Science.gov

Sample records for ryukyu islands japan

  1. Paleo-tsunami and storm records inferred from coastal boulders along the Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Goto, K.; Miyagi, K.; Imamura, F.

    2012-12-01

    After the 11 March 2011 Tohoku-oki earthquake and tsunami (Mw=9.0) at off the coast of Tohoku district of Japan, re-evaluation of the occurrence of large earthquake and tsunami along the subduction zone is one of the major issues in Japan. Along the Ryukyu trench, there are no known thrust type earthquakes of magnitude greater than 8.0 in the last 300 years [Ando et al., 2009, 2012], although there is one possible exception: the AD1771 event at the southern Ryukyu Islands which is characterized by the ~30 m run-up heights. Hence, the occurrence of tsunamigenic large earthquake along the Ryukyu trench in the past and future is controversial. The lack of thousands of years geological record of past earthquake and tsunami such as the sandy tsunami deposits along the Ryukyu trench has made the discussion more difficult, because there are very few suitable places to study such deposits. On the other hand, numerous coastal boulders are reported on the fringing reefs of each island [e.g. Goto et al., 2010]. They are mostly composed of the coralline and reef rocks and are regarded as useful markers of the past large tsunamis and storm events. In fact, some of them are fossil Porites sp. and hence 14C dating is possible for determining the depositional age [e.g. Araoka et al., 2010]. Moreover, boulders of tsunami and storm wave origins at Ryukyu Islands can be differentiated because difference of the wave lengths of tsunami and storm wave are affected the clast size and spatial distributions of boulders on the wide fringing reef (~1500 m) [e.g. Goto et al., 2010]. Therefore, presence or absence of tsunami boulders at each island may provide useful information of occurrence of past large tsunamis and the causative earthquakes along the Ryukyu Trench. In this study, we show the clast size and spatial distributions of more than 2,500 boulders at 11 islands along the Ryukyu trench. Based on the geological study and hydrodynamic analyses, boulders on the reefs at the Sakishima Islands (southern part of the Ryukyu Islands) are interpreted as both the tsunami and storm wave origins, while only boulders deposited by the storm waves are observed on the reefs at the Okinawa and Amami Islands (central to northern part of the Ryukyu Islands). Absence of the tsunami boulders (but presence of storm wave boulders) at these islands shows striking contrast to the Sakishima Islands. Our results may imply that large tsunamigenic earthquakes were heterogeneously occurred among the Ryukyu Islands. Namely, large tsunamis were frequently occurred around the Sakishima Islands, while there is no evidence of occurrence of large tsunamis that could have moved storm wave boulders on the reef to further inland over a thousand year at Okinawa and Amami Islands according to the boulders' distribution. On the other hand, storm wave impact seems to have been continued after the reef formation at all islands.

  2. Terrestrial gamma radiation dose rate in Ryukyu Islands, subtropical region of Japan.

    PubMed

    Furukawa, M; Kina, S; Shiroma, M; Shiroma, Y; Masuda, N; Motomura, D; Hiraoka, H; Fujioka, S; Kawakami, T; Yasuda, Y; Arakawa, K; Fukahori, K; Jyunicho, M; Ishikawa, S; Ohomoto, T; Shingaki, R; Akata, N; Zhuo, W; Tokonami, S

    2015-11-01

    In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h(-1), respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time. PMID:26065703

  3. The Quaternary adakite distribution of Kyushu Island, Ryukyu Arc, Japan

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Yoshikawa, M.; Takemura, K.

    2011-12-01

    The Quaternary volcanoes are widely distributed in Kyusu Island, Japan. Philippine Sea plate is subducting beneath Kyushu. Clear distribution of deep seismic foci is observed below the Quaternary volcanoes in southern area, but not in northern area. Notsu et al. (1990, JVGR) examined the contribution of subduction to the magma source, and emphasized that no slab derived material is observed in northern area from Sr isotopic compositions. Volcanic activity similar to the within-plate type volcanism has been also emphasized for the magma genesis of this area (e.g. Kita et al, 2001, JVGR). However, we found adakitic rocks, which show high Sr/Y ratios and low Y concentrations (e.g. Defant and Drummond, 1990, Nature) from some Quaternary volcanoes in north Kyushu on the basis of published data (Otha et al, 1990, GANKO; Itoh, 1990, GANKO). Therefore, the magma genesis is still controversial. We studied lateral variations of Sr, Nd and Pb isotopic and trace element compositions for Quaternary volcanics from Kyushu to investigate the magma genesis. From the results, a clear variation of Sr/Y ratio, decreasing from north to south, is observed along the volcanic front. Some of the Sr/Y ratio of the most northern part of Kyusu shows the value >100. The all analyzed Pb isotope compositions show a single liner trend in 208Pb/204Pb v.s. 206Pb/204Pb diagram. The liner trend of Pb isotope ratios can be explained by the binary mixing of the Shikoku Basin basalt and tereginious sediment which might be a constituent of the subducting slab. The similar binary mixing relationships are found in Sr and Nd isotopic systematics. The isotopic characteristics of the Quaternary magma in Kyushu can be explained by the magma generation process of island arc, in spite of the lack of deep seismic foci in northern area. It is considered that high and low Sr/Y ratios suggest the contributions of partial melt in the north and aqueous fluid derived from subducting slab in the south, respectively. If these suggestions are correct, the difference of magma genesis in north and south might be related with the ages of subducting Philippine Sea plate which are < 25Ma at northern and >50 Ma at southern area.

  4. The preliminary results of new submarine caldera on the west of Kume-jima island, Central Ryukyu Arc, Japan

    NASA Astrophysics Data System (ADS)

    Harigane, Y.; Ishizuka, O.; Shimoda, G.; Sato, T.

    2014-12-01

    The Ryukyu Arc occurs between the islands of Kyushu and Taiwan with approximately 1200 km in the full length. This volcanic arc is caused by subduction of the Philippine Sea plate beneath the Eurasia Plate along the Ryukyu trench, and is composed of forearc islands, chains of arc volcanoes, and a back-arc rift called Okinawa Trough. The Ryukyu Arc is commonly divided into three segments (northern, central and southern) that bounded by the Tokara Strait and the Kerama Gap, respectively (e.g., Konishi 1965; Kato et al., 1982). Sato et al. (2014) mentioned that there is no active subaerial volcano in the southwest of Iotori-shima in the Central Ryukyu Arc whereas the Northern Ryukyu Arc (i.e., the Tokara Islands) has active frontal arc volcanoes. Therefore, the existence of volcanoes and volcanotectonic history of active volcanic front in the southwestern part of the Central Ryukyu Arc are still ambiguous. Detailed geophysical and geological survey was mainly conducted using R/V Kaiyou-maru No.7 during GK12 cruise operated by the Geological Survey of Japan/National Institute of Advanced Industrial Science and Technology, Japan. As a result, we have found a new submarine volcanic caldera on the west of Kume-jima island, where located the southwestern part of Central Ryukyu Arc. Here, we present (1) the bathymetrical feature of this new submarine caldera for the first time and (2) the microstructural and petrological observations of volcanic rocks (20 volcanic samples in 13 dredge sites) sampled from the small volcanic cones of this caldera volcano. The dredged samples from the caldera consist of mainly rhyolite pumice with minor andesites, Mn oxides-crust and hydrothermally altered rocks. Andesite has plagioclase, olivine and pyroxene phenocrysts. Key words: volcanic rock, caldera, arc volcanism, active volcanic front, Kume-jima island, Ryukyu Arc

  5. Historical and geological evidence of boulders deposited by tsunamis, southern Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Goto, Kazuhisa; Kawana, Toshio; Imamura, Fumihiko

    2010-09-01

    Sedimentary features and identification criteria of boulders deposited by tsunamis and storm waves are highly controversial because of the lack of detailed studies of boulders that are known to have been deposited by tsunami or storm waves. The coastal boulder fields of the Ryukyu Islands, Japan are one of the few places where comparisons can be made between the distribution and characteristics of boulders deposited by a known historical tsunami and storm waves. The 1771 Meiwa Tsunami struck the southern Ryukyu Islands (Miyako-Yaeyama Islands) and reliable historical documents describe run-up heights of up to 30 m. The displacement of specific boulders by the tsunami is also described in detail. Some of the islands away from the Miyako-Yaeyama Islands were unaffected by this tsunami, but they have been extensively affected by typhoon-generated storm waves. On these islands, the boulders were commonly deposited on the reef flat within 300 m of the reef edge as an exponentially fining landward deposit. This provides a useful indication of the transport limit for storm waves on the Ryukyu Islands. In the tsunami-affected islands, boulders of different types have been deposited both on the reef crest and along the shoreline. The reef crest boulders are identified as storm wave emplaced, whereas those along the shoreline are interpreted as tsunami boulders ("tsunami-ishi" in Japanese) because they are exceedingly heavy and are deposited well beyond (ca. 1.5 km from the reef edge) the transport limit for storm waves. Their 1771 Meiwa Tsunami origin is supported by 14C age results, although prior tsunami(s) may have deposited some of the boulders. Based on these results, we infer that the difference between the wave periods of tsunami and storm waves is crucial to differentiating tsunami boulders from other enigmatic boulder deposits around the world. Differences in wave period are reflected in differences between the spatial and clast size distributions of boulder deposits. The distribution and sedimentary characteristics of tsunami boulders therefore provide useful data for estimating possible tsunami sources. The boulders on the Ryukyu Islands are also useful for differentiating between tsunami and storm wave emplacement and for estimating their hydrodynamic properties.

  6. Two new dwarfgobies of the genus Eviota from the Ryukyu Islands, Japan (Teleostei: Gobiidae).

    PubMed

    Greenfield, David W; Suzuki, Toshiyuki; Shibukawa, Koichi

    2014-01-01

    Two species of dwarfgoby are described from the Ryukyu Islands, Japan. Eviota flebilis n. sp. belongs to cephalic sensory-pore system pattern 2 (lacking only IT pore), has a dorsal/anal fin-ray formula of 8/7, unbranched pectoral-fin rays, the 5th pelvic-fin ray 12.9% of the 4th, a distinctive narrow, red-orange line under the eye, and a dark vertical line at the caudal-fin base. Eviota specca n. sp. has a cephalic sensory-pore system pattern 1 (complete), has a dorsal/anal-fin formula of 8/8, the body heavily sprinkled with chromatophores, and a single dark spot on the upper pectoral-fin base. PMID:24871515

  7. Description of female pupa and larva of Ficalbia ichiromiyagii from Iriomote Island, Ryukyu Archipelago, Japan.

    PubMed

    Higa, Yukiko; Toma, Takako; Miyagi, Ichiro

    2012-12-01

    We describe and illustrate for the 1st time the pupa and larva of adult female Ficalbia ichiromiyagii based on specimens collected from a swamp forest in Otomi, Iriomote Island, Ryukyu Archipelago, Japan. The pupa has a trumpet that is 6.25 times its breadth at halfway, with a long meatal cleft line; setae 6-I, II considerably long, usually single or bifid; median caudal seta absent; and paddle edge serrated only on the outer apical half. The larva is characterized by dark pigmentation of the head and siphon, seta I-C elongate and spiniform, usually with a short lateral spine on the inner basal side and siphon with 1 pecten spine and conspicuous seta 1-S at the base. The immature stages were found only in undisturbed jungle swamps with dense vegetation. PMID:23393749

  8. Quisarctus yasumurai gen. et sp. nov. (Arthrotardigrada: Halechiniscidae)from a submarine cave, off Iejima, Ryukyu Islands, Japan.

    PubMed

    Fujimoto, Shinta

    2015-01-01

    Quisarctus yasumurai gen. et sp. nov. (Arthrotardigrada: Halechiniscidae) is described from the submarine cave 'Daidokutsu', off Iejima, Okinawa Islands, Ryukyu Islands, Japan. It is characterised by a cylindrical body, long primary clava and shorter lateral cirrus inserted on a common cirrophore, and simple digits of unequal lengths (without folds, peduncles, proximal pads, pretarsi, or wrinkles) that terminate in a sheathed, small, crescent-shaped claw with a minute calcar. Quisarctinae subfam. nov. is erected for this unique new genus. PMID:25947769

  9. Spatial and temporal patterns of seagrass habitat use by fishes at the Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Nakamura, Yohei; Tsuchiya, Makoto

    2008-01-01

    To investigate whether or not regional-temporal patterns of seagrass habitat use by fishes existed at the Ryukyu Islands (southern Japan), visual surveys were conducted in seagrass beds and adjacent coral reefs in northern, central, and southern Ryukyu Islands, in November 2004, and May, August, and November 2005, the northern region having less extensive seagrass beds compared with the central and southern regions. During the study period, the seagrass beds were utilized primarily by 31 species, the densities of some of the latter differing significantly among regions. With the exception of Apogonidae and Holocentridae, all species were diurnal and could be divided into 6 groups based on seagrass habitat use patterns; (1) permanent residents A (10 species, e.g. Stethojulis strigiventer), juveniles and adults living in seagrass beds as well as other habitats; (2) permanent residents B (5 species, e.g. Calotomus spinidens), juveniles and adults living only or mainly in seagrass beds; (3) seasonal residents A (4 species, e.g. Cheilodipterus quinquelineatus), juveniles living in seagrass beds as well as other habitats; (4) seasonal residents B (6 species, e.g. Lethrinus atkinsoni), juveniles living only or mainly in seagrass beds; (5) transients (5 species, e.g. Parupeneus indicus), occurring in seagrass beds in the course of foraging over a variety of habitats; and (6) casual species (1 species, Acanthurus blochii), occurring only occasionally in seagrass beds. Regarding temporal differences, juvenile densities in each group were high in May and August compared with November in each region, whereas adult densities did not differ drastically in each month. For regional differences, juvenile and adult densities of permanent residents A and B were higher in the southern and central regions than in the northern region. Moreover, some seasonal residents showed possible ontogenetic habitat shift from seagrass beds to coral reefs in each region. These results indicated that seagrass habitat use patterns by fishes changed temporally and regionally and there may be habitat connectivity between seagrass beds and coral reefs via ontogenetic migration in the Ryukyu Islands.

  10. Mechanism of early meteoric diagenesis in carbonate dune sands, Tarama Island, Ryukyu Islands, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Kumai, N.; Matsuda, H.

    2012-12-01

    Carbonate sediments are useful for the interpretation of depositional environments and environmental changes because their components and chemistry reflect depositional environments sensitively. However, primary records on their depositional environments are often modified by various types of early carbonate diagenesis immediately after their deposition. Longman (1980) pointed out that sedimentary textures and mineral compositions of carbonate sediments near a subaerial exposure surface are easily changed by dissolution and cementation associated with early meteoric diagenesis. Hudson (1977) also suggested that their primary stable carbon and oxygen isotopic compositions are altered by early meteoric diagenesis. In this way, the qualitative changes of carbonate sediments with early meteoric diagenesis are well known. On the other hand, the quantitative changes, time scale and detailed mechanisms of early meteoric diagenesis are not fully understood at present. To clarify the detailed mechanism of early meteoric diagenesis, the Upper Pleistocene carbonate dune sands in Tarama Island, the Ryukyu Islands, southwestern Japan, were analyzed. These sediments consist mainly of unconsolidated to weakly-consolidated carbonate sands, composed mainly of a variety of shallow marine bioclasts. Detailed petrographical observation and XRD and isotopic analyses were carried out. As a result of examinations of these carbonate sediments, low-Mg calcite (LMC), high-Mg calcite (HMC) and aragonite (ARG) contents of unconsolidated carbonate sands (UCS) are 20 to 47%, 0 to 44% and 33 to 54%, respectively. On the other hand, LMC, HMC and ARG contents of weakly-consolidated carbonate sands (WCS) are 64 to 95%, 0 to 18% and 5 to 18%, respectively. ?13C and ?18O values of UCS have narrow ranges of 0.51 to 1.70 and -1.87 to -1.46, respectively. On the other hand, ?13C and ?18O values of WCS have wide ranges of -4.67 to 0.62 and -4.82 to 2.92, respectively. The mineral and isotopic compositions of both sediments are obviously different from the primary values of recent shallow-marine carbonates. It is, therefore, pointed out that the diagenetic alteration occurs within about 90,000 years at least after the deposition. With the increase in LMC content by early meteoric diagenesis, ARG contents within both UCS and WCS decrease linearly, while HMC is hardly included within WCS. Further, although ?13C and ?18O values change gradually at the same rates with the increase in LMC content within UCS, both values change quickly and the change rate of ?13C value is larger than that of ?18O value within WCS. The petrographical observation shows that transformation within UCS and transformation and cementation within WCS is dominant. It is, therefore, pointed out that the difference of diagenetic process within UCS and WCS controls the change rates of the mineral and isotopic compositions. REFERENCES Hudson, J. D. (1977) Stable isotopes and limestone lithification. Jour. Geol. Soc. London, 133, 637-660. Longman, M. W. (1980) Carbonate diagenetic textures from nearsurface diagenetic environments. Bull. Amer. Assoc. Petrol. Geol.,64, 461-487.

  11. Two new dwarfgobies (Teleostei: Gobiidae) from the Ryukyu Islands, Japan: Eviota flavipinnata and Eviota rubrimaculata.

    PubMed

    Suzuki, Toshiyuki; Greenfield, David W; Motomura, Hiroyuki

    2015-01-01

    Two new species of Eviota from Yoron Island, the Ryukyu Islands, Japan, are described. Both species belong to the cephalic sensory-canal pore system pattern 2 (lacking only the H [IT] pore); have some pectoral-fin rays branched; have a dorsal/anal-fin formula of 9/8; no dark spot over the ural centrum; no prominent distinct dark spots on the pectoral-fin base; no postocular spots; and no strong dark spots on the caudal fin. The species share the most characters with E. afelei, E. bimaculata and E. punctulata, but differ from Eviota afelei and E. punctulata by having two versus three dark marks over the anal-fin base, and from Eviota bimaculata by lacking the two dark, prominent occipital spots present in that species. Both species differ from all other described species of Eviota in fresh coloration. Eviota flavipinnata has bright golden-yellow dorsal fins and an orange anal fin, and a fifth pelvic-fin ray that is 12% the length of the fourth ray. Eviota rubrimaculata has clear dorsal fins with red spots, large red spots on the body, and lacks the fifth pelvic-fin ray. PMID:26623818

  12. A new species of the palaemonid shrimp genus Palaemonella Dana, 1852 (Crustacea: Decapoda: Caridea) from Okinawa Island, Ryukyu Islands, Japan.

    PubMed

    Komai, Tomoyuki; Yamada, Yusuke

    2015-01-01

    The palaemonid shrimp genus Palaemonella Dana, 1852 is currently represented by 21 formally described species worldwide, of which 17 species are known from the Indo-West Pacific. In this study, a new species, P. okunoi, is described and illustrated on the basis of two ovigerous female specimens collected from coastal waters in Okinawa Island, Ryukyu Islands, Japan, at depths of 5-30 m. The new species closely resembles P. hachijo Okuno, 1999, but the shorter rostrum, more anteriorly located postrostral teeth on the carapace, the presence of a pair of submedian teeth on the fourth thoracic sternite and the less slender pereopods distinguish P. okunoi n. sp. from P. hachijo. The discovery of the present new species raises the number of Japanese species of Palaemonella to eight. An updated key to the Indo-West Pacific species of the genus is presented. PMID:26249444

  13. Island of Okinawa, Japan

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The island of Okinawa, (26.5N, 128.0E) largest of the Ryukyu Islands, Japan. The Ryukyu island group lies south of the main home islands of Japan in an arc towards the Chinese island Republic of Taiwan. As is typical throughout the Japanese home islands, intense urban development can be observed all over the island in this near vertical view.

  14. Indoapseudes bamberi sp. nov. (Crustacea: Tanaidacea: Pagurapseudidae: Hodometricinae) from Iriomote Island, Ryukyu Islands, southwestern Japan.

    PubMed

    Kakui, Keiichi; Naruse, Tohru

    2015-01-01

    We describe Indoapseudes bamberi sp. nov., based on a specimen from Funaura Bay, Iriomote Island, Japan. This species can be distinguished from its five congeners by having the combination of the antenna with a squama and pereopods 1 and 2 with one dorsal spine on the basis. We also determined part of the nucleotide sequence for the cytochrome c oxidase subunit I (COI) gene in I. bamberi, and present a key to Indoapseudes species. PMID:26250310

  15. New records of Pagurixus Melin, 1939 (Crustacea: Decapoda: Paguridae) from the Ryukyu Islands, southwestern Japan, with description of a new species.

    PubMed

    Osawa, Masayuki; Kawai, Takashi; Sakamaki, Takashi

    2013-01-01

    Seven hermit crab species of the pagurid genus Pagurixus Melin, 1939 are reported on the basis of material recently collected from the northern and central islands of the Ryukyu Islands, southwestern Japan. Four species are new to the hermit crab fauna of the Ryukyu Islands: P. acanthocarpus Komai & Okuno, 2009; P. fasciatus Komai & Myorin, 2005; P. formosus Komai, 2010; and P. tweediei (Forest, 1956). One species is described as new to science: P vicinus sp. nov. is closely similar to P. fasciatus in both morphology and coloration, but distinguished by the armature on the left cheliped and right second pereopod. Paguruxus carininanus Komai & Osawa, 2006 and P. pseliophorus Komai & Osawa, 2006, both previously known from the Ryukyu Islands, are here reported from new localities. PMID:26312347

  16. A new species of the pontoniine shrimp genus Eupontonia (Crustacea: Decapoda: Caridea: Palaemonidae) from the Ryukyu Islands, Japan.

    PubMed

    Komai, Tomoyuki; Minemizu, Ryo

    2014-01-01

    A third species of the pontoniine shrimp genus Eupontonia Bruce, 1971, E. gracilipes n. sp., is described and illustrated on the basis of a single female specimen collected from shallow water of Ishigaki Island, southern Ryukyu Islands, Japan. The new species is readily distinguished from the two congeneric species, E. noctalbata Bruce, 1971 and E. oahu Bruce, 2010, by a number of morphological characters, including the presence of a distinct postrostral median ridge and of the postrostral median tooth on the carapace. It is considered to be a free-living species. The generic diagnosis of Eupontonia is slightly emended to accommodate the present new species. A key in aid of identification of species of Eupontonia is provided. PMID:24872045

  17. Radiocarbon dating of Porites coral boulders cast ashore by paleo-tsunamis at southern Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Araoka, D.; Yokoyama, Y.; Suzuki, A.; Goto, K.; Kawana, T.; Miyagi, K.; Miyazawa, K.; Yoshimura, T.; Matsuzaki, H.; Kawahata, H.

    2010-12-01

    It is important for future disaster mitigation to evaluate the recurrence period and/or frequency of extreme geohazard events such as earthquakes, tsunamis and severe storms. We focus on Porites spp. coral boulders scattered both along the shore and on the reef at southern Ryukyu Islands, Japan. Our previous works confirmed that Porites boulders on Ishigaki Island were cast ashore by the 1771 Meiwa tsunami, which was one of the largest tsunami disasters in Japanese history, according to radiometric dating [Suzuki et al. 2008; Araoka et al. 2010], thus these fossil coral boulders have possibilities for recording paleo-tsunami events. We performed extensive field survey over Ryukyu Islands, and the biggest Porites colony boulder was identified at the eastern coast of Ishigaki Island, which were cast ashore by 1771 Meiwa tsunami according to multiple radiocarbon dating on the surface of the colony. We also found several Meiwa-tsunami-derived Porites corals on several Islands, according to radiocarbon dating of these boulders. These results could help to constrain the simulation models of the 1771 Meiwa tsunami [Imamura et al. 2008; Goto et al. 2010], and lead to solving the source fault location of 1771 Meiwa tsunami, which has still been controversial. Our latest results from several Islands at southern Ryukyus also suggest that Porites coral boulders cast ashore by not only 1771 Meiwa tsunami but also other various paleo-tsunamis. These results would lead to estimate the recurrence period and/or frequency of tsunami events in the region. Moreover, modern and fossil Porites corals have been used to reconstruct high-resolution records of oceanographic and climatic changes. By splicing paleoenvironmental data reconstructed from several coral boulders which were cast at various dates, it has a potential to reconstruct high-resolution paleoenvironment records for several centuries.

  18. Marine terraces caused by fast steady uplift and small coseismic uplift and the time-predictable model: Case of Kikai Island, Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Shikakura, Yosuke

    2014-10-01

    Kikai Island, a part of the Ryukyu Islands in southwest Japan, is rimmed by marine terraces. This island has been studied in detail because these marine terraces record the fastest crustal uplift in Japan. Geological studies of the raised Holocene reef have concluded that coseismic uplift has been generating marine terraces since 6.3 ka. Analysis of GPS data suggests that Kikai Island is steadily uplifted several mm/yr. To examine the discrepancy between geological and geodetic surveys, I numerically modeled nearshore processes and simulated the generation of marine terraces under two conditions: 1) large stepwise uplift and no steady uplift and 2) steady uplift and small stepwise uplift. As a result, the emergence time of the marine terraces is the same and the heights of the terrace cliffs are consistent with the time-predictable recurrence model for large earthquakes. This result shows the possibility of overestimate of magnitudes of the past earthquakes.

  19. Two new species of ghost shrimp assigned to the genus Cheramus Spence Bate, 1888 (Crustacea: Decapoda: Axiidea: Callianassidae) from the Ryukyu Islands, Japan.

    PubMed

    Komai, Tomoyuki; Maenosono, Tadafumi; Fujita, Yoshihisa

    2014-01-01

    Two new species of the callianassid ghost shrimp are described and illustrated on the basis of specimens from the Ryukyu Islands, Japan. These are provisionally assigned to the genus Cheramus Spence Bate, 1888, and appear closest to Callianassa acutirostella Sakai, 1988, also provisionally transferred to Cheramus herewith. These three species can be differentiated by characters of the telson, third maxilliped, chelipeds and uropod. The taxonomic status of Cheramus is briefly discussed. PMID:25543584

  20. Additional record of Rayllianassa amboinensis (de Man, 1888) from Japan, and description of a new species from Okinawa Island, Ryukyu Islands (Crustacea: Decapoda: Axiidea: Callianassidae).

    PubMed

    Komai, Tomoyuki; Fujita, Yoshihisa; Maenosono, Tadafumi

    2014-01-01

    Two species referred to the callianassid ghost shrimp genus Rayllianassa Komai & Tachikawa, 2008 are reported herewith. Additional locality records from Japan are provided for R. amboinensis (de Man, 1888), and the synonymy of Callianassa ngochoae Sakai, 1999 with R. amboinensis is discussed. It is shown that R. amboinensis is associated with sponges or alcyonacean soft corals, representing unusual habitats for callianassids. Rayllianassa rudisulcus n. sp. is described on the basis of a single ovigerous female from shallow soft sediment in Ohura Bay, Okinawa Island, Ryukyu Islands. The new species is distinguished from R. amboinensis by the absence of a dorsal oval on the carapace, the antennal peduncle being longer than the antennular peduncle, and the different shape of the third maxilliped. The status of Rayllianassa is also briefly discussed. PMID:25081469

  1. 16ch high-resolution seismic reflection surveys on the active fault of upper fore-arc slope off Okinawa Island, central Ryukyu Island Arc, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Arai, K.; Inoue, T.; Sato, T.; Tuzino, T.

    2010-12-01

    The Ryukyu Island Arc extends from Kyushu to Taiwan, a distance of 1,200 km, along the Ryukyu Trench where the Philippine Sea Plate is subducting beneath the Eurasian Plate. The Okinawa Trough, a back arc basin has formed behind the Ryukyu Island Arc in late Pliocene to early Pleistocene. The research cruises of GH08 (from 28th July to 29th August 2008) and GH09 (from 16th July to 17th August 2009) were carried out around Okinawa Island, which is located on the central Ryukyu Island Arc. More than 4,500 miles multi channel high-resolution seismic profiles were acquired during these two cruises by the GI-gun (355cu. inch) or the Cluster-gun (30+30 cu. inch) systems with 16ch digital streamer cable. Survey area in the southeast off Okinawa Island is located on the upper fore-arc slope. Seismic reflections of the upper fore-arc slope show a distinct reflector which may represent erosional unconformable surface. The distinct reflector had tilted southeastward and was overlain by the stratified sediments. No obvious deformation such as the fold and faults parallel to the Ryukyu Trench axis was found under the upper slope. In contrast, some active faults which were perpendicular to the Ryukyu Trench axis (NW-SE direction) were observed. The most conspicuous normal fault was found on north off Okinawa Island. The fault with 70-80dipping toward northeast has been active since the early Pleistocene inferred from seismic stratigraphy and calcareous nannofossil biochronology. The maximum displacement reaches to 0.7 s two way travel time in depth. An average of maximum vertical displace component of the normal fault may reach up to ten cm/1000 years. Seismic profiles indicate that the tilting of Ryukyu Island Arc forward to the Ryukyu Trench plays the important role of formation of the fault in a NW-SE direction.

  2. Differential timing of vertical-axis block rotations in the northern Ryukyu Arc: Paleomagnetic evidence from the Koshikijima Islands, Japan

    NASA Astrophysics Data System (ADS)

    Tonai, Satoshi; Suganuma, Yusuke; Ashi, Juichiro; Itaya, Tetsumaru; Oiwane, Hisashi; Kiyokawa, Shoichi

    2011-01-01

    Over 300 samples for paleomagnetic analysis and K-Ar dating were collected from 27 sites at NW-SE and NE-SW trending dike swarms (herein, NW dikes and NE dikes, respectively) in the Koshikijima Islands, northern Ryukyu Arc. The NW dikes are Middle Miocene in age and have directions (D = - 37.7 ?, I = 51.8 ?, ?95 = 9.6 ?, and ? = 40.8) that are deflected westward relative to the stable eastern Asian continent. Conversely, the NE dikes, of Late Miocene age, have directions (D = 16.1 ?, I = 57.7 ?, ?95 = 7.1 ?, and ? = 41.9) that show no such deflection. These differences are interpreted as indicating that the Koshikijima Islands underwent approximately 40 ? of counter-clockwise rotation during the Middle to Late Miocene. A synthesis of the paleomagnetic and structural data suggests a three-stage history of extensional deformation: (1) displacement upon normal faults (F 1 faults) without vertical-axis block rotation, (2) strike-slip reactivation of F 1 faults and oblique-normal displacement on NE-SW-trending faults (F 2 faults) with vertical-axis block rotation, and (3) oblique-normal displacement on F 2 faults without vertical-axis block rotation. Regional differences in the timing and amount of counter-clockwise vertical-axis block rotations indicate that the northern Ryukyu Arc rotated as several distinct rigid blocks.

  3. New records of two species of the coral reef shrimp genus Thor Kingsley, 1878 (Crustacea: Decapoda: Thoridae) from the Ryukyu Islands, Japan.

    PubMed

    Komai, Tomoyuki; Okuno, Junji; Minemizu, Ryo

    2015-01-01

    The caridean shrimp genus Thor Kingsley, 1878 (Thoridae) is currently represented by 14 species distributed in shallow tropical to subtropical waters in the Indo-Pacific, East Pacific and West Atlantic oceans. In this study, two species of the genus are reported on the basis of material from Okinawa and Kume islands in the Ryukyu Archipelago, southern Japan. Thor leptochelus (Xu & Li, 2015) n. comb., recently described from Xisha Islands, China and originally assigned to Thinora Bruce, 1997, is transferred to Thor. Relationship of the species to three congeneric species (T. cordelli Wicksten, 1996, T. spinipes Bruce, 1983 and T. spinosus Boone, 1935) is discussed. The second is T. marguitae Bruce, 1973, representing the rediscovery since the original description and new record for Japanese waters. The four specimens of T. leptochelus were all free-living, whereas the single specimen of T. marguitae was found to be associated with a solitary fungiid coral, as previously reported. PMID:26623904

  4. A new genus and new species of Paguridae (Crustacea: Decapoda: Anomura) from shallow subtidal waters in Okinawa Island, the Ryukyu Islands, Japan.

    PubMed

    Komai, Tomoyuki

    2015-01-01

    During a survey on decapod crustacean fauna of shallow coral reefs and nearby environments in Okinawa Island, Ryukyu Archipelago, Japan, four specimens of a small but distinctive undescribed species of pagurid hermit crab, which could not be referred to any known genus, were collected. The new taxon, Eutrichopagurus shirakawai n. gen., n. sp., is described and illustrated herein. The new genus is characterized by the possession of 11 pairs of deeply quadriserial phyllobranchiate gills, the third maxilliped with well-developed crista dentata and one or two accessory teeth on the ischium, the presence of unpaired left gonopore in the female, the absence of paired first pleopods in the female, and the telson with prominent tuft of setae on the lateral margin of the posterior lobes; the male is unknown at present. It appears close to Trichopagurus de Saint Laurent, 1968, but the deeply quadriserial gills immediately distinguish Eutrichopagurus from Trichopagurus. The new genus is also compared with other genera characterized by the possession of 11 pairs of quadriserial phyllobranchiate gills and the lack of paired first pleopods in females. PMID:25781092

  5. Evaluation of genetic introgression from domesticated pigs into the Ryukyu wild boar population on Iriomote Island in Japan.

