Subsequent Tsunami Research Articles

Review: Agricultural Countermeasure against Radiocesium Contaminated Field

In 2011, Great East Japan Earthquake and subsequent tsunami caused severe damage on the TEPCO’s nuclear power plants in Fukushima prefecture. A large area of agricultural fields in Eastern Japan was suffered by substantial amount of radioactive materials (especially radiocesium) and tremendous efforts has been taken to remediate the contaminated fields. Though phytoremediation was expected to be effective to remove radiocesium, it did not work at least in this area. Actually physical decontamination was carried out, while it is still required to mitigate the transfer of the remaining radiocesium to the crops. For this purpose potassium application is adopted as a reliable method.

SPH simulation of the 2007 Chehalis Lake landslide and subsequent tsunami

A multi-phase smoothed particle hydrodynamics (SPH) formulation in combination with a granular rheological model is applied to simulate the 2007 Chehalis Lake landslide and the subsequent tsunami. The model is implemented within the open-source 3D code GPUSPH. The lake geometry is built using the British Colombia Hydro (BCH) topography and bathymetry surveys, and the landslide initial geometry is reconstructed from pre- and post-failure geological profiles under the assumption of constant thickness across the entire width. The water and the landslide are treated as immiscible continua, discretized in two distinct sets of SPH particles with different mass and behaviour laws. The landslide material is modelled as a continuum whose shear stresses obey a friction law that takes its granular nature into consideration. A sensitive analysis for various physical parameters is carried out, and numerical results are checked by comparing run-up heights to BCH's surveys.

A better way to forecast megathrust earthquakes and subsequent tsunami events

A better way to forecast megathrust earthquakes and subsequent tsunami events

Framework for estimating the risk and resilience of road networks with bridges and embankments under both seismic and tsunami hazards

To develop disaster mitigation measures in coastal regions affected by earthquakes, it is important to consider the effects of both seismic and tsunami hazards on road structures and assess the social impacts associated with the economic loss and reduction in network functionality. In this paper, a risk- and resilience-based assessment framework is established for road networks under both seismic and tsunami hazards. In the proposed methodology, the risk and resilience are quantified by the economic loss and postdisaster functionality of road networks, respectively. Uncertainties associated with estimations of fault movement, hazard intensity and structural vulnerability are considered when estimating the failure probability using Monte Carlo simulation. Moreover, structural vulnerability against tsunamis is estimated considering the effects of ground motion-induced damage on the reduction in tsunami capacity. As an illustrative example, the road networks in two Japanese cities expected to be affected by the anticipated Nankai Trough earthquake, which would cause strong ground motions and a subsequent tsunami, are analyzed. Finally, the retrofitting prioritization for various structures is discussed based on the risk and resilience quantified as performance indicators for social impacts.

Filling oceans on a spherical multiple-cell grid

Shallow water equations (SWEs) are discretised on a regional spherical multiple-cell (SMC) grid. The SMC grid uses unstructured techniques with rectangular cells and supports multi-resolutions like mesh refinement. The numerical schemes on the 2-D SMC grid are combinations of the conventional finite-difference ones and flux-form finite-volume formulations in 1-D loops. Semi-implicit schemes are used for both Coriolis terms and potential energy gradients. The water height equation is solved with a C-grid mass-conserving advection scheme and a diffusion term to suppress numerical instability. Mixed A- and D-grid schemes are applied on the momentum equation, plus a weighted average to remove short waves. Boundary conditions are incorporated on all cell faces so that any cell could be wet or dry depending on whether its water height is positive. Approximations across refinement interfaces are explained. A filling or flooding experiment on a four-level (3-6-12-25 km) Mediterranean Sea grid is used for demonstration. The test is done by emptying the whole Mediterranean Sea at start and then filling the basins with flood water from selected river mouths and strait channels, until the whole Mediterranean Sea is filled up. This experiment illustrates that the SWEs model on the multi-resolution SMC grid can simulate the filling process as expected and restore a flat sea surface at the end. Another test is carried out to simulate possible tsunami waves when the flat sea surface is disturbed by volcanic eruptions or earthquake movements. Results indicate that vertical shift of sea surface at one site in the Ionian Sea may generate tsunami waves and orientation of the initial disturbance has a profound influence on the subsequent tsunami waves, which could spread out to the whole Mediterranean Sea in a few hours. Further improvements are required to simulate real tsunamis and coastal surges.

