Northeastern Coast Of Japan Research Articles

Gravity Variation Estimation of the 2011 Tohoku Earthquake

Gravity variations due to the 2011 Tohoku (M9.0) earthquake, which occurred at the plate boundaries near the northeastern coast of Japan, were estimated through the GRACE spherical harmonic (Stokes) coefficients derived from the CSR. About -5 μGal gravity variation by the GRACE data was found in the back-arc basin area with respect to a reference gravity model. The mean gravity variations in the back-arc basin area and the Japan Trench area were -4.4 and -3.2 μGal in order. The small negative gravity variations around the Japan Trench area can be interpreted by both crustal dilatation and the seafloor topography change in comparison with the large negative gravity variations in the back-arc basin area by co-seismic crustal dilatation of the landward plate. From the results of the gravity variations, vertical displacements generated from relatively short wavelength caused by the earthquake were estimated by use of multi-beam bathymetric measurements obtained from JAMSTEC. The maximum seafloor topography changes of about ±50 m were found at west side of the Japan Trench axis by the earthquake. The seafloor topography change by the megathrust earthquake can be considered as the results of the landslide of the seafloor throughout the landward side.

Bathymetry Change Investigation of the 2011 Tohoku Earthquake

Bathymetry change due to the 2011 Tohoku (M9.0) earthquake was investigated through satellite altimetryderived free-air gravity anomalies (SAFAGA) and shipborne measurements. The earthquake occurred at the plate boundaries near the northeastern coast of Japan, where the oceanic plate subducts beneath the continental plate along deep-sea trench. Data analyzed in this study include SAFAGA from Scripps Institution of Oceanography (SIO), shipborne bathymetry (SB) from the U.S. National Geophysical Data Center (NGDC) and the Japan Agency for Marine-Earth-Science And Technology (JAMSTEC). To estimate the bathymetry change, a reference bathymetry before the earthquake was predicted by gravity-geologic method (GGM) and Smith & Sandwell’s (SAS) method. In comparison with the bathymetry models before the earthquake, GGM bathymetry model generated by a tuning density contrast of 17.04 g/cm3 by downward continuation method was selected because it shows better bathymetry in the short wavelength below about 6 km. From the results, remarkable bathymetry change of about ±50 m was found on the west side of the Japan Trench caused by the earthquake.

Growth and spatiotemporal distribution of juvenile shortfin mako (Isurus oxyrinchus) in the western and central North Pacific

This paper presents an estimation of growth curves and spatiotemporal distributions of juvenile shortfin mako shark (Isurus oxyrinchus) in the western and central North Pacific Ocean using port sampling data collected from 2005 to 2013. The monthly length compositions show a clear transition of three modes in the size range of smaller than 150-cm precaudal length (PCL), which were believed to represent the growth of age-0 to age-2 classes, and they were then decomposed into age groups by fitting a Gaussian mixture distribution. Simulation data of lengths at monthly ages were generated from the mean and standard deviation of each distribution, and fit with a von Bertalanffy growth function. Parameters of the estimated growth curves for males and females were 274.4 and 239.4cm PCL for the asymptotic length and 0.19 and 0.25 year–1 for the growth coefficient indicating apparently faster growth than previously reported. Generalised linear models were applied to age-0 to explore the seasonal changes of PCL by area. They were born during late autumn and winter off the coast of north-eastern Japan, an area known to have relatively high productivity compared with other pelagic areas, and gradually expanded their habitat eastward and northward with the seasons as they grew.

It May Be Useful to Assume the Policeman’s Perspective Now and Then

From “Black Collectivities: A Conference,” held May 3–4, 2013, at Northwestern University’s Mary and Leigh Block Museum of Art, the Museum of Contemporary Art Chicago, and the University of Chicago’s Arts Incubator. The text proceeds from the point of view of a fictional research consortium that seeks to leverage its role as a stakeholder in the aftermath of the earthquake, the tsunami, and the partial nuclear meltdown on March 11, 2011, on the northeastern coast of Japan. The consortium can be understood as a personification of the type of collective agent that constitutes the infrastructure of the global nuclear regime, as analyzed by the critic Sabu Kohso. The article adopts the perspective of a transnational scientific-corporate entity to unfold the implications of understanding the high scientific uncertainty of low-level radiation as a laboratory of financial and necropolitical calculation.

