Japan Earthquake Research Articles

Increased motor vehicle crashes following the 2016 Kumamoto earthquake, Japan: an interrupted time series analysis of property damage crashes

Driving after natural disasters entails a substantial amount of stress; therefore, the number of motor vehicle crashes may increase. However, few studies have examined this issue. This study investigated motor vehicle crashes after the 2016 Kumamoto earthquake in Japan. Monthly data about crashes resulting in property damage from 49 municipalities in Kumamoto from 2015 to 2018 were used. An interrupted time series analysis using Poisson or negative binomial regression models was conducted for 49 municipalities; the models were estimated for four classified areas to obtain the robust results. We found that property damage crashes increased significantly in the heavily affected area (Relative Risk (RR) = 1.48, 95% Confidence interval (CI): 1.29, 1.71) and the affected area (RR = 1.25, 95% CI: 1.15, 1.36) after the earthquake. A mountainous area showed a reduction in property damage crashes despite its heavy damage (RR = 0.74, 95% CI: 0.67, 0.82), which can be attributed to the closure of its main gate routes. The unaffected area showed no difference before and after the earthquake. Geographical presentation of the result demonstrates a clear positive association of earthquake damage and increased crashes. The findings of this study highlight the importance of motor-vehicle-crash alerts after an earthquake.

Tectonic Archaeology as a Foundation for Geoarchaeology

This article proposes a new subdiscipline, Tectonic Archaeology, based on the efforts of Japanese archaeologists to deal with the effects of earthquakes, volcanic tephra cover, and tsunami on archaeological sites. Tectonic Archaeology is conceived as an umbrella term for those efforts and as a foundation for Geoarchaeology in general. Comparisons distinguish between Geoarchaeology and Tectonic Archaeology, and a survey of major archaeological journals and textbooks reveals how the concept of ‘tectonics’ and specifically the processes of Plate Tectonics have been treated. Al-though the term ‘tectonics’ occurred fairly frequently, particularly as affecting coastlines and sea levels, it was not thoroughly defined and discussed. Volcanic activity was most mentioned in journals due to its provision of resources and modification of the landscape, while the 2011 earthquake and tsunami in Japan seems to have stimulated more studies in Archaeoseismology. The textbooks were found to have scattered references to Plate Tectonic processes but no clear approach tying these together. The major exception is the Encyclopedia of Archaeology which addresses volcanoes, Archaeoseismology, and tsunami—soon to be linked together vis à vis Earth processes. Tectonic Archaeology attempts first to explain the processes of Plate Tectonics to underwrite investigation of their effects; it is applicable worldwide, in continental and coastal contexts.

Rapid Assessment of Tsunami Offshore Propagation and Inundation with D-FLOW Flexible Mesh and SFINCS for the 2011 Tōhoku Tsunami in Japan

This study demonstrates the skills of D-FLOW Flexible Mesh (FM) and SFINCS (Super-Fast INundation of CoastS) in combination with the Delft Dashboard Tsunami Toolbox to numerically simulate tsunami offshore propagation and inundation based on the example of the 2011 Tōhoku tsunami in Japan. Caused by a megathrust earthquake, this is one of the most severe tsunami events in recent history, resulting in vast inundation and devastation of the Japanese coast. The comparison of the simulated with the measured offshore water levels at four DART buoys located in the north-western Pacific Ocean shows that especially the FM but also the SFINCS model accurately reproduce the observed tsunami propagation. The inundation observed at the Sendai coast is well reproduced by both models. All in all, the model outcomes are consistent with the findings gained in earlier simulation studies. Depending on the specific needs of future tsunami simulations, different possibilities for the application of both models are conceivable: (i) the exclusive use of FM to achieve high accuracy of the tsunami offshore propagation, with the option to use an all-in-one model domain (no nesting required) and to add tsunami sediment dynamics, (ii) the combined use of FM for the accurate simulation of the tsunami propagation and of SFINCS for the accurate and time efficient simulation of the onshore inundation and (iii) the exclusive use of SFINCS to get a reliable picture of the tsunami propagation and accurate results for the onshore inundation within seconds of computational time. This manuscript demonstrates the suitability of FM and SFINCS for the rapid and reliable assessment of tsunami propagation and inundation and discusses use cases of the three model combinations that form an important base for tsunami risk management.