    PubMed

    Murakami, K; Yoshikawa, S; Konishi, S; Ueno, Y; Watanabe, S; Mizoguchi, Y

    2014-08-01

    We evaluated genetic introgression from domesticated pigs into the Ryukyu wild boar (RWB) population on Iriomote Island based on their genetic structure and diversity. We used a combination of mitochondrial DNA D-loop region (596 bp) polymorphisms and 23 microsatellite markers. RWBs (n = 130) were collected from 18 locations on Iriomote Island and compared with 66 reference samples of European and Asian domestic pigs. We identified six distinct haplotypes, involving 22 single nucleotide polymorphisms (including one insertion) in the RWB population. The phylogenetic tree had two branches: the RWB group and domestic lineage. Fourteen of 130 RWBs (10.8%) belonged to the European domestic lineage, including 11 RWBs from the Panari Islands, northwest of Iriomote Main Island (IMI). The heterozygosity values, total number of alleles, number of effective alleles and polymorphism information content of the RWB groups were lower than those of the European domestic groups. The RWB population on IMI had a lower heterozygous deficiency index (FIS = 0.059) than did the other populations, which indicates that this population was more inbred. There was a large genetic distance (FST = 0.560) between RWBs on IMI and the Meishan populations. Structure analysis using the 23 microsatellite markers revealed that 16 RWBs had an admixture pattern between RWB and domesticated pig breeds. These results suggest that gene flow may have occurred from domestic pigs to RWBs and demonstrate that there was low genetic variation in the IMI population. PMID:24754898

  6. Spatial and Temporal Distribution of Water-Soluble Anions and Organic Carbons in Bulk Aerosols Collected at the Ryukyu Islands, Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Somada, Y.; Azechi, S.; Ijyu, M.; Nakaema, F.; Handa, D.; Oshiro, Y.; Miyagi, Y.; Arakaki, T.; Tanahara, A.; Furukawa, M.

    2011-12-01

    Atmospheric aerosols pose health risks to humans and change global climate. Ryukyu Islands in Japan are mainly covered with maritime air mass in summer and continental air mass for the rest of the seasons. Thus, it is possible to estimate the origins of chemical components, in particular transboundary air pollutants from East Asia. Ryukyu Islands are one of the best locations for monitoring the changes in Asia's atmosphere. This study tried to elucidate the spatial and temporal distribution of water-soluble anions and organic carbons, and chemical changes during the transportation processes. Aerosol samples were collected at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS, Sep. 2005 - Dec. 2010), Kume Island (KM, ca. 100 km from Naha), and Minami-Daitou Island (MD, ca. 350 km from Naha) from June 2008 to June 2010 on quartz filters by using identical high-volume air samplers. The sample filters were exchanged every week. The concentrations of water-soluble anions (Cl-,Br-,NO3-,NO2-,SO42-) and water-soluble organic carbon (WSOC) were determined by using ion chromatography and total organic carbon analyzer, respectively. And, concentrations of non-sea-salt SO(nss-SO42-) were calculated based on the concentrations of Na+. For the samples collected at CHAAMS, seawater component accounted for on average 565% of total aerosol mass. Monthly mean concentrations of nss-SO42- showed distinctive difference among the sampling sites (KM>CHAAMS>MD) during Jan. to May, suggesting that distance from Asian continent affected on its behavior. Yearly average concentrations of NO3- and nss-SO42- showed +42% and +16% increase, respectively between 2005 and 2011. Annual rate of NO3- increase was much faster than that of nss-SO42-, probably reflecting changes in lifestyles in Asian continent.

  7. Peltogasterella sensuru n. sp. (Crustacea: Cirripedia: Rhizocephala) from off Okinawa Island (Ryukyu Archipelago, Japan) with remarks on its single brood externae.

    PubMed

    Yoshida, Ryuta; Hirose, Mamiko; Hirose, Euichi

    2015-09-01

    Peltogasterella sensuru n. sp. infests Pagurixus hermit crabs inhabiting rocky shores off Okinawa Island (Ryukyu Archipelago, Japan). This species is clearly distinguishable from Peltogasterella gracilis (Boschma, 1927): the stalk emerges from the middle part of the externa in the present species and P. sulcata (Lilljeborg, 1859), while the stalk in P. gracilis emerges from the posterior end of the externae. The new species differs from P. sulcata based on the morphology of the mantle aperture. Peltogasterella sensuru n. sp. repeatedly produces single brood externae that have not been previously observed in species belonging to the suborder Kentrogonida Delage, 1884. We also determined partial sequences of the COI gene and 16S rRNA gene of the new species for use as molecular markers for species identification. PMID:26249520

  8. The genus Hatschekia (Copepoda: Hatschekiidae) from pufferfishes (Tetraodontiformes: Tetraodontidae) off the Ryukyu Islands, Japan, with descriptions of four new species and a redescription of H. pholas.

    PubMed

    Uyeno, Daisuke; Nagasawa, Kazuya

    2013-02-01

    Four new species of the genus Hatschekia Poche, 1902 (Copepoda: Siphonostomatoida: Hatschekiidae) are described based on female specimens collected from pufferfishes (Tetraodontiformes: Tetraodontidae) caught in coastal waters off the Ryukyu Islands, Japan: H. longiabdominalis sp. n. on Arothron hispidus (Linnaeus), H. geniculata sp. n. on A. hispidus (type host) and A. stellatus (Bloch et Schneider), H. ellipsocorpa sp. n. on A. mappa (Lesson), and H. boonah sp. n. on A. nigropunctatus (Bloch et Schneider) (type host) and A. meleagris (Schneider). Hatschekia longiabdominalis sp. n. and H. boonah sp. n. differ from all other congeners by sharing an unusual, projected abdomen and a fusiform trunk with posterior lobes; these two species are differentiated from each other by the shape of the dorsal chitinous frame on the cephalothorax. Hatschekia geniculata sp. n. can be distinguished by the combination of the following morphological characters: a rhomboidal cephalothorax with a pair of lateral conical protrusions, a cylindrical trunk with posterior lobes and a bent abdomen with a dorsal protrusion. Hatschekia ellipsocorpa sp. n. resembles H. pholas (Wilson, 1906) but can be distinguished from the latter by the possession of one distal and one inner setae on the terminal endopodal segment of legs 1 and 2. Hatschekiapholas is also redescribed based on female specimens from the tetraodontid A. stellatus. At present, 44 nominal species of the genus have been reported from Japan, including four new species described in this paper; 38 of them have been described originally from Japan. PMID:23539953

  9. A new cave-dwelling species of the alpheid shrimp genus Salmoneus Holthuis, 1955 (Crustacea: Decapoda: Caridea) from the Ryukyu Islands, southern Japan.

    PubMed

    Komai, Tomoyuki; Yamada, Yusuke; Yunokawa, Kyo

    2015-01-01

    A new species of the alpheid shrimp genus Salmoneus Holthuis, 1955, S. antricola n. sp., is described and illustrated on the basis of a single ovigerous specimen from an aphotic marine cave at a depth of 12 m, off Ie Island, Okinawa Islands, the Ryukyu Archipelago. It is morphologically similar to five species presently referred to the S. jarli (Holthuis, 1951) species group: S. erasimorum Dworschak, Anker & Abed-Navandi, 2000, S. komaii Anker, 2011, S. paulayi Anker, 2011, S. poupini Anker, 2011, and S. sketi Fransen, 1991. However, the minor cheliped with an elongate carpus being subequal to the chela, the lack of teeth on the cutting edges of the minor cheliped fingers, and the very slender third to fifth pereopods are obvious characters that distinguish S. antricola n. sp. from all of its presumed close relatives. Among the 50 species of Salmoneus, only S. sketi and the present new species are known from marine caves. PMID:26624318

  10. Two new species of Dracoderes (Kinorhyncha: Dracoderidae) from the Ryukyu Islands, Japan, with a molecular phylogeny of the genus.

    PubMed

    Yamasaki, Hiroshi

    2015-01-01

    Two new species, Dracoderes snufkini sp. nov. and Dracoderes toyoshioae sp. nov., are described from Okinawa, southern Japan. Diagnostic characters of D. snufkini include: lateroventral tubules on segments 2 and 5; a thick, plump middorsal spine on segments 2 and 9; thick plump paradorsal spines on segments 3-8, alternately laterally displaced; and a ventral primary pectinate fringe on segment 1, with long, wide conspicuous tips. Diagnostic characters of Dracoderes toyoshioae include: a middorsal subcuticular structure on segment 1; paradorsal subcuticular structures on segments 2-9, alternately laterally displaced; paradorsal acicular spines arising from subcuticular structures, at least on segment 5; ventrolateral acicular spines on segment 1; lateral accessory tubules on segment 2; lateral accessory subcuticular structures on segments 2-7; lateroventral tubules on segment 5; and lateroventral subcuticular structures on segments 2-10. Molecular phylogenetic analyses based on 18S rRNA, 28S rRNA and mitochondrial COI sequences indicate that D. abei and D. nidhug are more closely related to one another than either is to D. snufkini or D. toyoshioae. PMID:26249958

  11. Divergence and long-distance overseas dispersals of island populations of the Ryukyu five-lined skink, Plestiodon marginatus (Scincidae: Squamata), in the Ryukyu Archipelago, Japan, as revealed by mitochondrial DNA phylogeography.

    PubMed

    Kurita, Kazuki; Hikida, Tsutomu

    2014-04-01

    We assessed the historical biogeography of the Ryukyu five-lined skink, Plestiodon marginatus, and related species (P. stimpsonii and P. elegans). Our specific aims were to reveal the origin, tim- ing, and route of the colonization to three volcanic islands in the northern Tokara Group of the northern Ryukyus: Kuchinoshima, Nakanoshima, and Suwanosejima. We conducted phylogenetic analyses and divergence time estimation using a partial sequence of the mitochondrial cytochrome b gene for P. marginatus collected from across its whole range (the northern and central Ryukyus), and for P. stimpsonii (from the Yaeyama Group of the southern Ryukyus) and P. elegans (from Taiwan). Our results suggest three major clades (A, B, and C). Clades A and B consist of P. marginatus, excluding the Kuchinoshima population, and Clade C consisted of the Kuchinoshima population, P. stimpsonii, and P. elegans. These clades are estimated to have diverged during the Late Miocene to the Late Pliocene. Among the three examined northern Tokara populations, the Kuchinoshima population was shown to be a sister group of P. stimpsonii. The two other populations from Nakanoshima and Suwanosejima Islands were closely related to P. marginatus from the northern part of the Okinawa Group and that from Kodakarajima Island in the southern Tokara Group, respectively. These populations are estimated to have diverged from their respective related spe cies in various ages of the Early to Late Pleistocene, suggesting that they colonized the islands by independent overseas dispersals of approximately 50-850 km via the Kuroshio Current. Taxonomic implications for P. marginatus are also discussed. PMID:24694220

  12. A new subtidal species of the genus Petrolisthes Stimpson, 1858 (Crustacea: Decapoda: Porcellanidae) from Okinawa, with an account of species of the genus known from the Ryukyu Islands, southwestern Japan.

    PubMed

    Osawa, Masayuki; Uyeno, Daisuke

    2013-01-01

    A new porcellanid crab, Petrolisthes uruma sp. nov., is described based on a single specimen collected from Okinawajima Island in the Ryukyus, southwestern Japan. The unique holotype was collected from a subtidal depth of 10 m, though vast majority of the genus occur in intertidal to shallow subtidal zone. The new species is morphologically closest to P. noluccensis (De Man, 1888), but is distinguished by the weaker striation on the carapace, the proportionally longer carpus of the cheliped, the number of the anterior marginal teeth of the carpus of the cheliped, and the meri of the second and third pereopods each with a much stronger spine at the lateroventral distal angle. A brief note on species of Petrolisthes presently known from the Ryukyu Islands is given. PMID:26438943

  13. Angiostrongylus cantonensis (Nematoda: Metastrongylidae) in the Ryukyu Islands tree rat (Diplothrix legata).

    PubMed

    Okano, Tsukasa; Haga, Atsushi; Mizuno, Eriko; Onuma, Manabu; Nakaya, Yumiko; Nagamine, Takashi

    2014-04-01

    Angiostrongylus cantonensis is a zoonotic nematode with rodents serving as natural definitive hosts. We report A. cantonensis in the Ryukyu Islands tree rat (Diplothrix legata, Thomas, 1906), a native endangered species in Japan. Adult and larvae of A. cantonensis were macroscopically, histologically, and genetically detected in three tree rats collected between August 2011 and January 2012 in the Yambaru area of Okinawa Prefecture, Japan. Pathologic observations of the lungs of rats showed that infection may be lethal. We also conducted a retrospective genetic survey of helminths parasitic in lung in cryopreserved lung samples of Ryukyu Islands tree rats collected between 2007 and 2011 in the Yambaru area and found A. cantonensis DNA in one of 29 samples, which was collected in December 2010. PMID:24499332

  14. Multiple colonizations lead to cryptic biodiversity in an island ecosystem: comparative phylogeography of anchialine shrimp species in the Ryukyu Archipelago, Japan.

    PubMed

    Weese, David A; Fujita, Yoshihisa; Santos, Scott R

    2013-09-01

    Archipelagos of the Indo-West Pacific are considered to be among the richest in the world in biodiversity, and phylogeographic studies generally support either the center of origin or the center of accumulation hypothesis to explain this pattern. To differentiate between these competing hypotheses for organisms from the Indo-West Pacific anchialine ecosystem, defined as coastal bodies of mixohaline water fluctuating with the tides but having no direct oceanic connections, we investigated the genetic variation, population structure, and evolutionary history of three caridean shrimp species (Antecaridina lauensis, Halocaridinides trigonophthalma, and Metabetaeus minutus) in the Ryukyu Archipelago, Japan. We used two mitochondrial genes--cytochrome c oxidase subunit I (COI) and large ribosomal subunit (16S-rDNA)--complemented with genetic examination of available specimens from the same or closely related species from the Indian and Pacific Oceans. In the Ryukyus, each species encompassed 2-3 divergent (9.52%-19.2% COI p-distance) lineages, each having significant population structure and varying geographic distributions. Phylogenetically, the A. lauensis and M. minutus lineages in the Ryukyus were more closely related to ones from outside the archipelago than to one another. These results, when interpreted in the context of Pacific oceanographic currents and geologic history of the Ryukyus, imply multiple colonizations of the archipelago by the three species, consistent with the center of accumulation hypothesis. While this study contributes toward understanding the biodiversity, ecology, and evolution of organisms in the Ryukyus and the Indo-West Pacific, it also has potential utility in establishing conservation strategies for anchialine fauna of the Pacific Basin in general. PMID:24088794

  15. Tsunami hazard mitigation in tourism in the tropical and subtropical coastal areas: a case study in the Ryukyu Islands, southwest of Japan

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.

    2006-12-01

    Life and economy (including tourism) in tropical and subtropical coastal areas, such as Okinawa Prefecture (Ryukyu) are highly relying on the sea. The sea has both "gentle" side to give people healing and "dangerous" side to kill people. If we are going to utilise the sea for marine tourism such as constructing resort facilities on the oceanfront, we should know all of the sea, including the both sides of the sea: especially the nature of tsunamis. And also we islanders should issue accurate information about the sea towards outsiders, especially tourists visiting the island. We have already learned a lesson about this issue from the Sumatra tsunami in 2004. However, measures against the tsunami disaster by marine tourism industry are still inadequate in these areas. The goal of tsunami hazard mitigation for those engaged in tourism industry in tropical and subtropical coastal areas should be as follows. (1) Preparedness against tsunamis: "Be aware of the characteristics of tsunamis." "Prepare tsunamis when you feel an earthquake." "Prepare tsunamis when an earthquake takes place somewhere in the world." (2) Maintenance of an exact tsunami hazard map under quantitative analyses of the characteristics of tsunamis: "Flooding areas by tsunami attacks are dependent not only on altitude but also on amplification and inundation due to the seafloor topography near the coast and the onland topographic relief." "Tsunami damage happens repeatedly." (3) Maintenance of a tsunami disaster prevention manual and training after the manual: "Who should do what in case of tsunamis?" "How should the resort hotel employees lead the guests to the safe place?" Such a policy for disaster prevention is discussed in the class of the general education of "Ocean Sciences" in University of the Ryukyus (UR) and summer school for high school students. The students (most of them are from Okinawa Prefecture) consider, discuss and make reports about what to do in case of tsunamis as an islander. Especially, students of Department of Tourism Sciences (DTS) are keen on the discussion and make excellent reports/proposals. Here, the author would also like to introduce some of them in the presentation.

  16. Halechiniscidae (Heterotardigrada, Arthrotardigrada) of Oura Bay, Okinawajima, Ryukyu Islands, with descriptions of three new species

    PubMed Central

    Fujimoto, Shinta

    2015-01-01

    Abstract Marine tardigrades of the family Halechiniscidae (Heterotardigrada: Arthrotardigrada) are reported from Oura Bay, Okinawajima, one of the Ryukyu Islands, Japan, including Dipodarctus sp., Florarctus wunai sp. n., Halechiniscus churakaagii sp. n., Halechiniscus yanakaagii sp. n. and Styraconyx sp. The attributes distinguishing Florarctus wunai sp. n. from its congeners is a combination of two characters, the smooth dorsal cuticle and two small projections of the caudal alae caestus. Halechiniscus churakaagii sp. n. is differentiated from its congeners by the combination of two characters, the robust cephalic cirrophores and the scapular processes with flat oval tips, while Halechiniscus yanakaagii sp. n. can be identified by the laterally protruded arched double processes with acute tips situated dorsally at the level of leg I. A list of marine tardigrades reported from the Ryukyu Islands is provided. PMID:25755627

  17. Halechiniscidae (Heterotardigrada, Arthrotardigrada) of Oura Bay, Okinawajima, Ryukyu Islands, with descriptions of three new species.

    PubMed

    Fujimoto, Shinta

    2015-01-01

    Marine tardigrades of the family Halechiniscidae (Heterotardigrada: Arthrotardigrada) are reported from Oura Bay, Okinawajima, one of the Ryukyu Islands, Japan, including Dipodarctus sp., Florarctuswunai sp. n., Halechiniscuschurakaagii sp. n., Halechiniscusyanakaagii sp. n. and Styraconyx sp. The attributes distinguishing Florarctuswunai sp. n. from its congeners is a combination of two characters, the smooth dorsal cuticle and two small projections of the caudal alae caestus. Halechiniscuschurakaagii sp. n. is differentiated from its congeners by the combination of two characters, the robust cephalic cirrophores and the scapular processes with flat oval tips, while Halechiniscusyanakaagii sp. n. can be identified by the laterally protruded arched double processes with acute tips situated dorsally at the level of leg I. A list of marine tardigrades reported from the Ryukyu Islands is provided. PMID:25755627

  18. Commensal Leucothoidae (Crustacea, Amphipoda) of the Ryukyu Archipelago, Japan. Part I: ascidian-dwellers

    PubMed Central

    White, Kristine N.; Reimer, James Davis

    2012-01-01

    Abstract Commensal leucothoid amphipods have been collected from the branchial chambers of their ascidian hosts throughout the Ryukyu Archipelago, Japan. Seven new species are described in two genera with valuable location data and host records. An identification key to ascidian-dwelling Leucothoidae of the Ryukyu Archipelago is provided. PMID:22303128

  19. Reproductive traits of the Ryukyu long-furred rat (Diplothrix legata) on Okinawa-jima Island

    PubMed Central

    OKANO, Tsukasa; NAKATA, Katsuhi; NAKAYA, Yumiko; NAGAMINE, Takashi; ONUMA, Manabu

    2015-01-01

    The Ryukyu long-furred rat, Diplothrix legata, is a large rodent distributed only on Amami-ohshima Island, Tokuno-shima Island and Okinawa-jima Island, Japan. This animal is endangered as a result of deforestation, predation by introduced carnivores and mortality caused by vehicles. We performed theriogenological examinations of 32 male and 25 female Ryukyu long-furred rats carcasses collected from wild populations on northern Okinawa-jima Island from December 2005 to September 2013. Adult males had remarkably large preputial glands. Seminiferous diameter of adult was significantly small (136 28 m, n=8) from April to August. Numerous spermatozoa were observed from September through February, and seminiferous diameter was significantly large (216 27 m, n=12) during this time in adults; testes length changed in a similar pattern. These findings indicate that the mating season may occur from September through February. Size (body length) at sexual maturity was estimated to be >560 mm in both sexes. From observation of corpora lutea and placental scars, litter size was estimated to range from 2 to 12 (average=6, n=4). These results provide fundamental knowledge that will be beneficial for in situ and ex situ conservation of this rare species. PMID:25649850

  20. Enhancement of Eddy Heat Transport due to the Anticyclonic Submesoscale Eddies around Ryukyu Islands near Kuroshio in East China Sea

    NASA Astrophysics Data System (ADS)

    Kamidaira, Y.; Uchiyama, Y.; Mitarai, S.; Miyazawa, Y.

    2014-12-01

    A synoptic, regional downscaling experiment of Kuroshio off Ryukyu Islands, Japan, exhibits the evident predominance of submesoscale anticyclonic eddies over cyclones in the narrow strip between Kuroshio and the islands (Uchiyama et al., 2013). In the present study, the mechanism and impacts of the anticyclone dominance are examined with a detailed oceanic downscaling model in a double nested ROMS configuration at the horizontal resolution of 3km (ROMS-L1) and 1km (ROMS-L2), forced by the assimilative JCOPE2 oceanic reanalysis and the JMA GPV-MSM atmospheric hindcast. The model results are extensively validated against a variety of data including shipboard hydrography and satellite altimetry and temperature data to show a good agreement. An alternative ROMS-L2 experiment is also conducted to examine topographic effects on the anticyclones around the Ryukyu Islands by eliminating all the island topography above z > -1000 m, while the other configurations are held unchanged. If the islands are removed, the submesoscale negative vortices on the eastern side of the Kuroshio become much weaker than those of the original case with the islands. The experiment clearly demonstrates that dominance of the negative vorticity between Kuroshio and the Ryukyu Islands is caused by enhanced lateral shear due to the concentrated Kuroshio mean current associated with appropriate formation of the eastern branch, the northward-drifting Ryuku Current, and resultant eddy shedding in the narrow channel between the continental shelf of the East China Sea and the Okinawan ridge. A diagnostic eddy heat flux analysis illustrates that the submesoscale anticyclonic eddies play a crucial role in enhancing the eddy heat transport and thus the lateral mixing between Kuroshio and the islands as compared to those in the coarser resolution models (L1 and JCOPE2), resulting in promoting regional larval and material transport from Kuroshio to the islands.

  1. Situation Report--Hong Kong, Malawi, Pakistan, Panama, Philippines, Ryukyu Islands (Okinawa), Sabah, Sarawak.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    Data relating to population and family planning in eight foreign countries are presented in these situation reports. Countries included are Hong Kong, Malawi, Pakistan, Panama, Philippines, Ryukyu Islands (Okinawa), Sabah, and Sarawak. Information is provided where appropriate and available, under two topics, general background and family planning

  2. Variations of short-term slow slip events along the Nankai Trough to the Ryukyu Trench, southwest Japan

    NASA Astrophysics Data System (ADS)

    Nishimura, T.

    2013-12-01

    ETSs (Episodic Tremor and Slips) occur at a depth of 30-40 km on the plate interface of the subducting Philippine Sea plate along the Nankai trough, southwest Japan (e.g., Obara, 2010). Low-frequency tremors along the Nankai Trough suddenly disappeared southwest of the Bungo Channel between Shikoku and Kyushu, which is a junction between the southwest Honshu arc along the Nankai Trough and the Ryukyu arc along the Ryukyu Trench. Any short-term SSEs (slow slip events) have never been reported southwest of the Bungo Chanel, though Mw~7 long-term SSEs repeated in the Bungo Channel every ~6 years (e.g., Ozawa et al., 2013). Here, we apply a SSE detection method using continuous GNSS data (Nishimura et al., 2013) to find out SSEs in a region along the Nankai Trough to the Ryukyu Trench. We also compare the detected SSEs with epicenters of low-frequency tremors, very-low-frequency earthquakes (VLFEs), and regular earthquakes and discuss along-trench variations on short-term SSE characteristics. Daily coordinates of ~800 GEONET GNSS stations in southwest Japan were used to detect displacements caused by short-term SSEs. We divided a whole region into three regions for spatial filtering to reduce a noise of GNSS data. We fitted a step function with a linear trend to spatial-filtered daily coordinates to detect significant displacements in a direction opposite to the relative plate motion between the Philippine Sea plate and southwest Japan. If Akaike's information criterion expressing data fits exceeds a threshold, three-dimensional displacements were inverted to estimate a rectangular fault along the plate interface. We found more than 200 probable short-term SSEs in the region over 16 years. In western Shikoku, we detected 49 Mw ~6.0 ETSs. SSEs with a similar magnitude are found at the same depth range in northeast Kyushu without tremors although the number of detected SSEs is only 10. In the further southwest region, we found several shallow SSEs at a depth of 10-40 km. Some of them accompany regular earthquakes with the maximum magnitude of ~5. A shallow Mw~6.4 SSE was detected east off southern Kyushu around January 27, 2010. VLFEs were coincidentally activated in a shallow adjacent region near the trench. Although a resolving power of SSEs along the Ryukyu arc is limited due to sparse GNSS stations, we found series of repeated SSEs near Kikaijima and Okinawa Islands in a depth of 10-30 km. A cumulative slip of the estimated SSEs over 16 years suggests along-trench variations of SSEs distribution. A band of large (> 10 cm) slip at a depth of 30-40 km stretches from Shikoku to northeast Kyushu which is ~50 km southwest of the western limit of the tremors. However, the cumulative slip in the Bungo channel and northeast Kyushu is one-third of that in western Shikoku. No shallow slip of SSEs was found from Shikoku to northeast Kyushu. Shallow separated patches of SSEs exist in a region southwest of southern Kyushu along the Ryukyu trench. The variation of SSEs may be related with that of large megathrust earthquakes, that is, repeated Mw>8 and few earthquakes along the Nankai Trough and the Ryukyu Trench, respectively.

  3. Tsunami recurrence inferred from soil deposits on Ishigaki island along the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Ando, M.; Shishikura, M.; Tu, Y.; Nakamura, M.; Arashiro, Y.

    2012-12-01

    The Ryukyu trench at the northwestern boundary of the Philippine Sea plate had no known thrust earthquakes Mw>8.0 in approximately the last 250 years. Due to this lack of associated large thrust earthquakes, an accepted common idea is that Ryukyu trench is aseismic. However, in 1771 a large tsunami struck Ishigaki islands and Miyako islands with the run-up height of up to 30-35 m. The 1771 source is suggested to be a tsunami (slow) earthquake with Mw=8.0 that occurred near the trench axis. Furthermore, very-low frequency earthquakes at shallow depths near the trench axis and slow-slip events at depths of 30km have been identified in the western Ryukyu trench. These findings suggest that the Ryukyu subduction zone has the potential to generate large thrust earthquakes. If the slip deficit has accumulated at the interface, the accumulated slip of more than 30 m would cause a large earthquake and a huge tsunami. Considering the abovementioned findings, estimate for the size and recurrence intervals of past tsunamis along the western Ryukyu trench was undertaken through excavation surveys of the Holocene deposits in Ishigaki and Miyako islands. The excavated sites are located on the lower Holocene marine terraces and implemented using a geoslicer or backhoes at 10 sites on November 2011 and June 2012. Stratigraphic and foraminiferal assemblages of tsunami sediment were compared with shallow beach sand to gain information on sediment source and depositional style. Based on the excavations, two tsunami layers were identified at 5 sites and provided estimates of sedimentation ages. The results obtained from stratigaraphic and foraminiferal analyses together with C14 dates of tsunami sediment indicated an event between 9-11th C. on Ishigaki and another or the same event occurred between 11th C. and 1771 on Miyako island. Consequently, if the 1771 earthquake is the only event that had occurred in the last 300 years over the 120 km, large earthquakes would potentially occur in the future along the rest of segments along the Western Ryukyu boundary.

  4. A revision of the genus Amamiclytus Ohbayashi from Taiwan and the Ryukyu Islands (Coleoptera, Cerambycidae)

    PubMed Central

    Niisato, Tatsuya; Han, Chang-do

    2011-01-01

    Abstract The clytine genus Amamiclytus Ohbayashi, 1964, from Taiwan and the Ryukyu Islands is revised. Seven species and one subspecies are recognized as follows: Amamiclytus nobuoi nobuoi Ohbayashi, 1964, (Amami Islands); Amamiclytus nobuoi akusekianus Niisato, 2005, (Tokara Islands); Amamiclytus subnitidus Holzschuh, 1984, (Taiwan); Amamiclytus setiger sp. n. (Taiwan), Amamiclytus nubilus sp. n. (Taiwan), Amamiclytus juni sp. n. (Taiwan), Amamiclytus yulongi sp. n. (Taiwan) and Amamiclytus hirtipes (Matsushita, 1940), comb. n. (Taiwan). All of them are described or redescribed and a key to species is presented. The generic features of Amamiclytus, including male and female genitalia from these taxa, are presented. The systematic position of Amamiclytus within the tribe Clytini is discussed. PMID:21998509

  5. Genome-wide SNP analysis reveals population structure and demographic history of the ryukyu islanders in the southern part of the Japanese archipelago.

    PubMed

    Sato, Takehiro; Nakagome, Shigeki; Watanabe, Chiaki; Yamaguchi, Kyoko; Kawaguchi, Akira; Koganebuchi, Kae; Haneji, Kuniaki; Yamaguchi, Tetsutaro; Hanihara, Tsunehiko; Yamamoto, Ken; Ishida, Hajime; Mano, Shuhei; Kimura, Ryosuke; Oota, Hiroki

    2014-11-01

    The Ryukyu Islands are located to the southwest of the Japanese archipelago. Archaeological evidence has revealed the existence of prehistoric cultural differentiation between the northern Ryukyu islands of Amami and Okinawa, and the southern Ryukyu islands of Miyako and Yaeyama. To examine a genetic subdivision in the Ryukyu Islands, we conducted genome-wide single nucleotide polymorphism typing of inhabitants from the Okinawa Islands, the Miyako Islands, and the Yaeyama Islands. Principal component and cluster analyses revealed genetic differentiation among the island groups, especially between Okinawa and Miyako. No genetic affinity was observed between aboriginal Taiwanese and any of the Ryukyu populations. The genetic differentiation observed between the inhabitants of the Okinawa Islands and the Miyako Islands is likely to have arisen due to genetic drift rather than admixture with people from neighboring regions. Based on the observed genetic differences, the divergence time between the inhabitants of Okinawa and Miyako islands was dated to the Holocene. These findings suggest that the Pleistocene inhabitants, whose bones have been found on the southern Ryukyu Islands, did not make a major genetic contribution, if any, to the present-day inhabitants of the southern Ryukyu Islands. PMID:25086001

  6. Potential speciation of morphotypes in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago, Japan

    NASA Astrophysics Data System (ADS)

    Hirose, M.; Yokobori, S.; Hirose, E.

    2009-03-01

    Four morphotypes are recognized in the photosymbiotic ascidian Didemnum molle in the Ryukyu Archipelago: three color morphs (white, dark gray, and brown) of small-type colonies and one large-type colony (white with gray patches). The genetic variation among these four morphotypes was investigated by constructing phylogenetic trees based on a 401-bp fragment of the cytochrome oxidase subunit I (COI) gene of 29 specimens collected from five islands (Okinawajima, Sesokojima, Ikeijima, Kumejima, and Ishigakijima). The results support the monophyly of the genus Didemnum and that of the four morphotypes of D. molle. Moreover, the phylogenetic trees discriminated four clades corresponding to each morphotype. The geographic differences of the sequences were much smaller than the differences among the morphotypes, suggesting that the four morphotypes in D. molle are discrete sibling species.

  7. Tsunami preparedness at the resort facilities along the coast of the Ryukyu Islands - their actions against the 27 February 2010 Okinawan and Chilean tsunami warning

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.

    2010-12-01

    The economy (including tourism) in tropical and subtropical coastal areas, such as Okinawa Prefecture (Ryukyu) is highly relying on the sea. The sea has both gentle side to give people healing and fierce side to kill people. If we are going to utilise the sea for marine tourism such as constructing resort facilities on the oceanfront, we should know the whole nature of the sea, Tsunami is the typical case of the fierce side of the sea. We have already learned a lesson about this issue from the Sumatra tsunami in 2004. Early morning (5:31 am Japanese Standard Time = JST) on 27 February 2010, a M6.9 earthquake occurred near the coast of Okinawa Ryukyu Island Japan, and just after that Japanese Meteorological Agency (JMA) issued a tsunami warning along the coastal area of Okinawa Prefecture. About one hour later the tsunami warning was cancelled. The CMT solution of this earthquake was found to be strike-slip type with NE-SW P-axis. Therefore this did not induce a tsunami. However, in the afternoon on the same day (JST) a M8.6 earthquake occurred off the coast of Chile and soon after that a tsunami warning issued along the Pacific coastal area including Japan and Ryukyu Islands. Indeed maximum 1m tsunami hit the eastern coast of Okinawa Island on 28th February (Nakamura, 2010, personal communication). The author conducted a survey about the actions against the both tsunami after the 27 February tsunami warming to the major resort hotels along the coast of the Ryukyu Islands. A questionnaire was sent to about 20 hotels and 6 hotels replied to the questionnaire. Most of these hotels reported the regular training against tsunami attack, preparation of a disaster prevention manual, close communication with the local fire station authority, evacuation procedure towards high stories of the hotel building etc. It was winter season when the tsunami took place. However, if that were summer season, the other problem such as how they make the people enjoying on the beach evacuate as quickly as possible might be considered. The author will show the details of the answer to the questionnaire and would like to discuss the best way of the tsunami preparedness at the waterfront resort facilities through this presentation.