An INRS cause tree method assessment for complex accidents analysis: Application to the Fukushima Nuclear Power Plants accident

This article proposes a new approach to the Cause Tree Method (CTM) or also known as the INRS method (Institut National de Recherche et de Sécurité), with the aim of verifying its applicability for accidents in more complex environments, than they are often used, like work accidents. For this, the Analytic Hierarchy Process (AHP) methodology was used as a way of supporting the comparison with other accident investigation methods, in which, selected the most impacting criteria for the analysis of complex accidents. From which it allowed the comparison of the results of the analyses performed of the Fukushima accident by the NUREG - 0492 method and the INRS method.In addition, this is an innovative approach in the study of the Fukushima accident, since it makes it possible to know the influences of the main components in the occurrence of the accident and the spread of damage. It was observed that the INRS method obtains an advantage over the NUREG - 0492 method in 2 criteria of the 3 criteria selected as relevant in the investigation of complex accidents. In addition, to the analysis made of the accident, it is understood that although the geographic location of the nuclear station anticipates the occurrence of earthquakes and subsequent tsunamis, safety plans were inefficient to contain the damage. Thus, it is verified, through the comparative analysis between methods and case study, that the INRS method is a robust and viable option to assess complex accidents.

The Nuclear Legacy Today of Fukushima

The accident at the Fukushima Daiichi Nuclear Power Station (FDNPS) following the Great East Japan Earthquake and the subsequent tsunami in March 2011 changed people's perceptions regarding nuclear power generation in Japan and worldwide. The failure to prevent the accident and the response to it had an enormous impact specifically on the communities close to the site but also across Japan and globally. In this review, I discuss radiation detection technologies, their use and limits in the immediate assessment and response, and improvements since then. In particular, I examine recent developments in radiation detection and imaging systems that, in combination with the enormous advances in computer vision, provide new means to detect, map, and visualize radiation using manned and unmanned deployment platforms. In addition to smarter and more adaptable technologies to prevent and minimize the impact of such events, an important outcome of this accident is the need for informed and resilient citizens who are empowered by knowledge and technologies to make rational decisions. The accident at FDNPS leaves a legacy concerning the importance of historical information, technologies, and resilience as well as challenges regarding powerful technologies that can provide substantial benefits to human society but that are also associated with risks of which we must be aware.

Sensitivity analysis of core slumping and debris quenching behavior of Fukushima Daiichi Unit-3 accident

The Great East Japan earthquake and the subsequent tsunami which occurred on March 11th, 2011 put the operating Units 1–3 at Fukushima Daiichi Nuclear Power Plant (NPP) in severe accident conditions and core meltdown due to station blackout. Although research efforts have been made by various parties to study the accident scenarios since the Fukushima accident, there remain unresolved issues regarding the core degradation behavior suggested by measurement data such as water level, Reactor Pressure Vessel (RPV) pressure and Primary Containment Vessel (PCV) pressure. To analyze and resolve such issues would be helpful to promote further understanding of the severe accident scenario at Fukushima units as well as the decommissioning work undergoing.The current study focuses on a detailed analysis of the RPV pressure peak event that occurred in Unit-3 at 12:00 on March 13th 2011. Sensitivity analysis cases were carried out with MELCOR 2.2 codeiThe MELCOR code version applied in the current study is MELCOR 2.2.9541. The results used in this study were obtained before April 2018 under research collaboration with Waseda University.i with sensitivity parameters that can influence the RPV pressure behavior, such as the debris quenching heat transfer coefficient, the number of opening SRVs during the RPV pressure peak event, amount of core slumping and particulate debris diameter. The cases that could reproduce the RPV pressure peak were further discussed to show likely debris bed energy history and the water mass history in the lower plenum during the RPV pressure peak event. The current study suggests that 1) Opening of SRVs equivalent to the total area of 4–6 fully-open SRVs (or equivalent leak area) could have occurred during the pressurization phase of the RPV accompanied by heavy debris quenching effect, while the opening of SRVs equivalent to a total area of at least 2 fully-open SRVs (or equivalent leak area) could have occurred during the depressurization phase of the RPV accompanied by moderate debris quenching effect. 2) The particulate debris diameter is not a very sensitive parameter when evaluating the debris quenching effect of Unit-3 in the current MELCOR modeling. 3) The current modeling suggests that around 70–110 GJ of energy can be removed by coolant during the debris quenching period with 30 tons of water reduction from the lower plenum.