Tsunami Damage Investigation of Built-Up Areas Using Multitemporal Spaceborne Full Polarimetric SAR Images

This paper explores the use of full polarimetric synthetic aperture radar (PolSAR) images for tsunami damage investigation from the polarimetric viewpoint. The great tsunami induced by the earthquake of March 11th, 2011, which occurred beneath the Pacific off the northeastern coast of Japan, is adopted as the study case using the Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar multitemporal PolSAR images. The polarimetric scattering mechanism changes were quantitatively examined with model-based decomposition. It is clear that the observed reduction in the double-bounce scattering was due to a change into odd-bounce scattering, since a number of buildings were completely washed away, leaving relatively a rough surface. Polarization orientation (PO) angles in built-up areas are also investigated. After the tsunami, PO angle distributions from damaged areas spread to a wider range and fluctuated more strongly than those from the before-tsunami period. Two polarimetric indicators are proposed for damage level discrimination at the city block scale. One is the ratio of the dominant double-bounce scattering mechanism observed after-tsunami to that observed before-tsunami, which can directly reflect the amount of destroyed ground-wall structures in built-up areas. The second indicator is the standard deviation of the PO angle differences, which is used to interpret the homogeneity reduction of PO angles. Experimental results from after- and before-tsunami comparisons validate the efficiency of these indexes, since the built-up areas with different damage levels can be well discriminated. In addition, comparisons between before-tsunami pairs further confirm the stability of the two polarimetric indexes over a long temporal duration. These interesting results also demonstrate the importance of full polarimetric information for natural disaster assessment.

Impact of the Tohoku earthquake and tsunami on pneumonia hospitalisations and mortality among adults in northern Miyagi, Japan: a multicentre observational study

BackgroundOn 11 March 2011, the Tohoku earthquake and tsunami struck off the coast of northeastern Japan. Within 3 weeks, an increased number of pneumonia admissions and deaths occurred in local...

Safety regulations of food and water implemented in the first year following the Fukushima nuclear accident

An earthquake and tsunami of historic proportions caused massive damage across the northeastern coast of Japan on the afternoon of 11 March 2011, and the release of radionuclides from the stricken reactors of the Fukushima nuclear power plant 1 was detected early on the next morning. High levels of radioiodines and radiocesiums were detected in the topsoil and plants on 15 March 2011, so sampling of food and water for monitoring surveys began on 16 March 2011. On 17 March 2011, provisional regulation values for radioiodine, radiocesiums, uranium, plutonium and other transuranic α emitters were set to regulate the safety of radioactively contaminated food and water. On 21 March 2011, the first restrictions on distribution and consumption of contaminated items were ordered. So far, tap water, raw milk, vegetables, mushrooms, fruit, nut, seaweeds, marine invertebrates, coastal fish, freshwater fish, beef, wild animal meat, brown rice, wheat, tea leaves and other foodstuffs had been contaminated above the provisional regulation values. The provisional regulation values for radioiodine were exceeded in samples taken from 16 March 2011 to 21 May 2011, and those for radiocesiums from 18 March 2011 to date. All restrictions were imposed within 318 days after the provisional regulation values were first exceeded for each item. This paper summarizes the policy for the execution of monitoring surveys and restrictions, and the outlines of the monitoring results of 220 411 samples and the enforced restrictions predicated on the information available as of 31 March 2012.