  8. Situation Report--Antigua, Dominican Republic, Grenada, Guatemala, Honduras, Philippines, Ryukyu Islands, St. Lucia, and St. Vincent.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    Data relating to population and family planning in nine foreign countries are presented in these situation reports. Countries included are: Antigua, Dominican Republic, Grenada, Guatemala, Honduras, Philippines, Ryukyu Islands (Okinawa), St. Lucia, and St. Vincent. Information is provided under two topics, general background and family planning

  9. Descriptions of two azooxanthellate Palythoa species (Subclass Hexacorallia, Order Zoantharia) from the Ryukyu Archipelago, southern Japan.

    PubMed

    Irei, Yuka; Sinniger, Frederic; Reimer, James Davis

    2015-01-01

    Two new species of zoantharians (Hexacorallia, Zoantharia, Sphenopidae), Palythoamizigama sp. n. and Palythoaumbrosa sp. n., are described from the Ryukyu Archipelago, southern Japan. Unlike almost all other known Palythoa spp., both species are azooxanthellate and inhabit low-light environments such as floors or sides of caves, crevasses, or hollows of shallow coral reefs. The two species were initially considered to be the same species from their similar habitat environments and highly similar morphological features. However, phylogenetic analyses of nuclear internal transcribed spacer (ITS) ribosomal DNA, mitochondrial 16S ribosomal DNA, and cytochrome oxidase subunit I (COI) sequences revealed that these two species have a genetically distant relationship within the genus Palythoa. Morphological characteristics, including polyp size, tentacle number, external/internal coloration, and types and sizes of cnidae were examined in this study. As a result, only tentacle coloration was found to be useful for the morphological distinction between the two species. Palythoamizigama possesses white tentacles with black horizontal stripes while Palythoaumbrosa possesses white tentacles without any stripe patterns. Considering their distant phylogenetic relationship, it can be assumed that their unique yet similar morphological and ecological characteristics developed independently in each species as an example of parallel evolution. PMID:25685008

  10. Descriptions of two azooxanthellate Palythoa species (Subclass Hexacorallia, Order Zoantharia) from the Ryukyu Archipelago, southern Japan

    PubMed Central

    Irei, Yuka; Sinniger, Frederic; Reimer, James Davis

    2015-01-01

    Abstract Two new species of zoantharians (Hexacorallia, Zoantharia, Sphenopidae), Palythoa mizigama sp. n. and Palythoa umbrosa sp. n., are described from the Ryukyu Archipelago, southern Japan. Unlike almost all other known Palythoa spp., both species are azooxanthellate and inhabit low-light environments such as floors or sides of caves, crevasses, or hollows of shallow coral reefs. The two species were initially considered to be the same species from their similar habitat environments and highly similar morphological features. However, phylogenetic analyses of nuclear internal transcribed spacer (ITS) ribosomal DNA, mitochondrial 16S ribosomal DNA, and cytochrome oxidase subunit I (COI) sequences revealed that these two species have a genetically distant relationship within the genus Palythoa. Morphological characteristics, including polyp size, tentacle number, external/internal coloration, and types and sizes of cnidae were examined in this study. As a result, only tentacle coloration was found to be useful for the morphological distinction between the two species. Palythoa mizigama possesses white tentacles with black horizontal stripes while Palythoa umbrosa possesses white tentacles without any stripe patterns. Considering their distant phylogenetic relationship, it can be assumed that their unique yet similar morphological and ecological characteristics developed independently in each species as an example of parallel evolution. PMID:25685008

  11. [An exploration of the training of medical talents in China for Ryukyu islands based on the Liu qiu bai wen (One Hundred Question of Ryukyu)].

    PubMed

    He, Lanping

    2014-09-01

    Ryukyu sent more than 20 batches of returned students to China for studying during the Ming and Qing Dynasties, many of whom were studying medicine. Liu qiu bai wen (One Hundred Question of Ryukyu) was the record of discussion between Cao Cunxin, a famous doctor of the Qing Dynasty, and the oversea disciples of L Fengyi from Ryukyu. However, it was not only a medical book, but also served as an important witness on overseas dissemination of TCM, and the fresh case of Chinese training medical talented persons for Ryukyu. Training Ryukyu medical students in the Qing Dynasty was good for the expansion of Chinese medicine in the Ryukyu, and promoted the development and social progress of the Ryukyu medicine and health, made a significant contribution to maintain the friendly relationship between the two countries. PMID:25579213

  12. The current system east of the Ryukyu Islands as revealed by a global ocean reanalysis

    NASA Astrophysics Data System (ADS)

    Thoppil, Prasad G.; Metzger, E. Joseph; Hurlburt, Harley E.; Smedstad, Ole Martin; Ichikawa, Hiroshi

    2016-02-01

    The structure and variability of the Ryukyu Current System (RCS), which forms the western boundary current along the eastern slope of the Ryukyu Islands, are studied using results from a 32-layer, 1/12.5° global HYbrid Coordinate Ocean Model (HYCOM) and Navy Coupled Ocean Data Assimilation (NCODA) reanalysis for the period 1993-2012. It is confirmed that the reanalysis realistically reproduces salient features of the observed currents at three sections southeast of Miyakojima, Okinawa and Amami-Ohshima. The mean velocity sections show well-developed subsurface velocity maxima between 700 and 900 m. The current core southeast of Amami-Ohshima shows year-to-year variations with cyclonic (anticyclonic) circulation east of Amami-Ohshima generating weak (strong) velocity cores. Interaction of the RCS with an anticyclonic eddy often produces a two-core velocity structure, with a surface core in the upper 300 m and a deeper core near 700-900 m. The horizontal structure of the RCS at 15 m depth shows a well-developed northeastward current northeast of Okinawa, which is partly fed by the southwestward extension of the anticyclonic recirculation gyre. The RCS forms a continuous northeastward current from Miyakojima to Amami-Ohshima below 500 m with shoreward intensification. The circulation at 2000 m shows a seasonal flow reversal, which is northeastward from December to June and southwestward from August to October with July and November being the transition months. The volume transports across these three sections have respective mean values of 0.6, 6.2 and 12.4 Sv (1 Sv ≡ 106 m3 s-1) and standard deviations of 10.2, 7.1 and 11.3 Sv. They have dominant seasonal variations with the maximum in winter and spring and the minimum in summer. The interannual variation of the transport anomaly, which co-varies with the RCS core, results from westward propagating mesoscale eddies arriving from the Pacific interior.

  13. Detailed bathymetry and magnetic anomaly in the Central Ryukyu Arc, Japan: implications for a westward shift of the volcanic front after approximately 2.1 Ma

    NASA Astrophysics Data System (ADS)

    Sato, Taichi; Oda, Hirokuni; Ishizuka, Osamu; Arai, Kohsaku

    2014-12-01

    Detailed bathymetry and magnetic anomalies in the southern part of the Central Ryukyu Arc reveal recent volcanic structures in a southwestward extension of the active volcanic front of the Ryukyu Arc. A line of bathymetric highs running subparallel to this recent volcanic front was observed approximately 20 km to the east. A set of small, sharply defined magnetic anomalies extends southward from this line of bathymetric highs to the islands Kume-jima and Aguni-jima, suggesting the former existence of an ancient volcanic front. The ages of volcanic rocks from these islands indicate that magmatic activity along the ancient volcanic front continued until at least approximately 2.1 Ma. The presence of magnetic anomalies between the two volcanic fronts suggests that the volcanic front has moved gradually westward. This shift can be explained by the termination of asthenospheric upwelling and/or the rapid retreat of the Ryukyu Trench after its change in subduction direction.

  14. Detailed bathymetry and magnetic anomaly inthe Central Ryukyu Arc, Japan: implications for a westward shift of the volcanic front after ~2.1 Ma

    NASA Astrophysics Data System (ADS)

    Sato, T.; Oda, H.; Ishizuka, O.; Arai, K.

    2014-12-01

    Detailed bathymetry and magnetic anomalies in the southern part of the Central Ryukyu Arc reveal recent volcanic structures in a southwestward extension of the active volcanic front of the Ryukyu Arc. A line of bathymetric highs running subparallel to this recent volcanic front was observed ~20 km to the east. A set of small, sharply defined magnetic anomalies extends southward from this line of bathymetric highs to the islands Kume-jima and Aguni-jima, suggesting the former existence of an ancient volcanic front. The ages of volcanic rocks from these islands indicate that magmatic activity along the ancient volcanic front continued until at least ~2.1 Ma. The presence of magnetic anomalies between the two volcanic fronts suggests that the volcanic front has moved gradually westward. This shift can be explained by the termination of asthenospheric upwelling and/or the rapid retreat of the Ryukyu Trench after its change in subduction direction.

  15. Two new species of Asellota (Crustacea, Isopoda) from coral reefs on Iriomote Island, Okinawa, Japan.

    PubMed

    Shimomura, Michitaka; Naruse, Tohru

    2015-01-01

    Pleurocope iriomotensis sp. n. and Prethura tuberculata sp. n. are described from Iriomote Island, Ryukyu Archipelago, southern Japan. These are the first records of Pleurocope from the Pacific and of Prethura from the Asian Pacific coast. Pleurocope iriomotensis differs from its congeners in having lateral spine-like processes on pereonite 4 and coxal plates of pereonite 7. Prethura tuberculata can be distinguished from its single congener in having a lateral short projection of protopod of pleopod 2. PMID:26448712

  16. Two new species of Asellota (Crustacea, Isopoda) from coral reefs on Iriomote Island, Okinawa, Japan

    PubMed Central

    Shimomura, Michitaka; Naruse, Tohru

    2015-01-01

    Abstract Pleurocope iriomotensis sp. n. and Prethura tuberculata sp. n. are described from Iriomote Island, Ryukyu Archipelago, southern Japan. These are the first records of Pleurocope from the Pacific and of Prethura from the Asian Pacific coast. Pleurocope iriomotensis differs from its congeners in having lateral spine-like processes on pereonite 4 and coxal plates of pereonite 7. Prethura tuberculata can be distinguished from its single congener in having a lateral short projection of protopod of pleopod 2. PMID:26448712

  17. A new genus and species of hatschekiid copepod (Siphonostomatoida) from groupers (Actinopterygii: Serranidae) collected off the Ryukyu Archipelago, Japan.

    PubMed

    Uyeno, Daisuke

    2013-01-01

    A new genus and species of copepod, Mihbaicola sakamakii n. g., n. sp., belonging to the siphonostomatoid family Hatschekiidae, is described based on the females collected from inside the tissue of the branchiostegal membrane in three species of the groupers, Epinephelus fasciatus (Forsskl) (type-host), E. merra Bloch and Cephalopholis leopardus (Lacpde), collected off Okinawa-jima Island and Iriomote-jima Island, Ryukyu Archipelago, North Pacific Ocean. The new genus can be distinguished from other hatschekiid genera by a combination of the following characters in the female: the head is composed of the cephalosome and the pedigerous somite; the cephalothorax is expanded into a pair of posteroventral lobes carrying leg 1; legs 1 and 2 are biramous and composed of the protopod and both rami are 2-segmented; leg 3 is absent; and leg 4 is represented by a rounded lobe with a chitinous pointed apical process. PMID:23263944

  18. American Dissertations on Foreign Education: A Bibliography with Abstracts. Volume XVII. Pacific: American Samoa, Fiji, Guam, Papua New Guinea, Ryukyu Islands, Solomon Islands, Tonga, Trust Territory of the Pacific Islands (Micronesia), Tubuai (French Polynesia), Western Samoa.

    ERIC Educational Resources Information Center

    Parker, Franklin, Ed.; Parker, Betty June, Ed.

    The editors attempt to examine and abstract all locatable doctoral dissertations completed in the United States, Canada, and some European countries that pertain to the Pacific area. Specifically, these dissertations deal with American Samoa, Fiji, Guam, Papua New Guinea, Ryukyu Islands, Solomon Islands, Tonga, Trust Territory of the Pacific

  19. Catastrophic impact of typhoon waves on coral communities in the Ryukyu Islands under global warming

    NASA Astrophysics Data System (ADS)

    Hongo, Chuki; Kawamata, Hideki; Goto, Kazuhisa

    2012-06-01

    Typhoon-generated storm waves generally cause mechanical damage to coral communities on present-day reefs, and the magnitude and extent of damage is predicted to increase in the near future as a result of global warming. Therefore, a comprehensive understanding of potential future scenarios of reef ecosystems is of prime interest. This study assesses the current status of coral communities on Ibaruma reef, Ryukyu Islands, on the basis of field observations, engineering and fluid dynamic models, and calculations of wave motion, and predicts the potential effects of a super-extreme typhoon (incident wave height,H = 20 m; wave period, T = 20 s) on the reef. On the present-day reef, massive corals occur in shallow lagoons and tabular corals occur from the reef crest to the reef slope. The observed distribution of corals, which is frequently attacked by moderate (H = 10 m, T = 10 s) and extreme (H = 10 m, T = 15 s) typhoons, is consistent with the predictions of engineering models. Moreover, this study indicates that if a super-extreme typhoon attacks the reef in the near future, massive corals will survive in the shallow lagoons but tabular corals on the reef crest and reef slope will be severely impacted. The findings imply that super-extreme typhoons will cause a loss of species diversity, as the tabular corals are important reef builders and are critical to the maintenance of reef ecosystems. Consequently, reef restoration is a key approach to maintaining reef ecosystems in the wake of super-extreme typhoons.

  20. Morphological and genetic diversity of Briareum (Anthozoa: Octocorallia) from the Ryukyu Archipelago, Japan.

    PubMed

    Miyazaki, Yu; Reimer, James Davis

    2014-10-01

    The primary problem hindering the study of octocorals is the disordered situation regarding their taxonomy, chiefly caused by insufficient knowledge of valid morphological taxonomic characters. Briareum is an octocoral genus found in the Atlantic and Pacific in shallow tropical and subtropical waters, and occurs in both encrusting and branching colony forms. Their simple morphology and morphological plasticity have hindered taxonomic understanding of this genus. In this study three morphologically distinct types (= type-1, -2, and -3) of Briareum from the Ryukyu Archipelago and their genetic diversity were examined. Colony, anthostele morphology, and sclerite length were examined for each type. Four molecular markers (mitochondrial cytochrome c oxidase subunit 1, mitochondrial mismatch repair gene, nuclear 18S ribosomal DNA, internal transcribed spacer 2 (ITS2)) were used to evaluate molecular phylogenetic status of these variations. Although one morphological type ("deep" small colonies, = type-3) showed small differences in nuclear ITS2 sequences compared to the other two types, the remaining types had identical sequences for all molecular markers examined. The results suggest extremely low genetic diversity despite highly variable morphology of Briareum species in Okinawa. Nevertheless, considering the distribution patterns and discontinuous morphology of type-3 compared to the other two morphotypes, genetic isolation of type-3 is plausible. In Briareum, small variances in nuclear ITS2 sequences of type-3 may have much more importance than in molecular phylogenies of other octocorals. Further phylogenetic investigations and comparison with Briareum specimens from other regions are necessary to conclusively taxonomically identify the three types. PMID:25284389

  1. Distribution of marine organisms and its geological significance in the modern reef complex of the Ryukyu Islands

    NASA Astrophysics Data System (ADS)

    Iryu, Yasufumi; Nakamori, Toru; Matsuda, Shinya; Abe, Osamu

    1995-11-01

    Extensive investigations of biota in the reef complex around the Ryukyu Islands have revealed ecologic specificity of many benthic organisms and have shown that characteristic assemblages are found in each of the topographic zones and sub-areas. The moat is divisible into a nearshore seagrass bed and an offshore sand bottom. Both inner reef flat and outer reef flat are characterized by abundant occurrences of hermatypic corals and nonarticulated coralline algae. However, the former is dominated by branching and foliaceous forms of corals and various, large, fleshy, erect forms of algae, whereas the latter is dominated by encrusting and tabular forms of corals, lacking these algae. Corals and coralline algae are not present on the reef crest, which is covered by rubble and gravel, where algal turf and Sargassum are spreading. Encrusting and tabular forms of corals flourish on the shallower part of the reef slope, with high coverage, while, with increasing depth, the coverage decreases and the dominating coral forms change, with hemispherical and encrusting forms on the middle part of reef slope, and foliaceous and encrusting forms on the deeper part of reef slope. Nonarticulated coralline algae are distributed throughout the reef slope. The composition of coral and coralline algal assemblages changes dramatically with increasing depth. Foraminiferal-algal nodules, rhodoliths, are the most abundant constituent on the island shelf, commonly with Cycloclypeus carpenteri. There are likely to be two types of shelves in tropical to subtropical regions: nutrient-rich Halimeda-dominant and nutrient-poor rhodolith-dominant. Sediments abundant in bryozoan skeletons occur occasionally on the shelf.

  2. The radiolarian evidence for the accretion of the Fu-saki Formation with the inferred oceanic plate stratigraphy: A case of weakly-metamorphosed accretionary complex in Ishigaki Jima, southern Ryukyu Arc, Japan

    NASA Astrophysics Data System (ADS)

    Nakae, Satoshi

    2013-09-01

    The island of Ishigaki Jima, located in the western part of the southern Ryukyu Arc, Japan, is underlain by a basement comprising the Tumuru and Fu-saki formations. The former is a pelitic glaucophane schist with a metamorphic age of 220-190 Ma, and the latter is a weakly metamorphosed accretionary complex, composed mainly of chert, mudstone and sandstone with minor amounts of limestone and mafic rocks. The Fu-saki Formation was weakly metamorphosed at ?140 Ma. Latest Carboniferous-Early Jurassic microfossils have been obtained from the limestones, cherts and siliceous mudstones of this formation, but no fossils have been collected from the phyllitic mudstones. The radiolarian fauna of the phyllitic mudstones described herein indicates a late Pliensbachian-early Toarcian (Early Jurassic) age. This result, when combined with existing data, enables the reconstruction of an oceanic plate stratigraphy, showing a succession of (in ascending order) Upper Carboniferous-Triassic cherts, Sinemurian-lower Pliensbachian siliceous mudstones and upper Pliensbachian-lower Toarcian phyllitic mudstones and sandstones. The radiolarians from the phyllitic mudstones are important in constraining the timing of the accretion of the Fu-saki Formation to the base of the Tumuru Formation.

  3. Description of a new genus and a new species of gaeticine crab (Crustacea: Brachyura: Varunidae) from the Ryukyu Islands, and a review of Acmaeopleura Stimpson, 1858, and Sestrostoma Davie & N.K. Ng, 2007.

    PubMed

    Naruse, Tohru

    2015-01-01

    Acmaeopleura parvula Stimpson, 1858, the type species of the varunid Acmaeopleura Stimpson, 1858, is redescribed, and a neotype is designated. Examination of all three species of the gaeticine Sestrostoma Davie & N.K. Ng, 2007, revealed that, although the diagnostic characters of Sestrostoma proposed by the previous study are variable and mostly overlap with those of Acmaeopleura, they can still be distinguished from each other by the characters of the carapace, the thoracic sternite 2, the third maxillipeds, and the ambulatory legs. The subfamilial position of Acmaeopleura was assessed by comparing it with all gaeticine genera. Gaetice Gistel, 1848, the type genus of the subfamily, has a very characteristic structure of the third maxilliped and the anterior sternal plate, which are partially shared with Gopkittisak Naruse & Clark, 2009, Brankocleistostoma tev?i?, 2011, Sestrostoma and Acmaeopleura in different combinations. The generic diagnostic characters of these four genera are unique among Varunidae and they are tentatively placed in Gaeticinae. A new genus and new species, which is allied to Sestrostoma but clearly distinguishable from all varunine genera, is described from Iriomote Island, Ryukyu Islands, Japan. PMID:25781740

  4. Distant Mt. Fuji, Island of Honshu Japan

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This distant view of Mt. Fuji, on the main home island of Honshu, Japan (34.0N, 139.0E) was taken from about 450 miles to the south. Evan at that great distance, the majestic and inspiring Mt. Fuji is still plainly visible and easily recognized as a world renowned symbol of Japan. The snow capped extinct volcano lies just a few miles south of Tokyo.

  5. Interplate coupling along the central Ryukyu Trench inferred from GPS/acoustic seafloor geodetic observation

    NASA Astrophysics Data System (ADS)

    Nakamura, M.; Tadokoro, K.; Okuda, T.; Ando, M.; Watanabe, T.; Sugimoto, S.; Miyata, K.; Matsumoto, T.; Furukawa, M.

    2010-12-01

    The Ryukyu trench is a major convergent plate boundary where the Philippine Sea plate is subducting at a rate of about 8 cm/yr. Large earthquakes have not been reported along the Ryukyu subduction for the last 300 years. Because the rate of release of seismic moment in the Ryukyu Trench over the last 80 years is 5% in consideration of the plate convergence rate, interseismic coupling in the trench is assumed to be weak.The GPS measurements by Japan Geographical Survey Institute also show the southward motion (2.5 cm/yr) of Ryukyu arc relative to the Amurian plate, which is due to extensional rifting of Okinawa Trough. Backslip by the interplate coupling between the subducting Philippine Sea plate and the overriding Eurasian plate cannot have been detected in the GPS network along the Ryukyu Islands. We have started the GPS/acoustic seafloor observation to detect the inter-plate coupling in the central Ryukyu trench. For this measurement, we used a system capable of performing two main tasks: precise acoustic ranging between a ship station (observation vessel) and seafloor transponders, and kinematic GPS positioning of observation vessels. The seafloor reference point was set at about 33 km landward from the axis of the Ryukyu trench (southeast of Okinawa Island). A set of three acoustic transponders has been installed on the seafloor, at a depth of about 2900m. The transponders are placed to form a triangular. Five campaign observations were carried out for the period from January 2008 to November 2009. Each epoch consists of three observation days. The coordinates of the seafloor benchmark were calculated using the least-squares technique (Ikuta et al., 2008); this technique minimizes the square sum of acoustic travel-time residuals. The RMS of travel time residuals for each campaign analysis is about 70 micro-seconds. The result shows that the benchmark moved to northwest direction for two years at a rate of 4 cm/yr relative to the Amurian plate. Then we estimated the length and width of interplate coupling area using observed movement of the benchmark. The movements of the GPS stations on the Ryukyu Islands and the benchmark are described as the combination of the block rotation of the Ryukyu arc (Nakamura, 2004) and the displacement by the backslip in the coupled area. The results show that the estimated width of the interplate coupling area is 40-50 km from the Ryukyu trench. The results also show that the length of the coupled area is over 40 km. Since the calculated displacements are not sensitive to the change in the length of the coupled area, the accurate length is uncertain. These suggest that the interplate coupling occurs up-dip of the seismogenic zone in the Ryukyu subduction zone. The tsunami earthquake (M8.1) occurred near the south Ryukyu Trench in 1771. This suggests the interplate coupling near the Trench would be the cause of the tsunami earthquakes.

  6. A Crustal Structure Study of the Southern Ryukyu Subduction Zone by Using the Aftershock Data

    NASA Astrophysics Data System (ADS)

    Cho, Y.; Lin, J.; Lee, C.

    2011-12-01

    The region along the Ryukyu subduction zone is known as a tsunami disaster zone. The biggest tsunami (85 m) of Japan history was recorded in the Ishigaki Island, Ryukyu, in 1771. The paleo-tsunami events show that it has a frequency of about 150 years. This thread makes the Ryukyu subduction zone as a concerned field for the earthquake studies. However, due to the long distance from the east coast of Taiwan, this is an area out of the effective earthquake detection zone from the Central Weather Bureau network. A main shock of M = 6.9 occurred near the Ishigaki Island in 2009 August 17. After this event, we quickly deployed the OBS and found many aftershocks with the magnitude greater than 5.0. The main shock was 240 km, NE direction from the Hualien city, Taiwan. If a tsunami occurred, it took only less than 15 minutes to arrive the coast. From the recorded data, we picked the P- and S-wave using the 1-D module (iasp91). There were 1500 recorded events during those time range, and most of the earthquakes were located around the Nanao Basin. Based on this, we study the southern Ryukyu subduction zone structure by using the results from focal mechanism solution. From the earthquake relocation it shows that two main groups of aftershocks. They tend in northwest - southeast with a left-lateral strike-slip fault. The left-lateral strike-slip fault is the main structures that link with the splay faults at the southern Ryukyu Trench. The stability and extension of the splay faults are one of the major concerns for the occurrence of mega earthquake. More than 500-km long of the splay fault, such as that in the Indonesia, Chile and Japan subduction zones, has attacked by mega earthquakes in the recent years. The second group of those aftershocks was located in the Gagua Ridge near the Ryukyu Trench. This group may represent the ridge structure relate to the Taitung canyon fault. The front of Ryukyu Trench was being as a locked subduction zone where it is easily to accumulate the earthquake stress. Because of these two earthquake groups are out of range of Taiwan Central Weather Bureau network and lack of information, it is worthwhile to focus our attentions on it.

  7. Activity of Small Repeating Earthquakes along Izu-Bonin and Ryukyu Trenches

    NASA Astrophysics Data System (ADS)

    Hibino, K.; Matsuzawa, T.; Uchida, N.; Nakamura, W.; Matsushima, T.

    2014-12-01

    There are several subduction systems near the Japanese islands. The 2011 Mw9.0 Tohoku-oki megathrust earthquake occurred at the NE Japan (Tohoku) subduction zone. We have revealed a complementary relation between the slip areas for huge earthquakes and small repeating earthquakes (REs) in Tohoku. Investigations of REs in these subduction zones and the comparison with Tohoku area are important for revealing generation mechanism of megathrust earthquakes. Our target areas are Izu-Bonin and Ryukyu subduction zones, which appear to generate no large interplate earthquake. To investigate coupling of plate boundary in these regions, we estimated spatial distribution of slip rate by using REs. We use seismograms from the High Sensitivity Seismograph Network (Hi-net), Full Range Seismograph Network of Japan (F-net), and permanent seismic stations of Japan Meteorological Agency (JMA), Tohoku University, University of Tokyo, and Kagoshima University from 8 May 2003 (Izu-Bonin) and 14 July 2005 (Ryukyu) to 31 December 2012 to detect REs along the two trenches, by using similarity of seismograms. We mainly follow the procedure adopted in Uchida and Matsuzawa (2013) that studied REs in Tohoku area to compare our results with the REs in Tohoku. We find that the RE distribution along the Ryukyu trench shows two bands parallel to the trench axis. This feature is similar to the pattern in Tohoku where relatively large earthquakes occur between the bands. Along the Izu-Bonin trench, on the other hand, we find much fewer REs than in Tohoku or Ryukyu subduction zones and only one along-trench RE band, which corresponds to the area where the subducting Pacific plate contacts with the crust of the Philippine Sea plate. We also estimate average slip rate and coupling coefficient by using an empirical relationship between seismic moment and slip for REs (Nadeau and Johnson, 1998) and relative plate motion model. As a result, we find interplate slip rate in the deeper band is higher than shallower one along the Ryukyu trench suggesting larger locking along the shallower band. This feature is also similar to the pattern in the NE Japan. Our results indicate that the Ryukyu subduction zone is very similar to the NE Japan subduction zone, while the Izu-Bonin subduction zone appears to be different from the other two zones according to the RE analyses.

  8. Submerged karst landforms observed by multibeam bathymetric survey in Nagura Bay, Ishigaki Island, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Kan, Hironobu; Urata, Kensaku; Nagao, Masayuki; Hori, Nobuyuki; Fujita, Kazuhiko; Yokoyama, Yusuke; Nakashima, Yosuke; Ohashi, Tomoya; Goto, Kazuhisa; Suzuki, Atsushi

    2015-01-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the southern Ryukyu Islands, Japan. The coastal seafloor at depths shallower than ~ 130 m has been subjected to repeated and alternating subaerial erosion and sedimentation during periods of Quaternary sea-level lowstands. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 2.7 km) and visualized the high-resolution bathymetric results over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. Although these submerged karst landforms are covered by thick postglacial reef and reef sediments, their shapes and sizes are distinct from those associated with coral reef geomorphology. The submerged landscape of Nagura Bay likely formed during multiple glacial and interglacial periods. According to our bathymetric results and the aerial photographs of the coastal area, this submerged karst landscape appears to have developed throughout Nagura Bay (i.e., over an area of approximately 6 5 km) and represents the largest submerged karst in Japan.

  9. Two new species in the Echinoderes coulli group (Echinoderidae, Cyclorhagida, Kinorhyncha) from the Ryukyu Islands, Japan

    PubMed Central

    Yamasaki, Hiroshi; Fujimoto, Shinta

    2014-01-01

    Abstract Two new species belonging to the Echinoderes coulli group are described with their external morphologies and sequences of nuclear 18S rRNA and 28S rRNA genes, and mitochondrial COI gene. The first species, Echinoderes komatsui sp. n., is characterized by absence of acicular spines, and presence of lateroventral tubules on segments 5 and 8, laterodorsal tubules on segment 10, inverted triangle or wide oval shaped large sieve plates, lateral terminal accessory spines in female, and short tips of ventral pectinate fringe on segment 10. The second species, Echinoderes hwiizaa sp. n., is characterized by absence of acicular spines, and presence of lateroventral tubules on segments 5 and 79, midlateral tubules on segment 8, laterodorsal tubules on segment 10, large narrow oval shaped sieve plates on segment 9, and thick, short and blunt lateral terminal spines about 1015% of trunk length. The diagnostic characters and key to species of E. coulli group are provided as well. PMID:24624018

  10. Two new species in the Echinoderes coulli group (Echinoderidae, Cyclorhagida, Kinorhyncha) from the Ryukyu Islands, Japan.

    PubMed

    Yamasaki, Hiroshi; Fujimoto, Shinta

    2014-01-01

    Two new species belonging to the Echinoderes coulli group are described with their external morphologies and sequences of nuclear 18S rRNA and 28S rRNA genes, and mitochondrial COI gene. The first species, Echinoderes komatsui sp. n., is characterized by absence of acicular spines, and presence of lateroventral tubules on segments 5 and 8, laterodorsal tubules on segment 10, inverted triangle or wide oval shaped large sieve plates, lateral terminal accessory spines in female, and short tips of ventral pectinate fringe on segment 10. The second species, Echinoderes hwiizaa sp. n., is characterized by absence of acicular spines, and presence of lateroventral tubules on segments 5 and 7-9, midlateral tubules on segment 8, laterodorsal tubules on segment 10, large narrow oval shaped sieve plates on segment 9, and thick, short and blunt lateral terminal spines about 10-15% of trunk length. The diagnostic characters and key to species of E. coulli group are provided as well. PMID:24624018

  11. Photosymbiotic ascidians from Pari Island (Thousand Islands, Indonesia).

    PubMed

    Hirose, Euichi; Iskandar, Budhi Hascaryo; Wardiatno, Yusli

    2014-01-01

    Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo-West Pacific coral reefs. PMID:25061385

  12. Submerged Humid Tropical Karst Landforms Observed By High-Resolution Multibeam Survey in Nagura Bay, Ishigaki Island, Southwestern Japan

    NASA Astrophysics Data System (ADS)

    Kan, H.; Urata, K.; Nagao, M.; Hori, N.; Fujita, K.; Yokoyama, Y.; Nakashima, Y.; Ohashi, T.; Goto, K.; Suzuki, A.

    2014-12-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the South Ryukyu Islands, Japan. This is the first description of submerged humid tropical karst using multibeam bathymetry. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results with a grid size of 1 m over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. We assume that Nagura Bay was a large karst basin in which older limestone remained submerged, thus preventing corrosion and the accumulation of reef sediments during periods of submersion, whereas the limestone outcropping on land was corroded during multiple interglacial and glacial periods. Based on our bathymetric result together with aerial photographs of the coastal area, we conclude that the submerged karst landscape has likely developed throughout the whole of Nagura Bay, covering an area of ~6 × 5 km. Accordingly, this area hosts the largest submerged karst in Japan. We also observed abundant coral communities during our SCUBA observations. The present marine conditions of Nagura Bay are characterized by low energy (calm sea) and low irradiance owing to the terrestrial influence. Such conditions have been emphasized by the presence of large undulating landforms, which cause decreases in wave intensity and irradiance with depth. These characteristics have acted to establish unique conditions compared to other coral reef areas in the Ryukyu Islands. It may play an important role in supporting the regional coral reef ecosystem.

  13. Elucidation of denitrification mechanism in karstic Ryukyu limestone aquifer

    NASA Astrophysics Data System (ADS)

    Hijikawa, K.

    2014-12-01

    Nitrate (NO3-) concentrations in public water supplies have risen above acceptable levels in many areas of the world including Japan, largely as a result of contamination by human and animal waste and overuse of fertilizers. A previous study has characterized nitrate concentrations in groundwater in this area is a higher than the upper value (44mgL-1) of environmental quality criteria on one hands. On the other hand, there exists points where the concentration of nitric acid is not detected, which suggests the possibility of denitrification. During early 2000, a new analytical procedure for nitrate isotopic measurement, termed the "denitrifier method", was established. With the development of the nitrate isotope tracer method, much research has been reported detailing sources of groundwater nitrate and denitrification mechanisms. This study presents a pilot case study (in the southern part of Okinawa Main Island, Japan, where Ryukyu limestone is extensively distributed) using the combined stable isotope ratios of major elements (C, N and S) as net recorders of the biogeochemical reactions with the aim of elucidation of denitrification mechanism in Ryukyu limestone aquifer. As a result, significant decreases in nitrate concentrations due to denitrification were observed in groundwater at some locations, which induced increases in isotope ratios up to 59.7‰ for δ15NNO3. These points of groundwater were located above the cutoff wall of the underground dam and near the fault. It is considered that the residence time of the groundwater is longer than the other points at these denitrification points, and that reduction condition tends to be formed in the groundwater. However, the rapid rise of the groundwater level due to rainfall is likely to occur in the Ryukyu limestone aquifer, where the ground water was found to have changed dynamically from the reduction condition to the oxidation condition which a denitrification (has not occured)does not occur. Moreover, the occurrence of autotrophic denitrification was suggested by the δ15NNO3,δ13CDIC,and δ34SSO4 values in Ryukyu limestone aquifer.

