Tsunami Database Research Articles

Tsunami Database Development in the Sunda Arc Indonesia to Support Early Warning through Artificial Intelligence Technology

The Sunda Arc-Indonesia is very vulnerable to tsunamis. There have been at least 55 tsunamis from 416–2018. Tsunami in the Sunda Arc is classified as a near-field tsunami with an arrival time of < 30 minutes after the earthquake. Meanwhile, the BMKG issued a warning within 5 minutes after the earthquake; therefore, speed in giving warnings is very vital. Artificial intelligence is an alternative technology that can quickly predict a tsunami's height and arrival time. For developing this technology, adequate quality and quantity of data and information on tsunamis are needed. Therefore, this study was conducted to build a tsunami database based on the results of simulations and numerical modeling of multiple scenarios from hypothetical and historical earthquake sources. This study used the open-source TUNAMI F1 model. This model simulates the propagation of tsunami waves using a linear equation. This study obtained 465 hypothetical earthquake sources, 534 historical earthquake sources, and 9,990 datasets from tsunami model simulation results. Each dataset contains ten information. Based on the 8.2 magnitude earthquake scenario, the potential tsunami hazard is 3–47 m with an estimated arrival time of < 30 minutes. An earthquake < 7 Mw can trigger a tsunami, especially an earthquake that is shallow and close to the coast, even though the tsunami height is < 0.5m. This data will be used to train an artificial intelligence-based tsunami prediction system. The artificial intelligence-based tsunami prediction system is expected to be used to strengthen the Indonesia tsunami early warning system (InaTEWS).

Meteotsunamis at global scale: problems of event identification, parameterization and cataloguing

Meteorological tsunamis (meteotsunamis) are defined as anomalous long-period (2 to 120 min) sea-level oscillations resulting from atmospheric forcing. In the current version of the Global Historical Tsunami Database covering almost 4000 years and including about 2500 tsunamis and tsunami-like events, meteotsunamis constitute a very small fraction of all events (4.1%). In the twenty-first century, when digital instruments for sea-level recording became widely available, identified meteotsunamis still only constitute 5.8% of all catalogued tsunami events. At the same time, there are many regions (Great Lakes, northeastern Gulf of Mexico, US East coast, southern Britain, Balearic Islands, Adriatic Sea, Yellow Sea, south-west coast of Japan, south-east coast of Brazil), where meteotsunamis dominate over all the other types of tsunamigenic events. Cataloguing of meteotsunami events, as reported in mass media, and described in scientific publications, faces the problems of their correct parameterization within the adopted format of the tsunami database. This format was developed in the late 1980s primarily for parameterization of seismogenic tsunamis, which at that time constituted more than 90% of the database’s content. As a result, most of the meteotsunamis included in the database lack some basic parameters, such as time of origin, location of source as well as run-up heights. The present paper addresses these issues and discusses the ways for their possible resolution. Several well-known cases of recent meteotsunamis are considered from the standpoint of their parameterization and hazard assessment.

A Comprehensive Review of the Worldwide Existing Tsunami Databases

Tsunami databases contain general information of historical tsunamis, which provides valuable and fundamental data to tsunami-related researches. Nevertheless, before adopting the information stored in various tsunami databases, users should be familiar with these databases’ individual features due to their inhomogeneity in data storage. To this end, a comprehensive review of the worldwide existing tsunami databases was conducted in this study. Two kinds of existing databases are recognized, i.e. the individual database and the organizational database. The individual tsunami databases are generally simple and descriptive with less information about tsunami and associated earthquake. Update of individual database is also out of date. Nevertheless, the organizational tsunami databases, with the retrieval function and timely update, are more sophisticated with significant research orientated information, upon which we can obtain the detailed characteristics of a specified tsunami event. In addition, a further comparison is made between two main organizational databases, i.e. the databases of NTL/WLD and NGDC/WDS. In which, the number of recorded tsunami wave heights per event and the number of definite tsunami events per decade both witness an apparent increase after 1900s, and the landslide-generated tsunamis are found to gradually increase after 1960s. The total tsunami events per decade fluctuate around one hundred since 1990s, whereas the definite tsunami events per decade experience a linear increase in this period. It turns out that though quite a part of the data in NTL/WLD is referred to NGDC/WDS, they do collect different tsunami events, and even for the same event, their recording datasets are still not consistent with each other. Figuring out the structural features of different databases and unveiling their connections and differences facilitate relevant research for disaster prevention and mitigation.