Anatomy of a crustal-scale accretionary complex: Insights from deep seismic sounding of the onshore western Makran subduction zone, Iran

Abstract The Makran subduction zone has produced M 8+ earthquakes and subsequent tsunamis in historic times, hence indicating high risk for the coastal regions of southern Iran, Pakistan, and neighboring countries. Besides this, the Makran subduction zone is an end-member subduction zone featuring extreme properties, with one of the largest sediment inputs and the widest accretionary wedge on Earth. While surface geology and shallow structure of the offshore wedge have been relatively well studied, primary information on the deeper structure of the onshore part is largely absent. We present three crustal-scale, trench-perpendicular, deep seismic sounding profiles crossing the subaerial part of the accretionary wedge of the western Makran subduction zone in Iran. P-wave travel-time tomography based on a Monte Carlo Markov chain algorithm as well as the migration of automatic line drawings of wide-angle reflections reveal the crustal structure of the wedge and geometry of the subducting oceanic plate at high resolution. The images shed light on the accretionary processes, in particular the generation of continental crust by basal accretion, and provide vital basic information for hazard assessment and tsunami modeling.

Methodology of seismic-response-correlation-coefficient calculation for seismic probabilistic safety assessment of multi-unit nuclear power plants

In 2011, an earthquake and subsequent tsunami hit the Fukushima Daiichi Nuclear Power Plant, causing simultaneous accidents in several reactors. This accident shows us that if there are several reactors on site, the seismic risk to multiple units is important to consider, in addition to that to single units in isolation. When a seismic event occurs, a seismic–failure correlation exists between the nuclear power plant’s structures, systems, and components (SSCs) due to their seismic-response and seismic-capacity correlations. Therefore, it is necessary to evaluate the multi-unit seismic risk by considering the SSCs’ seismic-failure-correlation effect. In this study, a methodology is proposed to obtain the seismic-response-correlation coefficient between SSCs to calculate the risk to multi-unit facilities. This coefficient is calculated from a probabilistic multi-unit seismic-response analysis. The seismic-response and seismic-failure-correlation coefficients of the emergency diesel generators installed within the units are successfully derived via the proposed method. In addition, the distribution of the seismic-response-correlation coefficient was observed as a function of the distance between SSCs of various dynamic characteristics. It is demonstrated that the proposed methodology can reasonably derive the seismic-response-correlation coefficient between SSCs, which is the input data for multi-unit seismic probabilistic safety assessment.

Los efectos del terremoto de 1868 en Iquique y la provincia de Tarapacá: Opinión pública, vulnerabilidad urbana, fenómenos naturales y desastre en un escenario de crisis económica y polótica (Perú, segunda mitad del siglo xix)

The following article addresses, from a review of the local press, the repercussions of the earthquake and subsequent tsunami of August 13, 1868 on the public opinion of the province of Tarapaca. The article describes how a series of political, social, and economic problems that existed before the earthquake resulted in the idea that behind the impact of a natural hazard there was, strictly speaking, another type of disaster that was much broader and profound, referring to the condition of structural vulnerability linked not only to the complex situation that Peru was experiencing in those years because of a deep tax and financial crisis, but also the weak presence of the State in the southernmost province of the country. This situation mainly affected the port of Iquique as a result of its accelerated and uncontrolled urban growth driven by the expansion of saltpeter mining.

Possibilities of social and solidarity economies in reconstruction activities of areas affected by the Great East Japan Earthquake

The Great East Japan Earthquake changed Japan forever. The subsequent tsunami and nuclear plant disaster shocked the world and devastated large swaths of the Japanese countryside. While truly saddening and catastrophic for those who lived through it, nine years later the affected areas continue to persevere and recover. Their determination and effort are not only inspiring but also provide a unique glimpse at how communities can be built and also rebuilt with sustainable goals in mind. According to Dr Fumihiko Saito, a professor at the Faculty of International Studies at Ryukoku University, the rebuilding process is way ahead of academic theories and offers a lot of insight for the research community. Saito, who has worked on international development, local renewal efforts and sustainability, is now visiting the areas affected by the earthquake to conduct interviews and questionnaires in an effort to understand and learn from the people there.

