard map system of the Naha City, Okinawa Prefecture

Source mechanisms of volcanic tsunamis.

Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness.

Uncertainty modeling and visualization for tsunami hazard and risk mapping: a case study for the 2011 Tohoku earthquake

This study presents a rigorous computational framework for visualizing uncertainty of tsunami hazard and risk assessment. The methodology consists of three modules: (i) earthquake source characterization and stochastic simulation of slip distribution, (ii) tsunami propagation and inundation, and (iii) tsunami damage assessment and loss estimation. It takes into account numerous stochastic tsunami scenarios to evaluate the uncertainty propagation of earthquake source characteristics in probabilistic tsunami risk analysis. An extensive Monte Carlo tsunami inundation simulation is implemented for the 2011 Tohoku tsunami (focusing upon on Rikuzentakata along the Tohoku coast of Japan) using 726 stochastic slip models derived from eleven inverted source models. By integrating the tsunami hazard results with empirical tsunami fragility functions, probabilistic tsunami risk analysis and loss estimation are carried out; outputs from the analyses are displayed using various visualization methods. The developed framework is comprehensive, and can provide valuable insights in promoting proactive tsunami risk management and in improving emergency response capability.

A Decade After the 2004 Indian Ocean Tsunami: The Progress in Disaster Preparedness and Future Challenges in Indonesia, Sri Lanka, Thailand and the Maldives

The 2004 Indian Ocean tsunami was one of the most devastating tsunamis in world history. The tsunami caused damage to most of the Asian and other countries bordering the Indian Ocean. After a decade, reconstruction has been completed with different levels of tsunami countermeasures in most areas; however, some land use planning using probabilistic tsunami hazard maps and vulnerabilities should be addressed to prepare for future tsunamis. Examples of early-stage reconstruction are herein provided alongside a summary of some of the major tsunamis that have occurred since 2004, revealing the tsunami countermeasures established during the reconstruction period. Our primary objective is to report on and discuss the vulnerabilities found during our field visits to the tsunami-affected countries—namely, Indonesia, Sri Lanka, Thailand and the Maldives. For each country, future challenges based on current tsunami countermeasures, such as land use planning, warning systems, evacuation facilities, disaster education and disaster monuments are explained. The problem of traffic jams during tsunami evacuations, especially in well-known tourist areas, was found to be the most common problem faced by all of the countries. The readiness of tsunami warning systems differed across the countries studied. These systems are generally sufficient on a national level, but local hazards require greater study. Disaster reduction education that would help to maintain high tsunami awareness is well established in most countries. Some geological evidence is well preserved even after a decade. Conversely, the maintenance of monuments to the 2004 tsunami appears to be a serious problem. Finally, the reconstruction progress was evaluated based on the experiences of disaster reconstruction in Japan. All vulnerabilities discussed here should be addressed to create long-term, disaster-resilient communities.

Numerical modelling and evacuation strategies for tsunami awareness: lessons from the 2012 Haida Gwaii Tsunami

On October 28, 2012, an earthquake occurred offshore Canada, with a magnitude Mw of 7.8, triggering a tsunami that propagated through the Pacific Ocean. The tsunami numerical model results show it would not be expected to generate widespread inundation on Hawaii. Yet, two hours after the earthquake, the Pacific Tsunami Warning Centre (PTWC) issued a tsunami warning to the state of Hawaii. Since the state was hit by several tsunamis in the past, regular siren exercises, tsunami hazard maps and other prevention measures are available for public use, revealing that residents are well prepared regarding tsunami evacuation procedures. Nevertheless, residents and tourists evacuated mostly by car, and because of that, heavy traffic was reported, showing that it was a non-viable option for evacuation. The tsunami caused minor damages on the coastline, and several car accidents were reported, with one fatality. In recent years, there has been a remarkable interest in tsunami impacts. However, if risk planners seem to be very knowledgeable about how to avoid or mitigate their potential harmful effects, they seem to disregard its integration with other sectors of human activity and other social factors.