Global Occurrence of Large Tsunamis and Tsunami-like Waves Within the Last 120 years (1900–2019)

The run-up catalogs of two global tsunami databases maintained by the NCEI/WDC NOAA and NTL/ICMMG SD RAS are examined to compile the list of annual maximum runups observed or measured in the oceanic, marine and inland basins during the last 120 years (from 1900 to 2019). All the retrieved annual maximum runups were divided into four groups according to four main types of tsunami sources (seismogenic, landslide-generated, volcanic, and meteorological). Their distribution over the type of sources shows that of the 120 maximum runups only 78 (65%) resulted from seismogenic sources, while the remaining 42 runups were divided between landslide-generated (19%), volcanic (8%), and meteorological (7.5%) sources. The analysis of geographical distribution of source locations demonstrates that tsunamis are not exclusively a marine hazard—over 15% of all maximum runups were observed in coastal and inland water basins (narrow bays, fiords, lakes, and rivers). Temporal distribution of the collected runups shows that annual occurrence of large tsunamis was more or less stable throughout the twentieth century and only demonstrates some increase during the last 27 years (since 1992) when the practice of post-event surveys of all damaging tsunamis was implemented. This paper also outlines the existing problems with data compilation, cataloguing, and distribution, and discusses incompleteness of runup and wave-form data for a considerable number of non-damaging tsunamis, even those resulting from the strong (magnitude higher than 7.5) submarine earthquakes.

Application of tsunami scenario database and numerical simulation to tsunami warning and notification process

Over a decade since 2007, Korea Meteorological Administration (KMA) has constructed and modified tsunami scenario database in order to issue tsunami warning soon after a large offshore earthquake and when tsunami is expected to affect Korean coasts. Based on the scenario tsunami database, KMA has improved tsunami issuance criteria and notification process. Moreover, we have developed numerical simulation process using parallelized code of tsunami modeling program. This will be used to provide additional and detailed tsunami information with better accuracy. On the basis of this achievement, it is needed to improve the system and process to be faster and more accurate. Furthermore, researches on non-typical sources of tsunami and complexity and non-linearity near the coast are needed for the coming decade.