  14. The Melithaeidae (Cnidaria: Octocorallia) of the Ryukyu Archipelago: molecular and morphological examinations.

    PubMed

    Aguilar-Hurtado, Catalina; Nonaka, Masanori; Reimer, James D

    2012-07-01

    The family Melithaeidae (Octocorallia: Alcyonacea) is distributed in the West Pacific, Indian Ocean and the Red Sea. They are most abundant in warmer waters but can also be found in temperate waters. At present six genera are assigned to this family (Melithaea, Mopsella, Clathraria, Acabaria, Wrightella and Asperaxis), however overlapping characteristics make this group's taxonomic identification difficult and their relationships unclear. There are only a few reports from the Ryukyu Archipelago in southern Japan of melithaeids and most other octocorals, despite the islands being an area of high octocoral diversity. To help resolve the taxonomic confusion in this family, samples from various Ryukyu Archipelago locations were collected and DNA sequences of nuclear 28S ribosomal DNA and mitochondrial cytochrome oxidase I (COI) were obtained. Additionally, SEM micrographs of the sclerites of specimens were taken to further confirm the molecular results. Three strongly supported clades were recovered from the COI and 28S rDNA analyses, corresponding to Melithaea, Acabaria, and Mopsella, and in most cases clades were clearly related with the sclerite shape reported for each genus. These results show clearly that molecular differences are present between the three genera, and also demonstrates the strong need of other molecular markers for resolving intra-generic phylogenies. Our results provide baseline data for future studies of this octocoral family, not only on taxonomy, but also with regards to their distribution in the Ryukyu Islands. PMID:22465401

  15. Studies on the chironomid midges (Diptera, Chironomidae) of the Nansei Islands, southern Japan.

    PubMed

    Sasa, M

    1990-06-01

    The Nansei Islands are located in the subtropical zone of the western Pacific Ocean between Kyushu and Taiwan, and are composed of the two main island groups, the Amami and the Ryukyu Archipelagoes. This area has been known for the presence of a number of indigenous animal species. Prior to the present studies, collections of the chironomids mainly in the urban areas of the three main islands of the Ryukyus were carried out by Sasa and Hasegawa, and a total of 42 species, including 25 new species, were recorded. Additional collections of the chironomids mainly in the mountainous areas of this region were carried out by the present author during 1988 and 1989, and a total of 26 species (including 12 new species) were recorded from Amami Island, and a total of 27 species (including 10 new species) were recorded from the Ryukyu Islands. Eight species among them, including 3 new species, were common to the two archipelagos. PMID:2214255

  16. Exhumation of Triassic HP-LT rocks by upright extrusional domes and overlying detachment faults, Ishigaki-jima, Ryukyu islands

    NASA Astrophysics Data System (ADS)

    Osozawa, Soichi; Wakabayashi, John

    2012-10-01

    The Tomuru Formation of Ishigaki-jima in the southernmost part of the Ryukyu arc, comprises blueschist facies subduction complex rocks metamorphosed in Triassic time. D1 structures related to subduction, blueschist facies mineral growth, and possibly early stages of exhumation, are deformed by D2 structures that appear to reflect the last stage of exhumation. D2 structures define several anticlines with parasitic overturned folds verging away from anticlinal axes. The shortening recorded by this deformation appears to reflect upward extrusion relative to flanking material. The anticlines are flanked by detachment faults with normal sense-of-shear parallel to D2 vergence. Hanging wall rocks that include the Fusaki Formation, an accretionary prism with early Cretaceous metamorphic ages, and late Eocene limestone, conglomerate, and andesitic volcanics. The Eocene strata contain metamorphic detritus derived from the Tomuru and Fusaki Formations indicating pre-late Eocene surface exposure of these units. Ultramafic rocks and gabbro blocks of the Tomuru Formation were incorporated by sedimentary sliding into the trench prior to subduction and high-pressure metamorphism rather than being emplaced as diapirs along a post-metamorphic fault as previously proposed. Geochronologic, metamorphic, and thermal considerations suggest exhumation of the Tomuru Formation to relatively shallow crustal depths prior to or concurrent with early Cretaceous metamorphism of the Fusaki Formation. Arcward-vergent thrusting may have placed the younger, and formerly structurally lower, subduction complex (Fusaki Formation) over the older one (Tomuru Formation). D2 extrusional doming began after the emplacement of the Fusaki Formation at high structural levels. The D2 transport directions are subparallel to the strike of the orogen suggesting that the upright extrusion may have occurred along a forearc strike-slip fault system. This final stage of exhumation concluded in the late Eocene with extensional collapse and the development of detachment faults. The progression from initial exposure of the Tomuru and Fusaki Formations, deposition of late Eocene strata, extrusional doming and late detachment faulting may have been associated with migrating step-overs rather than changes in regional tectonics.

  17. Bathymetric patterns of ? and ? diversity of harpacticoid copepods at the genus level around the Ryukyu Trench, and turnover diversity between trenches around Japan

    NASA Astrophysics Data System (ADS)

    Kitahashi, Tomo; Kawamura, Kiichiro; Kojima, Shigeaki; Shimanaga, Motohiro

    2014-04-01

    The diversity of harpacticoid copepods was investigated around the Ryukyu Trench (430-7150 m), which lies below an oligotrophic subtropical ocean. The ? diversity, which is based on the number of genera and Shannon diversity decreased with increasing water depth. The community structure of harpacticoids gradually changed as the water depth increased from the bathyal zone to the hadal zone. Turnover (?) diversity values were equally high between the trench slope, trench floor and abyssal plain. We compared the harpacticoid assemblage obtained from the Ryukyu region with the assemblage from a region around the Kuril Trench (Kitahashi et al., 2013). Turnover diversity values between the two regions (? diversity) were relatively low at shallow depths, but they increased with increasing water depth and reached their maximum between the trench floors and abyssal plains. These findings indicate that the bathymetric patterns of harpacticoid assemblages differ among regions and that these discrepancies reflect differences in environmental conditions, such as primary productivity level.

  18. Numerical simulation of the 1771 Yaeyama tsunami in the southwestern Ryukyu arc

    NASA Astrophysics Data System (ADS)

    Nakamura, M.

    2007-12-01

    Numerical simulation of 1771 Yaeyama tsunami was computed and showed that M7-class earthquake would cause very high run-up locally without landslide. The 1771 Yaeyama tsunami occurred on April 24, 1771 in southwestern Ryukyu area, Japan. Maximum run-up heights reached over 30 m. About 12000 people were dead by the tsunami. Previous tsunami source models for this event have included both seismological faults along the Ryukyu Trench and submarine landslides. However, no evidence of landslides in the source has been obtained, despite marine surveying of the area. The fault along the Ryukyu trench also cannot have reproduced the distribution of run-up heights. Recently, CMT solutions of earthquakes and GPS measurement showed that the Ryukyu arc was extending parallel to the Ryukyu Trench. This suggests that the normal faulting cutting the island arc would be possible source for tsunami. Although the arc-cutting normal faults had been observed previously, they had not been examined as a source of the tsunami. Then the numerical tsunami simulation was employed and the possibility of the source of the 1771 Yaeyama tsunami was investigated. The tsunami propagation was computed using nonlinear shallow-water equations. The area for computation extended from 23.7N to 25.5N, and from 123.7E to 125.75E. The bathymetry and topography data were gridded at 75 m intervals over the entire area, and a finer grid interval of 25 m was employed for six areas for detailed analysis. The time interval for computation was 0.1 s. The model was computed for a wave travel time of two hours. Assumed fault length is 50 km (Mw7.6). As a result, the arc-cutting normal fault model proposed in this study successfully reproduced the distribution of tsunami run-up. Since the fault is located at the shallow area (about 300m in water depth), the tsunami waves refract at the shelf and concentrate locally to coast of islands. The arc-cutting normal fault and focusing effect would have caused very high run-up height in this area.

  19. Mid to late Holocene sea-surface temperature reconstruction using fossil corals from Kume Island, Ryukyu, Japan

    NASA Astrophysics Data System (ADS)

    Seki, A.; Yokoyama, Y.; Suzuki, A.; Kawakubo, Y.; Okai, T.; Miyairi, Y.; Matsuzaki, H.; Namizaki, N.; Kan, H.

    2012-12-01

    The relative warmth and stability of the Holocene was punctuated by several brief cold events. Although these cold events on a global scale are widely reported, the lack of records from regions such as the East China Sea (ECS) results in an incomplete understanding of the underlying cooling mechanism. Late Quaternary climate anomaly, at around 4.2 ka evidence found in elsewhere, is a time of such abrupt climate change, and mechanisms of this event have not been understood. Here, we present a coral-based paleo-SST (sea-surface temperature) reconstruction from the ECS to unveil Holocene variability in strength of the Kuroshio Western Boundary Current and the East Asian Monsoon (EAM). Our new data confirm that cold conditions prevailed at 3.8 cal kyr BP, and were started after 4.5 cal kyr BP. The timing of this cold event is consistent with previously reported Pulleniatina Minimum Event (PME, 4.5-3.0 ka) (e.g., Ujiié and Ujiié, 1999). While PME had not been resolved seasonality, our high-resolution data clearly indicate a different seasonal response of summer and winter SST . This result provides an important insight into the mechanism of the millennium scale cold event in the ECS, where the region affected by EAM (Seki et al., 2012).

  20. Discrepancy in the degree of population differentiation between color-morph frequencies and neutral genetic loci in the damselfly Ischnura senegalensis in Okinawa Island, Japan.

    PubMed

    Inomata, Nobuyuki; Hironaka, Kumiko; Sawada, Kouji; Kuriwada, Takashi; Yamahira, Kazunori

    2015-06-01

    Evaluation of relative contribution of natural selection and stochastic processes to population differentiation has been of great interest in evolutionary biology. In a damselfly, Ischnura senegalensis, females show color dimorphism (gynochrome vs. androchrome), and color-morph frequencies are known to greatly vary among local populations within Okinawa Island, a small island of Ryukyu Archipelago, Japan. In this study, to examine the effects of natural selection and stochastic processes on the within-island variation in color-morph frequencies, we compared the degree of population differentiation at the color-morph locus with that at a mitochondrial DNA region and ten nuclear microsatellite loci. F ST values at the neutral loci were close to zero, indicating presence of sufficient gene flow (dispersal of adult individuals) between the local populations. In contrast, F ST values at the color-morph locus were significantly different from zero. These results suggest that variation in female color-morph frequencies observed among local populations in Okinawa Island has been caused by divergent selection acting on the phenotype and/or genes tightly linked with the color locus. PMID:25633100

  1. Genetic Differentiation and Spatial Structure of Phellinus noxius, the Causal Agent of Brown Root Rot of Woody Plants in Japan

    PubMed Central

    Akiba, Mitsuteru; Ota, Yuko; Tsai, Isheng J.; Hattori, Tsutomu; Sahashi, Norio; Kikuchi, Taisei

    2015-01-01

    Phellinus noxius is a pathogenic fungus that causes brown root rot disease in a variety of tree species. This fungus is distributed in tropical and sub-tropical regions of Southeast and East Asia, Oceania, Australia, Central America and Africa. In Japan, it was first discovered on Ishigaki Island in Okinawa Prefecture in 1988; since then, it has been found on several of the Ryukyu Islands. Recently, this fungus was identified from the Ogasawara (Bonin) Islands, where it has killed trees, including rare endemic tree species. For effective control or quarantine methods, it is important to clarify whether the Japanese populations of P. noxius are indigenous to the area or if they have been introduced from other areas. We developed 20 microsatellite markers from genome assembly of P. noxius and genotyped 128 isolates from 12 of the Ryukyu Islands and 3 of the Ogasawara Islands. All isolates had unique genotypes, indicating that basidiospore infection is a primary dissemination method for the formation of new disease foci. Genetic structure analyses strongly supported genetic differentiation between the Ryukyu populations and the Ogasawara populations of P. noxius. High polymorphism of microsatellite loci suggests that Japanese populations are indigenous or were introduced a very long time ago. We discuss differences in invasion patterns between the Ryukyu Islands and the Ogasawara Islands. PMID:26513585

  2. Genetic Differentiation and Spatial Structure of Phellinus noxius, the Causal Agent of Brown Root Rot of Woody Plants in Japan.

    PubMed

    Akiba, Mitsuteru; Ota, Yuko; Tsai, Isheng J; Hattori, Tsutomu; Sahashi, Norio; Kikuchi, Taisei

    2015-01-01

    Phellinus noxius is a pathogenic fungus that causes brown root rot disease in a variety of tree species. This fungus is distributed in tropical and sub-tropical regions of Southeast and East Asia, Oceania, Australia, Central America and Africa. In Japan, it was first discovered on Ishigaki Island in Okinawa Prefecture in 1988; since then, it has been found on several of the Ryukyu Islands. Recently, this fungus was identified from the Ogasawara (Bonin) Islands, where it has killed trees, including rare endemic tree species. For effective control or quarantine methods, it is important to clarify whether the Japanese populations of P. noxius are indigenous to the area or if they have been introduced from other areas. We developed 20 microsatellite markers from genome assembly of P. noxius and genotyped 128 isolates from 12 of the Ryukyu Islands and 3 of the Ogasawara Islands. All isolates had unique genotypes, indicating that basidiospore infection is a primary dissemination method for the formation of new disease foci. Genetic structure analyses strongly supported genetic differentiation between the Ryukyu populations and the Ogasawara populations of P. noxius. High polymorphism of microsatellite loci suggests that Japanese populations are indigenous or were introduced a very long time ago. We discuss differences in invasion patterns between the Ryukyu Islands and the Ogasawara Islands. PMID:26513585

  3. A new species of Procolobomatus Castro Romero, 1994 (Copepoda: Philichthyidae) endoparasitic in a deepwater longtail red snapper (Actinopterygii: Lutjanidae) off Ishigaki Island, Japan, with records of philichthyid copepods reported from Asian waters.

    PubMed

    Madinabeitia, Ione; Iwasaki, Sadaharu

    2013-03-01

    A new species of the Philichthyidae Vogt, 1877 (Copepoda: Poecilostomatoida), Procolobomatus hoi n. sp., is described based on adult female specimens recovered from the cephalic sensory canals of Etelis coruscans Valenciennes (Actinopterygii: Lutjanidae) caught off Ishigaki Island, the Ryukyu Islands, southern Japan. The new species differs from its congeners by having the following combination of characters: a long medial cephalic lobe about one-third the length of the body; an armature of five spines on the distal exopodal segment of leg 2; one long apical seta on the papillose leg 4; a caudal ramus armed with one medial and four terminal setae (two middle setae are inflated); and spinulose ornamentation covering the body. Procolobomatus hoi n. sp. is the first member of the genus reported from the western Pacific Ocean and from a host of the family Lutjanidae. Previous records of philichthyid copepods from Asian waters are also reported. PMID:23404758

  4. Effects of herbicides on coral and seasonal distribution in water and sediments collected from rivers and coral reefs of the Ryukyu Archipelago, Japan

    NASA Astrophysics Data System (ADS)

    Kaneshiro, A.; Fujimura, H.; Oomori, T.; Gima, S.; Suzuki, Y.; Casareto, B. E.; Higuchi, T.; Sagawa, T.

    2011-12-01

    Introduction Coral reefs are subjected to artificial chemicals such as herbicide and pesticides. Diuron [N'-(3, 4-dichlorophenyl)-N, N-dimethylurea] is one of the active constituent contained in a herbicide. Although acute effects of diuron on coral are reported by several researchers, longer-period toxicity with lower level concentration and synergistic effect between the herbicide and soil sedimentation from river water have not been studied. We investigated the concentration level, distribution, seasonal variation and accumulation of several herbicides and pesticides in coral reef and river in Ishigaki Island and Okinawa Island, and estimated the rates of carbon production of calcification and photosynthesis to access the effects of herbicides on coral. Materials and Methods Water and sediment samples were collected from Todoroki river and Shiraho coral reef in Ishigaki Island and several rivers from Okinawa Island in August 2010 to August 2011. Diuron and other active constituents were extracted using a solid-phase column and measured with a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Corals for the experiment were collected from Okinawa Island and incubated in glass bottles. Seawater adjusted several concentrations of herbicide was continuously supplied to the bottles. Coral calcification and photosynthesis were estimated based on the change in total alkalinity and pH during a few hours when we temporary cease the water flow. Results and Discussion Higher diuron of 563 ng/L in water and 26 μg/kg in sediment was detected at the headwater of the Todoroki river in Ishigaki. in June. Sugarcane plantation is prevailing in Todoroki river area and rainwater can tend to gather topographically to upstream of the river. The higher concentration at the headwater decreased to 23 ng/L toward the river mouth. On the whole, the concentrations were higher during summer and lower in the other seasons in Ishigaki. On the other hand, seasonal variation was not observed at Okinawa Is., because the volume of the water in rivers is more affluent and usage duration of herbicides is longer in Okinawa than Ishigaki. Some herbicides and pesticides in seawater were slightly detected at the area where the river mouth is connected to the Shiraho coral reef. The concentration has not reached to the acute level at which metabolic activities (i.e. calcification and photosynthesis) of coral colony are degraded. The decrease of calcification and photosynthesis of coral was observed at 1-10μg/L of diuron concentration.

  5. Heterogeneous electrical structure of Kozu-shima volcanic island, Japan

    PubMed Central

    Orihara, Yoshiaki; Kamogawa, Masashi; Nagao, Toshiyasu; Uyeda, Seiya

    2009-01-01

    Nearly twenty anomalous geoelectric field changes were observed before earthquakes at Kozu-shima Island, Japan, from 1997 to 2000. In order to help locating the current sources of the observed anomalous changes, a bipole-dipole resistivity survey was conducted. From the resistivity survey, including current injection into the ground, it was found that various features of the anomalous changes were systematically different from those of changes caused by artificial sources and induction of geomagnetic disturbances. Moreover, it is suspected that the currents of anomalous changes were generated not near the ground surface but deep under the ground. PMID:20009380

  6. Heterogeneous electrical structure of Kozu-shima volcanic island, Japan.

    PubMed

    Orihara, Yoshiaki; Kamogawa, Masashi; Nagao, Toshiyasu; Uyeda, Seiya

    2009-01-01

    Nearly twenty anomalous geoelectric field changes were observed before earthquakes at Kozu-shima Island, Japan, from 1997 to 2000. In order to help locating the current sources of the observed anomalous changes, a bipole-dipole resistivity survey was conducted. From the resistivity survey, including current injection into the ground, it was found that various features of the anomalous changes were systematically different from those of changes caused by artificial sources and induction of geomagnetic disturbances. Moreover, it is suspected that the currents of anomalous changes were generated not near the ground surface but deep under the ground. PMID:20009380

  7. Forearc deformation and megasplay fault system of the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Hsu, S.; Yeh, Y.; Sibuet, J.; Tsai, C.; Doo, W.

    2011-12-01

    A great tsunami caused by a subduction earthquake had struck south Ryukyu islands and killed ~12000 people in 1771. Here we report the existence of a megasplay fault system along the south Ryukyu forearc. Analyses of deep multi-channel seismic reflection profiles indicate that the megasplay fault system is rising from the summit of a ~1 km high mount sitting on a ~5 landward dipping subducted plate interface. The fault system has accumulated large strain as evidenced by the active and widespread normal faults in the inner wedge. The along-trench length of the megasplay fault system is estimated to be ~450 km. The origin of this south Ryukyu megasplay fault system is linked to the subduction of elevated ridges parallel to the fracture zones. In contrast, no similar splay fault system is found in the west of 125. 5E where the oblique subduction has produced shear zones along the south Ryukyu forearc. We infer that the megasplay fault system is responsible for the 1771 south Ryukyu tsunami. Likewise, after a quiescence of ~240 years, a near-future great earthquake and tsunami is anticipated as the extensional feature is strongly widespread over the south Ryukyu forearc.

  8. Japan.

    PubMed

    1987-02-01

    Japan is composed of 4 main islands and more than 3900 smaller islands and has 317.7 persons/square kilometer. This makes it one of the most densely populated nations in the world. Religion is an important force in the life of the Japanese and most consider themselves Buddhists. Schooling is free through junior high but 90% of Japanese students complete high school. In fact, Japan enjoys one of the highest literacy rates in the world. There are over 178 newspapers and 3500 magazines published in Japan and the number of new book titles issued each year is greater than that in the US. Since WW1, Japan expanded its influence in Asia and its holdings in the Pacific. However, as a direct result of WW2, Japan lost all of its overseas possessions and was able to retain only its own islands. Since 1952, Japan has been ruled by conservative governments which cooperate closely with the West. Great economic growth has come since the post-treaty period. Japan as a constitutional monarchy operates within the framework of a constitution which became effective in May 1947. Executive power is vested in a cabinet which includes the prime minister and the ministers of state. Japan is one of the most politically stable of the postwar democracies and the Liberal Democratic Party is representative of Japanese moderate conservatism. The economy of Japan is strong and growing. With few resources, there is only 19% of Japanese land suitable for cultivation. Its exports earn only about 19% of the country's gross national product. More than 59 million workers comprise Japan's labor force, 40% of whom are women. Japan and the US are strongly linked trading partners and after Canada, Japan is the largest trading partner of the US. Foreign policy since 1952 has fostered close cooperation with the West and Japan is vitally interested in good relations with its neighbors. Relations with the Soviet Union are not close although Japan is attempting to improve the situation. US policy is based on the following 3 principles: 1) the US views Japan as an equal trade partner, 2) that the relationship is global in scope, and 3) that Japan has become increasingly assertive in world matters and plays a greater international role. The combined efforts of the US and Japan will be utilized to promote world peace. PMID:12177912

  9. Magma Genesis of Sakurajima, the Quaternary post- Aira caldera volcano, southern Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Suzuki, J.; Yoshikawa, M.; Kobayashi, T.; Miki, D.; Takemura, K.

    2012-12-01

    Sakurajima volcano is the Quaternary post-caldera volcano of Aira caldera, which was caused by the eruption of huge amount of silicic pyroclastics, situated on Ryukyu arc, southern Kyushu Island, Japan. This volcano is quite active, so it can be considered that the preparation of next caldera-forming eruption with huge amount of silicic magma is proceeding. It is, therefore, expected that the investigation of magma genesis of Sakurajima volcano give us information for the mechanism generating huge amount of silicic magma, which cause the caldera formation. We analyzed major and trace elements with Sr, Nd and Pb isotopic compositions of volcanic rocks from Sakurajima volcano. We sampled (ol) - opx - cpx - pl andesite and dacite from almost all the volcanic units defined by Fukuyama and Ono (1981). In addition to Sakurajima samples, we also studied basaltic rocks erupted at pre-caldera stage of the Aira caldera to estimate the primary magma of Sakurajima volcano. Major and trace element variations generally show linear trends on the Harker diagrams, with the exception of P2O5 and TiO2. Based on the trend of P2O5 vs.SiO2, we divided studied samples low-P (P2O5 < 0.15 wt. %) and high-P (P2O5 > 0.15 wt. %) groups and these groups also display two distinct trends on TiO2-SiO2 diagram. The composition of trace elements shows typical island arc character as depletion of Nb and enrichments of Rb, K and Pb, suggesting addition of aqueous fluids to the mantle wedge. The Zr and Nb concentrations make a liner trend (Zr/Nb = 27) and this trend across from tend of MORB (Zr/Nb = 35) to that of crustal materials (Zr/Nb=17). The Sr, Nd and Pb isotopic compositions broadly plot to on the mixing curve connecting MORB-type mantle and sediments of the Philippine Sea Plate, indicating that the primary magma was generated by partial melting of MORB-type mantle wedge, which was hydrated with fluids derived from the subducted Philippine Sea sediments. But we found that our data plot apart from the mixing curve to the direction of being more radiogenic when we observe in more detail. This observation supports our conclusion that the crustal materials contribute the magma genesis of Sakurajima volcano emphasized from Zr/Nb ratios. Low-P and high-P groups show different trends of SiO2, P2O5, TiO2 concentrations and 87Sr/86Sr ratios relative to plagioclase modal abundances. The high-P group samples show continuous trends, and their 87Sr/86Sr ratios increase with decreasing plagioclase, representing simple AFC process. The SiO2 content of low-P group rapidly increases from 63 to 66 wt. % at the modal abundance of pl is nearly 20 vol. %. The Sr isotope ratios of low-P group with < 20 vol. % of pl are obviously high (87Sr/86Sr = 0.70556 to 0.70569) compared to those of high-P group (87Sr/86Sr = 0.705136 to 0.705285). From these observations, we conclude that the rapid increase of SiO2 with high 87Sr/87Sr ratio infer involvement of crustal materials to the magma chamber, in which the ACF process is proceeding.

  10. Numerical analysis of the paleotsunami sizes through simulation of a large coralline boulder movement at Ishigaki Island, Japan

    NASA Astrophysics Data System (ADS)

    Hisamatsu, A.; Goto, K.; Imamura, F.

    2013-12-01

    Sakishima Islands (southern Ryukyu Islands), Japan, have been frequently affected by large tsunamis through the historical ages. The AD1771 Meiwa tsunami was an extreme event and the run-up height was ~30 m in maximum. The source model of the AD1771 Meiwa tsunami is still controversial: (1) earthquake plus landslide, (2) tsunami earthquake, and (3) splay fault models. The islands were also affected by the prehistoric tsunamis according to the geological evidence. For example, numerous coral boulders that were transported by paleotsunamis, including AD1771 event, were reported at the islands. The corals that constitute the boulders had once lived in the coral reefs fringing the islands and died when they were cast ashore to the land. Therefore, it is possible to estimate the timing of their deposition by using radiocarbon dating technique. In fact, the radiocarbon dating of Porites tsunami boulders at Sakishima Islands indicates that tsunamis had occurred repeatedly within a 150-400 years interval. However, the sizes of each tsunami are still uncertain. Hence, an important question has remained: whether there were any tsunami(s) in the past that were equivalent or larger in size comparing with the AD1771 Meiwa tsunami. In this study, we numerically investigated the transportation of a very large paleotsunami boulder at the southeastern part of Ishigaki Island, one of Sakishima Islands, using a boulder transport model in order to evaluate the sizes of paleotsunamis prior to the AD1771 event. The boulder that we used is called 'tsunami ufu-ishi' and it is the largest coralline boulder (>500 t) in Ishigaki Island. It is deposited approx. 100 m from the shoreline and 10 m in elevation. It was probably transported from the coral reef by the tsunami around 2000 years ago according to the radiocarbon dating. However, it is not necessarily that the boulder reached its present position due to one tsunami event 2000 years ago. In fact, according to the paleomagnetic analysis, it is proposed that the boulder was rotated twice possibly by two tsunami events. Alternatively, we cannot fully exclude the possibility that the boulder reached its present position due to one tsunami event. Therefore, we assumed that the boulder was deposited either by the two tsunamis or one tsunami. The result of the calculation showed that if we assumed tsunami ufu-ishi was moved by two tsunami events, the sizes of each tsunami are almost equivalent to the AD1771 Meiwa tsunami. In contrast, if we assume that the boulder was deposited by the single tsunami event, the flow depth at the boulder's position should have been 2-4 times higher than that of the AD1771 Meiwa tsunami. However, it is unlikely that such a size of tsunami was generated because the slip amount of the fault is unusually large in this case. Therefore, we interpreted that the AD1771 Meiwa tsunami was not a special event and similar size of the tsunamis had occurred repeatedly in this region.

  11. Japan.

    PubMed

    1989-02-01

    Japan consists of 3900 islands and lies off the east coast of Asia. Even though Japan is one of the most densely populated nations in the world, its growth rate has stabilized at .5%. 94% of all children go to senior high school and almost 90% finish. Responsibility for the sick, aged, and infirmed is changing from the family and private sector to government. Japan was founded in 600 BC and its 1st capital was in Nara (710-1867). The Portuguese, the 1st Westerners to make contact with Japan in 1542, opened trade which lasted until the mid 17th century. US Navy Commodore Matthew Perry forced Japan to reopen in 1854. Following wars with China and Russia in the late 1800s and early 1900s respectively, Japan took part in World Wars I and II. In between these wars Japan invaded Manchuria and China. The US dropped an atomic bomb on Hiroshima and Nagasaki and the Japanese surrendered in September, 1945 ending World War II (WWII). Following, WWII, the Allied Powers guided Japan's establishment as a nonthreatening nation and a democratic parliamentary government (a constitutional monarchy) with a limited defense force. Japan remains one of the most politically stable of all postwar democracies. The Liberal Democratic Party's Noboru Takeshita became prime minister in 1987. Japan has limited natural resources and only 19% of the land is arable. Japanese ingenuity and skill combine to produce one of the highest per hectare crop yields in the world. Japan is a major economic power, and its and the US economies are becoming more interdependent. Its exports, making up only 13% of the gross national product, mainly go to Canada and the US. Many in the US are concerned, however, with the trade deficit with Japan and are seeking ways to make trade more equitable. Japan wishes to maintain good relations with its Asian neighbors and other nations. The US and Japan enjoy a strong, productive relationship. PMID:12178004

  12. Distinct Phylogeographic Structures of Wild Radish (Raphanus sativus L. var. raphanistroides Makino) in Japan

    PubMed Central

    Han, Qingxiang; Higashi, Hiroyuki; Mitsui, Yuki; Setoguchi, Hiroaki

    2015-01-01

    Coastal plants with simple linear distribution ranges along coastlines provide a suitable system for improving our understanding of patterns of intra-specific distributional history and genetic variation. Due to the combination of high seed longevity and high dispersibility of seeds via seawater, we hypothesized that wild radish would poorly represent phylogeographic structure at the local scale. On the other hand, we also hypothesized that wild radish populations might be geographically differentiated, as has been exhibited by their considerable phenotypic variations along the islands of Japan. We conducted nuclear DNA microsatellite loci and chloroplast DNA haplotype analyses for 486 samples and 144 samples, respectively, from 18 populations to investigate the phylogeographic structure of wild radish in Japan. Cluster analysis supported the existence of differential genetic structures between the Ryukyu Islands and mainland Japan populations. A significant strong pattern of isolation by distance and significant evidence of a recent bottleneck were detected. The chloroplast marker analysis resulted in the generation of eight haplotypes, of which two haplotypes (A and B) were broadly distributed in most wild radish populations. High levels of variation in microsatellite loci were identified, whereas cpDNA displayed low levels of genetic diversity within populations. Our results indicate that the Kuroshio Current would have contributed to the sculpting of the phylogeographic structure by shaping genetic gaps between isolated populations. In addition, the Tokara Strait would have created a geographic barrier between the Ryukyu Islands and mainland Japan. Finally, extant habitat disturbances (coastal erosion), migration patterns (linear expansion), and geographic characteristics (small islands and sea currents) have influenced the expansion and historical population dynamics of wild radish. Our study is the first to record the robust phylogeographic structure in wild radish between the Ryukyu Islands and mainland Japan, and might provide new insight into the genetic differentiation of coastal plants across islands. PMID:26247202

  13. Distinct Phylogeographic Structures of Wild Radish (Raphanus sativus L. var. raphanistroides Makino) in Japan.

    PubMed

    Han, Qingxiang; Higashi, Hiroyuki; Mitsui, Yuki; Setoguchi, Hiroaki

    2015-01-01

    Coastal plants with simple linear distribution ranges along coastlines provide a suitable system for improving our understanding of patterns of intra-specific distributional history and genetic variation. Due to the combination of high seed longevity and high dispersibility of seeds via seawater, we hypothesized that wild radish would poorly represent phylogeographic structure at the local scale. On the other hand, we also hypothesized that wild radish populations might be geographically differentiated, as has been exhibited by their considerable phenotypic variations along the islands of Japan. We conducted nuclear DNA microsatellite loci and chloroplast DNA haplotype analyses for 486 samples and 144 samples, respectively, from 18 populations to investigate the phylogeographic structure of wild radish in Japan. Cluster analysis supported the existence of differential genetic structures between the Ryukyu Islands and mainland Japan populations. A significant strong pattern of isolation by distance and significant evidence of a recent bottleneck were detected. The chloroplast marker analysis resulted in the generation of eight haplotypes, of which two haplotypes (A and B) were broadly distributed in most wild radish populations. High levels of variation in microsatellite loci were identified, whereas cpDNA displayed low levels of genetic diversity within populations. Our results indicate that the Kuroshio Current would have contributed to the sculpting of the phylogeographic structure by shaping genetic gaps between isolated populations. In addition, the Tokara Strait would have created a geographic barrier between the Ryukyu Islands and mainland Japan. Finally, extant habitat disturbances (coastal erosion), migration patterns (linear expansion), and geographic characteristics (small islands and sea currents) have influenced the expansion and historical population dynamics of wild radish. Our study is the first to record the robust phylogeographic structure in wild radish between the Ryukyu Islands and mainland Japan, and might provide new insight into the genetic differentiation of coastal plants across islands. PMID:26247202

  14. Chemical characteristics of precipitation in Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Sakihama, Hideaki; Ishiki, Maki; Tokuyama, Akira

    This study examined the chemical composition and characteristics of precipitation collected from March 2003 to February 2005 in the central part of Okinawa Island, Japan. Chloride ions contributed most to the total ion equivalent concentration, and followed in order by Na +>Mg 2+, SO 42->Ca 2+>H +, NH 4+, K +>NO 3-, HCO 3-. Concentrations of Na +, K +, Ca 2+, Mg 2+, Cl -, and sea salt SO 42- (ss-SO 42-) increased from summer to autumn and decreased from winter to spring. In contrast, concentrations of NH 4+, NO 3- (except for July 2004), non-sea salt SO 42- (nss-SO 42-), and H + were lower in summer and higher in winter. During periods with typhoons, concentrations of sea salt components, such as Na + and Cl -, increased while NO 3- and nss-SO 42- concentrations decreased. Wet deposition driven by typhoons accounted for about 77% of the total annual wet deposition. The pH values ranged from 3.89 to 7.61. Acid rain (pH<5.6) occurred in 72% of the collected samples, even though Okinawa Island is considered to be an unpolluted area. Principal component analysis indicated three main origins of the chemical components in precipitation: (1) sea salt generated from local surrounding ocean (Na +, K +, ss-Ca 2+, Mg 2+, Cl -, and ss-SO 42-), (2) soil generated from local land (nss-Ca 2+ and D-SiO 2), and (3) anthropogenic source of Asian Continent (NH 4+, NO 3-, and nss-SO 42-).