Advances in earthquake and tsunami sciences and disaster risk reduction since the 2004 Indian ocean tsunami

The December 2004 Indian Ocean tsunami was the worst tsunami disaster in the world’s history with more than 200,000 casualties. This disaster was attributed to giant size (magnitude M ~ 9, source length >1000 km) of the earthquake, lacks of expectation of such an earthquake, tsunami warning system, knowledge and preparedness for tsunamis in the Indian Ocean countries. In the last ten years, seismology and tsunami sciences as well as tsunami disaster risk reduction have significantly developed. Progress in seismology includes implementation of earthquake early warning, real-time estimation of earthquake source parameters and tsunami potential, paleoseismological studies on past earthquakes and tsunamis, studies of probable maximum size, recurrence variability, and long-term forecast of large earthquakes in subduction zones. Progress in tsunami science includes accurate modeling of tsunami source such as contribution of horizontal components or “tsunami earthquakes”, development of new types of offshore and deep ocean tsunami observation systems such as GPS buoys or bottom pressure gauges, deployments of DART gauges in the Pacific and other oceans, improvements in tsunami propagation modeling, and real-time inversion or data assimilation for the tsunami warning. These developments have been utilized for tsunami disaster reduction in the forms of tsunami early warning systems, tsunami hazard maps, and probabilistic tsunami hazard assessments. Some of the above scientific developments helped to reveal the source characteristics of the 2011 Tohoku earthquake, which caused devastating tsunami damage in Japan and Fukushima Dai-ichi Nuclear Power Station accident. Toward tsunami disaster risk reduction, interdisciplinary and trans-disciplinary approaches are needed for scientists with other stakeholders.

Tsunami hazard assessment of Chabahar bay related to megathrust seismogenic potential of the Makran subduction zone

Tsunami inundation mapping is the first step in the development of effective evacuation plans for communities at risk. These maps also provide bases for land use planners in communities to reduce risk by locating critical facilities out of the potential tsunami flood plain. The Makran subduction zone, located off the Indian Ocean coasts of Iran and Pakistan, is an important tsunamigenic zone for the region. On the 27th November, 1945, it was the site of a major earthquake with a moment magnitude of 8.1 and killed about 4,000 people. This event is a proof that Makran coastal areas are unsafe since the tsunami is quite probable. The objective of this study was providing tsunami inundation and hazard maps in Chabahar bay which is located in South East of Iran and the northern coast of Oman Sea. Three different source magnitude scenarios along Makran subduction zone are considered and for each scenario, numerical modeling of tsunami propagation is performed using MIKE 21 FM numerical software. Because the Makran subduction zone is very close to the Chabahar bay, unstructured triangular mesh with a higher level of refinement closer to the area of interest was used so that the tsunami was not numerically dissipated. After analyzing the data obtained from the results, inundation maps were produced, and by combining these maps, tsunami hazard map was provided for the bay. Tsunami wave amplification has been observed mainly in the outer coasts of the bay where the uplifted rocky shore experience up to 18 m wave height. Chabahar bay omega form and two eastern and western headlands cause a considerable depreciation in tsunami wave. Longer distance of coasts within the bay is another reason of tsunami depreciation inside the bay. Based on the generated inundation and hazard maps, two flood zones are specified. The first zone associated with no inundation or low inundation on cliffy shores, and the second zone would experience extensive inundation on the coast of kenarak areas, areas with sandy beaches and gentle slope.

Tsunami Recurrence Function: Structure, Methods of Creation, and Application for Tsunami Hazard Estimates

This paper considers a theoretical basement for a Poissonian probability model for tsunami run-up heights, with emphasis on the tsunami recurrence function. It is shown that the tsunami recurrence function of a general type contains at least two scale parameters: asymptotic frequency of big tsunamis f related to the considered region and characteristic tsunami height H* for the considered location in the region. A method for the correct statistical evaluation of the parameters f and H*, and their variations, using observational data from tsunami catalogues, is created. The paper considers some theoretical and applied problems related to the tsunami recurrence function, an example of a two-parameter tsunami hazard map, and also the problem of probabilistic tsunami hazard estimation.