A study of the students’ travel Japan intentions from Departments of Applied Japanese in Taiwan after 311 East Japan Earthquake

On March 11, 2011, a 9 Richter scale earthquake occurred off the northeastern coast of Japan. The earthquake caused a major tsunami, resulting in the radiation leak of Fukushima I nuclear power plant, which seriously affected Japan’s tourism. The purpose of this research is to explore the correlation between the attitudes of Taiwan’s students from departments of applied Japanese to travel safety, and their intentions to travel to Japan. The results showed that 1. from a cognitive perspective, the radiation pollution’s threat in east Japan after the earthquake did weaken the intentions of the subject students from departments of applied Japanese to travel there; however, 2. from an affective perspective, because of the affection for Japanese culture and customs, although the students’ affective attitudes of travel safety significantly increased their hesitation in travel decisions, ultimately their overall feelings and intentions of travelling to Japan were still positive.

Characteristics of the 2011 Tohoku Earthquake and Tsunami and Its Impact on the Northern Iwate Coast

On March 11, 2011, at 14:46 local time, a powerful earthquake occurred off the Sanriku coast of northeastern Japan. It was immediately apparent that this was the strongest earthquake on the historical record, and the resulting series of tsunami ravaged the Tohoku region. In Iwate Prefecture, the tsunami height generally exceeded the design tsunami level for safety, which had been determined on the basis of the 1896 Meiji-Sanriku tsunami, the 1933 Showa-Sanriku tsunami, and the 1960 Chile tsunami. As of January 10, the number of dead and missing in Iwate rose to 6,035. Over 24,000 buildings had been destroyed. After the 1933 Showa-Sanriku, disaster prevention facilities were built along the coast. However, many tsunami seawalls and water gates suffered enormous damage from the impact of the 2011 Tohoku Tsunami. This paper sketches out the characteristics and scope of the damage in the coastal areas of Iwate Prefecture, with a particular focus on the northern coast of Iwate.

MEASURES AGAINST RADIOACTIVE CONTAMINATION DUE TO FUKUSHIMA FIRST NUCLEAR POWER PLANT ACCIDENTS PART I: DAMAGE SITUATION OF THE GREAT EAST JAPAN EARTHQUAKE

The great East Japan earthquake consisted of three catastrophes. The first one was the earthquake, the second one was the tsunami and the third one was nuclear power plant accidents. The magnitude 9 was recorded. After the earth quake, huge tsunami waves of above 16m height hit the east coast of Northeastern Japan. Many people died and many things were lost. The tsunami caused the accident of Fukushima first nuclear power plant which resulted in a serious radioactive pollution.

Technology and the forces of nature: A lesson of humility calling for ecocentrism

The incident at the Fukushima Daiichi nuclear power plant, resulting from the powerful earthquake and tsunami that struck the northeastern coast of Japan in March 2011, reminds humankind of the powerful natural forces that shape our world. This article calls for a new ecocentric approach to human interaction with the environment, with particular reference to the environmental consequences of radiation.

Initial Phase Crisis Communications Following High Perceived Risk Events: The Volcanic Ash Crisis and the Japanese Tsunami as Examples

On 14 April 2010 the Icelandic volcano, Eyjafjallajökull, erupted resulting in a volcanic ash cloud across European airspace. The ash cloud caused a moratorium on flying and concerns over health effects to vulnerable populations. Not even a year since the volcanic ash cloud; on 11 March 2011 a massive 9.0-magnitude earthquake occurred near the northeastern coast of Japan, creating extremely destructive tsunami waves which hit Japan just minutes after the earthquake, triggering evacuations and warnings across the Pacific Ocean. The disaster also led to concerns over nuclear power plant meltdowns in the affected areas and risk of radiation. High perceived risks associated with the Japanese tsunami and volcanic ash crisis are examples of scenarios where accurate and timely health and safety communications are vital for effective emergency response. However, communications immediately following such events face unique challenges. This report describes the challenges faced in terms of crisis communication immediately following high perceived risk events and positions the example case studies in the context of an existing crisis communication paradigm.