An update of proposed Sri Lanka warning system for east and west coast tsunamis

PurposeBased on the existing provisions/operations of tsunami warning in the Indian Ocean, authors observed that detection as well as arrival time estimations of regional tsunami service providers (RTSPs) could be improved. In particular, the detection mechanisms have been eccentrically focussed on Sunda and Makran tsunamis, although tsunamis from Carlsberg ridge and Chagos archipelago could generate devastating tsunamis for which inadequate provisions exist for detection and arrival time/wave height estimation. RTSPs resort to assess estimated arrival time/wave heights from a scenario-based, pre-simulated database. These estimations in terms of Sri Lanka have been found inconsistent. In addition, current warning mechanism poorly manages non-seismic tsunamis. Thus, the purpose of this study is to investigate these drawbacks and attempt to carve out a series of suggestions to improve them.Design/methodology/approachThe work initiated with data retrieved from global earthquake and tsunami databases, followed by an estimation of probabilities of tsunamis in the Indian Ocean with particular emphasis on Carlsberg and Chagos tsunamis. Second, probabilities of tsunami detection in each sub-region have been estimated with the use of available tide gauge and tsunami buoy data. Third, the difficulties in tsunami detection in the Indian Ocean are critically assessed with case studies, followed by recommendations to improve the detection and warning.FindingsProbabilistic estimates show that given the occurrence of a significant earthquake, both Makran and Carlsberg/Chagos regions possess higher probabilities to harbour a tsunami than the Sunda subduction zone. Meanwhile, reliability figures of tsunami buoys have been declined from 79-92 to 68-91 per cent over the past eight years. In addition, a Chagos tsunami is left to be detected by only one tide gauge prior to it reaching Sri Lankan coasts.Research limitations/implicationsThe study uses an averaged tsunami speed of 882 km/h based on 2004 Asian tsunami. However, using exact bathymetric data, Tsunamis could be simulated to derive speeds and arrival times more accurately. Yet, such refinements do not change the main derivations and conclusions of this study.Practical implicationsTsunami detection and warning in the Indian Ocean region have shown room for improvement, based on the inadequate detection levels for Carlesberg and Chagos tsunamis, and inconsistent warnings of regional tsunami service providers. The authors attempted to remedy these drawbacks by proposing a series of suggestions, including a deployment of a new tsunami buoy south of Maldives, revival of offline buoys, real-time tsunami simulations and a strategy to deal with landslide tsunamis, etc.Social implicationsIndian Ocean is prone to mega tsunamis as witnessed in 2004. However, more than 50 per cent of people in the Indian Ocean rim countries dwell near the coast. This is verified with deaths of 227,898 people in 14 countries during the 2004 tsunami event. Thus, it is of paramount importance that sufficient detection levels are maintained throughout the Indian Ocean without being overly biased towards Sunda tsunamis. With respect to Sri Lanka, Makran, Carlesberg or Chagos tsunamis could directly hit the most populated west coast and bring about far worse repercussions than a Sunda tsunami.Originality/valueThis is the first instance where the threats from Carlesberg and Chagos tsunamis to Sri Lanka are discussed, probabilities of tsunamis are quantified and their detection levels assessed. In addition, reliability levels of tsunami buoys and tide gauges in the Indian Ocean are recomputed after eight years to discover that there is a drop in reliability of the buoy data. The work also proposes a unique approach to handle inconsistencies in the bulletins of regional tsunami service providers, and to uphold and improve dwindling interest on tsunami buoys.

The Impact of Post-tsunami Surveys on the NCEI/WDS Global Historical Tsunami Database

Since the late nineteenth century, post-tsunami survey teams have been collecting water height data (e.g. maximum inundation, runup, flow depth) as well as other types of data, including geologic and socio-economic effects. The NOAA National Centers for Environmental Information (NCEI) and co-located World Data Service (WDS) for Geophysics provide data management and access to global tsunami data. NCEI’s Global Historical Tsunami Database includes information on over 2200 tsunami sources and over 26,000 runup points. The tsunami database has adapted to capture the advancements of post-tsunami survey data collection and distribution methods. The first International Tsunami Survey Team (ITST), which surveyed the impacts of the 02 September 1992 Nicaragua tsunami, spurred the formalization of standards and guidance for post-tsunami surveys. The post-tsunami survey data analyzed are a significant contribution, in quality and quantity, to the runup database. The 26 December 2004 Indonesia and 11 March 2011 Japan events alone account for over 25% of the total number of runup points in the database. Further, the analysis indicates that post-tsunami survey data capture a more complete representation of the tsunami that is being documented, not just the highest runup measurements. This range in post-tsunami survey runup heights for events, in the NCEI/WDS tsunami database, provides a more reliable historical tsunami dataset to test tsunami models against. This study also provides readers an understanding of the evolution of the tsunami database, particularly regarding the ongoing need to adapt to emerging scientific advances and standards.

Correlation Equation of Fault Size, Moment Magnitude, and Height of Tsunami Case Study: Historical Tsunami Database in Sulawesi

Sulawesi, one of the biggest island in Indonesia, located on the convergence of two macro plate that is Eurasia and Pacific. NOAA and Novosibirsk Tsunami Laboratory show more than 20 tsunami data recorded in Sulawesi since 1820. Based on this data, determination of correlation between tsunami and earthquake parameter need to be done to proved all event in the past. Complete data of magnitudes, fault sizes and tsunami heights on this study sourced from NOAA and Novosibirsk Tsunami database, completed with Pacific Tsunami Warning Center (PTWC) catalog. This study aims to find correlation between moment magnitude, fault size and tsunami height by simple regression. The step of this research are data collecting, processing, and regression analysis. Result shows moment magnitude, fault size and tsunami heights strongly correlated. This analysis is enough to proved the accuracy of historical tsunami database in Sulawesi on NOAA, Novosibirsk Tsunami Laboratory and PTWC.