Damage and Reconstruction of Village Communities in the Great East Japan Earthquake and Tsunami:

Damage and Reconstruction of Village Communities in the Great East Japan Earthquake and Tsunami:

Individualism and collectivism in small-scale fisheries post-3.11 Japan

PurposeThis study examines fisheries affected by the Great East Japan Earthquake and Tsunami in 2011 to explore how the collectivism appears during the recovery process.Design/methodology/approachThe author questions the context of collaboration after the disaster among independent small-scale fishers in Miyagi by conducting semistructured interviews with more than 50 local fishers with anthropological observations of boat fishing operations and using local documents and statistics.FindingsThe corresponding collaboration among the fishers after the disaster is not a mere “disaster utopia,” but is embedded in the socioecological context of fishing. Fishers have developed individual and group fishing. They have institutionalized competitive distribution for sedentary fish with low resource fluctuation, while outcome-equal distribution is adopted for migratory fish with high resource fluctuation. This forms a fishing continuum that connects competitive individualism with collectivism in the community, which has contributed to resilience for disaster recovery.Originality/valueThe balance between individualism and collectivism is decisively coordinated in socioecological contexts. The multifaceted resource strategy for maritime biodiversity that features family-based occupational differentiation in a community is crucial for disaster recovery of small-scale fishers.

Displacements Before and After Great Earthquakes: Geodetic and Seismic Viewpoints

Analysis of geodetic data obtained by the global positioning system (GPS) leads to better understanding of earthquake origins and helps to interpret their sequences. For this, we cross-compare the pre- and postseismic displacements associated with great earthquakes and derived from GPS observations and seismic catalogs. In a pilot study of the 2004 Sumatra–Andaman Mw9.2 earthquake in the Indian Ocean, the 2011 Tohoku Mw9.1 earthquake in Japan, the 2010 offshore Maule Mw8.8 and the 2015 Illapel Mw8.3 earthquakes in Chile, the 2018 Kodiak Mw7.9 earthquake in the Gulf of Alaska, and the 2016 Kaikoura Mw7.8 earthquake in New Zealand, we consider GPS data from stations of the Global Navigation Satellite System (GNSS) along with integral characteristics of the regional seismic regime, including the accumulated displacement derived from the catalogs of earthquake hypocenter parameters. We did not find any prominent transient pattern in the daily geodetic measurements registered before the six great earthquakes at the nearest GNSS stations. We found that (a) the six cases exhibit different GPS versus seismic displacement correlation patterns before and after the great earthquakes, (b) the observed high variability of the correlation between geodetic ρ(t) and seismic ∑(t) integrals appears indicative of a partial contribution of earthquakes to naturally haphazard sporadic movement of lithospheric blocks of different size, and (c) GPS data confirm the existence of intermittent long periods of regionally stable levels of seismic regime reflected in the control parameter of the Unified Scaling Law for Earthquakes that may change as a result of mid- or even short-term bursts of activity associated with catastrophic events.

Commentary: The Role of Geodetic Algorithms for Earthquake Early Warning in Cascadia

AbstractThe ShakeAlert earthquake early warning (EEW) system issues public alerts in California and will soon extend to Oregon and Washington. The Cascadia subduction zone presents significant new challenges and opportunities for EEW. Initial publications suggested that EEW algorithms based on Global Navigation Satellite System (GNSS) data could provide improved warning for intraslab events and dramatically improved warning for offshore megathrust events, both of which contribute significantly to hazard in Cascadia. We find that some expectations in these publications were unrealistic, and we demonstrate that in general geodetic algorithms would not produce timely warnings for intraslab events nor warning times of two minutes or more for severe shaking from megathrust earthquakes. Nonetheless, lessons from recent earthquakes in Japan and California, for which alerts from seismic algorithms suffered from magnitude saturation and high data latencies, demonstrate the urgent need for rigorous testing of geodetic EEW as a potential complement to seismic EEW.