Tsunami evacuation simulation considering road blockage by collapsed buildings evaluated from predicted strong ground motion

Tsunami evacuation simulations are often used to determine necessary countermeasures that will reduce human loss effectively after earthquakes and subsequent tsunamis. However, so far there has been no simulation for the estimated building damage using up-to-date knowledge of seismic engineering. In this study, in order to clarify the effect of building damage on a tsunami evacuation, we first predicted building damage based on the nonlinear response analysis for a realistic strong ground motion and then simulated a tsunami evacuation considering road blockage due to the collapsed buildings. We used one district in Tanabe City in Wakayama Prefecture in Japan where we expect to have a 12 m of tsunami height after an earthquake along the Nankai Trough plate boundary. We found that the prepared capacity of evacuation sites is not enough to let everyone evacuate and that the number of survivors increases by 3–4% if all of the buildings and houses are seismically reinforced. Considering this, plus 1% of expected casualties inside the collapsed houses, it appears to be not as efficient to reinforce buildings and houses to prevent human loss in comparison with increasing the capacity of tsunami evacuation sites in the target district. However, the damage to building and houses will cause a lot of side effects which are not considered here, but will prolong the evacuation time. Thus, we concluded that we need to reinforce the buildings and houses as well as consider the appropriate placement, number, and capacity of the evacuation sites.

Potential tsunami hazard along the southern Turkish coast

The aim of this study is to determine the tsunami potential of the southern Turkish coast through hypothetical earthquake scenarios developed for several critical coastal sites in the region. A well-known tsunami numerical model (MOST) is utilized to calculate the run-up and inundation of the subsequent tsunami waves. The coastal regions selected to realize the aim of the study are Akkuyu and Yeşilovacık from Mersin and Yumurtalık from Adana, which are chosen for their industrial and environmental importance. Time series of wave amplitudes at these three sites as well as contour plots presenting maximum wave amplitudes within the computational domain are generated for different earthquake moment magnitudes. Results obtained from the numerical model suggest that while earthquakes having magnitude smaller than 7.5 generate weak oscillations, earthquakes with magnitude greater than 7.5 result in significant waves reaching maximum wave height of a few meters at the selected coastal regions. Given the number and the magnitude scale of tsunamigenic earthquakes occurred in the region in the past, the modeling effort here indicates that hazard induced by tectonic tsunamis should seriously be taken into account by both the central and the local government authorities, who are responsible for pre- and post-disaster action planning. This issue is critical for minimizing the damage of a possible tsunami event. The proposed study is hoped to be used as a basis for future tsunami risk maps to be developed for the region.

Reassessment of early 131I inhalation doses by the Fukushima nuclear accident based on atmospheric 137Cs and 131I/137Cs observation data and multi-ensemble of atmospheric transport and deposition models

The Fukushima Dai-ichi Nuclear Power Plant accidents following the March 11, 2011 Tohoku earthquake, and subsequent tsunami released radioactive materials into the atmosphere and caused significant public health concerns, particularly thyroid cancers in children. However, the lack of measurement data for atmospheric concentrations of 131I has caused persistent and widespread uncertainty. This study estimated the maximum potential thyroid doses of inhaled 131I in the early post-accident phase between March 12 and 23, 2011 by using the hourly measured data of the 137Cs concentrations at 101 suspended particulate matter (SPM) monitoring sites, a new multi-model ensemble (MME) method of simulating 137Cs concentrations using two Atmospheric Transport and Deposition Models (ATDMs), the 131I/137Cs ratio obtained from measurement data analysis, and the internal exposure model. Based on the measurements, the maximum potential thyroid doses were estimated at 3.1–160 mSv at 5 sites in the Fukushima-Hamadori area for 1-year-old children assumed to remain outdoors, whereas they were less than 4.3 mSv at the other sites in the base case of the 131I/137Cs ratio. The spatial distribution of the maximum potential of early inhalation doses was estimated by using the MME and measurements. The inhalation thyroid doses in the evacuation scenarios were compared to the estimates reported by previous studies. The results of the present study were almost congruent with the outcomes of previous investigations except for thyroid doses contributed by highly contaminated plumes on March 12 and 15. The sensitivity analysis for the 131I/137Cs ratio indicated that these plumes carried the potential to significantly increase the thyroid doses of residents.

Impact of 2004 co-seismic coastal uplift on the mangrove cover along the North Andaman Islands

The December 2004 earthquake and the subsequent tsunami have incurred devastating impacts on vital habitats along the Indian coastal region, where few of them are irreversible. The earthquake has uplifted the northern Andaman coast, resulting in a drastic reduction of tidal water influx into the adjoining mangrove-laden mudflats. Satellite images of the period from 2003 to 2019 were used to assess the impact of coastal upliftment on the northern Andaman mangroves. Through satellite data analysis, we report a loss of 6500 ha of northern Andaman mangroves. Tidal hydrodynamics simulation under the post-earthquake scenario showed a vast area of mudflats deprived of tidal influx. This reduction in the tidal inundation has incurred a gradual and permanent mangrove area degradation. The earthquake impact on the mangroves was not spontaneous, but a gradual process, where the mangroves were intact until Mach 2006. The earthquake and the resultant coastal uplift have significantly altered the coastal geomorphology as well as the plant demography of the study area. Field visit revealed the terrestrial vegetation growth along the erstwhile mudflats, and vast areas of mangrove peat are observed, surrounded by successions of marshy and terrestrial plants. As mangroves are preferred habitat for diverse marine and terrestrial organisms and act as a vital food source and juvenile shelters for various fish species, the extensive loss of mangrove area may adversely affect a large scale biological ecosystem.