Preparing for the Future Nankai Trough Tsunami: A Data Assimilation and Inversion Analysis From Various Observational Systems

AbstractThe future Nankai Trough tsunami is one of the imminent threats to the Japanese coastal communities that could potentially cause a catastrophic event. As a part of the countermeasure efforts for such an occurrence, this study analyzes the efficacy of combining tsunami data assimilation (DA) and waveform inversion (WI). The DA is used to continuously refine a wavefield model whereas the WI is used to estimate the tsunami source. We consider a future scenario of the Nankai Trough tsunami recorded at various observational systems, including ocean bottom pressure (OBP) gauges, global positioning system (GPS) buoys, and ship height positioning data. Since most of the OBP gauges are located inside the source region, the recorded tsunami signals exhibit significant offsets from surface measurements due to coseismic seafloor deformation effects. Such biased data are not applicable to the standard DA, but can be taken into account in the WI. On the other hand, the use of WI for the ship data may not be practical because a considerably large precomputed tsunami database is needed to cope with the spontaneous ship locations. The DA is more suitable for such an observational system as it can be executed sequentially in time and does not require precomputed scenarios. Therefore, the combined approach of DA and WI allows us to concurrently make use of all observational resources. Additionally, we introduce a bias correction scheme for the OBP data to improve the accuracy, and an adaptive thinning of observations to determine the efficient number of observations.

Challenges in Defining Tsunami Wave Heights

The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) and co-located World Data Service for Geophysics maintain the global tsunami archive consisting of the historical tsunami database, imagery, and raw and processed water level data. The historical tsunami database incorporates, where available, maximum wave heights for each coastal tide gauge and deep-ocean buoy that recorded a tsunami signal. These data are important because they are used for tsunami hazard assessment, model calibration, validation, and forecast and warning. There have been ongoing discussions in the tsunami community about the correct way to measure and report these wave heights. It is important to understand how these measurements might vary depending on how the data were processed and the definition of maximum wave height. On September 16, 2015, an 8.3 M w earthquake located 48 km west of Illapel, Chile generated a tsunami that was observed all over the Pacific region. We processed the time-series water level data for 57 coastal tide gauges that recorded this tsunami and compared the maximum wave heights determined from different definitions. We also compared the maximum wave heights from the NCEI-processed data with the heights reported by the NOAA Tsunami Warning Centers. We found that in the near field different methods of determining the maximum tsunami wave heights could result in large differences due to possible instrumental clipping. We also found that the maximum peak is usually larger than the maximum amplitude (½ peak-to-trough), but the differences for the majority of the stations were <20 cm. For this event, the maximum tsunami wave heights determined by either definition (maximum peak or amplitude) would have validated the forecasts issued by the NOAA Tsunami Warning Centers. Since there is currently only one field in the NCEI historical tsunami database to store the maximum tsunami wave height for each tide gauge and deep-ocean buoy, NCEI will consider adding an additional field for the maximum peak measurement.

The New Zealand Tsunami Database: Historical and Modern Records

A database of historical (preinstrumental) and modern (instrumentally recorded) tsunamis that have impacted or been observed in New Zealand has been compiled and published online. New Zealand’s tectonic setting, astride an obliquely convergent tectonic boundary on the Pacific Rim, means that it is vulnerable to local, regional, and circum‐Pacific tsunamis. Despite New Zealand’s comparatively short written historical record of about 200 years, there is a wealth of information about the impact of past tsunamis. The New Zealand Tsunami Database (NZTD) currently has 800+ entries that describe >50 high‐validity tsunamis. Sources of historical information include witness reports recorded in diaries, notes, newspapers, books, and photographs. Information on recent events comes from tide gauges and other instrumental recordings such as Deep‐ocean Assessment and Reporting of Tsunamis (DART) buoys, and media of greater variety, for example, video and online surveys. The NZTD is an ongoing project with information added as further historical records come to light. Modern tsunamis are also added to the database once the relevant data for an event have been collated and edited. This article briefly overviews the procedures and tools used in the recording and analysis of New Zealand’s historical tsunamis, with emphasis on database content.