Fluid-structure interaction computational analysis and experiments of tsunami bore forces on coastal bridges

PurposeTwo disastrous Tsunamis, one on the west coast of Sumatra Island, Indonesia, in 2004 and another in North East Japan in 2011, had seriously destroyed a large number of bridges. Thus, experimental tests in a wave flume and a fluid structure interaction (FSI) analysis were constructed to gain insight into tsunami bore force on coastal bridges.Design/methodology/approachVarious wave heights and shallow water were used in the experiments and computational process. A 1:40 scaled concrete bridge model was placed in mild beach profile similar to a 24 × 1.5 × 2 m wave flume for the experimental investigation. An Arbitrary Lagrange Euler formulation for the propagation of tsunami solitary and bore waves by an FSI package of LS-DYNA on high-performance computing system was used to evaluate the experimental results.FindingsThe excellent agreement between experiments and computational simulation is shown in results. The results showed that the fully coupled FSI models could capture the tsunami wave force accurately for all ranges of wave heights and shallow depths. The effects of the overturning moment, horizontal, uplift and impact forces on a pier and deck of the bridge were evaluated in this research.Originality/valuePhotos and videos captured during the Indian Ocean tsunami in 2004 and the 2011 Japan tsunami showed solitary tsunami waves breaking offshore, along with an extremely turbulent tsunami-induced bore propagating toward shore with significantly higher velocity. Consequently, the outcomes of this current experimental and numerical study are highly relevant to the evaluation of tsunami bore forces on the coastal, over sea or river bridges. These experiments assessed tsunami wave forces on deck pier showing the complete response of the coastal bridge over water.

Building Damage Detection Based on OPCE Matching Algorithm Using a Single Post-Event PolSAR Data

Synthetic aperture radar (SAR) is an effective tool in detecting building damage. At present, more and more studies detect building damage using a single post-event fully polarimetric SAR (PolSAR) image, because it permits faster and more convenient damage detection work. However, the existence of non-buildings and obliquely-oriented buildings in disaster areas presents a challenge for obtaining accurate detection results using only post-event PolSAR data. To solve these problems, a new method is proposed in this work to detect completely collapsed buildings using a single post-event full polarization SAR image. The proposed method makes two improvements to building damage detection. First, it provides a more effective solution for non-building area removal in post-event PolSAR images. By selecting and combining three competitive polarization features, the proposed solution can remove most non-building areas effectively, including mountain vegetation and farmland areas, which are easily confused with collapsed buildings. Second, it significantly improves the classification performance of collapsed and standing buildings. A new polarization feature was created specifically for the classification of obliquely-oriented and collapsed buildings via development of the optimization of polarimetric contrast enhancement (OPCE) matching algorithm. Using this developed feature combined with texture features, the proposed method effectively distinguished collapsed and obliquely-oriented buildings, while simultaneously also identifying the affected collapsed buildings in error-prone areas. Experiments were implemented on three PolSAR datasets obtained in fully polarimetric mode: Radarsat-2 PolSAR data from the 2010 Yushu earthquake in China (resolution: 12 m, scale of the study area: 50 km2); ALOS PALSAR PolSAR data from the 2011 Tohoku tsunami in Japan (resolution: 23.14 m, scale of the study area: 113 km2); and ALOS-2 PolSAR data from the 2016 Kumamoto earthquake in Japan (resolution: 5.1 m, scale of the study area: 5 km2). Through the experiments, the proposed method was proven to obtain more than 90% accuracy for built-up area extraction in post-event PolSAR data. The achieved detection accuracies of building damage were 82.3%, 97.4%, and 78.5% in Yushu, Ishinomaki, and Mashiki town study sites, respectively.