Displacement Above the Hypocenter of the 2011 Tohoku-Oki Earthquake

The moment magnitude (M(w)) = 9.0 2011 Tohoku-Oki mega-thrust earthquake occurred off the coast of northeastern Japan. Combining Global Positioning System (GPS) and acoustic data, we detected very large sea-floor movements associated with this event directly above the focal region. An area with more than 20 meters of horizontal displacement, that is, four times larger than those detected on land, stretches several tens of kilometers long along the trench; the largest amount reaches about 24 meters toward east-southeast just above the hypocenter. Furthermore, nearly 3 meters of vertical uplift occurred, contrary to observed terrestrial subsidence.

Globalised chaos [effect of post-earthquake and post-tsunami in car manufacturing industries

After the earthquake and ensuing tsunami hit the north eastern coast of Japan, carmakers in the region were still struggling to produce cars. One reason is the lack of power caused by the damage caused to the nuclear reactor, but of more worrying long-term concern is the lack of components from an ailing supply chain. But it is not just manufacturers in the region who are struggling with inventory, the backlash is being felt all around the globe;the reasons being intricate interwoven supply chains and globalisation. Suzuki temporarily restarted vehicle production at its Kosai, Iwata, and Sagara plants in Japan, but lack of parts caused them to close again a week later, while Mitsubishi has suspended production at its plant in Okayama prefecture. Toyota is putting all its emphasis on resuming production of three hybrid models but it has postponed the launch of the Prius wagon and minivan hybrid. The company has already extended production shutdowns at all of its assembly plants in Japan. The expected delay in the resumption of deliveries of components by Japanese suppliers is threatening the global supply chain. However, the impact is not limited to the Japanese companies. Most auiomakers source components from Japanese suppliers and the disruption to the supply chain has hit the production schedules of even non-Japanese automakers.

Seasonal to interannual variations of the western boundary current of the subarctic North Pacific by a combination of the altimeter and tide gauge sea levels

Seasonal to interannual variations of the East Kamchatka Current (EKC) and the Oyashio are examined by focusing on their barotropic response to wind forcing by a combined use of altimeter‐derived and tide gauge sea levels. An empirical orthogonal function (EOF) analysis is performed on the 9‐year altimeter sea level maps with thermosteric signals removed. A second EOF (EOF2) shows a spin‐up and spin‐down of the subarctic gyres, and its temporal variation is almost accounted for by the time‐dependent Sverdrup balance. Tide gauge sea levels at Petropavlovsk‐Kamchatsky (PK) agree with EOF2 and the Sverdrup transports in terms of not only the seasonal variation but also its year‐to‐year variability in winter when the subarctic gyre is spun up most. We also detect two types of EKC/Oyashio variations from the altimeter data: drifting velocities of sea level disturbances and geostrophic velocity anomalies. These two EKC/Oyashio temporal variations are also accounted for by the Sverdrup balance and agree with the PK sea levels and EOF2. The results imply that the PK sea levels can be a good representative of the subarctic gyre and EKC/Oyashio variations. On the basis of this relation, interannual variations during winter are discussed. The 44‐year wintertime sea levels at PK correlate with the wintertime Sverdrup transport and springtime sea surface temperature off the northeastern coast of Japan with decadal‐scale variability. This demonstrates that EKC/Oyashio is primarily explained by a barotropic response to large‐scale atmospheric forcing and fluctuates on a decadal timescale almost in phase with atmospheric changes and influences the oceanic condition east of Japan.

Evidence of a local spawning site of marine eels along northeastern Japan, based on the distribution of small leptocephali

AbstractEvidence of recent spawning by several species of marine eels of the families Congridae, Ophichthidae, and Nettastomatidae was found over the continental shelf along the coast of northeastern Japan in October 2003. Sixty‐three leptocephali of at least three taxa that ranged from 3.8 to 12.3 mm total length were collected in a relatively small area, just to the south of Cape Shioya, primarily over the 100‐and 200‐m‐depth contours. The leptocephali of Gnathophis nystromi nystromi were the most abundant, followed by those of G. nystromi ginanago. This spawning area is located in an area that appeared to include water originating from the Tsugaru Warm Current and is further south than the typical latitude of the cold water of the Oyashio First Intrusion. These findings suggest that some species of marine eels may not migrate past the slope to spawn, and that the oceanographic features of the region may provide favorable conditions for the growth and retention of leptocephali in the area to the south of Cape Shioya.