Assessment of tsunami resilience of Haydarpaşa Port in the Sea of Marmara by high-resolution numerical modeling

Turkey is highly prone to earthquakes because of active fault zones in the region. The Marmara region located at the western extension of the North Anatolian Fault Zone (NAFZ) is one of the most tectonically active zones in Turkey. Numerous catastrophic events such as earthquakes or earthquake/landslide-induced tsunamis have occurred in the Marmara Sea basin. According to studies on the past tsunami records, the Marmara coasts have been hit by 35 different tsunami events in the last 2000 years. The recent occurrences of catastrophic tsunamis in the world’s oceans have also raised awareness about tsunamis that might take place around the Marmara coasts. Similarly, comprehensive studies on tsunamis, such as preparation of tsunami databases, tsunami hazard analysis and assessments, risk evaluations for the potential tsunami-prone regions, and establishing warning systems have accelerated. However, a complete tsunami inundation analysis in high resolution will provide a better understanding of the effects of tsunamis on a specific critical structure located in the Marmara Sea. Ports are one of those critical structures that are susceptible to marine disasters. Resilience of ports and harbors against tsunamis are essential for proper, efficient, and successful rescue operations to reduce loss of life and property. Considering this, high-resolution simulations have been carried out in the Marmara Sea by focusing on Haydarpaşa Port of the megacity Istanbul. In the first stage of simulations, the most critical tsunami sources possibly effective for Haydarpaşa Port were inputted, and the computed tsunami parameters at the port were compared to determine the most critical tsunami scenario. In the second stage of simulations, the nested domains from 90 m gird size to 10 m grid size (in the port region) were used, and the most critical tsunami scenario was modeled. In the third stage of simulations, the topography of the port and its regions were used in the two nested domains in 3-m and 1-m resolutions and the water elevations computed from the previous simulations were inputted from the border of the large domain. A tsunami numerical code, NAMI DANCE, was used in the simulations. The tsunami parameters in the highest resolution were computed in and around the port. The effect of the data resolution on the computed results has been presented. The performance of the port structures and possible effects of tsunami on port operations have been discussed. Since the harbor protection structures have not been designed to withstand tsunamis, the breakwaters’ stability becomes one of the major concerns for less agitation and inundation under tsunami in Haydarpaşa Port for resilience. The flow depth, momentum fluxes, and current pattern are the other concerns that cause unexpected circulations and uncontrolled movements of objects on land and vessels in the sea.

Tsunamigenic slope failures: the Pacific Islands ‘blind spot’?

We discuss issues related to a recognised shortcoming in existing tsunami hazard assessments for Pacific Island Countries and Territories (PICTs), that of tsunamigenic slope failures (TSFs). Currently, TSFs are most likely underrepresented as sources in existing tsunami databases for two key reasons. First, relatively low magnitude earthquakes associated with subduction zones are generally assigned as the tsunamigenic source, as opposed to the TSFs they generate. A reassessment of such ‘anomalous tsunamis’ may yield clues that serve to reassign their tsunamigenic source. Second, there are thousands of oceanic islands and seamounts scattered across the Pacific and flank collapse of volcanic edifices such as these is a largely unquantified tsunamigenic threat. However, while it is now possible to model such TSFs, this is unlikely to happen in the near future because of the lack of detailed bathymetry and landslide mass data. Recent developments in the identification of past tsunamis in the Pacific Islands have developed a unique range of indicators that can be used for identifying such events. These are geological, oral tradition and archaeological components that include, but are not limited to, a modified Darwinian model of atoll formation, coastal megaclasts, oral traditions of vanished islands and giant waves, and the abandonment of prehistoric coastal sites. As such, the most logical way forward is to use the multiple indicators available to us to identify evidence of past tsunamis.