  15. Field Observations of Meteotsunami in Kami-koshiki Island, Japan

    NASA Astrophysics Data System (ADS)

    Asano, T.; Yamashiro, T.; Nishimura, N.

    2012-12-01

    BACKGROUND Meteotsunami; atmospherically induced destructive ocean waves in the tsunami frequency band, are known in Japan by the local term "abiki", literally meaning "net-dragging waves" in Japanese. Large abiki occur in bays and harbors along the west coast of Kyushu almost every year during winter and early spring. On 24-25 February, 2009, Urauchi Bay, located on west coast of Kami-Koshiki Island on the southeast coast of Kyushu, was subjected to a destructive meteotsunami. In this event, a maximum sea surface height of 3.1 m was observed at the inner part of the bay. At least 18 boats capsized and eight houses were flooded. This event surpassed the previous record height for an abiki in Japan: 278 cm in Nagasaki Bay, also located west coast of Kyushu, in 1979. Generally, such an elongated inlet with narrow mouth as Urauchi bay provides calm water conditions even when offshore weather is stormy. Therefore, the area is regarded as a suitable place for the farming of large fish with a high market value. Possible damage to the extensive fish cage system as a result of meteotsunami events is of concern, especially because aquaculture is the main industry in the isolated islands. Forecasting of meteotsunami is a serious request from the local people. AIMS The objectives of the present study are to detect a meteotsunami event in Urauchi Bay and to clarify the meteorological and hydrodynamic conditions related to its occurrence. This work attempts to observe the whole process of a meteotsunami event: generation offshore, resonance while it propagates, and finally amplification in the bay. Observations were conducted over a period of 82 days; 12 January to 4 April, 2010, aiming to record large secondary oscillations. A comprehensive measuring system for sea level, current and barometric pressure fluctuations was deployed covering not only inside and near Urauchi Bay but also further offshore in the vicinity of Mejima in the East China Sea. MAIN RESULTS 1) Large meteotsunami events with total height in excess of 150 cm were observed five times during the 82-day observation period. On 1 February, 2010, one such event coincided with the high water of a spring tide, which resulted in flooding. The present observations have revealed that meteotsunami events occur more frequently than previously estimated from existing records of flooding. Even if a meteotsunami event does not result in flooding (e.g., if it coincides with a low tide), attention should be paid to the seiche induced strong currents that may damage fishing boats or aquaculture installations. 2) Three dominant modes were found to exist in sea level fluctuation data in Urauchi Bay using spectra analysis, wavelet analysis and phase analysis of the extracted period band components. The node and anti-node structure for each node governs more energetic areas for sea level and the current velocity fluctuations. 3) Analyses of barometric pressure data show that abrupt pressure changes of 1-2 hPa are generated in the open sea area at Mejima when major meteotsunami events occur. The pressure waves propagated eastward or northeastward to reach Kami-Koshiki within 1-2 hours. The propagation speed was found to nearly coincide with ocean long waves over the East China Sea. This air-sea resonant coupling is considered to be a source mechanism of meteotsunami generation.

  16. A mega-splay fault system and tsunami hazard in the southern Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Kun; Yeh, Yi-Ching; Sibuet, Jean-Claude; Doo, Wen-Bin; Tsai, Ching-Hui

    2013-01-01

    In April 1771, a subduction earthquake generated a great tsunami that struck the south Ryukyu islands and killed 12,000 people, whereas its mechanism is still enigmatic (Nakata and Kawana, 1995; Nakamura, 2006; Matsumoto et al., 2009). In this paper, we show its probable source on a mega-splay fault system existing along the southern Ryukyu forearc. Analyses of deep multi-channel seismic reflection profiles indicate that the mega-splay fault system is rising from the summit of a 1 km high ridge situated at a 5 landward dipping plate interface. An outer ridge marks the seafloor outcrop of the splay fault system and separates the landward inner wedge and the oceanward outer wedge. The inner wedge is uplifting and exhibits widespread normal faulting while the outer wedge shows folded structures. The mega-splay fault system is parallel to the Ryukyu Trench east of 125.5E and is estimated to be 450 km long. The origin of this south Ryukyu mega-splay fault system is ascribed to a resistant subduction of the elevated transverse ridges associated with the subducting portion of the trench-parallel Luzon-Okinawa Fracture Zone. In contrast, no similar splay fault is found west of 125.5E where the oblique subduction has produced large shear zones along the south Ryukyu forearc. We infer that a thrust earthquake linked to the mega-splay fault system is responsible for the south Ryukyu tsunami. However, another possible scenario of generating a large tsunami affecting the south Ryukyu islands is that the subducted ridge in the western end of the mega-splay fault system nucleated a large earthquake and simultaneously triggered the 100 km long E-W trending strike-slip fault west of 125.5E and induced a southward-dipping tsunami-genic subsidence. In any case, after a quiescence of 241 yr, a large earthquake and tsunami is anticipated in the south Ryukyu forearc in the near future.

  17. Blood meal identification and feeding habits of uranotaenia species collected in the ryukyu archipelago.

    PubMed

    Toma, Takako; Miyagi, Ichiro; Tamashiro, Mikako

    2014-09-01

    To know the blood meal in the stomach of Uranotaenia species, blood-fed mosquitoes were collected by 4 methods at different sites in the mountain forest of 3 islands, Amamioshima, Okinawajima, and Iriomotejima in the Ryukyu Archipelago, Japan from 2005 to 2012. One hundred twenty-four blood-fed Uranotaenia mosquitoes of 7 species (Ur. jacksoni, nivipleura, ohamai, yaeyamana, annandalei, lateralis, and macfarlanei) were collected. The collection rates are 0.26, 0.6, 0.31, and 0.66 by black light trap, black light blue with dry ice trap, frog call trap, and sweeping net, respectively. The blood meals of 107 females (86.3%) were successfully identified by a polymerase chain reaction-based method. All Uranotaenia species fed on cold-blooded animals, especially amphibians (99.1%), and notably on frogs. They would feed readily on available frogs in a given region having no close connection with the breeding (calling) season of each frog. They also fed on reptiles (0.9%), but not on warm-blooded animals. PMID:25843097

  18. The 1768 and 1791 Okinawa tsunamis in the Ryukyu Trench region

    NASA Astrophysics Data System (ADS)

    Nakamura, M.

    2013-12-01

    Risk of the great earthquakes and tsunamis has been assumed to be low in the Ryukyu Trench because the interplate coupling is weak and great interplate earthquakes (> M8.0) had not been recorded historically for about 300 years. However, recent study revealed that the 1771 Yaeyama earthquake (M8.5 from tsunami heights distribution) at south Ryukyu Trench and the 1911 Kikaijima earthquake (M 8.0) at north-central Ryukyu Trench were the interplate earthquakes. We need re-examine the great historical earthquakes in the Ryukyu Trench. Two historical tsunamis which occurred on 1768 and 1791 in the Okinawa Island were documented in the old document 'Kyuyo' (formal chronicles of Ryukyu). I investigated the source fault model of two tsunami events using numerical simulations of tsunami and earthquake shaking, and showed that their events would be the interplate earthquakes. One earthquake occurred at noon of July 22th, 1768. The rock-walls of castle, grave of royal family were collapsed by the earthquake shaking around Naha, Okinawa Island. After the shaking, tsunami arrived Naha port and Zamami Island, which is west of Okinawa Island. Recorded tsunami heights were about 1 m at Naha port. Nine houses and rice fields were damaged by the inundation of the tsunami in the Zamami Island. Estimated tsunami heights were 4 and 5 m in the villages of the Zamami Island. The numerical modeling of tsunami and the estimation of earthquake shaking using empirical formula were employed, and the fault parameters of the 1768 earthquake were estimated. The faults were set to Okinawa Trough (M7.5 normal faults), southwest of Okinawa island (M7.5 normal faults), southwest of Okinawa island (M7.5 reverse fault), and Ryukyu Trench (M8.0 thrust faults). The computed tsunami heights and intensities of the ground shaking of the M7.5 reverse fault near the Zamami Island and the M8.0 interplate earthquake models are consistent with to the recorded ones. Another tsunami was also recorded in the 'Kyuyo'. The abrupt abnormal increases of sea-level were recorded in the Okinawa Island on May 13th, 1791. The recorded tsunami heights were 1.5 m at Naha port, 2 m at the port of northwestern coast of Okinawa Island, and 11 m at the eastern coast of Okinawa Island. Large historical earthquakes have not been reported around the Pacific Ocean in this period. The numerical simulation of tsunami was employed to estimate the fault parameters of the 1791 tsunami. The computed tsunami heights of the magnitude between 8.0 and 8.3 interplate earthquake models, whose fault top is along the Ryukyu Trench, are consistent with the recorded ones. The arrivals of the tsunamis without earthquake shaking suggest that the 1791 tsunami would be the tsunami earthquake which occurred near the Ryukyu Trench.

  19. Subterranean electrical structure of Kozu-shima volcanic island, Japan.

    PubMed

    Orihara, Yoshiaki; Kamogawa, Masashi; Takeuchi, Akihiro; Fukase, Hiroaki; Nagao, Toshiyasu

    2010-01-01

    Following the electric current injection experiment carried out in 2009, a VLF-MT (Very Low Frequency Magnetotelluric) survey has been conducted in Kozu-shima Island to obtain further information on the subterranean electrical structure that might help understanding the results of our monitoring of geoelectric potentials. A number of VAN-type pre-seismic geoelectric potential anomalies were observed in 1997-2000, even showing a remarkable "Selectivity". However, similar pre-seismic anomalies were not observed during the Izu-Island volcano-seismic swarm 2000. All these observations would require extremely high degree of heterogeneity in the subterranean electrical structure of the volcanic island and its possible time changes. Several correlations between the results of this survey and the volcanic geology of the island and ground water distribution were found. Further investigation is needed for a complete explanation of the observed phenomena. PMID:21084774

  20. Subterranean electrical structure of Kozu-shima volcanic island, Japan

    PubMed Central

    ORIHARA, Yoshiaki; KAMOGAWA, Masashi; TAKEUCHI, Akihiro; FUKASE, Hiroaki; NAGAO, Toshiyasu

    2010-01-01

    Following the electric current injection experiment carried out in 2009, a VLF-MT (Very Low Frequency Magnetotelluric) survey has been conducted in Kozu-shima Island to obtain further information on the subterranean electrical structure that might help understanding the results of our monitoring of geoelectric potentials. A number of VAN-type pre-seismic geoelectric potential anomalies were observed in 19972000, even showing a remarkable Selectivity. However, similar pre-seismic anomalies were not observed during the Izu-Island volcano-seismic swarm 2000. All these observations would require extremely high degree of heterogeneity in the subterranean electrical structure of the volcanic island and its possible time changes. Several correlations between the results of this survey and the volcanic geology of the island and ground water distribution were found. Further investigation is needed for a complete explanation of the observed phenomena. PMID:21084774

  1. The variations of long time period slow slip events along the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Tu, Y. T.; Heki, K.

    2014-12-01

    Slow slip events (SSEs) are a type of slow earthquakes that can be observed with Global Positioning System (GPS) networks in the world. Those events are detected on intensely coupled plate boundaries such as Cascadia subduction zone (Dragert et al., 2001), western North America, Mexico (Kostoglodov et al., 2003), Alaska (Ohta et al., 2007) and Tokai and Boso areas (Ozawa et al., 2002, 2003), central Japan and are considered to have relations to large subduction thrust earthquakes. However, in southwestern Ryukyu trench where most of researchers believe that it should be a decoupled plate boundary, SSEs recur regularly and are located at a patch that is as deep as 20 to 40 km (Heki and Kataoka, 2008). For comprehending the characteristics and time variations of SSEs in this area, the GEONET GPS data of 16 years are used in this study. During 1997 to 2014, more than thirty SSEs are identified near Hateruma Island, Ryukyu. The average recurrence interval is calculated to be 6.3 months and release seismic moment is Mw 6.6 on average. However, the values of recurrence interval are not invariable. From 1997 to 2002, interval period of SSEs is 7.5 months, but during 2002 to 2008, the interval period decreases suddenly to 5.5 months. After 2008, the value restores to 7.2 months again. Furthermore, the slip amount of SSEs in this area varies with time. From 1997 to 2002, the slip is 9.5 cm/year; and during 2002 to 2008, the value slightly increases to 10.5 cm/year. However, in 2008 to 2013, the slip drops to 6.6 cm/year, but accord to the trend of cumulative slip, the slip value would increase in 2014. Considering these data, we find the slip values increase conspicuously in 2002 and 2013. Coincidentally, one Mw 7.1 thrust earthquake occurred in 2002 and earthquake swarm activity started in the Okinawa trough approximately 50km north of the SSE patch. In 2013, another earthquake swarm activity occurred in nearly the same area as the 2002 activity. This suggests that the slip amount varies due to the earthquake swarm activities in Okinawa trough; the external stress perturbations such as magma injection and the Mw 7.1 earthquake could accelerate the slip amount of SSEs.

  2. Verrucostoma, a new genus in the Bionectriaceae from the Bonin Islands, Japan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verrucostoma freycinetiae gen. et sp. nov. collected on dead leaves of Freycinetia boninensis (Pandanaceae) in Hahajima, Bonin (Ogasawara) Islands, Tokyo, Japan, is described and illustrated. The new genus is characterized by having pale orange perithecia with protuberances around the perithecial ap...

  3. Souther portion of Island of Kyushu, Japan, as seen from the Apollo 7

    NASA Technical Reports Server (NTRS)

    1968-01-01

    City of Kagoshima and Kagoshima Bay area of the southern portion of the island of Kyushu, Japan, as seen from the Apollo 7 spacecraft during its 9th revolution of the earth. Photographed from an altitude of 125 nautical miles, at ground elapsed time of 12 hours and 10 minutes.

  4. A new strikingly-colored species of the genus Galathea Fabricius, 1793(Crustacea: Decapoda: Anomura: Galatheidae) from the Ryukyu Islands, Japan.

    PubMed

    Osawa, Masayuki

    2015-01-01

    A new shallow-water squat lobster, Galathea ryuguu, is described on the basis of material obtained from a colony of unidentified sea fan of the genus Muricella Verrill, 1868. The new species is most closely allied to G. squamea Baba, 1979, but is distinguished by the ornamentation and armature of the carapace, third maxilliped, and ambulatory legs. PMID:26624645

  5. Laboratory experiments and observations of cyclonic and anticyclonic eddies impinging on an island

    NASA Astrophysics Data System (ADS)

    Andres, Magdalena; Cenedese, Claudia

    2013-02-01

    experiments are conducted to investigate the interactions of self-propagating barotropic cyclones and baroclinic anticyclones with an island. Results are interpreted in the context of observations around Okinawa Island, Japan, where ubiquitous arrivals of cyclones and anticyclones on the southeastern side of the island influence the flow around it, thereby impacting both the Ryukyu Current's and the Kuroshio's transport. In the laboratory, baroclinic anticyclones generate a buoyant current that flows clockwise around an island whereas barotropic cyclones generate a counterclockwise current. In both cases, the interaction is governed by conservation of circulation ? around the island, which establishes a balance between the dissipation along the island in contact with the eddy and the dissipation along the island in contact with the generated current. Laboratory results and scaling analysis suggest that the interaction between an anticyclone (cyclone) and Okinawa Island should result in an instantaneous increase (decrease) of the Ryukyu Current transport and a delayed increase (decrease) of the Kuroshio transport. The estimated delays are in good agreement with those obtained with field measurements suggesting that the dynamics at play in the laboratory may be relevant for the flow around Okinawa Island.

  6. Chikungunya Fever in Japan Imported from the Caribbean Islands.

    PubMed

    Imai, Kazuo; Nakayama, Eri; Maeda, Takuya; Mikita, Kei; Kobayashi, Yukiko; Mitarai, Aoi; Honma, Yasuko; Miyake, Satoru; Kaku, Koki; Miyahira, Yasushi; Kawana, Akihiko

    2016-03-23

    A 53-year-old Japanese woman who was working as a volunteer in the Commonwealth of Dominica in the Caribbean islands presented with a high-grade fever and severe incapacitating generalized arthralgia. The Asian genotype of the chikungunya virus was confirmed using reverse transcription-PCR and serology, based on the presence of a specific neutralization titer and immunoglobulin M antibodies. She was diagnosed with post-chikungunya chronic arthritis based on persistence of her polyarthritis for 3 months and the presence of rheumatoid factor, immunoglobulin G-rheumatoid factor, and matrix metalloproteinase-3. Chikungunya virus should be considered as a causative pathogen in travelers returning from Caribbean islands. Clinicians should consider chikungunya fever in the differential diagnosis of patients who complain of chronic arthritis and have a history of travel to an endemic area. PMID:26166501

  7. Superconducting gravimeter observation for identifying slow slip events at Ryukyu Trench

    NASA Astrophysics Data System (ADS)

    Imanishi, Y.; Nawa, K.; Tamura, Y.; Ikeda, H.; Miyaji, T.; Tanaka, Y.

    2012-12-01

    Analysis of the data from the dense GPS network of Japan (GEONET) revealed quasi-periodic occurrences of long-term slow slip events at the Ryukyu Trench (Heki and Kataoka, 2008). The recurrence period of the events is about half a year, much shorter than typically found in other regions where slow slips are known to take place. Therefore, this region provides an interesting field for investigating the nature of slow slip events. In February 2012, we started gravity observation using a superconducting gravimeter (SG) at the VERA Ishigakijima Station, National Astronomical Observatory of Japan. The Ishigakijima island is located slightly east off the presumed fault area of the slow slip events. Our purpose is to detect gravity changes associated with the slow slip events by making full use of the high resolution of the SG. Of particular interest is the possible effect of water on the slow slip events, which might be identified from gravity observations. In addition to the SG, we installed an FG5 absolute gravimeter at the Iriomotejima island, located about 10 km west of the Ishigakijima island. The SG used in this study (serial number CT36) is the one which was in operation at the Inuyama Seismological Observatory, Nagoya University for about ten years. Before moving it to Ishigakijima, we made a thorough examination of the instruments. Because we found a serious problem in transferring liquid helium because of the ice inside, we warmed up the Dewar to initialize it. This not only solved the ice problem but also resulted in a significant decrease of the heater power for the gravity sensor. As of this writing, we have about six months worth of data from the SG. The condition of the gravimeter is good except for the first month when temperature control was unstable. Because of the ground vibrations caused by the movement of the 20-m VLBI antenna (about 30 m apart from the SG), the noise level is significantly enhanced compared with other domestic SG stations. Also we are aware of the strong effect of groundwater on gravity, which is yet to be modeled. According to the GPS observations, the most recent slow slip event appears to have taken place from May through June this year. We will present our first results on the tidal analysis of the SG data, characterization of the gravity spectra, and hopefully identification of the signals associated with slow slip event.

  8. Millennial-scale variability in vegetation records from the East Asian Islands: Taiwan, Japan and Sakhalin

    NASA Astrophysics Data System (ADS)

    Takahara, Hikaru; Igarashi, Yaeko; Hayashi, Ryoma; Kumon, Fujio; Liew, Ping-Mei; Yamamoto, Masanobu; Kawai, Sayuri; Oba, Tadamichi; Irino, Tomohisa

    2010-10-01

    High-resolution pollen records from Taiwan, Japan and Sakhalin document regional vegetation changes during Dansgaard-Oeschger (D-O) cycles during the last glacial. During the period from the cold phase (GS 18/19) to warm phase (D-O 19), the biome shift from temperate conifer forest to cold/cool conifer forest in Japan and from subtropical forest to temperate deciduous/conifer forest in Taiwan. The vegetation in D-O 17, cool mixed forest in central Japan, temperate deciduous broadleaf forest in western Japan and subtropical forest in Taiwan, indicates warm condition but not wet in all area. These vegetation changes lead to biome shift from MIS (Marine Isotope Stage) 4 to MIS 3. The abundance of Cryptomeria japonica and Fagus crenata in D-O 12 and D-O 8 indicates wet conditions brought by the strong summer monsoon through the Islands and high snowfall brought by the inflow of the Tsushima Warm Current into the Sea of Japan. The registration of other D-O warming events in MIS 3, although reflected by shifts in the abundance of key species, is not sufficient to produce changes in biomes. Development of cold deciduous forest in HS (Heinrich events) 1 in Sakhalin, Hokkaido and central Japan was conspicuous and was much larger than that in YD. Vegetation response in YD was small scale and within the same biome in the East Asian Islands. In D-O 1 at the termination of the last glacial, the same taxa that developed in the early Holocene, cold evergreen needleleaf trees in northern region, temperate deciduous broadleaf trees in central and western Japan, and warm-temperate evergreen trees in Taiwan, increased.

  9. Seismic structure of subducted Philippine Sea plate beneath the southern Ryukyu arc by receiver function and local earthquakes tomography

    NASA Astrophysics Data System (ADS)

    Nakamura, M.

    2012-12-01

    Seismic coupling of the Ryukyu subduction zone is assumed to be weak from the lack of historical interplate large earthquakes. However, recent investigation of repeating slow slip events (Heki & Kataoka, 2008), shallow low frequency earthquakes (Ando et al., 2012), and source of 1771 Yaeyama mega-tsunami (Nakamura, 2009), showed that the interplate coupling is not weak in the south of Ryukyu Trench. The biannually repeating SSEs (Mw=6.5) occur at the depth of 20-40 km on the upper interface of the subducted Philippine Sea plate beneath Yaeyama region, where earthquake swarm occurred on 1991 and 1992. To reveal the relation among the crustal structure, earthquake swarms, and occurrence of slow slip events (SSE), local earthquake tomography and receiver function (RF) analysis was computed in the southwestern Ryukyu arc. A tomographic inversion was used to determine P and S wave structures beneath Iriomote Island in the southwestern Ryukyu region for comparison with the locations of the SSE. The seismic tomography (Thurber & Eberhart-Phillips, 1999) was employed. The P- and S- wave arrival time data picked manually by Japan Meteorological Agency (JMA) are used. The 6750 earthquakes from January 2000 to July 2012 were used. For the calculation of the receiver function, the 212 earthquakes whose magnitudes are over 6.0 and epicentral distances are between 30 and 90 degrees were selected. The teleseicmic waveforms observed at two short-period seismometers of the JMA, and one broadband seismometer of F-net of National Research Institute for Earth Science and Disaster Prevention were used. The water level method (the water level is 0.01) is applied to original waveforms. Assuming that each later phase in a RF is the wave converted from P to S at a depth, I transformed the time domain RF into the depth domain one along each ray path in a reference velocity model. The JMA2001 velocity model is used in this study. The results of tomography show that the low Vp and high Vp/Vs anomalies are distributed along the hypocenters in the subducted slab. The plate interface is about 10 km above the slab earthquakes from the trace of negative RF amplitude. The slab earthquakes are distributed along the trace of positive RF amplitude. Therefore the slab earthquakes occur near the oceanic Moho of the PHS. The fault depth of the SSEs corresponds to the plate interface within 5 km. The fault-planes of the SSE are located above the low Vp and high Vp/Vs zone. Assuming that the difference between high Vp/Vs and low Vp/Vs originates to the fluid contents, this would be interpreted that the fluids from the subducted oceanic crust cannot be transported upward and is trapped at the plate interface. The observed strong S-wave reflector (Nakamura, 2001) in the upper interface of the subducted plate also supports the idea. The top of the faults of the SSEs connects to the cluster of earthquake swarms in the lower crust. This suggests that the trapped fluids are transported upward along the faults, accumulates in the lower crust, and induce the swarm of micro-earthquakes in the lower crust.

  10. The Role of Philippine Sea Plate to the Genesis of Quaternary Magmas of Northern Kyushu Island, Japan, Inferred from Along-Arc Geochemical Variations

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Yoshikawa, M.; Itoh, J.; Ujike, O.; Miyoshi, M.; Takemura, K.

    2013-12-01

    Quaternary volcanoes on Kyushu Island comprise volcanoes Himeshima, Futagoyama, Yufu-Tsurumi, Kuju, Aso, Kirishima and Sakurajima from north to south alongstrike the volcanic front. Adakitic lavas are observed from Yufu-Tsurumi and Kuju volcanoes in northern Kyushu (Kita et al., 2001; Sugimoto et al., 2007), whereas no Quaternary adakites were observed at Aso (e.g., Hunter, 1998) and the volcanoes south of Aso along the entire Ryukyu arc. Sugimoto et al. (2007) suggested that the trace element and Sr, Nd, and Pb isotopic compositions of adakitic magmas from Yufu-Tsurumi volcano indicate derivation of the magmas by partial melting of the subducting PSP. In contrast, Zellmer et al. (2012) suggested that these adakites may have formed by fractional crystallization of mantle-derived mafic magmas within the garnet stability field in the crust. The Honshu-Kyushu arc transition is a particular favorable setting to address these controversial models for the origin of the adakitic lavas, because of the potential relationship between the PSP materials and the alongstrike variation of the lava chemistry. The Palau-Kyushu ridge divides the oceanic crust of the PSP into northeastern and southwestern segments with ages of 26-15 (Shikoku Basin) and 60-40 Ma (West Philippine Basin), respectively (Mahony et al., 2011). Although there are no clear plate images beneath northern Kyushu, the northern extension of the Palau-Kyushu ridge potentially corresponds to the boundary between the SW Japan and Ryukyu arcs. If adakite genesis was related to the subducted slab rather than the overlying crust, then the spatial distribution of Quaternary adakites should correlate with the age of the subducted PSP. In order to test such correlation and elucidate the petrogenesis of the northern Kyushu adakites, we compiled major and trace elements and Sr-Nd-Pb isotope ratios from volcanoes along the arc front that includes the transition from adakitic to non-adakitic arc volcanism. Comprehensive geochemical data, including Sr, Nd, and Pb isotope ratios, were restricted to Kuju and Yufu-Tsurumi volcanoes (Kita et al., 2001; Sugimoto et al., 2007), and hence we present new geochemical and Sr-Nd-Pb isotope ratios of lavas from Himeshima and Futagoyama volcanoes and Nd-Pb isotope ratios of Aso volcano. The Sr/Y ratios of the arc lavas decrease from north to south along the volcanic front. Mixing relations in Sr-Nd-Pb isotope space suggest recycling of the subducted slab materials from the Philippine Sea Plate to the arc. The 87Sr/86Sr ratios decrease with increasing Sr/Y and SiO2, which argues against a genetic link of fractional crystallization between adakites and basaltic magmas. The observations further suggest that partial melting of the hot and young Shikoku Basin slab produces the high Sr/Y component visible in the arc magmas in the north, whereas dehydration of the older West Philippine Basin slab produces the low Sr/Y arc magmas in the south. References Hunter, 1998, Chemical Geology, 201: 19-36. Kita et al., 2001, Journal of Volcanology and Geothermal Research, 111, 99-109. Mahony et al., 2011, Geological Society of America Bulletin, 123, 2201-2223. Sugimoto et al., 2007, Journal of Mineralogical and Petrological Sciences, 101: 270-275. Zellmer et al., 2012, Geology, 40: 487-490.

  11. Island-Arc Collision Dominates Japan's Sediment Flux to the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Codilean, A. T.; Korup, O.; Hayakawa, Y. S.; Matsushi, Y.; Saito, H.; Matsuzaki, H.

    2013-12-01

    Quantifying volumes and rates of delivery of terrestrial sediment to subduction zones is indispensable for refining estimates of the thickness of trench fills that may eventually control the location and timing of submarine landslides and tsunami-generating mega-earthquakes. Despite these motivating insights, knowledge about the rates of erosion and sediment export from the Japanese islands to their Pacific subduction zones has somewhat stagnated despite the increasing availability of highly resolved data on surface deformation, climate, geology, and topography. Traditionally, natural erosion rates across the island arc have been estimated from catchment topographic predictors of reservoir sedimentation rates that were recorded over several years to decades. We correct for a systematic bias in these predictions, and present new estimates of decadal to millennial-scale erosion rates of the Japanese terrestrial inner forearc, drawing on several unprecedented inventories of mass wasting, reservoir sedimentation, and concentrations of cosmogenic 10Be in river sands. Our data reveal that catchments draining Japan's eastern seaboard have distinctly different tectonic, lithological, topographic, and climatic characteristics, underscored by a marked asymmetric pattern of erosion rates along and across the island arc. Erosion rates are highest in the Japanese Alps that mark the collision of two subduction zones, where high topographic relief, hillslope and bedrock-channel steepness foster rapid denudation by mass wasting. Comparable, if slightly lower, rates characterize southwest Japan, most likely due to higher typhoon-driven rainfall totals and variability rather than the similarly high relief and contemporary uplift rates that are linked to subduction earthquake cycles, and outpace long-term Quaternary uplift. In contrast, our estimated erosion and flux rates are lowest in the inner forearc catchments that feed sediment into the Japan Trench. We conclude that collisional mountain-building of the Japanese Alps causes the highest erosion rates anywhere on the island arc despite similar uplift and precipitation controls in southwest Japan. We infer that, prior to extensive river damming and reservoir construction, the gross of Japan's total sediment export to the Pacific Ocean entered the accretionary margin of the Nankai Trough as opposed to the comparatively sediment-starved Japan Trench. Although this pattern mimics the long-term mass balance of incoming sediment to these subduction zones, future work will be needed to constrain the relative contribution of terrestrial sediment input on 103-yr timescales.

  12. Ribosomal DNA haplotype distribution of Bursaphelenchus xylophilus in Kyushu and Okinawa islands, Japan

    PubMed Central

    Nose, Mine; Miyahara, Fumihiko; Ohira, Mineko; Matsunaga, Koji; Tobase, Masashi; Koyama, Takao; Yoshimoto, Kikuo

    2009-01-01

    Ribosomal DNA region sequences (partial 18S, 28S and complete ITS1, 5.8S, and ITS2) of the pinewood nematode (Bursaphelenchus xylophilus) were obtained from DNA extracted directly from wood pieces collected from wilted pine trees throughout the Kyushu and Okinawa islands, Japan. Either a 2569bp or 2573bp sequence was obtained from 88 of 143 samples. Together with the 45 rDNA sequences of pinewood nematode isolates previously reported, there were eight single nucleotide polymorphisms and two indels of two bases. Based on these mutations, nine haplotypes were estimated. The haplotype frequencies differed among regions in Kyushu island (northwest, northeast and center, southeast, and southwest), and the distribution was consistent with the invasion and spreading routes of the pinewood nematode previously estimated from past records of pine wilt and wood importation. There was no significant difference in haplotype frequencies among the collection sites on Okinawa island. PMID:22736814

  13. Ribosomal DNA haplotype distribution of Bursaphelenchus xylophilus in Kyushu and Okinawa islands, Japan.

    PubMed

    Nose, Mine; Shiraishi, Susumu; Miyahara, Fumihiko; Ohira, Mineko; Matsunaga, Koji; Tobase, Masashi; Koyama, Takao; Yoshimoto, Kikuo

    2009-09-01

    Ribosomal DNA region sequences (partial 18S, 28S and complete ITS1, 5.8S, and ITS2) of the pinewood nematode (Bursaphelenchus xylophilus) were obtained from DNA extracted directly from wood pieces collected from wilted pine trees throughout the Kyushu and Okinawa islands, Japan. Either a 2569bp or 2573bp sequence was obtained from 88 of 143 samples. Together with the 45 rDNA sequences of pinewood nematode isolates previously reported, there were eight single nucleotide polymorphisms and two indels of two bases. Based on these mutations, nine haplotypes were estimated. The haplotype frequencies differed among regions in Kyushu island (northwest, northeast and center, southeast, and southwest), and the distribution was consistent with the invasion and spreading routes of the pinewood nematode previously estimated from past records of pine wilt and wood importation. There was no significant difference in haplotype frequencies among the collection sites on Okinawa island. PMID:22736814

  14. Cheilopallene ogasawarensis, a New Species of Shallow-Water Pycnogonid (Arthropoda: Pycnogonida) from the Ogasawara (Bonin) Islands, Japan, Northwest Pacific.