Stratospheric ozone and ClO measurement using Balloon-Borne submillimeter limb sounder

Stratospheric O/sub 3/ and ClO were simultaneously observed off the northeastern coast of Japan by the Balloon-Borne Superconducting Submillimeter-Wave Limb-Emission Sounder (BSMILES) developed at National Institute of Information and Communications Technology. BSMILES is a highly sensitive submillimeter radiometer that exploits the superconductor-insulator-superconductor (SIS) technology for atmospheric research. This paper presents the first BSMILES spectra, and describes the details of the calibration process. The vertical profiles of O/sub 3/ and ClO have been also retrieved. In spite of some calibration uncertainties the obtained profiles are in relatively good agreement with previous and other available measurements.

Numerical Study on the Oyashio Water Pathways in the Kuroshio–Oyashio Confluence*

Abstract In this paper, results of a high-resolution regional model of the Kuroshio–Oyashio confluence, where the mixed water region (MWR) forms off the northeastern coast of Japan, are discussed. The model simulates major characteristics of the Kuroshio and the Oyashio system well, such as the separation of the Kuroshio Extension from the Japanese coast and southward intrusion of the Oyashio. Further, potential temperature and salinity structures in the intermediate layer σθ = 27.0 resemble those obtained from historical data. Upon the success of this simulation, the authors focus on the diagnosis of the Oyashio water pathways intruding into the subtropics. It is found that the pathways of the Oyashio water form in the vicinity of the Japanese coast, where warm core rings and the Oyashio intrusion are active. These pathways are shown to be primarily eddy driven. Of particular interest is the water that originates in the Sea of Okhotsk, characterized by low potential vorticity (PV). Impacts of the Okhotsk...

A new species in the genus Cyrtostrombidium (Ciliophora, Oligotrichia, Oligotrichida): its morphology, seasonal cycle and resting stage.

Cysts of an oligotrich ciliate were collected from natural sediment samples in Onagawa Bay, northeastern coast of Japan, and examined for their excystment capability. A high excystment ratio was obtained at lower temperatures of 10 or 15 degrees C; no excystment occurred at 20 degrees C. Excysted vegetative cells were observed after protargol staining and were identified as a new species, Cyrtostrombidium boreale n. sp. The seasonal changes in the vegetative population and sedimentation of newly formed cysts were also investigated in situ. Planktonic vegetative cells were abundant during the cold season from February to May, when the water temperature was lower than 10 degrees C. Mass encystment occurred abruptly just after the seasonal peak of the vegetative population in April. These results indicate that C. boreale is a cold-water species and aestivates during the longer, warm period from late spring to fall.

Active erosion of Undaria pinnatifida Suringar (Laminariales, Phaeophyceae) mass-cultured in Otsuchi Bay in northeastern Japan

Production and erosion of the commercially mass-cultured kelp Undaria pinnatifida Suringar f. distans Miyabe et Okamura were investigated between January and April 1998 in Otsuchi Bay, ca. 8 km long and 2 km wide, located on the northeastern coast of Japan. Steady growth in total kelp length was observed from January to March, with rates of 1.1 to 1.8 cm day −1. Erosion rates were consistently low at <0.2 cm day −1 in January and February, but increased to 0.5 cm day −1 in March, and were comparable to the growth rate in April. Biomass erosion represented 30–40% of production in March and over 80% in April. The greater erosion in April was attributed to a low supply of dissolved inorganic nitrogen and aging of the alga. Total net production of the cultured kelp in the bay was 49.5 tonne C, of which, 81% (38.7 tonne C) was harvested while 19% (10.8 tonne C) was lost due to erosion. In terms of nitrogen, 33% of total production (4.68 tonne N) was eroded, while 67% was harvested. Active erosion of the kelp thus appears to be an important source of organic matter for heterotrophic processes in the coastal waters of eastern Asia where kelp cultivation is a major aquaculture industry.