Left in the wake of the 2011 Japan tsunami

Left in the wake of the 2011 Japan tsunami

Centennial to Multi-Decadal Morphology Change and Sediment Budget Alteration with Consideration of the Impacts of the 2011 Tohoku Earthquake Tsunami along the Nobiru Coast, Japan

The Nobiru Coast is situated on the southwest of the Ishinomaki Bay. The 2011 Great East Japan Tsunami severely devastated the Nobiru Coast and the adjacent Naruse River mouth. In this study, an investigation was conducted based on the available historic maps and images combined with in situ surveys that revealed the century-to-decade morphology change and sediment budget alteration in the Nobiru Coast. During the past two centuries, the longshore transport on the northeast coast and sediment supply from the Naruse River were the principal sediment supply onto the Nobiru Coast and the estimated annual net sediment input into the coast was 87,000 m3/y. Until several decades ago, the construction of the Ishinomaki Port and the erosion preventing constructions (breakwaters, headlands) along the Ohmagari Coast on the northeast areas caused a dramatic reduction of longshore transport to the Nobiru Coast. Hence, the net sediment input fell to 46,000 m3/y. After the tsunami, the sediment input was further reduced to 29,000 m3/y and this loss was closely related to the intruded sediment into the Naruse River. The outcomes of this study are highly valuable for the government authorities to manage the long-term coastal and riverine morphological changes after the 2011 tsunami.

EVALUATION OF EARTHQUAKE-INDUCED SLOPE FAILURE DISTRIBUTION USING THE AHP METHOD AND GIS

Landslides or slope failures are often caused by earthquakes. The 2018 Hokkaido Eastern Iburi Earthquake and the 2016 Kumamoto Earthquakes in Japan caused many slope failures that were distributed both widely and densely. This study proposes an earthquake-induced slope failure hazard mapping method that uses the analytic hierarchy process (AHP) and a geographic information system (GIS) for specific districts, the Atsuma district in Hokkaido and Minamiaso district in Kumamoto. The earthquakeinduced slope failure hazard assessment system used here is based on the landslide distribution (NIED catalog, Japan), which includes tens of thousands of locations in the Atsuma and Minamiaso districts. We considered the relationships between landslide distribution and landslide hazard factors (elevation, slope angle, slope type, catchment degree, geology, and vegetation). These relations were introduced to pairwise comparisons of factors in the AHP method. The AHP method was applied to evaluate the slope failure hazard rank. An earthquake-induced slope failure hazard map was created based on slope failure hazard ranks of I–V. As a result, slope angle, slope type, and catchment degree were found to exert maximum effects on slope failure distribution due to earthquakes in both the Atsuma district in Hokkaido and the Minamiaso district in Kumamoto. The two earthquake-induced slope failure distributions are almost consistent with the slope failure hazard rank. These results provide a practical method for evaluating earthquake-induced slope failure hazards.

Live Recovery After Post Earthquake and Tsunami: Economic Review Case Studies of Earthquake and Tsunami in Japan and Indonesia

Natural disaster is a natural event that often gives such impact on the living things populations. The purpose of this research is to determine whether the occurrence of earthquake and tsunami has the potential to cause economic loss, thus, mitigation measures can be taken as an effort to reduce these losses. The method used in this research is quantitative. The data used are primary data from questionnaires, and secondary data were gained from various literatures. Data analysis was performed using Microsoft Excel. Based on the data analysis that has been conducted, the results show that earthquake and tsunami have a relation to the economy. All respondents agreed that earthquake and tsunami caused disruption to the public facilities operation. All respondents also agreed that the detriment after the earthquake and tsunami had an effect on fulfillment of needs and economic activities. This answer affirms that the damage of various facilities and production resources caused the increasing of limited satisfaction tools and scarcity arises, then resulting in economic problems.

The prevalence of psychological distress during pregnancy in Miyagi Prefecture for 3 years after the Great Eas t Japan Earthquake