3D Tsunami Hazard Map and Models of Safe Shelters

3D Tsunami Hazard Map and Models of Safe Shelters

The earthquake and tsunami hazard map of 1854

The earthquake and tsunami hazard map of 1854

SEISMIC MICROZONATION FOR BANDA ACEH CITY PLANNING

Of all natural disasters of the twentieth century, earthquakes caused the largest amount of losses. Although the number of earthquakes remains fairly unchanged, the loss of properties and human lives in recent periods has increased manifolds due to increasing concentration of human population and urbanisation in earthquake-prone areas. Recent improvement in documentations and computational facilities, however, allows for the preparation of seismic microzonation maps of such areas for urban planning and earthquake mitigation purposes. This paper discusses the development of seismic microzonation maps for Banda Aceh which lies close to the Sumatra Subduction Zone and the Sumatran Transform Faults, making the city extremely vulnerable to earthquake hazards. The development of the maps employs Geographic Information Systems (GIS) techniques that make use of several layers of parameters influencing earthquake hazards such as seismological data, faults, tsunami, etc. and site characteristic data such as soil type, groundwater distribution and depth, geological and geophysical data. The seismic microzonation maps incorporate various seismic hazard maps including ground shaking hazard map, liquefaction susceptibility hazard map, landslide potential hazard map, surface faulting hazard map and tsunami hazard map. The final composite map identifies zones with various degrees of hazards which will enable planners to avert hazardous locations during site selection processes, thus reducing losses.

SEISMIC MICROZONATION FOR BANDA ACEH CITY PLANNING

Of all natural disasters of the twentieth century, earthquakes caused the largest amount of losses. Although the number of earthquakes remains fairly unchanged, the loss of properties and human lives in recent periods has increased manifolds due to increasing concentration of human population and urbanisation in earthquake-prone areas. Recent improvement in documentations and computational facilities, however, allows for the preparation of seismic microzonation maps of such areas for urban planning and earthquake mitigation purposes. This paper discusses the development of seismic microzonation maps for Banda Aceh which lies close to the Sumatra Subduction Zone and the Sumatran Transform Faults, making the city extremely vulnerable to earthquake hazards. The development of the maps employs Geographic Information Systems (GIS) techniques that make use of several layers of parameters influencing earthquake hazards such as seismological data, faults, tsunami, etc. and site characteristic data such as soil type, groundwater distribution and depth, geological and geophysical data. The seismic microzonation maps incorporate various seismic hazard maps including ground shaking hazard map, liquefaction susceptibility hazard map, landslide potential hazard map, surface faulting hazard map and tsunami hazard map. The final composite map identifies zones with various degrees of hazards which will enable planners to avert hazardous locations during site selection processes, thus reducing losses.

Advancing tsunami risk assessment by improving spatio-temporal population exposure and evacuation modeling

Tsunamis are among the most destructive and lethal of coastal hazards. These are time-specific events, and despite directly affecting a narrow strip of coastline, a single occurrence can have devastating effects and cause massive loss of life, especially in urbanized coastal areas. In this work, in order to consider the time dependence of population exposure to tsunami threat, the variation of spatio-temporal population distribution in the daily cycle is mapped and analyzed in the Lisbon Metropolitan Area. High-resolution daytime and nighttime population distribution maps are developed using ‘intelligent dasymetric mapping,’ that is, applying areal interpolation to combine best-available census data and statistics with land use and land cover data. Workplace information and mobility statistics are considered for mapping daytime distribution. In combination with a tsunami hazard map, information on infrastructure, land use and terrain slope, the modeled population distribution is used to assess people’s evacuation speed, applying a geospatial evacuation modeling approach to the city of Lisbon. The detailed dynamic population exposure assessment allows producing both daytime and nighttime evacuation time maps, which provide valuable input for evacuation planning and management. Results show that a significant amount of population is at risk, and its numbers increase dramatically from nighttime to daytime, especially in the zones of high tsunami flooding susceptibility. Also, full evacuation can be problematic in the daytime period, even if initiated immediately after a major tsunami-triggering earthquake. The presented approach greatly improves tsunami risk assessment and can benefit all phases of the disaster management process.