    PubMed

    Nakamura, Koichiro; Akiyama, Tadashi

    2015-01-01

    A new species of pycnogonid recorded from the shallow waters of Ogasawara (Bonin) Island, Japan, Cheilopallene ogasawarensis n. sp. is described, illustrated and compared with similar species. Cheilopallene ogasawarensis is only the third pycnogonid species recorded from these islands. Morphological characters clearly distinguish the new species from its geographically closest congener C. nodulosa Hong and Kim, 1987, also recorded from Japanese waters. PMID:26250303

  15. The outbreak of mumps in a small island in Japan.

    PubMed

    Oda, K; Kato, H; Konishi, A

    1996-06-01

    A major mumps outbreak occurred on a small island, Ikeshima. in Nagasaki Prefecture from August 1994 to February 1995. There were 236 patients with the mumps at Ikeshima Miners' Hospital during that period. The Measles-Mumps-Rubella (MMR, Toitsukabu) vaccination coverage in the 43 children at the nursery school was 65.1% and it was 61.9% in the 21 children aged 4-5 years not attending the nursery school. Coverage was 66.6% in the 63 kindergarten students and 53.7% in 56 first-graders. The overall MMR vaccination coverage among these children was 61.7% (113/183) from 1989 to 1992. Children from the second grade to junior high school received monovalent mumps vaccine, Torii strain. None received Zishakabu MMR. The age of the patients ranged from 1 to 43 years, with a mean of 9.1 years. The majority (77.5%) were primary school children. The attack rates for vaccinated and unvaccinated children in grades one to six were: 6.7% (2/30) and 88.5% (23/26), 25% (3/12) and 44.1% (30/68), 11.1% (1/9) and 64.4% (29/45), 25% (2/8) and 60% (45/79), 22.2% (2/9) and 35.9% (28/78). 0% (0/5) and 24.7% (18/73), respectively. The overall frequency in the primary school was 41.4% (183/442 children). The frequency in the nursery school for children aged 4-5 years was 14.0% (6/43). It was 17.5% (11/63) in children aged 5-6 years in the kindergarten, 5.2% (11/213) in children not attending school with an age range of 1-5 years, and 4.2% (10/237) in junior high school students. Although the frequencies of MMR coverage for the nursery school children and kindergarteners were not high enough to eradicate mumps outbreaks, the MMR vaccination program was thought to have influenced the low frequency of mumps among the children. Close physical interactions among the first-graders would have contributed to their high frequency of mumps. Some patients presented with suspected mumps parotitis several times, but no such serological confirmation of reinfection was obtained. PMID:8741310

  16. Science education in Elementary school by using of "Geopark", Oki Islands, Japan

    NASA Astrophysics Data System (ADS)

    Oku, S.; Matsumoto, I.

    2012-12-01

    The Oki islands are located at Japan sea coast side of southwest Japan and belonging to Shimane Prefecture. And there is rich Nature which is consist of mainly alkaline volcanic rocks and metamorphic rocks. Aiming at authorization "Geopark" authorization of Oki Islands, Geologist, Biologist, and residents of Oki Islands are doing investigation and advertisement. Promotion of the science education which utilized the precious Nature, or environmental education is very important in the viewpoint of the science literacy which can protect a Nature and the earth. In this presentation, we mainly propose activity at an elementary school about how to advance the science education by using of this precious Nature. Children learn about the geology which constitutes the ground, and its petro-genesis in the Science of the sixth grade of elementary school. The viewpoint of having been formed by volcano, Earthquake, etc, in long global time is important for the precious and beautiful geology which constitutes the ground. It is at the same time important for a global change to teach also about often doing serious damage to human beings or a living thing with an Earthquake, a volcano, tsunami, etc. That is, we can push (teaching beautiful geology and a precious living thing using "Geopark"), and can learn about the blessing and disaster of a Nature. Moreover, teaching materials and teaching tools like a local textbook or a signboard with which a teacher and a resident can teach them to a child are required.

  17. Modeling Deformation Processes of Northeastern Japan Island Arc Considering Rheological Structure Affected by Hot Mantle Fingers

    NASA Astrophysics Data System (ADS)

    Shibazaki, B.; Muto, J.; Matsumoto, T.; Iinuma, T.

    2014-12-01

    The northeastern Japan island arc is one of the most favorable locations for studying rheological structures because many observational data are available, including seismological, geodetic, and geothermal data, and also because significant crustal deformation has been taking place since the 2011 Tohoku-oki earthquake. Dense geothermal observations were conducted using Hi-net boreholes (Matsumoto, 2007). By considering a thermal structure based on the dense geothermal observations, we model the stress state of the northeastern Japan island-arc crust using a finite element method with viscoelasticity and elastoplasticity. We consider realistic petrological structures of the upper crust, lower crust, and uppermost mantle to define flow properties. We apply an E-W contraction as a boundary condition. We reproduce several elongate low-stress regions as shown in the figure, where brittle-ductile transition zones are shallow, striking transverse to the arc with viscous deformation. These low-stress regions correspond to hot fingers (high-temperature regions in the mantle wedge, indicated by white lines in the figure). Regions with seismicity correspond to regions with high stress accumulation outside of the hot fingers and many intraplate earthquakes occur within these regions. The viscous relaxation process after the 2011 Tohoku-oki earthquake could have been affected by the existence of low-viscosity regions caused by the hot fingers. A finite element model is developed to investigate the viscoelastic deformation processes after the earthquake, which consider the realistic crustal and mantle structures, viscoelasticity, and coseismic fault slip distribution (Iinuma et al., 2012). We also consider the realistic 3D heterogeneous viscosity distribution in the crust and the upper mantle beneath the northeastern Japan island arc. Our numerical results indicate that significant extensional viscous deformation occurrs in the low-viscosity regions in the hot fingers. This affects the crustal movements in the inland area significantly.

  18. Resilience in schizophrenia: A comparative study between a remote island and an urban area in Japan.

    PubMed

    Yoshida, Kazunari; Suzuki, Takefumi; Imasaka, Yasushi; Kubo, Ken-Ichiro; Mizuno, Yuya; Saruta, Juri; Tsukinoki, Keiichi; Mimura, Masaru; Uchida, Hiroyuki

    2016-03-01

    The resilience levels between patients with schizophrenia residing in a rural island and a metropolitan area in Tokyo, Japan, was compared and the factors associated with resilience were explored. The Resilience Scale (RS) and EuroQol were assessed, together with biological markers and multiple demographic variables. No significant difference was found in the RS scores between the two groups (40 subjects each). However, longer duration of illness and higher EuroQol score were significantly associated with a greater RS score, which indicates that potentially successful adaptation and subjective perspectives appear more pertinent than the degree of urbanicity in determining resilience levels. PMID:26805409

  19. Japan.

    ERIC Educational Resources Information Center

    Geiger, Rita; And Others

    The document offers practical and motivating techniques for studying Japan. Dedicated to promoting global awareness, separate sections discuss Japan's geography, history, culture, education, government, economics, energy, transportation, and communication. Each section presents a topical overview; suggested classroom activities; and easily

  20. Japan.

    ERIC Educational Resources Information Center

    Geiger, Rita; And Others

    The document offers practical and motivating techniques for studying Japan. Dedicated to promoting global awareness, separate sections discuss Japan's geography, history, culture, education, government, economics, energy, transportation, and communication. Each section presents a topical overview; suggested classroom activities; and easily…

  1. Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Lynett, Patrick; Weiss, Robert; Renteria, Willington; De La Torre Morales, Giorgio; Son, Sangyoung; Arcos, Maria Elizabeth Martin; MacInnes, Breanyn Tiel

    2013-06-01

    On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the Mw 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the archipelago; (from west to east) Isabela, Santiagio, Santa Cruz, and San Cristobal. Access to the tsunami affected areas was one of the largest challenges of the field survey. Aside from approximately ten sandy beaches open to tourists, all other shoreline locations are restricted to anyone without a research permit; open cooperation with the Galapagos National Park provided the survey team complete access to the Islands coastlines. Survey locations were guided by numerical simulations of the tsunami performed prior to the field work. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum tsunami heights were generally in the range of 3-4 m with the highest runup of 6 m measured in a small pocket beach on Isla Isabela. Puerto Ayora, on Santa Cruz Island, the largest harbor in the Galapagos experienced significant flooding and damage to structures located at the shoreline. A current meter moored inside the harbor recorded relatively weak tsunami currents of less than 0.3 m/s (0.6 knot) during the event. Comparisons with detailed numerical simulations suggest that these low current speed observations are most likely the result of data averaging at 20-min intervals and that maximum instantaneous current speeds were considerably larger. Currents in the Canal de Itabaca, a natural waterway between Santa Cruz Island and a smaller island offshore, were strong enough to displace multiple 5.5-ton navigation buoys. Numerical simulations indicate that currents in the Canal de Itabaca exceeded 4 m/s (~8 knots), a very large flow speed for a navigational waterway.

  2. Spatial variations in the Kuroshio nutrient transport from the East China Sea to south of Japan

    NASA Astrophysics Data System (ADS)

    Guo, X. Y.; Zhu, X.-H.; Long, Y.; Huang, D. J.

    2013-04-01

    Based on absolute geostrophic velocity calculated from repeated hydrographic data of 39 cruises from 2000 to 2009 and nitrate concentrations measured at the same sections from 1964 to 2011, we obtained temporally averaged nitrate flux (the product of velocity and nitrate concentration) and nitrate transport (integration of flux over a section) through 4 sections along the Kuroshio path from the East China Sea (sections PN and TK) to south of Japan (sections ASUKA and 137E). In addition, we examined section OK east of the Ryukyu Islands in order to understand the contribution of Ryukyu Current to the Kuroshio nutrient transport south of Japan. The mean nitrate flux shows a subsurface maximum core with a value of 10, 10, 11, 11, and 6 mol m-2 s-1 at sections PN, TK, ASUKA, 137E, and OK, respectively. The depth of subsurface maximum core changes among five sections and is approximately 400, 500, 500, 400, and 800 m at sections PN, TK, ASUKA, 137E, and OK respectively. The mean downstream nitrate transport is 199.3, 176.3, 909.2, 1385.5, and 341.2 kmol m-1 at sections PN, TK, ASUKA, 137E, and OK respectively. The nutrient transports at these sections suggest the presence of Kuroshio nutrient stream from its upstream region to downstream. The deep current structure of Ryukyu Current (section OK) makes it contribute more nitrate transport than the Kuroshio in the East China Sea (section TK) to the Kuroshio south of Japan. In addition, the positive difference between the downstream nitrate transport through section ASUKA and the sum of nitrate transports through sections TK and OK, as well as the positive difference of downstream nitrate transport between sections 137E and ASUKA, suggest that the Kuroshio recirculation significantly intensifies the downstream (eastward) nitrate transport by the Kuroshio.

  3. Philippine Sea Slab and South-Ryukyu Arc Sliver Accommodation of Arc-Continent Collision East of Taiwan

    NASA Astrophysics Data System (ADS)

    Lallemand, S.; Theunissen, T.; Font, Y.; Schnurle, P.; Lee, C.; Liu, C.

    2011-12-01

    The southern termination of the Ryukyu arc-trench system underwent a complex polyphased and extremely rapid tectonic evolution during the last 5 to 8 My. At first, the relative motion of the Philippine Sea plate (PSP) has changed about 5 My ago from a northward to a northwestward motion relative to Eurasia. Secondly, the Ryukyu trench has propagated from east to west during the same time period resulting in a tectonic inversion along the former passive margin of the South China Sea into the active margin of the S-Ryukyu trench. Thirdly, the convergence rate along the neo-formed S-Ryukyu trench dramatically increased from 8 to 13 cm/yr since at least 2 My when the Southern Okinawa Trough (SOT) started to rift. At the same time, the oceanic subduction of the South China Sea beneath the northern Manila arc progressively evolved into a continental subduction of the Chinese platform at the origin of the Taiwan orogen. The timing of these various kinematic and tectonic events should have been recorded in the deformed sedimentary basins and fold-and-thrust belts in the region. Unfortunately, a large part is now below the sea-level and no or a few age constraints are available. The recent joint project between Taiwan-USA & France (TAIGER & ACTS) gave us the opportunity to considerably increase the resolution of the seismic imagery around the island and especially in the most highly deformed area east of Taiwan along the S-Ryukyu forearc. We already knew that the seismic activity focussed in this region but we ignored how the converging plates deformed. We can now argue that the PSP strongly deforms in the vicinity of its deep interaction with the root of the Taiwan orogen. The north-dipping PSP slab buckles and tears along two diverging directions with a down-faulted part subducting beneath the SOT.

  4. Analysis of ?O2/?CO2 ratios for the pollution events observed at Hateruma Island, Japan

    NASA Astrophysics Data System (ADS)

    Minejima, C.; Kubo, M.; Tohjima, Y.; Yamagishi, H.; Koyama, Y.; Maksyutov, S.; Kita, K.; Mukai, H.

    2012-03-01

    Pollution events extracted from the in situ observations of atmospheric CO2 and O2 mixing ratios at Hateruma Island (HAT, 24 N, 124 E) during the period from October 2006 and December 2008 are examined. The air mass origins for the pollution events are categorized by using back trajectory analysis, and the oxidative ratios (OR = -O2:CO2 molar exchange ratio) for selected pollution events are calculated. We find that there is a significant difference in the average oxidative ratios between events from China (OR = 1.14 0.12, n = 25) and Japan/Korea (OR = 1.37 0.15, n = 16). These values are in a good agreement with the national average oxidative ratios for the emissions from fossil fuel burning and cement production (FFBC) in China (ORFFBC = 1.11 0.03) and Korea/Japan (ORFFBC = 1.36 0.02). Compared with the observation, simulations of the atmospheric O2 and CO2 mixing ratios using Lagrangian particle dispersion models do a good job in reconstructing the average oxidative ratio of the pollution events originating in China but tend to underestimate for events originating in Japan/Korea. A sensitivity test suggests that the simulated atmospheric oxidative ratios at HAT are especially sensitive to changes in Chinese fuel mix.

  5. Assessment of the Chile 2010 and Japan 2011 Tsunami Events in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Renteria, Willington; Lynett, Patrick

    2015-04-01

    The object of this study is to present an analysis of measurements and observations from the Chile 2010 and Japan 2011 tsunamis, in order to understand the particular response of the Galápagos Islands to the occurrence of these extreme events. There was very limited data measured in the Galápagos during the tsunami events, other than a high-frequency and continuous record of each event logged at the two tidal gauge stations. With this data, a wavelet analysis is performed with the aim of discriminating different patterns in wave periods along the record of observation and to recognize the frequency response of the islands to an incoming tsunami. During both events, a clear and persistent signal is found in the period range of ten to twelve minutes for Baltra tide gauge, and in the range of seventeen to twenty minutes for Santa Cruz tide gauge. Both of these persistent signals are speculated to be a shelf resonant mode particular to the Galápagos Islands and the Galápagos Platform.

  6. Japan.

    ERIC Educational Resources Information Center

    Jones, Savannah C.

    Materials for a secondary level, interdisciplinary social studies course on Japan are divided into introductory information, 14 classroom units, and study and evaluation materials. Introductory material includes lists of objectives and skills, an outline of Japanese history, and an explanation of Japan's name and flag. The units cover the

  7. Japan.

    ERIC Educational Resources Information Center

    Jones, Savannah C.

    Materials for a secondary level, interdisciplinary social studies course on Japan are divided into introductory information, 14 classroom units, and study and evaluation materials. Introductory material includes lists of objectives and skills, an outline of Japanese history, and an explanation of Japan's name and flag. The units cover the…

  8. A new species of Jesogammarus from the Iki Island, Japan (Crustacea, Amphipoda, Anisogammaridae)

    PubMed Central

    Tomikawa, Ko

    2015-01-01

    Abstract A new species of anisogammarid amphipod, Jesogammarus (Jesogammarus) ikiensis sp. n., is described from freshwaters in the Iki Island, Nagasaki Prefecture, Japan, based on results of morphological and molecular analyses. The new species is distinguished from all members of the genus by the combination of small number of setae on dorsal margins of pleonites 1–3, short and small number of setae on posterior margins of peduncular articles of antennae, mandibular article 1 without setae, well developed posterior lobes of accessory lobes of coxal gills on gnathopod 2 and pereopods 3–5, and pectinate setae on palmar margin of female gnathopod 2. A key to all the species of Jesogammarus is provided. PMID:26692798

  9. Factors Affecting Groundwater Chemistry in Abandoned Terraced Paddy Fields on Sado Island, Japan

    NASA Astrophysics Data System (ADS)

    Oyanagi, Nobuhiro; Nakata, Makoto; Matsuyama, Keiko; Tsujii, Norie; Tsuchida, Takeyoshi

    The factors affecting the groundwater level and chemistry in abandoned terraced paddy fields on Sado Island, Japan, were investigated. Seasonal changes of the groundwater level in site A, which is on the bottom of the slope, was slight throughout the year compared with that in site B, which is on the middle part of the gentle slope. EC, pH, and some components involved in mineral weathering (Na+, Ca2+ and alkalinity) in the groundwater from site A were higher than those from site B. These results showed that the infiltrating water from the upper part of the slope was the main source of the groundwater in site A. On the other hand, the impact of sea salt components (Na+ and Cl-) was evident in site B, because the concentration of these components increased during winter. Groundwater chemistry was also affected by other factors such as the dilution of groundwater caused by rainfall, sulfur redox, and nutrient uptake by vegetation. The effects of each factor on groundwater chemistry differed between sites because the topography of the two adjacent sites was different. The characteristics of water environment, such as the groundwater level and chemistry, should be considered in the management of abandoned terraced paddy fields on Sado Island.

  10. Delineation of the distributions of sand bodies in the offshore Sado Island, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, T.; Saeki, T.; Takano, O.; Shimoda, N.

    2009-12-01

    The Sadooki Nansei 3D seismic survey was carried out in the deep water of the southwest offshore Sado Island in the Sea of Japan by the Ministry of Economics, Trade and Industry (METI). The bottom simulating reflectors (BSRs) in the Pleistocene Haizume Formation on the seismic data indicate the existence of methane hydrates (MH) in the region, and MH nodules have been collected from mud layers beneath the sea floor. According to several recent researches that have been done in other areas around Japan, MH can concentrate within porous media such as turbidite sand layers, and the distributions of sand bodies within turbidite systems are successfully imaged by higher amplitude reflectors on 3D seismic data. In this study, the 3D seismic cube is mainly used to map the distributions of sand bodies, which leads to estimation of MH concentrations. The greater part of sediments in the Haizume Formation consists of mud or fine-grained sediments deposited in deep marine environment. The coarse-grained deposits generally yield acoustic impedance contrasts to their surrounding mud layers, and they should be shown as relatively higher amplitude reflectors, either peaks or troughs, on the 3D seismic data. Therefore, several high amplitude reflectors are tracked upon the assumptions that the high amplitude reflectors correspond to sand bodies. Numerous submarine fans and landslide deposits in the Haizume Formation are identified along the flanks of the northward-striking Umitaka Spur on the seismic data. The turbidites deposited in numerous submarine channels can be observed east of the spur. The reflectors of coarse-grained deposits in submarine fans or channels tend to have relatively higher amplitude values than their surroundings. The landslide deposits exhibit chaotic low amplitude reflectors overlain by high amplitude reflectors on the seismic cross sections. The depositional patterns can be estimated by images of seismic amplitude values draped onto interpreted horizons. Imaging and estimating the distributions of sand bodies within turbidite deposits using high amplitude reflectors will help the evaluation of the MH concentrations in the offshore Sado Island region. Acknowledgment: This study was carried out in the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium). The authors express their gratitude to MH21 Research Consortium for the permission to publish the result of this study.

  11. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people.

    This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features.

    The ASTER instrument is a cooperative project between NASA, JPL, and the Japanese Ministry of International Trade and Industry.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

    Size: Island is approximately 8 kilometers (5 miles) in diameter Location: 34.1 deg. North lat., 139.5 deg. East lon. Orientation: View toward the west-southwest. Image Data: ASTER visible and near infrared Date Acquired: February 20, 2000 (SRTM), July 17, 2000 (ASTER)

  12. Contributions of increased agricultural abandonment area to recent surface warming trend in Shikoku Island, Japan

    NASA Astrophysics Data System (ADS)

    Yoshida, R.; Nishimori, M.; Iizumi, T.; Osawa, T.

    2012-04-01

    A remarkable increasing trend in abandoned cropland has already been observed in hilly and mountainous areas, Japan. Changes to abandoned areas from cropland (typically, paddy fields) could have impacts on surface air temperatures and their trends. We evaluated contributions of land surface change, specifically, the recently reported increases in abandoned cropland on daily maximum, mean, and minimum temperature with Shikoku Island, Japan where croplands have been significantly decreasing taken as an example. Land use change was expressed by the modifications of physical land surface parameters, i.e., surface albedo, evaporative efficiency, roughness length, heat capacity, and thermal conductivity. The sensitivity of the air temperatures to each land surface parameter was then derived from the numerical experiments using three-dimensional regional atmospheric model (JMA-NHM) and artificially modified land surface conditions. An accurate estimation of the contributions is expected as the JMA-NHM model allows us to consider three-dimensional land-atmosphere interactions that are impossible for one-dimensional land surface model alone. We set the five land surface parameters and calculated a sensitivity of temperatures in regard to each land surface parameter change for the periods of 15th June to 15th August 1985, 1990, 1995, 2000, and 2005 when cropland area are presented in Japan. The experiment result showed that surface albedo and evaporative efficiency had significant sensitivity on the daily maximum and mean temperatures whereas heat capacity and thermal conductivity were impactful on the daily minimum temperature. Roughness length was less impactful for any temperatures. Parameter sensitivity showed geographical distribution, such as significant impact in inland area rather than coastal area for the response of daily mean temperature by surface albedo and evaporative efficiency changes. Lower sensitivity in coastal area was attributed to thermal advection from surrounding sea (e.g. land and sea breeze), mitigating air temperature changes caused by land surface parameter change. We derived geographical distributions of parameter sensitivity on air temperatures with these processes. Temperature changes for 1985-2005 caused by cropland decreasing or abandoned cropland and building lots increasing were estimated based on parameter sensitivity to temperatures which were derived in previous calculation and cropland area data obtained from the Census for Agriculture, Forestry and Fisheries data set (Ministry of Agriculture, Forestry and Fisheries, Japan). Calculated temperature changes for 21-years using the sensitivity and the dataset were respectively 39.6, 46.0, and 27.5 % for the daily maximum, mean and minimum temperature to trends of 18-sites averaged observation stations in Shikoku Island, indicating significant impact of land surface change on air temperatures. An evaluation method we applied in this study first calculated land surface parameter sensitivities on air temperatures with three-dimensional atmospheric model and secondly calculated linear combination of products of each sensitivity and cropland change ratio. Although first calculation needs high calculation cost because it uses three-dimensional atmospheric model, second one has little cost if once sensitivities were derived. This method would enable us to make air temperature change scenario caused by various land use change scenario without high numerical calculation costs.

  13. Analysis of ?O2/?CO2 ratios for the pollution events observed at Hateruma Island, Japan

    NASA Astrophysics Data System (ADS)

    Minejima, C.; Kubo, M.; Tohjima, Y.; Yamagishi, H.; Koyama, Y.; Maksyutov, S.; Kita, K.; Mukai, H.

    2011-05-01

    In-situ observations of atmospheric CO2 and O2 concentrations at Hateruma Island (HAT, 24 N, 124 E) often show synoptic scale pollution events when air masses are transported from East Asian source regions. We calculate the regression slopes (-?O2/?CO2 molar ratios) of the correlation plots between O2 and CO2 for selected pollution events observed between October 2006 and December 2008. The observed -?O2/?CO2 ratios vary from 1.0 to 1.7. Categorizing the air mass origins for the pollution events by using back trajectory analysis, we find that there is a significant difference in the average -?O2/?CO2 ratios between events from China (1.140.12, n = 25) and Japan/Korea (1.370.15, n = 16). These values are comparable to the -O2:CO2 molar exchange ratios, which are estimated from the national fossil fuel inventories from CDIAC. Simulations using a particle dispersion model reveal that the pollution events at HAT are predominantly CO2 emissions from the combustion of fossil fuels in East Asian countries, which is consistent with the above observational results. Although the average value of the model-predicted -?O2/?CO2 ratios for Japan/Korea origin is underestimated in comparison with the observation, that for China origin agree well with the observation. The sensitivity experiment suggests that the -?O2/?CO2 ratio at HAT reflects about 90% of the change in the -O2:CO2 exchange ratio for the fossil carbon emissions from China.

  14. Past environmental reconstruction by coral annual bands collected near the Yonaguni Island, southwest Japan

    NASA Astrophysics Data System (ADS)

    Abe, O.; Kobayashi, F.

    2006-12-01

    Ninety-year record of stable isotope ratios (O-18/O-16 and C-13/C-12) of the Porites coral skeleton collected from Yonaguni Island, southwestern end of Japan was retrieved to reconstruct past seawater temperature and anthropogenic carbon input to the ocean. In order to use coral delta O-18 as a proxy for water temperature, it is first essential to calibrate the oxygen isotope ratio of coral skeletal CaCO3 with the observed temperature variations. So we had measured water temperature continuously next to the coral colony from March 1999 to March 2001. Using water temperature and associated records of coral delta O-18, the following equation was obtained. delta O-18coral (permil wrtPDB) = - 0.204 t (deg.C) + 0.461 r2= 0.95 Reconstructed Long-term trend of reconstructed water temperature was almost consistent with those of ship- based and gridded SST and surface air temperature at Isigaki island (1911~2001). Coral delta C-13 time series record shows a marked depletion by ~1.5E (1911~2001). In particular, there exists a remarkable depletion by 0.18E per decade between 1970s and 1990s, which shows a similar trend to the global average of change in surface DIC-delta C-13 of -0.16E reported by Quey et al. (2003). This result is probably due to the oceanic uptake of anthropogenic CO2 that has been progressively depleted in 13C mainly by fossil fuel combustion.

  15. Macrogenomic Evidence for the Origin of the Black Fly Simulium suzukii (Diptera: Simuliidae) on Okinawa Island, Japan

    PubMed Central

    Adler, Peter H.; Huang, Yao-Te; Reeves, Will K.; Kim, Sam Kyu; Otsuka, Yasushi; Takaoka, Hiroyuki

    2013-01-01

    To determine the geographic origin of the black fly Simulium suzukii on Okinawa Island, Japan, macrogenomic profiles derived from its polytene chromosomes were compared with those of mainland and other insular populations of S. suzukii and of the isomorphic Simulium tani species complex. The Okinawan population is a chromosomally unique cytoform, designated D, which is essentially monomorphic and differs by about 27 fixed rearrangements from the chromosomal standard sequence for the subgenus Simulium and by two fixed differences from its nearest known relative, representing the type of S. suzukii, on the main islands of Japan. Chromosomal band sequences revealed two additional, sympatric cytoforms of S. suzukii, designated A and B, each with species status, in Korea, and a third cytoform, designated C, on Hokkaido, Japan. A new cytoform, K, of S. tani from Malaysia, representing the type of S. tani, is more closely related to cytoforms in Thailand, as are populations from Taiwan previously treated as S. suzukii but more closely aligned with S. tani and newly recognized as cytoform L of the latter nominal species. Rooting of chromosomal band sequences by outgroup comparisons allowed directionality of chromosomal rearrangements to be established, enabling phylogenetic inference of cytoforms. Of 41 macrogenomic rearrangements discovered in the five new cytoforms, four provide evidence for a stepwise origin of the Okinawan population from populations characteristic of the main islands of Japan. The macrogenomic approach applied to black flies on Okinawa Island illustrates its potential utility in defining source areas for other species of flies including those that might pose medical and veterinary risks. PMID:23951001

  16. Topography-specific seed dispersal by Japanese macaques in a lowland forest on Yakushima Island, Japan.

    PubMed

    Tsujino, Riyou; Yumoto, Takakazu

    2009-01-01

    1. We investigated patterns of seed dispersal (i.e. dispersal distances and topography of seed-deposition sites) via the cheek pouches of Japanese macaques (Macaca fuscata yakui) during three seasons in a lowland forest on Yakushima Island, Japan. 2. The mean seed-dispersal distances were 16.7, 26.1, 41.8, and 32.4 m from the trunks of mother trees of Myrica rubra, Persea thunbergii, Neolitsea sericea, and Litsea acuminata, respectively. 3. We assessed the possible effect of macaque foraging patterns and the spatial distribution of fruiting trees on topography-specific seed dispersal. The topography of the locations of macaques differed across seasons, likely because the spatial distribution of fruiting trees determined the seasonal foraging patterns of macaques. 4. In early summer, macaques foraged on a ridge and fed on fruits of M. rubra and P. thunbergii, which were primarily distributed and dispersed within this area. In contrast, during the winter, macaques foraged within a valley and fed on fruits of L. acuminata, which were chiefly distributed and dispersed within the valley. 5. Seeds of M. rubra, P. thunbergii, and L. acuminata were directly dispersed to the specific topographic areas in which adult trees were distributed and in which juveniles have a predictably high probability of survival relative to random sites. PMID:19120599

  17. Litter dynamics and particulate organic matter outwelling from a subtropical mangrove in Okinawa Island, South Japan

    NASA Astrophysics Data System (ADS)

    Mfilinge, Prosper L.; Meziane, Tarik; Bachok, Zainudin; Tsuchiya, Makoto

    2005-04-01

    Litter dynamics and outwelling of particulate organic matter (POM) was investigated in a subtropical mangrove (Okinawa Island, South Japan) in order to quantify the impact of mangrove POM on adjacent intertidal sediments. A distinct seasonal pattern was found with maximum litter fall during the autumn season, and minimum during winter. Total litter production between sites did not differ significantly. Tall mangroves (average 7 m) did not show any higher contribution to the litter production than short mangroves (average 4 m). The mean annual litter production was 12.95 2.95 t ha -1 (dry weight) with leaf fall contributing more than 70% of the total litter production. Analysis of fatty acids (FAs) in the surface sediments of an adjacent mud flat and sand flat during the winter, spring and autumn seasons indicated that outwelling of POM from the mangrove ecosystem occurs. However, it is spatially restricted to within 300 m from the mangrove forest. The magnitude of the outwelling increased during spring and autumn consistent with the increase in the total litter production. Despite the presence of mangrove-derived organic matter in the estuarine surface sediments, autochthonous sources of organic matter, green macroalgae ( Ulva pertusa and Enteromorpha intestinalis), diatoms and bacteria are the main contributors of sedimentary organic matter and ?3 and ?6 PUFAs than mangrove-derived (POM) during winter and spring. While the contribution of mangrove-derived POM to sedimentary organic matter is limited to the autumn season.

  18. Coverage, Diversity, and Functionality of a High-Latitude Coral Community (Tatsukushi, Shikoku Island, Japan)

    PubMed Central

    Denis, Vianney; Mezaki, Takuma; Tanaka, Kouki; Kuo, Chao-Yang; De Palmas, Stphane; Keshavmurthy, Shashank; Chen, Chaolun Allen

    2013-01-01

    Background Seawater temperature is the main factor restricting shallow-water zooxanthellate coral reefs to low latitudes. As temperatures increase, coral species and perhaps reefs may move into higher-latitude waters, increasing the chances of coral reef ecosystems surviving despite global warming. However, there is a growing need to understand the structure of these high-latitude coral communities in order to analyze their future dynamics and to detect any potential changes. Methodology/Principal Findings The high-latitude (32.75N) community surveyed was located at Tatsukushi, Shikoku Island, Japan. Coral cover was 602% and was composed of 73 scleractinian species partitioned into 7 functional groups. Although only 6% of species belonged to the plate-like functional group, it was the major contributor to species coverage. This was explained by the dominance of plate-like species such as Acropora hyacinthus and A. solitaryensis. Comparison with historical data suggests a relatively recent colonization/development of A. hyacinthus in this region and a potential increase in coral diversity over the last century. Low coverage of macroalgae (2% of the benthic cover) contrasted with the low abundance of herbivorous fishes, but may be reasonably explained by the high density of sea urchins (12.93.3 individuals m?2). Conclusions/Significance The structure and composition of this benthic community are relatively remarkable for a site where winter temperature can durably fall below the accepted limit for coral reef development. Despite limited functionalities and functional redundancy, the current benthic structure might provide a base upon which a reef could eventually develop, as characterized by opportunistic and pioneer frame-building species. In addition to increasing seawater temperatures, on-going management actions and sea urchin density might also explain the observed state of this community. A focus on such marginal communities should be a priority, as they can provide important insights into how tropical corals might cope with environmental changes. PMID:23342135

  19. Genome-wide SNP analysis explains coral diversity and recovery in the Ryukyu Archipelago.

    PubMed

    Shinzato, Chuya; Mungpakdee, Sutada; Arakaki, Nana; Satoh, Noriyuki

    2015-01-01

    Following a global coral bleaching event in 1998, Acropora corals surrounding most of Okinawa island (OI) were devastated, although they are now gradually recovering. In contrast, the Kerama Islands (KIs) only 30 km west of OI, have continuously hosted a great variety of healthy corals. Taking advantage of the decoded Acropora digitifera genome and using genome-wide SNP analyses, we clarified Acropora population structure in the southern Ryukyu Archipelago (sRA). Despite small genetic distances, we identified distinct clusters corresponding to specific island groups, suggesting infrequent long-distance dispersal within the sRA. Although the KIs were believed to supply coral larvae to OI, admixture analyses showed that such dispersal is much more limited than previously realized, indicating independent recovery of OI coral populations and the necessity of local conservation efforts for each region. We detected strong historical migration from the Yaeyama Islands (YIs) to OI, and suggest that the YIs are the original source of OI corals. In addition, migration edges to the KIs suggest that they are a historical sink population in the sRA, resulting in high diversity. This population genomics study provides the highest resolution data to date regarding coral population structure and history. PMID:26656261

  20. Genome-wide SNP analysis explains coral diversity and recovery in the Ryukyu Archipelago

    PubMed Central

    Shinzato, Chuya; Mungpakdee, Sutada; Arakaki, Nana; Satoh, Noriyuki

    2015-01-01

    Following a global coral bleaching event in 1998, Acropora corals surrounding most of Okinawa island (OI) were devastated, although they are now gradually recovering. In contrast, the Kerama Islands (KIs) only 30 km west of OI, have continuously hosted a great variety of healthy corals. Taking advantage of the decoded Acropora digitifera genome and using genome-wide SNP analyses, we clarified Acropora population structure in the southern Ryukyu Archipelago (sRA). Despite small genetic distances, we identified distinct clusters corresponding to specific island groups, suggesting infrequent long-distance dispersal within the sRA. Although the KIs were believed to supply coral larvae to OI, admixture analyses showed that such dispersal is much more limited than previously realized, indicating independent recovery of OI coral populations and the necessity of local conservation efforts for each region. We detected strong historical migration from the Yaeyama Islands (YIs) to OI, and suggest that the YIs are the original source of OI corals. In addition, migration edges to the KIs suggest that they are a historical sink population in the sRA, resulting in high diversity. This population genomics study provides the highest resolution data to date regarding coral population structure and history. PMID:26656261

  1. Neostygarctus lovedeluxe n. sp. from the Miyako Islands, Japan: the first record of Neostygarctidae (Heterotardigrada: Arthrotardigrada) from the Pacific.