BackgroundTo examine changes in psychological distress prevalence among pregnant women in Miyagi Prefecture, which was directly affected by the Great East Japan Earthquake and tsunami, and compare it with the other, less damaged areas of Japan.MethodsThis study was conducted in conjunction with the Japan Environment and Children`s Study. We examined 76,152 pregnant women including 8270 in Miyagi Regional Center and 67,882 in 13 other regional centers from the all-birth fixed data of the Japan Environment and Children’s Study. We then compared the prevalence and risk of distress in women in Miyagi Regional Center and women in the 13 regional centers for 3 years after the disaster.ResultsWomen in the Miyagi Regional Center suffered more psychological distress than those in the 13 regional centers: OR 1.38 (95% CI, 1.03–1.87) to 1.92 (95% CI, 1.42–2.60). Additionally, women in the inland area had a consistently higher prevalence of psychological distress compared to those from the 13 regional centers: OR 1.67 (95% CI, 1.18–2.38) to 2.19 (95% CI, 1.60–2.99).ConclusionsThe lack of pre-disaster data in the Japan Environment and Children’s Study made it impossible to compare the incidence of psychological distress before and after the March 2011 Great East Japan Earthquake. However, 3 years after the Great East Japan Earthquake, the prevalence of pregnant women with psychological distress did not improve in Miyagi Regional Center. Further, the prevalence of mental illness in inland areas was consistently higher than that in the 13 regional centers after the disaster.

Experimental investigation of tsunami bore-induced forces and pressures on skewed box section bridges

Tsunamis in Indonesia (2004) and Japan (2011) severely affected communities bordering the Indian Ocean and Japan's east coast. Despite the plausible findings arising from the available studies, the research on the impact of tsunami bore forces applied to bridges of different designs is limited. This is because the estimation methods for tsunami-induced loads presented in the literature have mainly been developed for buildings and require careful adaptation to apply to bridges. The main focus of the present study is to experimentally examine the interaction between a tsunami bore and a box section bridge with different orientations to the direction of the incoming bore, bore strengths, and deck clearances. The experiments were conducted in a 15-m-long, 1.2-m-wide, and 1.2-m-deep wave flume. The forces and pressures applied to the bridge, the bore heights, and the velocities were measured. It was found that the skewed bridge deck is subjected to additional force and moment components, namely the cross-stream force (Fy) and the rolling and yawing moments (Mx and Mz). These components are non-existent for the unskewed bridge deck. Based on the experimental results, equations were proposed for estimating tsunami forces for a box section bridge deck.

Building destination resilience in the tourism disaster management process from the past experiences: The case of the 2018 Hokkaido Eastern Iburi earthquake in Japan

ABSTRACT This exploratory research reports the perception of local tourism stakeholders towards the distinctive contribution of tourism to the disaster management process and the destination resilience across the pre-to-post period of the September 2018 Hokkaido Eastern Iburi earthquake in Japan through a series of in-depth interviews with 15key informants in summer 2019. The qualitative content analysis identifies, firstly, the multi-functionality of tourism resources, spaces and industries for disaster preparation. Secondly, it points out that information and communication barriers are the major difficulties to be tackled, especially in a complicated situation involving different people and problems during prodromal and emergency phases. The study reveals that post-disaster recovery may lead to new product creation, image improvement, local knowledge enrichment, people-to-people and people-to-place connections, which facilitate sustainable tourism development with long-term vision and strategy. The research concludes that the strengthened destination resilience must be achieved through an effective collaboration among local stakeholders including public sector, private sector and other non-governmental or community-based organizations.

Seismic response and failure mechanism of underground frame structures based on dynamic centrifuge tests

AbstractDuring the 1995 Kobe earthquake in Japan, the Daikai subway station suffered total collapse, which made the research on the seismic failure mechanism of underground frame structures become a hot topic. The author has carried out a lot of research on earthquake failure mechanism of underground frame structures based on numerical method. To validate and further study the seismic failure response and mechanism of underground frame structures, a series of comparative dynamic centrifuge tests were carried out. The research conclusions are as follows. The vertical earthquake action significantly increased the axial pressure on the columns of an underground frame structure, reducing their horizontal deformation capacity. The columns subjected to high axial compression were prone to brittle damage under a relatively strong horizontal earthquake, which led to the overall collapse of an underground frame structure. The areas near the intersection of the ceiling slab and the sidewalls were the weak part of the underground frame structure and were vulnerable to tensile cracks under earthquake. The columns' top and bottom were the fragile parts and were prone to concrete cracking or even shear failure under an earthquake. If the columns could remain intact and effectively provided vertical support under a strong earthquake, it was beneficial to reduce the risk of the overall collapse of an underground frame structure.