Microbial life in the nascent Chicxulub crater

Abstract The Chicxulub crater was formed by an asteroid impact at ca. 66 Ma. The impact is considered to have contributed to the end-Cretaceous mass extinction and reduced productivity in the world’s oceans due to a transient cessation of photosynthesis. Here, biomarker profiles extracted from crater core material reveal exceptional insights into the post-impact upheaval and rapid recovery of microbial life. In the immediate hours to days after the impact, ocean resurge flooded the crater and a subsequent tsunami delivered debris from the surrounding carbonate ramp. Deposited material, including biomarkers diagnostic for land plants, cyanobacteria, and photosynthetic sulfur bacteria, appears to have been mobilized by wave energy from coastal microbial mats. As that energy subsided, days to months later, blooms of unicellular cyanobacteria were fueled by terrigenous nutrients. Approximately 200 k.y. later, the nutrient supply waned and the basin returned to oligotrophic conditions, as evident from N2-fixing cyanobacteria biomarkers. At 1 m.y. after impact, the abundance of photosynthetic sulfur bacteria supported the development of water-column photic zone euxinia within the crater.

“I Feel Like I Can’t Avoid Dying”: A Poetic Representation of a Survivor’s Traumatic Experience in the Great East Japan Earthquake

This article is a poetic rendition of a recorded and transcribed oral personal life story of a survivor of the Great East Japan Earthquake in 2011. The aim of the current study is to reproduce and explore his series of dramatic experiences in poetic form and better understand cultural trauma caused by the massive disaster–the magnitude 9.0 earthquake, subsequent tsunami, and nuclear meltdown. This article provides insight into the relatively unexamined issue of cultural trauma emerging from the unprecedented disaster and presents what the earthquake survivor saw and felt through such a catastrophe.

Cambios en el imaginario barrial tras el 27F de 2010: caso del Barrio Norte Histórico de Talca, Chile

El terremoto de 8.8 grados de magnitud, y posterior tsunami, que afectó a la macrozona central de Chile el 27 de febrero de 2010, tuvo efectos catastróficos que modificaron el paisaje, la geografí­a y el cotidiano de las personas residentes en las zonas afectadas. Esta investigación tiene como objetivo ahondar en los cambios generados en el imaginario barrial tras la catástrofe. Para ello se analizará el Barrio Norte Histórico de Talca, ubicado en el centro histórico de la capital de la Región del Maule, una de las más devastadas tras el sismo.La metodologí­a utilizada es cualitativa y está orientada a recopilar relatos de los residentes del barrio a través de entrevistas semi estructuradas y focus group. Los resultados develan los profundos cambios que generó el terremoto en el imaginario de las personas afectadas, modificando su percepción respectodel lugar en el que habitan, en lo fí­sico-construido y lo social.

Measurements of radiocesium in animals, plants and fungi in Svalbard after the Fukushima Daiichi nuclear power plant disaster

An earthquake struck the eastern part of Japan on March 11, 2011. The Fukushima Daiichi nuclear power plant was severely damaged by the earthquake and subsequent tsunami, leading to the emission of large amounts of radioactive pollutants, including 134Cs and 137Cs, into the environment. From August 23 to September 1 in 2011, and from August 27 to September 4 in 2013, we collected samples of animals, plants, fungi and lichens from Svalbard, Norway and measured the radioactivity of 134Cs and 137Cs contained in the samples. Though no radioactivity of 134Cs, which has a half-life of approximately 2 years, was observed, radioactivity of 137Cs, which has a half-life of approximately 30 years, was observed in some samples of lichens and fungi. We failed to detect the radioactivity of 134Cs in any of the samples we collected, therefore, it was impossible to say clearly that the radioactivity is derived from Fukushima or not. Nevertheless, the radioactivity data documented in this report are a useful reference for the future surveys of radioactivity within the Arctic.