    PubMed

    Fujimoto, Shinta; Miyazaki, Katsumi

    2013-05-01

    A new species of the previously monospecific marine tardigrade family Neostygarctidae is described. Neostygarctus lovedeluxe n. sp. was found from a submarine cave in Miyako Islands, Japan. This is the first record of Neostygarctidae from the Pacific. The new species is easily distinguished from the previously known N. acanthophorus by its number of dorsal spines, as N. lovedeluxe has two spines each on the three dorsal body plates in contrast to one in N. acanthophorus. Furthermore the morphology of the two clawed juvenile is reported for the first time in Neostygarctidae, providing new insights into the common sequence in some ontogenic traits. PMID:23646947

  2. A new species of Plestiodon (Squamata: Scincidae) from Kuchinoshima Island in the Tokara Group of the Northern Ryukyus, Japan.

    PubMed

    Kurita, Kazuki; Hikida, Tsutomu

    2014-07-01

    A scincid lizard of the genus Plestiodon from Kuchinoshima Island in the Tokara Group of the Northern Ryukyus, Japan, has proved to be genetically and morphologically differentiated from any previously recognized species in the genus. We thus describe this island population as a new species, Plestiodon kuchinoshimensis. The new species shows characteristics of the P. latiscutatus species group, but differs from other species of this group by the combination of the following character states: postnasal absent; hatchling with five longitudinal light lines on dorsum; lateral light line on each side passing over ear opening and the sixth to eighth scale rows at midbody; dorsolateral light line beginning from behind supraoculars; patch of enlarged irregular scales on posterior femur absent; scale rows around midbody 27-32; and brownish background on the dorsal surface of the juvenile. PMID:25001918

  3. Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

    PubMed Central

    Uyeda, S.; Hayakawa, M.; Nagao, T.; Molchanov, O.; Hattori, K.; Orihara, Y.; Gotoh, K.; Akinaga, Y.; Tanaka, H.

    2002-01-01

    Significant anomalous changes in the ultra low frequency range (?0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals. PMID:12032286

  4. Stable isotope compositions and water contents of boninite series volcanic rocks from Chichi-jima, Bonin Islands, Japan

    USGS Publications Warehouse

    Dobson, P.F.; O'Neil, J.R.

    1987-01-01

    Measurements of stable isotope compositions and water contents of boninite series volcanic rocks from the island of Chichi-jima, Bonin Islands, Japan, confirm that a large amount (1.6-2.4 wt.%) of primary water was present in these unusual magmas. An enrichment of 0.6??? in 18O during differentiation is explained by crystallization of 18O-depleted mafic phases. Silicic glasses have elevated ??18O values and relatively low ??D values indicating that they were modified by low-temperature alteration and hydration processes. Mafic glasses, on the other hand, have for the most part retained their primary isotopic signatures since Eocene time. Primary ??D values of -53 for boninite glasses are higher than those of MORB and suggest that the water was derived from subducted oceanic lithosphere. ?? 1987.

  5. New records of the caridean shrimp genus Processa Leach, 1815 (Crustacea: Decapoda: Processidae) from Japan, with descriptions of two new species.

    PubMed

    Komai, Tomoyuki; Fujita, Yoshihisa

    2014-01-01

    Three species of the processid shrimp genus Processa Leach, 1815, including two new species, are reported from shallow coastal waters in Okinawa Island, Ryukyu Islands, Japan: P. affinis Hayashi, 1975, P. filipes n. sp. and P. hayashii n. sp. The present specimens of P. affinis represent the rediscovery and range extension of this poorly known species, originally described from Indonesia. Male characteristics of P. affinis are documented for the first time. The two new species are referred to the P. aequimana Paulson, 1875 species group. Processa filipes n. sp. is characteristic in the greatly elongate fifth pereopod and the transverse ridge on thoracic sternite 8 consisting of soft cuticle. Processa hayashii n. sp. is characterized by the presence of a deep concavity on the anterolateral margin of the carapace just inferior to the antennal tooth. The number of species of Processa known from Japanese waters is raised from five to eight. PMID:24870323

  6. Neural network analysis for geological interpretation of tomographic images beneath the Japan Islands

    NASA Astrophysics Data System (ADS)

    Kuwatani, T.; Toriumi, M.

    2009-12-01

    Recent advances in methodologies of geophysical observations, such as seismic tomography, seismic reflection method and geomagnetic method, provide us a large amount and a wide variety of data for physical properties of a crust and upper mantle (e.g. Matsubara et al. (2008)). However, it has still been difficult to specify a rock type and its physical conditions, mainly because (1) available data usually have a lot of error and uncertainty, and (2) physical properties of rocks are greatly affected by fluid and microstructures. The objective interpretation and quantitative evaluation for lithology and fluid-related structure require the statistical analyses of integrated geophysical and geological data. Self-Organizing Maps (SOMs) are unsupervised artificial neural networks that map the input space into clusters in a topological form whose organization is related to trends in the input data (Kohonen 2001). SOMs are powerful neural network techniques to classify and interpret multiattribute data sets. Results of SOM classifications can be represented as 2D images, called feature maps which illustrate the complexity and interrelationships among input data sets. Recently, some works have used SOM in order to interpret multidimensional, non-linear, and highly noised geophysical data for purposes of geological prediction (e.g. Klose 2006; Tselentis et al. 2007; Bauer et al. 2008). This paper describes the application of SOM to the 3D velocity structure beneath the whole Japan islands (e.g. Matsubara et al. 2008). From the obtained feature maps, we can specify the lithology and qualitatively evaluate the effect of fluid-related structures. Moreover, re-projection of feature maps onto the 3D velocity structures resulted in detailed images of the structures within the plates. The Pacific plate and the Philippine Sea plate subducting beneath the Eurasian plate can be imaged more clearly than the original P- and S-wave velocity structures. In order to understand more precise prediction of lithology and its structure, we will use the additional input data sets, such as tomographic images of random velocity fluctuation (Takahashi et al. 2009) and b-value mapping data. Additionally, different kinds of data sets, including the experimental and petrological results (e.g. Christensen 1991; Hacker et al. 2003) can be applied to our analyses.

  7. Long-Range Transport of Perchlorate Observed in the Atmospheric Aerosols Collected at Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Arakaki, T.; Tanahara, A.; Oomori, T.; Miyagi, T.; Kadena, H.; Ishizaki, T.; Nakama, F.

    2007-12-01

    The study of perchlorate has become quite active in the U.S. in the last several years. Perchlorate has been recognized as a new environmental pollutant and it attracted much attention quickly in the world. The health concern about perchlorate stems from the fact that it displaces iodide in the thyroid gland, while iodine-containing thyroid hormones are essential for proper neural development from the fetal stage through the first years of life. In this study, we determined the concentrations of perchlorate ion present in the atmospheric aerosols collected in Okinawa Island, Japan. We then examined the relationships between the perchlorate concentrations and the environmental parameters and the climatic conditions peculiar to Okinawa. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS). Each sampling duration was one week. The quartz filters with aerosols were stirred with Milli-Q pure water for three hours before perchlorate ion was extracted. The extracted perchlorate ion concentrations were determined by ion chromatography (ICS-2000, DIONEX). The mean perchlorate concentration for the samples collected at CHAAMS was 1.83 ng/m3, and the minimum was 0.18 ng/m3. The samples collected during November 21-27, 2005, January 23-30, 2006 and April 24-01, 2006 had highest perchlorate concentrations. For these three samples, we performed back trajectory analysis, and found that the air mass for the three samples arrived from the Asian continent. A relatively strong correlation (r2 = 0.55) was found between perchlorate and nss-sulfate concentrations for the CHAAMS samples. Furthermore, we analyzed perchlorate in the soils and the fertilizers used for sugar cane farming around the CHAAMS area. The Milli-Q extract of the soil and the fertilizers did not contain any detectable levels of perchlorate ions. Therefore, it was suggested that perchlorate found in the atmospheric aerosols collected at CHAAMS was probably transported from the Asian continent.

  8. Influence of Land Development on Holocene Porites Coral Calcification at Nagura Bay, Ishigaki Island, Japan

    PubMed Central

    Sowa, Kohki; Watanabe, Tsuyoshi; Kan, Hironobu; Yamano, Hiroya

    2014-01-01

    To evaluate the relationships between coral calcification, thermal stress, and sedimentation and eutrophication linked to human impact (hereafter referred to as “land development”) by river discharge, we analyzed growth characteristics in the context of a paleoenvironment that was reconstructed from geochemical signals in modern and fossil (1.2 cal kyr BP and 3.5 cal kyr BP, respectively) massive Porites corals from Nagura Bay (“Nagura”) and from modern Porites corals from the estuary of the Todoroki River, Shiraho Reef (“Todoroki”). Both sites are on Ishigaki Island, Japan, and Nagura is located approximately 12 km west of Todoroki. At Nagura, the individual corals provide time windows of 13 (modern), 10 (1.2 cal kyr BP), and 38 yr in length (3.5 cal kyr BP). Here, we present the coral annual calcification for Nagura and Todoroki, and (bi) monthly resolved records of Sr/Ca (a proxy of sea surface temperature (SST)) and Ba/Ca (a proxy of sedimentation and nutrients related to land development) for Nagura. At Nagura, the winter SST was cooler by 2.8°C in the 1.2 cal kyr BP, and the annual and winter SSTs in the 3.5 cal kyr BP were cooler by 2.6°C and 4.6°C, respectively. The annual periodicity of Ba/Ca in modern coral is linked to river discharge and is associated with land development including sugar cane cultivation. Modern coral calcification also has declined with SST warming and increasing Ba/Ca peaks in winter. However, calcification of fossil corals does not appear to have been influenced by variations in Sr/Ca and Ba/Ca. Modern coral growth characteristics at Nagura and Todoroki indicate that coral growth is both spatially and temporally influenced by river discharge and land development. At Nagura, our findings suggest that land development induces negative thermal sensitivity for calcification in winter due to sugar cane harvest, which is a specifically modern phenomenon. PMID:24586393

  9. Gravity changes observed during the long-term slow slip events at the Ryukyu Trench in May 2012 and December 2012

    NASA Astrophysics Data System (ADS)

    Tanaka, Y.; Imanishi, Y.; Okubo, S.; Nawa, K.; Ikeda, H.; Miyaji, T.; Kazama, T.; Okamura, S.; Miyazaki, T.; Nakamura, M.

    2013-12-01

    Long-term slow-slip events (SSEs) have been observed in many plate-boundary zones along the circum-Pacific seismic belt. Previous studies have revealed that high-pressure fluids supplied from the subducted oceanic plate can generate SSEs. SSEs in different areas have different recurrence intervals. In general, the tectonic stress accumulation rates and the frictional properties on the plate boundaries control the intervals. Therefore, their differences are considered to cause the differences in the intervals. However, variations in fluid pressure will also change the intervals, because they affect the effective normal stress. Variations in fluid pressure are predicted by the earthquake-cycle model based on the fault valve behavior of Sibson (1992). So far, variations in fluid pressure associated with SSEs have not been detected by field observations. If a massive fluid pressure change occurred, gravity change could be observed since the corresponding density redistribution in the underground occurred. In the Tokai district in Japan, the SSE occurred during the years from 2000 to around 2006, and gravity changes in 2004-2009 that could be explained by a fluid pressure variation were detected (Tanaka et al., 2010). However, the quality of the data was not good due to the lower temporal resolution of the campaign data and the observation period did not cover the whole cycle of the SSE. So, a clear evidence of fluid-pressure change has not been obtained yet. In this study, we conduct a continuous gravity measurement using two absolute gravimeters and a superconducting gravimeter in Ishigakijima and Iriomotejima Islands at the Ryukyu Trench where SSEs have occurred twice a year (Heki and Kataoka, 2008) to observe a transient gravity change during the whole cycle of an SSE. In this presentation, we report gravity changes during the two slow slip events that occurred in May 2012 and December 2012.

  10. Underground dams for irrigation supplies in coastal limestone aquifer, Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Yasumoto, J.; Nakano, T.; Nawa, N.

    2011-12-01

    The use of underground dams to store water in regions with arid or tropical climates is a method that has received considerable attention in the last few decades. And now, for the tropical and subtropical islands that are highly vulnerable to climate change underground dams have been attracting attention again as a method of groundwater management. Okinawa Prefecture is Japan's southernmost prefecture, which consists of hundreds of islands in a chain over 1,000 km long, called the Ryukyu Islands which extend southwest from Kyushu to Taiwan. The national irrigation project of the Ryukyu Islands has been carried out, and several underground dams have been constructed. The Komesu and Giiza underground dams are first full scale underground dam facilities constructed for irrigation in Japan. The Komesu underground dam is a salt-water proof type. It prevents salt-water intrusion and provides storage fresh-water for irrigation in coastal limestone aquifer. Giiza underground dam is a dam up type for storage of fresh-water. These groundwater reservoirs are located in the coastal region of southern part of Okinawa (main island), where Ryukyu limestone is extensively distributed. We studied the behaviour of groundwater flow, saltwater intrusion and nitrate nitrogen (NO3-N) in groundwater in this region by using observation data of groundwater and springs through long term (from 1993 to 2010) monitoring. And, a groundwater flow and salt-water intrusion analysis have been conducted with three dimensional numerical model applied to these dam reservoir areas. The MODFLOW-NWT with SWI code and PEST was used to simulate the complex groundwater flow patterns. Through the comparison with simulation and observed data, it was concluded that the cut off wall of underground dams effectively stores the groundwater and prevents the salt-water intrusion in the reservoir areas. The observed groundwater levels at the reservoir areas were almost reproduced by the numerical model, but there were a few differences between the calculation and observation. The numerical model introducing non-darcian flow could be carried out to improve the model by inputting various data of geological structure of Ryukyu limestone. It was found that the NO3-N concentrations in springs ranged from 6.2 mg/L to 16.6mg/L during 17 years in this area. The NO3-N concentrations had decreased from the mid-1990s to early 2000s. And The NO3-N concentrations have not decreased or increased since early 2000s. Distribution of NO3-N concentrations shows variations according to location and they are roughly classified into two types (stable type and unstable type). It was considered that NO3-N concentrations were influenced by the rainfall, geological structure and land use of upland fields. The results show that the underground dams are a contribution in sustainable development of irrigation in Okinawa islands. The results also demonstrate that underground dam may be a very useful instrument of sustainable increase in the available storage in the tropical and subtropical coastal aquifers. The future challenge is how to decrease the high NO3-N concentrations in underground dam areas.

  11. Seasonal variation of water-soluble chemical components in the bulk atmospheric aerosols collected at Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Handa, D.; Nakajima, H.; Nakaema, F.; Arakaki, T.; Tanahara, A.

    2008-12-01

    The economic development and population growth in recent Asia spread air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. The study of the air pollution transported from Asian continent has gained a special attention in Japan. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location is ideal in observing East Asian atmospheric aerosols because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air masses which have been affected by anthropogenic activities. In 2005, Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) was established by the National Institute for Environmental Studies (NIES) at the northern tip of Okinawa Island, Japan to monitor the air quality of Asia. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations and dissolved organic carbon in the bulk aerosols collected at the CHAAMS, using ion chromatography, atomic absorption spectrometry, and total organic carbon analyzer, respectively. Seasonal variation of water-soluble chemical components showed that the concentrations were relatively low in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian Continent, the concentrations of water-soluble chemical components were much higher compared to the other directions.

  12. Spatial and temporal variations of chemicals in the TSP aerosols simultaneously collected at three islands in Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Arakaki, Takemitsu; Azechi, Sotaro; Somada, Yuka; Ijyu, Moriaki; Nakaema, Fumiya; Hitomi, Yuya; Handa, Daishi; Oshiro, Yoshito; Miyagi, Youichi; Tsuhako, Ai; Murayama, Hitomi; Higaonna, Yumi; Tanahara, Akira; Itoh, Akihide; Fukushima, Soko; Higashi, Kazuaki; Henza, Yui; Nishikawa, Rin; Shinjo, Hibiki; Wang, Hongyan

    2014-11-01

    East Asia's rapid economic growth has led to concerns about the emission of air pollutants. We collected total suspended particle (TSP) aerosol samples simultaneously at three islands in Okinawa, Japan, which are downwind of East Asia, during the Asian dust season, to examine the spatial and temporal variations and chemical transformations of major chemicals in the aerosols. Weekly samples were collected from July 2008 to June 2010, and the concentrations of water-soluble cations, anions, and organic carbon (WSOC) were determined (n = 303). Spatial distribution analysis showed that monthly mean concentrations of non-sea-salt (nss)-SO42- in the spring (Asian dust season) decreased with increasing distance from Asia, while the trend for NO3- was less evident, suggesting that chemical transformation affected the long-range transport of certain chemicals. Temporal variation analysis showed that concentrations of nss-SO42-, NO3-, and WSOC during the spring were about 2.0, 2.4, and 1.8 times those in the summer (cleaner air mass from the Pacific Ocean), respectively. This study demonstrated that air pollutants were transported from the Asian continent to the Okinawa islands and affected the air quality in the region. There may also be impacts on ecosystems, because increased concentrations of particulate NO3- could increase nutrient levels around the Okinawa islands.

  13. Pempheris ufuagari sp. nov., a new species in the genus Pempheris (Perciformes, Pempheridae) from the oceanic islands of Japan.

    PubMed

    Koeda, Keita; Yoshino, Tetsuo; Tachihara, Katsunori

    2013-01-01

    Pempheris ufuagari sp. nov. is described based on 10 specimens, 143.9-196.8 mm in standard length, collected from Mi-nami Daito Island and Ogasawara Islands, which are oceanic islands of Japan. Pempheris ufuagari is characterized by a distinct black spot on the pectoral fin base, a bright yellow dorsal and caudal fin, and a blackish band on the outer margin of the anal fin. Pempheris oualensis also has a large body and a distinct black spot on the pectoral fin base, and forms mixed schools with P. ufuagari, but can be distinguished by the different fin coloration (dorsal and caudal fin brown or pale; no blackish band on anal fin margin), and the presence of a villiform tooth band extending outside the lips. Although P. otaitensis, which is found in French Polynesia and Samoa, has similar coloration as P. ufuagari, the latter has lower scale counts than those of the former species: pored lateral-line scales 62-71 (vs. 70-79); scale rows above lateral line 6 1/2-7 1/2 (vs. 8 1/2); predorsal scales 37-43 (vs. 44-48). PMID:24699585

  14. Melon Fly, Bactrocera cucurbitae (Diptera: Tephritidae), Infestation in Host Fruits in the Southwestern Islands of Japan Before the Initiation of Island-wide Population Suppression, as Recorded in Publications of Japanese Public Institutions.

    PubMed

    McQuate, Grant T; Teruya, Tadashi

    2015-01-01

    Bactrocera cucurbitae (Coquillett) is a tephritid fruit fly native to the Indo-Malayan region. Its distribution, though, has extended to include Africa, temperate Asia, and a number of Pacific islands. It became established in Japan in 1919 in the Yaeyama Islands and spread north in the Southwestern Islands of Japan. It was subsequently eradicated from these islands by an eradication program that extended from 1972 to 1993. As part of an effort to develop a worldwide database on the status of fruits as hosts of melon fly, the infestation data gathered from host fruits collected in this eradication program, before the initiation of suppression activities, are summarized here. Bactrocera cucurbitae infestation was documented in 24 plant taxa of four plant families (Caricaceae, Cucurbitaceae, Moraceae, and Solanaceae), with the following four new hosts identified: Ficus erecta Thunb., F. pumila L. (Moraceae), Solanum erianthum D. Don (Solanaceae), and Zehneria liukiuensis Jeffrey ex Walker (Cucurbitaceae). PMID:26816487

  15. Melon Fly, Bactrocera cucurbitae (Diptera: Tephritidae), Infestation in Host Fruits in the Southwestern Islands of Japan Before the Initiation of Island-wide Population Suppression, as Recorded in Publications of Japanese Public Institutions

    PubMed Central

    McQuate, Grant T.; Teruya, Tadashi

    2015-01-01

    Bactrocera cucurbitae (Coquillett) is a tephritid fruit fly native to the Indo-Malayan region. Its distribution, though, has extended to include Africa, temperate Asia, and a number of Pacific islands. It became established in Japan in 1919 in the Yaeyama Islands and spread north in the Southwestern Islands of Japan. It was subsequently eradicated from these islands by an eradication program that extended from 1972 to 1993. As part of an effort to develop a worldwide database on the status of fruits as hosts of melon fly, the infestation data gathered from host fruits collected in this eradication program, before the initiation of suppression activities, are summarized here. Bactrocera cucurbitae infestation was documented in 24 plant taxa of four plant families (Caricaceae, Cucurbitaceae, Moraceae, and Solanaceae), with the following four new hosts identified: Ficus erecta Thunb., F. pumila L. (Moraceae), Solanum erianthum D. Don (Solanaceae), and Zehneria liukiuensis Jeffrey ex Walker (Cucurbitaceae). PMID:26816487

  16. Spatial variations in the Kuroshio nutrient transport from the East China Sea to south of Japan

    NASA Astrophysics Data System (ADS)

    Guo, X. Y.; Zhu, X.-H.; Long, Y.; Huang, D. J.

    2013-10-01

    Based on absolute geostrophic velocity, which was calculated using repeated hydrographic data of 39 cruises from 2000 to 2009 and nitrate concentrations measured in the same areas from 1964 to 2009, we obtained the temporally averaged nitrate flux (the product of velocity and nitrate concentration) and nitrate transport (integration of flux over one section) of four sections across the Kuroshio from the East China Sea (sections PN and TK) to an area south of Japan (sections ASUKA and 137E). In addition, we examined section OK east of the Ryukyu Islands in order to understand how the Ryukyu Current contributes to the transport of nutrients by the Kuroshio south of Japan. The mean nitrate flux shows a subsurface maximum core with values of 9.6, 10.6, 11.2, 10.5, and 5.7 mol m-2 s-1 at sections PN, TK, ASUKA, 137E, and OK, respectively. The depth of the subsurface maximum core changes among these five sections and is approximately 400, 500, 500, 400, and 800 m at sections PN, TK, ASUKA, 137E, and OK, respectively. The mean downstream nitrate transport is 204.8, 165.8, 879.3, 1230.4, and 338.6 kmol s-1 at sections PN, TK, ASUKA, 137E, and OK, respectively. The transport of nutrients in these sections suggests the presence of the Kuroshio nutrient stream from its upstream to downstream regions. The deep current structure of the Ryukyu Current (section OK) contributes to the same order of nitrate transport as does the Kuroshio from the East China Sea (section TK) to the area south of Japan; however, the former only has one-fifth the volume transport of the latter. A budget calculation suggests that the downstream increase of transported nitrate along the Kuroshio is mainly caused by the recirculation of nitrate into the Kuroshio. This conclusion, however, depends on water depth. In the upper layers (< 26.5??), the downstream change of nitrate concentration along the Kuroshio and that from the recirculation of nitrate has a significant contribution to the downstream increase of nitrate transport along the Kuroshio. In the deep layers (> 26.5??), the change in nitrate concentration is small and the Kuroshio recirculation dominates the downstream increase of nitrate transport.

  17. Newly found submerged reefs on the Miyako-Sone platform, Ryukyu Arc, northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Arai, K.; Matsuda, H.; Sasaki, K.; Machiyama, H.; Inoue, T.; Iryu, Y.

    2013-12-01

    Bathymetric mapping and observations of the seafloor using a remotely operated vehicle were carried out on the top of the Miyako-Sone submarine platform, northeast of Miyako-jima, Ryukyu Islands, northwestern Pacific. The high-resolution bathymetric map provides a detailed geomorphology and spatial distribution of submerged reefs and terraces on the platform. Our observations show that a submerged reef occurs at a water depth of ca. 55 m as a barrier reef that are up to 500 m across (from east to west) and 1,000 m lonng (from north to south) with a prominent ridge structure (reef crest). The submerged reef deepens westward from the crest along which spurs and grooves are well developed. A shallow lagoon extends on the east of the crest. Submersible observations confirm that the submerged reef now serves a hard substrate on which soft corals and algae grow. Terraces form at a water depth of ca. 110 m around a submerged reef on the northwestern Miyako-Sone platform. Submersible observations show the terrace surface is extensivbely covered with modern rhodoliths and living larger benthic foraminifers. Well-preserved coral-reef topography likely indicates limited sediment transportion from Miyako-jima and Okinwa-jima islands to the Miyako-Sone submarine platform. We plan to provide chronological constraint by direct sampling from the submerged reef and terraces, which enable to delineate a global deglacial sea-level history especially during early deglacial times in the northwestern Pacific.

  18. Concentration of organic sun-blocking agents in seawater of beaches and coral reefs of Okinawa Island, Japan.

    PubMed

    Tashiro, Yutaka; Kameda, Yutaka

    2013-12-15

    The concentration of UV filters (UVFs) and UV light stabilizers (UVLSs) were measured in seawater and river water collected from sites at four beaches, two reefs, and one river on Okinawa Island, Japan. UVFs and/or UVLSs of 8-10 types were detected in beaches samples and 6-9 types were detected in reef samples. The total UVF concentrations at the beach sites were highest either in July or August with a maximum of 1.4 μg L(-1). The concentrations at the reef sites did not show peaks in summer and the maximum values were close to 10 ng L(-1). The detected UVF profiles reflected the ingredients of sunscreens used in each region. The highest UVLS concentrations at the reefs were observed not only in summer but also in June and September. The UVLS concentrations at the reefs were similar to or even higher than that at the beaches or in the river. PMID:24139648

  19. Specific accumulation of arsenic compounds in green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) from Ishigaki Island, Japan.

    PubMed

    Agusa, Tetsuro; Takagi, Kozue; Kubota, Reiji; Anan, Yasumi; Iwata, Hisato; Tanabe, Shinsuke

    2008-05-01

    Concentrations of total arsenic (As) and individual compounds were determined in green and hawksbill turtles from Ishigaki Island, Japan. In both species, total As concentrations were highest in muscle among the tissues. Arsenobetaine was a major compound in most tissues of both turtles. High concentrations of trimethylarsine oxide were detected in hawksbill turtles. A significant negative correlation between standard carapace length (SCL), an indicator of age, and total As levels in green turtles was found. In contrast, the levels increased with SCL of hawksbill turtles. Shifts in feeding habitats with growth may account for such a growth-dependent accumulation of As. Although concentrations of As in marine sponges, the major food of hawksbill turtles are not high compared to those in algae eaten by green turtles, As concentrations in hawksbill turtles were higher than those in green turtles, indicating that hawksbill turtles may have a specific accumulation mechanism for As. PMID:17728031

  20. Food habits of fishes on an exposed sandy beach at Fukiagehama, South-West Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Nakane, Yukinori; Suda, Yusuke; Sano, Mitsuhiko

    2011-06-01

    To clarify the feeding habits and major food sources of sandy beach fishes, the gut contents of 55 fish species collected on a sandy beach at Fukiagehama, South-West Kyushu Island, Japan, were examined. Ontogenetic changes in food preference were recognized in nine species ( Hypoatherina valenciennei, Lateolabrax japonicus, Trachurus japonicus, Sillago japonica, Sphyraena japonica, Paralichthys olivaceus, Heteromycteris japonica, Paraplagusia japonica, and Takifugu niphobles). A cluster analysis based on dietary overlaps showed that the sandy beach fish assemblage comprised six trophic groups (mysid, amphipod, zooplankton, juvenile fish, terrestrial insect, and mollusk feeders). Of these, the first three groups were the most abundantly represented, whereas the last two were represented by only a single species. These results indicated that epibenthic macrofauna, such as mysids and gammaridean amphipods, and zooplankton, were important food resources for the fish assemblage at the study site, but infaunal macrobenthos, such as polychaetes and bivalves, being relatively unimportant.

  1. Distribution of trace metals in the Pacific Oyster, Crassostrea gigas, and crabs from the east coast of Kyushu Island, Japan

    SciTech Connect

    Szefer, P.; Frelek, K.; Geldon, J.

    1997-01-01

    Oysters are known to be exceptional accumulators of Zn and Cu, and their tissue concentrations appear to reflect contamination of metals. According to Lauenstein and Dolvin, oysters clearly have a greater affinity for Ag, Cu and Zn than do mussels, while mussels have greater affinity for Cr and Pb. Oysters have been considered to be potential bioindicators for monitoring metallic pollution in marine environments. Extensive investigations of oysters from the east coast of Kyushu Island, Japan, have been performed. The aim of the study was to examine spatial differences in metal concentrations in soft tissues of the Pacific oyster (Crassostrea gigas) and whole bodies (soft tissues with shells) of the crabs Goetice depressa and Leptodius exaratus inhabiting the Japanese coastal region of the Pacific. 18 refs., 3 figs.

  2. Halogen and ^{129}I Distributions in Pore Waters From Actively Venting Gas Hydrate Fields Near Sado Island, Eastern Japan Sea

    NASA Astrophysics Data System (ADS)

    Tomaru, H.; Lu, Z.; Fehn, U.; Snyder, G. T.; Hiruta, A.; Matsumoto, R.

    2006-12-01

    Large amounts of massive gas hydrates were recovered by piston coring from the Umitaka Spur-Joetsu Knoll area near Sado Island in the eastern margin of the Japan Sea during UT04, KY05-08, and UT06 cruises. Enormous methane seepages were observed in the echogram, reflecting active and large methane- storage/discharge systems in the continental margin. We report here halogen concentrations and ^{129}I/I ratios in pore waters collected from piston cores taken during cruises in 2004 to 2006. Depth profiles of these halogen concentrations are used to investigate geochemical characteristics of fluids associated with methane delivery. In addition, the presence of the long-lived radioisotope ^{129}I (half life; 15.7 Myr), provides information on potential source materials for iodine and methane in gas hydrates. The Cl concentrations in the Sado fields increase to 800 mM or decrease to 400 mM at the bottom of the cores from seawater values. These variations reflect the input of brines during gas hydrate formation and the pore water freshening during dissociation of gas hydrates below the cored depths, respectively. In contrast to the Cl profiles, I and Br gradually increase with depth in all profiles, reaching values of 170 ?M and 1400 ?M, respectively, which represent strong enrichment of deep fluids in I and Br compared to seawater (I; 0.4 ?M, Br; 840 ?M). The ^{129}I/^{127}I ratios rapidly decrease with depth from the seawater value of 150010^{-15} to values between 40010^{-15} and 60010^{-15}, which are equivalent to ages between 20 and 30 Ma. These ages of potential source formations of iodine (and, by association, of methane) correspond well with the time when the opening of the Japan Sea was initiated at ~28 Ma, followed by the rotation of NE and SW geological parts of Japan forming the Fossa Magna sedimentary basin at ~18 Ma. Methane in the Sado gas hydrate fields is thus principally associated with the tectonic processes forming the Japan Sea and derived from deep sources accumulated during the early stages of the formation of the Japan Sea.

  3. Geographic genetic structure in two laticaudine sea kraits, Laticauda laticaudata and Laticauda semifasciata (Serpentes: Elapidae), in the Ryukyu-Taiwan region as inferred from mitochondrial cytochrome b sequences.

    PubMed

    Tandavanitj, Nontivich; Ota, Hidetoshi; Cheng, Yuan-Cheng; Toda, Mamoru

    2013-08-01

    The Ryukyu-Taiwan region is an island arch with intervening waters of varying distances and depths. This study examines the geographic genetic structure of two sympatric sea kraits, Laticauda laticaudata and L. semifasciata, in the region, to infer factors affecting the extent of dispersal and other biogeographical traits of these amphibious reptiles. Sequence analyses of the mitochondrial cytochrome b gene revealed four and 16 haplotypes for L. laticaudata (136 individuals) and L. semifasciata (177 individuals), respectively. For both species, population pairwise F ST analyses revealed significant genetic differentiations among islands and island groups, which are separated by deep straits, suggesting that deep waters serve as obstacles for dispersal in both species. Significant genetic differentiation was detected even among islands of the same basin in L. laticaudata, but not in L. semifasciata, and the isolation by distance analyses revealed no significant correlation between geographic and genetic distances in the former species. These results further suggest that L. laticaudata has stronger site fidelity or degree of philopatry than L. semifasciata. Based on the geographic genetic patterns, the historical biogeography of the two species in the Ryukyu-Taiwan region is also discussed. PMID:23915156

  4. Observation of coral reefs on Ishigaki Island, Japan, using Landsat TM images and aerial photographs

    SciTech Connect

    Matsunaga, Tsuneo; Kayanne, Hajime

    1997-06-01

    Ishigaki Island is located at the southwestern end of Japanese Islands and famous for its fringing coral reefs. More than twenty LANDSAT TM images in twelve years and aerial photographs taken on 1977 and 1994 were used to survey two shallow reefs on this island, Shiraho and Kabira. Intensive field surveys were also conducted in 1995. All satellite images of Shiraho were geometrically corrected and overlaid to construct a multi-date satellite data set. The effects of solar elevation and tide on satellite imagery were studied with this data set. The comparison of aerial and satellite images indicated that significant changes occurred between 1977 and 1984 in Kabira: rapid formation in the western part and decrease in the eastern part of dark patches. The field surveys revealed that newly formed dark patches in the west contain young corals. These results suggest that remote sensing is useful for not only mapping but also monitoring of shallow coral reefs.