Radon degassing triggered by tidal loading before an earthquake

The presence of anomalous geochemical changes related to earthquakes has been controversial despite widespread, long time challenges for earthquake prediction. Establishing a quantitative relationship among geochemical changes and geodetical and seismological changes can clarify their hidden connection. Here we determined the response of atmospheric radon (222Rn) to diurnal tidal (K1 constituent) loading in the reported 11-year-long variation in the atmospheric radon concentration, including its anomalous evolution for 2 months before the devastating 1995 Kobe earthquake in Japan. The response to the tidal loading had been identified for 5 years before the occurrence of the earthquake. Comparison between these radon responses relative to crustal strain revealed that the response efficiency for the diurnal K1 tide was larger than that for the earthquake by a factor of 21–33, implying the involvement of crustal fluid movement. The radon responses occurred when compressional crustal stress decreased or changed to extension. These findings suggest that changes in radon exhaled from the ground were induced by ascent flow of soil gas acting as a radon carrier and degassed from mantle-derived crustal fluid upwelling due to modulation of the crustal stress regime.

Role of EQ preparatory processes on ionospheric parameters through analysis of ionization density of Spread F-layer and Sporadic E

In this paper, the approaches adopted for the extraction of earthquake-induced features from ionospheric irregularities like spread F and sporadic E are discussed. For this purpose, a few Japan earthquakes (EQ) with magnitude M > 7 are selected. The selection procedures for identifying earthquake-induced effects in these irregularity parameters are discussed, and the EQ time signature in these irregularities is then defined as enhancement in fxI and foEs prior to an earthquake. The analysis output shows that the critical frequency of spread F index increases by 16–83%, 3–5 days prior to the earthquakes and the critical frequency of sporadic E increases by 50–110%, 2–4 days prior to the EQ. In case of May 30, 2015, Japan EQ with M = 7.8, the critical frequency of sporadic E increased up to 18 MHz prior to an EQ.

Strong-Motions From Damaging Moderate Magnitude (5.9 ≥ Mw) Earthquakes in Japan Recorded by K-NET and KiK-net

Strong-motions from 79 moderate magnitude (5.9 ≥ Mw) earthquakes that caused various degrees of impact on humans and built-environment in Japan between 1996 and 2019, after the start of K-NET and KiK-net, are presented. As such, most of the earthquakes occurred beneath the land, and agencies had reported damages from events as small as Mw 4.1. Together, large peak ground accelerations exceeding 500 cm/s2were recorded during 15 earthquakes, reaching approximately 1128 cm/s2during one event. Similarly, large peak ground velocities exceeding 30 cm/s were recorded during ten earthquakes, reaching about 76 cm/s to the maximum. Most of the large values aforementioned were recorded within a hypocentral distance of approximately 30 km and on soil site conditions. Intermediate to long-period ground motions are of growing concerns in urban areas located on sedimentary basins with mid-rise and high-rise buildings. The threshold magnitude for the large ground motions at the periods of about 2–5 s is not well understood. In March 2013, the Japan Meteorological Agency introduced four levels of long-period ground motion intensity (LPGMI) based on absolute velocity response spectra (AVRS) between 1.6 and 7.8 s. In the present data set, LPGMI of level 3 (AVRS 50–100 cm/s) and level 4 (AVRS >100 cm/s) were observed each at a single site from shallow-focus earthquakes of Mw 5.8 and 5.9 at distances of approximately 12 and 15 km, respectively. However, the peak response periods were relatively short (1.6–1.8 s). The data showed that LPGM from moderate earthquakes is of lower concern regarding earthquake early warning at distances beyond 200 km. The 2018 Mw 5.5 North Osaka earthquake, despite the moderate magnitude, caused the loss of six human lives and brought significant damage to buildings and lifelines. Comparing the data with the ground motion prediction equations (GMPEs) and other events suggested that the North Osaka earthquake was probably a higher stress drop event. These moderate earthquakes’ observations hinted that the commonly used GMPEs in Japan may not sufficiently grasp these earthquakes' hazards.