Estimation of Tsunami-Inundated Areas in Asahi City, Chiba Prefecture, after the 2011 Tohoku-Oki Earthquake

The 2011 off the Pacific coast of Tohoku-oki earthquake triggered an extremely large tsunami. The authors conducted a field survey in Asahi City, Chiba Prefecture, after the occurrence of the earthquake. Although located farther away from the source region of the earthquake, there was still significant damage in this area. 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 totally collapsed buildings to the total number of buildings, that is, damage ratio, in terms of the estimated inundation depths was evaluated.

Development of tsunami disaster response system using hazard mapping

Park, H.S., Hong, S.J. and Kim, D.S., 2013. Development of tsunami disaster response system using hazard mapping,The purpose of this study is to develop the Tsunami Disaster Response System (TDRS) to reduce the damage caused by tsunami in the eastern coast of Korea. TDRS is constructed by using “hazard mapping techniques” along with several other methods. The highly populated and potentially dangerous areas of the eastern coast have been selected and a test is performed on forty-three different target regions to establish a tsunami disaster response system and hazard mapping. In addition, the existing tsunami response measures are analyzed including shelters, evacuation methods, and maps; and surveys are conducted to assess the climate, population and land-use of the selected regions. Topography and bathymetry data are also acquired and processed for numerical modeling, through which a total of forty-four hazard maps are prepared to estimate tsunami in four magnitudes (M7.5~M9.0) from eleven seismic zones for each study region. As a result, tsunami hazard maps are prepared on the eastern coast regions, which allows for a fast and accurate response to tsunami. Through this study, the study region for tsunami hazard mapping is selected, detailed topographical information and grid systems (4.5 m resolution) in the coastal zone are acquired, inundation characteristics are analyzed for each study region, and tsunami hazard maps are prepared for each study region. The “tsunami disaster response system” developed in this research will be employed as a comprehensive decision making system for tsunami; and will be utilized as a disaster prevention system to make an anticipative response against disasters by central and local governments; as well as a guide for evacuation and disaster management.

Analysis of evacuation system on tsunami disaster prevention in Korea

Kim, D.S., Hong, S.J and Park, H.S., 2013. Analysis of evacuation system on tsunami disaster prevention in Korea.The purpose of this study is to develop tsunami hazard maps by analyzing the coastal inundation characteristics on the eastern coast of Korea. The Korean peninsula is mistakenly considered to be a country safe from tsunamis as it is located next to Japanese islands which are believed to act as a barrier in various disaster situations. However, in reality, it is rather disaster-prone as it is located in the seismic zone along the western coast of Japan in the East Sea. To date, five tsunamis have affected Korea, including the Kanpo tsunami in 1741, the Shankotan tsunami in 1940, the Niigata tsunami in 1964, the Central East Sea tsunami in 1983, and the Hokkaido south western tsunami in 1993, of which the Central East Sea tsunami and Hokkaido south western tsunami resulted in casualties and caused property damages, especially in the Gangwon province. In this study, future tsunamis with a high probability of occurrence are investigated through an analysis of the seismic zone in the East Sea. For the analysis, hypothetical tsunami scenarios are developed to examine the inundation characteristics and create tsunami hazard maps of the eastern coast of Korea; tsunami inundation characteristics are analyzed for the subject areas based on the numerical simulation results using different scenarios. According to the analysis, tsunamis tend to land in the eastern coastal areas of the Korea peninsula due to bathymetric features of the East Sea. Furthermore, tsunami heights are calculated to be up to twelve meters above mean sea level (MSL). Finally, the tsunami hazard maps are developed based on the inundation analyses of the study areas. By developing tsunami hazard maps, inundation areas, evacuation routes, and shelters can be easily predicted, established, and selected. In non-emergency situations, tsunami hazard map can be used for education and promotion purposes and as a reference for risk assessment and disaster prediction.

Relation between Understanding of Tsunami Hazard Map and Evacuation Intension from Tsunami at Kamisu-city in Ibaraki prefecture

Relation between Understanding of Tsunami Hazard Map and Evacuation Intension from Tsunami at Kamisu-city in Ibaraki prefecture