Evaluation of Intensity of Recent Seismogenic Tsunamis in the World Ocean from 2000 to 2014

Tsunami intensity on the Soloviev–Imamura scale is one of the most important parameters for characterizing the overall size of a tsunami generated by submarine earthquakes. Consequently, this parameter is included in both global tsunami databases maintained by the National Centers for Environmental Information/World Data Service (NCEI/WDS) and the Novosibirsk Tsunami Laboratory of the Institute of Computational Mathematics and Mathematical Geophysics (NTL/ICMMG). S. Soloviev made the initial evaluation of the intensities of a large number of destructive historical tsunamis while compiling his two historical catalogs of tsunamis in the Pacific. The Novosibirsk Tsunami Laboratory under the Expert Tsunami Database Project made further determinations of tsunami intensity for the events after 1975. These intensities have been periodically incorporated into the NCEI/WDS tsunami database under the Global Tsunami Database Joint ICG/ITSU-IUGG/TC Project. In the on-line version of the NCEI/WDS Tsunami Database, the data on tsunami intensity are available only for the events prior to 2003. The main purpose of this paper is to extend the temporal coverage of this important parameter for characterizing tsunamigenic events to the present in order to provide researchers with more data for analyzing the temporal and spatial tsunami occurrence. However, of the 164 tsunamigenic events in the World Ocean from 2000 to the present, we could determine the intensity value for only 44 events that is less than 27 % of the total. For the rest of the events (that is, 73 %), the intensity value cannot be determined due to the lack of data on wave heights from the nearest coast. This shows that despite a great improvement in the tsunami-recording network in the Pacific and other oceanic basins during the last two decades, the data for reliable estimates of tsunami intensity are still problematic.

Spatiotemporal distributions of tsunami sources and discovered periodicities

Both spatial and spatiotemporal distributions of the sources of tsunamigenic earthquakes of tectonic origin over the last 112 years have been analyzed. This analysis has been made using tsunami databases published by the Institute of Computational Mathematics and Mathematical Geophysics (Siberian Branch, Russian Academy of Sciences) and the National Aeronautics and Space Administration (United States), as well as earthquake catalogs published by the National Earthquake Information Center (United States). It has been found that the pronounced activation of seismic processes and an increase in the total energy of tsunamigenic earthquakes were observed at the beginning of both the 20th (1905–1920) and 21st (2004–2011) centuries. Studying the spatiotemporal periodicity of such events on the basis of an analysis of the two-dimensional distributions of the sources of tectonic tsunamis has made it possible to determine localized latitudinal zones with a total lack of such events (90°−75° N, 45°–90° S, and 35°−25° N) and regions with a periodic occurrence of tsunamis mainly within the middle (65°−35° N and 25°–40° S) and subequatorial (15° N–20° S) latitudes of the Northern and Southern hemispheres. The objective of this work is to analyze the spatiotemporal distributions of sources of tsunamigenic earthquakes and the effect of the periodic occurrence of such events on the basis of data taken from global tsunami catalogs.

An Investigation on Multi-Buoy Inversion Method for Tsunami Warning System in South China Sea

The key technologies for the development of tsunami warning system include the establishment of tsunami database and inversion method for evaluating source parameters of earthquake by monitored wave data. A tsunami model based on the shallow water equations is adopted to simulate the 2011 Tohoku tsunami to validate the numerical model of generation and propagation of tsunami. The numerical results match well with measured data by DART buoys in terms of the wave height and the arrival time of the tsunami. For the potential earthquake source in the Manila Trench, the numerical model is used to compute the elementary wave fields triggered by unit sources of potential tsunami source with unit slip. Using the tsunami database derived by the elementary wave fields, an inversion method for plate slip based on multi-buoy measurements is applied to compute the time series of surface elevation at the given locations around the coasts in the South China Sea region. Through numerical simulations and multi-buoy inversion computation, the inversed time series of wave profile induced by earthquakes with the magnitudes Mw= 8.0, 8.5, 8.8, 9.35 are obtained. The comparisons of the inversion results and direct simulation data show good agreement. It turns out that, the multi-buoy inversion method works well and, according to the numerical results, deploying one or two buoys along the west side of the Manila Trench is necessary to provide tsunami warning information for the west coasts in the South China Sea. It is suggested that we should deploy one buoy between the south part of Taiwan and the north end of the Manila Trench subduction zone so that we could obtain a good predicted wave height at the south part of Taiwan by the multi-buoy inversion method.

The Australian tsunami database

There has been a significant increase in the number of peer-reviewed publications, critical reviews and searchable web-based databases, since the first substantial tsunami database for Australia was published in 2007. This review represents a complete reorganization and restructuring of previous work coupled with the addition of new data that takes the number of events from 57 (including 2 erroneous events) to 145. Several significant errors have been corrected including mistaken run-up heights for the event of 19 August 1977, Sumba Island, Indonesia, that suggested it was the largest tsunami in Australia’s history. The largest historical event in the database is now the 17 July 2006, Java, Indonesia, tsunami that had a run-up height of 7.90 m at Steep Point, Western Australia. Although estimated wave heights of 40 ft (∼13 m) were noted for the 8 April 1911 event at Warrnambool, Victoria, no run-up data were provided. One of the more interesting findings has been the occurrence of at least 11 deaths, albeit for events that are generally poorly defined. Data gathered during the construction of this database were rigorously reviewed and as such several previous palaeotsunami entries have been removed and other potentially new ones discarded. The reasons for inclusion or exclusion of data are discussed, and it is acknowledged that while there has been an almost three-fold increase in the number of entries the database is still incomplete. With this in mind the database architecture has been brought in line with others in the region with the ultimate goal of merging them all in order to provide a larger, interrogatable and updatable data set. In essence, the goal is to enhance our understanding of the national and regional tsunami hazard (and risk) and to move towards an open-source database.

史料に記録された中世における東日本太平洋沿岸の津波

To find tsunamis that affected the Pacific coast of eastern Japan during period between A.D. 869 and the 1600s, we searched a historical earthquake and tsunami database for tsunami descriptions. We examined reliability of the descriptions considering the written dates and independence of documents. As a result, at least two events were found. One is the Oei tsunami which occurred on September 1st, 1420 on the Julian calendar (the 7th month 23rd day, 27th year of Oei era on the Japanese calendar). The tsunami affected Kawarago and Aiga villages in Hitachi city, Ibaraki prefecture. Sea receded 9 times during 4 hours, exposing the coastal seafloor, and many fish were carried to the land. No description of earthquake ground shaking was found. The other is the Kyotoku earthquake tsunami which occurred on December 12th, 1454 (11th month 23rd day, 3rd year of Kyotoku era). An earthquake occurred in night and the tsunami widely inundated the coastal area of “Oshu” (the old name of province from Aomori to Fukushima prefectures). Many people were killed in the tsunami. Another entry in the database on December 31st, 1455 (11th month 23rd day, first year of Kosho era) is likely to be a fake event.

DART® Tsunameter Retrospective and Real-Time Data: A Reflection on 10 Years of Processing in Support of Tsunami Research and Operations

In the early 1980s, the United States National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory established the fundamentals of the contemporary tsunameter network deployed throughout the world oceans. The decades of technological and scientific advancements that followed led to a robust network that now provides real-time deep-ocean tsunami observations routinely incorporated into operational procedures of tsunami warning centers around the globe. All aspects of the network, from research to operations, to data archive and dissemination, are conducted collaboratively between the National Data Buoy Center, the Pacific Marine Environmental Laboratory, and the National Geophysical Data Center, with oversight by the National Weather Service. The National Data Buoy Center manages and conducts all operational network activities and distributes real-time data to the public. The Pacific Marine Environmental Laboratory provides the research component in support of modeling and network enhancements for improved forecasting capability. The National Geophysical Data Center is responsible for the processing, archiving, and distribution of all retrospective data and integrates DART® tsunameter data with the National Geophysical Data Center global historical tsunami database. The role each agency plays in collecting, processing, and disseminating observations of deep-ocean bottom pressure is presented along with brief descriptions of data processing procedures. Specific examples of challenges and the approaches taken to address these are discussed. National Geophysical Data Center newly developed and available tsunami event web pages are briefly described and demonstrated with processed data for both the Tohoku 11 March 2011 and the Haiti 12 January 2010 tsunami events.

Synthetic tsunamis along the Israeli coast

The new mathematical model for tsunami evolution by Tobias & Stiassnie (Tobias & Stiassnie 2011 J. Geophys. Res. Oceans 116, C06026) is used to derive a synthetic tsunami database for the southern part of the Eastern Mediterranean coast. Information about coastal tsunami amplitudes, half-periods, currents and inundation levels is presented.