  5. Late Cenozoic evolution of epithermal gold metallogenic provinces in Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Watanabe, Yasushi

    2005-11-01

    Kyushu Island, Japan, is located at the junction of the Southwest Japan arc and the Ryukyu arc. There are two major late Cenozoic epithermal gold-silver provinces in Kyushu, which are termed the Northern and Southern provinces. The provinces are characterized by: 1) Pliocene volcanism dominated by calc-alkaline andesite, followed by Quaternary volcanism including extrusion of both calc-alkaline and tholeiitic magmas; 2) formation of extensional grabens; 3) Pliocene to Pleistocene mineralization, which was dominated by abundant low sulfidation (LS) epithermal deposits with a few high sulfidation (HS) examples. The two epithermal gold-silver provinces have evolved differently since about 5 Ma; the Northern province has exhibited diminished hydrothermal activity from the Pliocene to Pleistocene, whereas the Southern province has witnessed increased hydrothermal activity mainly in easterly and northerly directions. Changes of tectonic setting from the Pliocene to Pleistocene account for the variable trends in epithermal gold deposit formation. Westward oblique subduction of the Philippine Sea plate beneath the Southwest Japan arc caused development of the Hohi graben and arc-related volcanism at about 6 Ma. This was associated with widespread LS mineralization in and surrounding the Hohi graben, as is represented by the Bajo and Taio deposits. The subduction of the relatively buoyant Kyushu-Palau ridge during the early Pliocene strengthened the coupling between the slab and overriding Ryukyu arc, leading to polygenetic andesite volcanism with associated HS (Kasuga, Iwato, and Akeshi) and LS (Kushikino) mineral deposits forming in the Southern province. A change of the subduction direction of the Philippine Sea plate, from west to north-northwest in the early Pliocene, increased the orthogonal convergence rate between the Southwest Japan arc and the Philippine Sea plate, resulting in a decrease of volcanic and hydrothermal activity in the Hohi graben of the Northern province. The more northerly subduction of the Philippine Sea plate shifted the locus of the Kyushu-Palau ridge subduction northward, resulting in underplating of the older (85-60 Ma), negatively buoyant Amami basin oceanic slab in the Southern province, rather than continued subduction of the young (27-15 Ma), buoyant Shikoku basin slab. This replacement caused steepening of the slab angle and slab-rollback in the Southern province, which was associated with regional extension, an eastward shift of the Ryukyu volcanic front, and development of the Kagoshima and Shimabara grabens, as well as the Okinawa trough. Rhyolite and basalt volcanism, in addition to andesite volcanism, have occurred since 2 Ma in the area of the Ryukyu back arc; coincident LS mineralization at Hishikari and Ohkuchi was affiliated with the rhyolite volcanism. Another change of the subduction direction of the Philippine Sea plate to the northwest occurred at 2-1 Ma. The forearc sliver of the Southwest Japan arc shifted westward, in association with right-lateral strike-slip faulting along the Median tectonic line, due to the increase of the westward convergence rate. This shift resulted in shortening and cessation of graben development in the Hohi area, restricting the subsequent volcanism and related hydrothermal activity to the central part of the graben.

  6. Strain Energy Flow and the Accumulation of Large Earthquake Energies in the Island Arc-Trench Dynamics ( NE Japan Arc)

    NASA Astrophysics Data System (ADS)

    Nagumo, S.

    2002-12-01

    A gravitational shear flow of the island-arc rock-mass was newly revealed under the Japan trench inner slope on the artifact-free and distortion-free seismic reflection profiles (Nagumo and Tsuru (2001), Eos. Trans. AGU82(47), Fall.Meet. Suppl. Abstract T12D-0934). Based on such a shear flow phenomena, I envision a picture of the island arc-trench dynamics as below. The hot upper mantle under the volcanic arc generates buoyancy, and uplifts the volcanic arc. The uplifted island arc rock-mass gains excess gravitational potential energy. The surface inclination from the central arc towards the trench axis generates horizontal driving force within the arc mass, and generates shear stresses, shear deformations, and shear strain energies. In the deep part of the crust, such shear stresses exceed the critical value, and the rock-masses are in a state of shear flow. Because of rather hot thermal regime, such a shear flow of rock-masses predominates within the ductile intermediate zone of the crust, which ranges from the basal granitic layer to the upper part of the basaltic layer. The shear flow carries the whole island-arc mass towards trench axis from the central volcanic arc and transports the strain energies, which are involved within the deformed rock-mass, and forms a flow of strain energy. Such a gravitational flow of the rock-mass is a behavior of viscous fluids in a long time scale. When the strain energy flow is obstructed by some mechanism, a part of the strain energy flow is trapped, and stored around the obstacles. The stored energies accumulate with elapse of time, and results in an occurrence of large earthquake. I postulate that the occurrence condition of a large earthquake is such that the average density of the accumulated strain energy within the volume of the self-adjoined domain attains a certain critical level. Then, we can estimate the earthquake radiation energy by the product of the critical strain energy and the volume of the self-adjoined domain. The gravitational potential energy is sufficient enough to generate the large earthquake energies in the forearc region. The energy supply by the subducting oceanic plate is not required. Such a view of strain energy accumulation process may relate to the variety of the asperity, repetition interval of occurrence, and the types of earthquakes, such as main shock type, swarm type and etc. The above picture of the island arc-trench dynamics does not require subduction-accretion tectonics.

  7. Mmax Inferred from the Back Slip Rate Distributions along the Japan Islands

    NASA Astrophysics Data System (ADS)

    Koketsu, K.; Yokota, Y.; Higuchi, S.

    2012-12-01

    The devastating Tohoku earthquake of magnitude (M) 9.0 occurred on 11 March 2011 UTC along the Japan Trench, where the Pacific plate is subducting beneath the Tohoku district. Koketsu, Yokota, Kato, and Kato (2012) recovered annual rates of back slip, which is the drag of the overriding plate by interplate coupling, using GPS data in northeastern Japan before the Tohoku earthquake. They then recovered coseismic slips through an inversion of GPS data during the earthquake. The distributions of recovered coseismic slips and back slip rates bear a close resemblance to each other. They also calculated the recurrence period of such a megathrust event to be about 400 years using the coseismic moment releases and moment accumulation rate. They confirmed these relations by conducting seismic cycle simulations.The national program of seismic hazard assessment, which was initiated by the Japanese government after the 1995 Kobe earthquake, failed to foresee the Tohoku earthquake. However, the above results suggest the Tohoku earthquake could be foreseen with respect to at least its location and extent, if we monitored GPS data. In addition, the above method can be applicable to consider the Mmax of an other subduction zone, because the size of the Tohoku earthquake is propably the Mmax in the subduction zone along the Japan Trench. We first inspected the back slip rate distribution by Koketsu, Yokota, Kato and Kato (2012) carefully, and found similar areas of large back slip rate along the southernmost Kuril Trench and the Sagami Trough. The former area is as large as that along the Japan Trench. Therefore, the Mmax along the southernmost Kuril Trench should be around the M of the Tohoku earthquake, though Nanayama et al. (2003) estimated it to be 8.4 from tsunami deposit surveys. The latter area looks like the source region of the 1703 Genroku earthquake. Since this region is twice larger than that of the 1923 Kanto earthquake, the Mmax along the Sagami Trough should be around 8.1. We secondly recovered annual rates of back slip using GPS data in southwestern Japan. The resultant distribution shows a long area of large back slip rate along the Nankai Trough. This area looks larger than the source region of the 1707 Hoei earthquake. Accordingly, the Mmax along the Nankai Trough should be greater than 8.6, which was estimated by Utsu (1999) for the Hoei earthquake.

  8. Tectonic evolution of the Koshiki Islands at Kyushu in Japan: Extentinal tectonics of the eastern Asian margin at Cenozoic

    NASA Astrophysics Data System (ADS)

    Satoshi, T.; Shoichi, K.; Tetsumaru, I.; Yoshitaka, H.

    2004-12-01

    The Koshiki islands contain one of the best-preserved exposures of upper Cretaceous to Paleogene sedimentary successions in western Kyushu of Japan. These stratified sedimentary sequences also contain well-preserved deformations, used to identify surface conditions and tectonics of the Eastern part of the Asian continental margin. The upper Cretaceous Himenoura Group is approximately 800m thick in this area. It consists of well-rounded conglomerate, cross-bedded sandstone, and black shale and forms coarsening-upward sequence with HCS (hummocky cross stratification) containing many upper cretaceous fossils. This group had been formed in an offshore environment. The Eocene Kamikoshikijima Group, approximately 1700m thick, unconformably overlies the Himenoura Group. It consists of quartz rich cross-bedded sandstone, fine laminated greenish siltstone, and red shale, which are identified as fluvial sediment. Two types of faults are identified; 1) type1: NW-SE trending normal faults composed of thick shear zone with brittle-ductile fabric, and 2) type2: NNE-SSW trending normal faults with sharp fault planes with dip-slip slickenside. The type1 faults have 10m to more than 100m of displacement. Kanoko Fault, which is the biggest type1 fault in this area, has a 5m wide shear zone containing highly foliated shales with dip-slip lineations and asymmetric fabrics. This fault was affected by top to the northeast movement. Based on the comparison between each group stratigraphy, approximately 500m displacements are estimated. We determined the two K-Ar clay mineral ages in the type1 fault gouges. One, which is the Kanoko Fault, dated 16.5-19.1 Ma in age, and another fault, which is deeper situation in Himenoura Group, is 20.6-24.1 Ma in age. The temperature estimation from the fluid inclusions within lineated calcite veins in Kanoko Fault shows that the veins were formed at more than 166?C. Type2 faults contain thin fault gouge with slickenside. These faults clearly truncate the type1 faults. The NNE orientation of the type2 faults is almost parallel to the Koshiki islands and the northeastern Okinawa trough. Three deformations and one intrusive event are identified in this area; 1) tilting of the Himenoura Group (D1), 2) NW-trending normal faults (24-16.5Ma)(D2), 3) intrusion of igneous rocks (14.0+-1.6Ma) and 4) NNE-trending normal faults (D3). During early to middle Miocene in southwest Japan, regional extended stress filed occurred, and D2 to D3 deformations in Koshiki islands might correspond to the changed regional stress filed.

  9. Preseismic anomalous telluric current signals observed in Kozu-shima Island, Japan.

    PubMed

    Orihara, Yoshiaki; Kamogawa, Masashi; Nagao, Toshiyasu; Uyeda, Seiya

    2012-11-20

    Monitoring of telluric current, which is practically a synonym for geoelectric potential difference, was conducted on Kozu-shima Island about 170 km south of Tokyo from May 14, 1997 to June 25, 2000. During the monitoring period, 19 anomalous telluric current changes (ATCs) were observed. Their possible correlation with nearby earthquakes was statistically examined by assuming various lead times for different ranges of magnitude and focal distance. The best correlation may be obtained for earthquakes with a magnitude greater than 3.0 occurring within 20 km of focal distance. There were 23 such earthquakes, of which 11 were preceded by ATCs within 30 d. Of these 11 earthquakes, preceding ATCs of 5 and 6 were positive and negative polarities of telluric current, respectively. Their epicenters were spatially well clustered in the east and west of the island. These facts were clearly beyond those expected by chance and led to a simple speculative model. PMID:23115337

  10. Preseismic anomalous telluric current signals observed in Kozu-shima Island, Japan

    PubMed Central

    Orihara, Yoshiaki; Kamogawa, Masashi; Nagao, Toshiyasu; Uyeda, Seiya

    2012-01-01

    Monitoring of telluric current, which is practically a synonym for geoelectric potential difference, was conducted on Kozu-shima Island about 170 km south of Tokyo from May 14, 1997 to June 25, 2000. During the monitoring period, 19 anomalous telluric current changes (ATCs) were observed. Their possible correlation with nearby earthquakes was statistically examined by assuming various lead times for different ranges of magnitude and focal distance. The best correlation may be obtained for earthquakes with a magnitude greater than 3.0 occurring within 20 km of focal distance. There were 23 such earthquakes, of which 11 were preceded by ATCs within 30 d. Of these 11 earthquakes, preceding ATCs of 5 and 6 were positive and negative polarities of telluric current, respectively. Their epicenters were spatially well clustered in the east and west of the island. These facts were clearly beyond those expected by chance and led to a simple speculative model. PMID:23115337

  11. Three new species of Hatschekia Poche, 1902 (Copepoda: Siphonostomatoida: Hatschekiidae) parasitic on Abalistes filamentosus (Pisces: Tetraodontiformes: Balistidae) from off Okinawa, Japan.

    PubMed

    Uyeno, Daisuke; Nagasawa, Kazuya

    2009-11-01

    Three new species of the copepod genus Hatschekia Poche, 1902, H. lima n. sp., H. cylindrus n. sp. and H. sunaoi n. sp., are described from the gill filaments of a triggerfish, Abalistes filamentosus Matsuura & Yoshino, caught off the Ryukyu Islands, Okinawa, Japan. These new species share an unusual morphological character, i.e. four stout posterior spines on the intercoxal sclerites of legs 1 and 2. H. lima n. sp. differs from its congeners in having a robust inner lobe on the maxillule and leg 3 with a swollen basal lobe. H. cylindrus n. sp. is distinguishable from its congeners by having a cephalothorax fused to the trunk and a double-semicircular chitinous frame. H. sunaoi n. sp. is characterised by leg 3 with a swollen basal lobe and an oval cephalothorax. PMID:19790002

  12. An investigation for population maintenance mechanism in a miniature garden: genetic connectivity or independence of small islet populations of the Ryukyu five-lined skink.

    PubMed

    Kurita, Kazuki; Hikida, Tsutomu; Toda, Mamoru

    2014-01-01

    The Ryukyu five-lined skink (Plestiodon marginatus) is an island lizard that is even found in tiny islets with less than half a hectare of habitat area. We hypothesized that the island populations are maintained under frequent gene flow among the islands or independent of each other. To test our hypotheses, we investigated genetic structure of 21 populations from 11 land-bridge islands that were connected during the latest glacial age, and 4 isolated islands. Analyses using mitochondrial cytochrome b gene sequence (n = 67) and 10 microsatellite loci (n = 235) revealed moderate to high levels of genetic differentiation, existence of many private alleles/haplotypes in most islands, little contemporary migration, a positive correlation between genetic variability and island area, and a negative correlation between relatedness and island area. These evidences suggest a strong effect of independent genetic drift as opposed to gene flow, favoring the isolation hypothesis even in tiny islet populations. Isolation-by-distance effect was demonstrated and it became more prominent when the 4 isolated islands were excluded, suggesting that the pattern is a remnant of the land-bridge age. In a few island populations, however, the possibility of occasional overwater dispersals was partially supported and therefore could not be ruled out. PMID:25189776

  13. Seismic structure related to the Philippine Sea plate subduction beneath the southwestern Nansei-Shoto (Ryukyu) Trench

    NASA Astrophysics Data System (ADS)

    Nishizawa, A.; Kaneda, K.; Oikawa, M.; Horiuchi, D.; Fujioka, Y.

    2013-12-01

    The northwestern part of the Philippine Sea plate (PSP) is subducting beneath the Nansei-Shoto (Ryukyu) Trench. Earthquakes larger than M8 have not been recorded instrumentally in the southwestern part of the Ryukyu Trench. However, there was a large tsunami killed around 12,000 people in 1771 and the position of the source area has not been established. The direction of the PSP subduction is almost perpendicular to the Ryukyu Trench to the northeast of 126.5 E and changes to oblique to the southwest. Seismicity varies along the trench axis and lower seismicity seems to correspond to the free-air gravity anomaly high region in the forearc at around 126 E. On the other hand, the Okinawa-Luzon fracture zone extending from southwest to northeast on the PSP subducts beneath Ryukyu Trench to the northeast of 126 E and seems to relate to the high gravity anomaly. We carried out seismic experiments to elucidate these inhomogeneous crustal structures along the southwestern part of the trench and provide valuable information on potential source areas for large earthquakes and/or tsunamis. We conducted five seismic lines across southwestern Ryukyu Trench region. Multichannel reflection seismic (MCS) data using 240 ch. and 3000 m long hydrophone streamer were collected for airgun shots at an interval of 50 m. We also deployed ocean bottom seismographs (OBSs) as a receiver at an average interval of 5 km along each line. A tri-gun cluster with a volume of 1,050 (350 * 3) cubic inches (17.2 liters) was used for the reflection surveys and a non-tuned airgun array with a volume of 6,000 (1500 * 4) cubic inches (98 liters) was shot at an interval of 200 m (90 sec) for the wide-angle seismic survey. Depth conversion from the MCS time section was carried out using the refraction results. In this paper, we present the seismic structure related to the PSP subduction in the forearc region of the Nansei-Shoto island arc. The subducting Okinawa-Luzon fracture zone was able to be clearly imaged beneath two MCS lines to the northeast of 126 E. The fracture zone has several rows of valleys, of which the maximum relative depths are more than 0.5 km. The MCS records show such fracture topography subducts without deformation. P-wave velocity structure beneath the high free-air gravity region in the forearc at 125-127 E shows that materials with a high velocity of around 4 km/s ascend to 1 km below the seafloor at the shallowest region, which indicates that the gravity anomaly high does not reflect the fracture zone directly. There are not clear splay faults in the seaward of the high gravity region, but this might be due to insufficient energy of the airgun source. On the other hand, distinctive signals from the plate boundary and the fault branching from the plate boundary were detected in the oblique subduction area to the southwest of 125 E.

  14. Osteological and genetic analysis of the extinct Ezo wolf (Canis lupus hattai) from Hokkaido Island, Japan.

    PubMed

    Ishiguro, Naotaka; Inoshima, Yasuo; Shigehara, Nobuo; Ichikawa, Hideo; Kato, Masaru

    2010-04-01

    The Ezo wolf (Canis lupus hattai Kishida, 1931 ) is an extinct subspecies that inhabited Hokkaido in Japan until the middle of the Meiji Period. Because there are very few preserved skeletons, no osteological and/or genetic analyses of the Ezo wolf have been conducted. In this study, 20 cranial and eight mandibular characters were measured on Ezo wolf skeletons, and mitochondrial DNA (mtDNA) was analyzed to assess genetic relationships between the Ezo wolf and other wolf lineages, including the Japanese wolf on Honshu. The morphological study showed that the Ezo wolf is larger than the Japanese wolf and similar in size to the grey wolf of the Asian and American Continents. MtDNA control sequences (751 bp) from two Ezo wolves were identical to those from the Canadian grey wolf. The morphological and genetic characters indicate that the ancestor of the Ezo wolf was genetically related to that of the grey wolf in Canada. PMID:20377350

  15. Mosquito biodiversity patterns around urban environments in South-central okinawa island, Japan.

    PubMed

    Hoshi, Tomonori; Imanishi, Nozomi; Higa, Yukiko; Chaves, Luis Fernando

    2014-12-01

    Okinawa is the largest, most urbanized, and densely populated island in the Ryukyus Archipelago, where mosquito species diversity has been thoroughly studied. However, the south-central Okinawa mosquito fauna has been relatively poorly studied. Here, we present results from a mosquito faunal survey in urban environments of Nishihara city, south-central Okinawa. Mosquitoes were sampled biweekly, from April 2007 to March 2008, at 3 different environments: a forest preserve, an animal farm, and a water reservoir. We employed 4 mosquito collection methods: 1) oviposition traps; 2) light traps; 3) sweep nets; and 4) larval surveys of tree holes, leaf axils, and artificial water containers. We collected a total of 568 adults and 10,270 larvae belonging to 6 genera and 13 species, including 6 species of medical importance: Aedes albopictus, Armigeres subalbatus, Anopheles Hyrcanus group, Culex bitaeniorhynchus, Cx. quinquefasciatus, and Cx. tritaeniorhynchus. Mosquito species composition was similar to data from previous studies in Okinawa Island. The flattening of the species accumulation curve suggests that our diversity sampling was exhaustive with light and oviposition traps, as well as the coincidence between the species richness we found in the field and estimates from the Chao2 index, a theoretical estimator of species richness based on species abundance. This study highlights the importance of combining several sampling techniques to properly characterize regional mosquito fauna and to monitor changes in the presence of mosquito species. PMID:25843131

  16. Eleven-years-long record of ferric hydroxide sedimentation in Satsuma Iwo-Jima island, Kagoshima, Japan

    NASA Astrophysics Data System (ADS)

    Ueshiba, T.; Kiyokawa, S.; Goto, S.; Oguri, K.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Nagata, T.; Ninomiya, T.; Ikegami, F.

    2011-12-01

    Satsuma Iwo-Jima island is active in volcanic activity located about 40 km south of Kyushu Island, Japan. It has many hot springs, and is surrounded by patches of reddish brown and white colored seawater. Nagahama Bay, a small port located in the southern part of the island, retains reddish brown seawater and precipitates ferric hydroxide (Ninomiya and Kiyokawa, 2009). We conducted multidisciplinary study to investigate mechanisms and histories of precipitation of the sediments. From 2009 to 2011, we obtained 1.5m-long core samples in the bay that record sedimentation of mainly ferric hydroxide during the last 11~13 years since dredging in 1998. We compare their stratigraphy with (a) 11 years meteorological data and (b) volcanic activity record in that period. Stratigraphy: Thirteen short cores (<1m long) were collected from Nagahama Bay. The lower unit contains three layers of white and pink tuff beds (T1, T2 and T3) with thickness of 1~9cm. The upper unit mainly contains sand bed and reddish-brown mud. The tuff beds are mainly composed of volcanic glass. Sand bed is essentially a mixture of felsic rock fragments, volcanic glass, and ferric-rich fine materials. The reddish brown sediment between T1 and T2 has very fine orange-colored laminations (1~2mm thick/each). (a) Meteorological data: 11-years-long meteorological data of the Satsuma Iwo-Jima island suggest that heavy rainfalls (precipitation over 100mm/day) occurred in June 2000 (189mm/day), June 2001 (124.5mm/day), and June 2002 (122mm/day), and that three events of strong typhoon occurred in 2004 (maximum wind speed: 40.3m/s, 54.3m/s and 44.6m/s), 2005 (43.3m/s), and 2007 (50.2m/s). These meteorological events are reflected in, sometimes disturb, the sediment record. (b) Volcanic data: Volcanic activity has occurred from 1997 (Shinohara, 2002) to October 2004 (Japan Meteorological Agency, 2010). During that time, ash was spewed out from and deposited near the volcano. Tuffaceous beds in the sediments of Nagahama Bay record such volcanic activity, however reworking of sediments by meteorological events are found to obscure such record. Conclusions: We found two sedimentological events that play important role in forming sediments in Nagahama Bay; heavy rainfall and strong typhoon. The thick tuff beds (T1, T2 and T3) formed by reworking sediments induced by heavy rainfall. The sand bed formed by hydrodynamic mixings due to strong typhoon events in 2004. The ferric hydroxide-rich surface sediments are very loose and easily flown by hydrodynamic currents in the bay. However, once particles of the ferric hydrate precipitate at the seafloor, only strong current could move them. Neap tide may enhance their sedimentation and thus help to form strata.

  17. Spatial variations of present crustal stresses in the Japan island arc by using stress tensor difference map technique

    NASA Astrophysics Data System (ADS)

    Otsubo, M.; Miyakawa, A.; Imanishi, K.

    2014-12-01

    Stress tensor inversions determine an optimal stress tensor from a population of fault-slip data or earthquake focal mechanism data (double couple component of focal mechanisms). Otsubo et al. (2013, RS2013 proceedings) proposed a stress tensor difference map technique to provide a visual representation of stress heterogeneity patterns in the crust based on the stress tensors. The technique displays calculated stress differences between stress tensors estimated from focal mechanism data processed using the stress tensor inversion and an established reference stress. The technique procedure consists of three steps: (1) We chose locations of earthquake event as grid points; (2) We treat states of stress that activates earthquake events at each location as stress tensors at each grid point; (3) We then map the difference between each tensor and a reference stress tensor. States of stress can be detected by the stress tensor inversions (e.g., Otsubo et al., 2008, Tectonophysics 457, 150-160). The technique uses the "stress difference" defined by Orife and Lisle (2003; Journal of Structural Geology 25, 949-957) to show the similarity or dissimilarity between the stress tensors, in which each stress tensor is represented by a point in the four-dimensional parameter space (i.e., the three Euler angles for the principal stress axes and the stress ratio (s2-s3/s1-s3)). We apply the technique to natural earthquake data in Japan island arc that is situated in a subduction zone where four tectonic plates converge. In this study, we show the stress map on the different spatial scales (regional and local scales). In the regional scale, the E-W compressional stress characterized in NE Japan arc is also mapped in central Japan, whose region is concordant with the high strain rate zone (i.e., Niigata-Kobe Tectonic zone). Results in the local scale indicate the spatial stress heterogeneity acting on fault planes of the active faults. The stress mapping technique provides important potential to compare the stress state and spatial geophysical information (e.g. geodesic data, seismic velocity structure and gravity anomaly).

  18. Crustal structure off the northwestern Sado Island in the eastern margin of the Japan Sea deduced from seismic refraction and reflection surveys

    NASA Astrophysics Data System (ADS)

    Sato, T.; No, T.; Kodaira, S.; Takahashi, N.; Kaneda, Y.; Kato, N.; Kurashimo, E.; Ishiyama, T.; Koshiya, S.; Yoshida, T.; Toyoshima, T.; Ishikawa, M.; Toda, S.; Saito, H.; Abe, S.; Sato, H.

    2010-12-01

    In the eastern margin of the Japan Sea, the fault-fold belts are developed by the deformation of the extension by the opening of this Sea during the early Miocene and the shortening since the late Pliocene (e.g., Sato, 1994) and some destructive earthquakes occurred. However, it is unknown to the relation between the mechanism of the deformation including the concentration of this shortening and the occurrence of destructive earthquakes in the eastern margin of the Japan Sea. To understand this mechanism, it is important to clarify the crust structure in the areas without the deformation of the shorting and with one in this margin. For this study, we present the crustal structure from off the northwestern Sado Island in the eastern margin of the Japan Sea to the back-arc area of the northeastern Japan arc, and the results of seismic reflection surveys conducted in this margin. In 2009, the offshore seismic refraction/reflection survey using ocean bottom seismographs (OBSs) and airguns was conducted off the northwestern Sado Island (from Yamato Basin, Hakusan-se, to Toyama Trough) and in the Sado Basin in the eastern margin of the Japan Sea, Japan. And, the onshore seismic refraction/reflection survey using controlled sources was conducted from Sado Island to the back-arc area in the northeastern Japan arc (e.g., Sato H. et al, 2010JPGU). To obtain crustal structure of the seismic velocity and reflection image in the crust and uppermost mantle, we used the seismic refraction tomography using first-arrival phases (Zhang et al., 1998) and reflection travel-time mapping method (Fujie et al., 2006). In off the northwestern Sado Island in the eastern margin of the Japan Sea (from the Yamato Basin, the Hakusan-se, to the Toyama trough), the upper and middle crust, and lower crust have 5.6-6.5 km/s, and 6.7-7.0 km/s of P-wave velocity, respectively. The thickness of the upper and middle crusts has a lateral large variation although that of the lower crust seems uniform in these areas. The crusts beneath the basin area (Yamato Basin and Toyama trough) and the topographic high area (Hakusan-se) are estimated as having approximately 15 km and 20 km, respectively. In off the northwestern Sado Island, the high velocity layer (greater than 7.4 km/s of P-wave velocity) does not exist in the lower crust. In the results of the seismic reflection, the deformation of the shorting is not developed in off the northwestern Sado Island. These results suggest that the crustal structure off the northwestern Sado Island was mainly formed by the extension by the opening of the Japan Sea.

  19. Acanthaster planci infestations of reefs and coral assemblages in Japan: a retrospective analysis of control efforts

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masashi

    1986-08-01

    Reef-building corals have been extensively degraded by Acanthaster planci infestations which have continued to spread throughout the Ryukyu archipelago since 1969. Intensive control efforts were undertaken by fishermen and divers by hand-collecting and disposal on land with removal of about 13 million starfish at the total cost of over 600 million yen from 1970 to 1983 fiscal year. The control programs were mostly unsuccessful for saving the reefs from predation because the efforts were executed on the basis of collecting efficiency, so that significant numbers of starfish continued predation after each belated campaign. Certain coral assemblages outside the Ryukyus were infested with unusually large numbers of A. planci simultaneously with the northern part of Okinawa Island and its neighboring islands in the early seventies. A shift of infestation sites occurred in the extratropical waters in the mid-seventies when the warm current, Kuroshio, changed its path and left the coast of Honshu, the main island of Japan. The Kuroshio is considered to be transporting larval A. planci downstream from the Ryukyus where large aggregations have continued to exist at different areas all through the period.

  20. Characterization of Early Microbial Communities on Volcanic Deposits along a Vegetation Gradient on the Island of Miyake, Japan

    PubMed Central

    Guo, Yong; Fujimura, Reiko; Sato, Yoshinori; Suda, Wataru; Kim, Seok-won; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Narisawa, Kazuhiko; Ohta, Hiroyuki

    2014-01-01

    The 2000 eruption of Mount Oyama on the island of Miyake (Miyake-jima) created a unique opportunity to study the early ecosystem development on newly exposed terrestrial substrates. In this study, bacterial and fungal communities on 9- and 11-year-old volcanic deposits at poorly to fully vegetation-recovered sites in Miyake-jima, Japan, were characterized by conventional culture-based methods and pyrosequencing of 16S rRNA and 18S rRNA genes. Despite the differences in the vegetation cover, the upper volcanic deposit layer samples displayed low among-site variation for chemical properties (pH, total organic carbon, and total nitrogen) and microbial population densities (total direct count and culturable count). Statistical analyses of pyrosequencing data revealed that the microbial communities of volcanic deposit samples were phylogenetically diverse, in spite of very low-carbon environmental conditions, and their diversity was comparable to that in the lower soil layer (buried soil) samples. Comparing with the microbial communities in buried soil, the volcanic deposit communities were characterized by the presence of Betaproteobacteria and Gammaproteobacteria as the main bacterial class, Deinococcus- Thermus as the minor bacterial phyla, and Ascomycota as the major fungal phyla. Multivariate analysis revealed that several bacterial families and fungal classes correlated positively or negatively with plant species. PMID:24463576

  1. [Toxin profiles in fish implicated in ciguatera fish poisoning in Amami and Kakeroma Islands, Kagoshima Prefecture, Japan].

    PubMed

    Yogi, Kentaro; Oshiro, Naomasa; Matsuda, Seiko; Sakugawa, Satsuki; Matsuo, Toshiaki; Yasumoto, Takeshi

    2013-01-01

    Ciguatoxins (CTXs) responsible for ciguatera fish poisoning (CFP) in Amami Islands, Kagoshima, Japan in 2008 were determined by LC-MS/MS analysis. Ciguatoxin-1B (CTX1B), 54-deoxyCTX1B, and 52-epi-54-deoxyCTX1B were detected in Variola louti and Lutjanus monostigma. The toxin profile distinctly differed from that of a CFP-related fish from Miyazaki, which mainly contained ciguatoxin-3C type toxins. Toxin profiles were species-specific, as observed in fish from Okinawa. The LC-MS/MS and mouse bioassay (MBA) methods produced comparable data, though 54-deoxyCTX1B was not taken into consideration owing to the lack of toxicity data. To improve assessment, toxicity data for this compound are needed. A reef fish caught on the same occasion and judged nontoxic by MBA (<0.025 MU/g) was found to contain low levels of CTX, indicating a potential risk for CFP. PMID:24389468

  2. Characterization of early microbial communities on volcanic deposits along a vegetation gradient on the island of Miyake, Japan.

    PubMed

    Guo, Yong; Fujimura, Reiko; Sato, Yoshinori; Suda, Wataru; Kim, Seok-won; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Narisawa, Kazuhiko; Ohta, Hiroyuki

    2014-01-01

    The 2000 eruption of Mount Oyama on the island of Miyake (Miyake-jima) created a unique opportunity to study the early ecosystem development on newly exposed terrestrial substrates. In this study, bacterial and fungal communities on 9- and 11-year-old volcanic deposits at poorly to fully vegetation-recovered sites in Miyake-jima, Japan, were characterized by conventional culture-based methods and pyrosequencing of 16S rRNA and 18S rRNA genes. Despite the differences in the vegetation cover, the upper volcanic deposit layer samples displayed low among-site variation for chemical properties (pH, total organic carbon, and total nitrogen) and microbial population densities (total direct count and culturable count). Statistical analyses of pyrosequencing data revealed that the microbial communities of volcanic deposit samples were phylogenetically diverse, in spite of very low-carbon environmental conditions, and their diversity was comparable to that in the lower soil layer (buried soil) samples. Comparing with the microbial communities in buried soil, the volcanic deposit communities were characterized by the presence of Betaproteobacteria and Gammaproteobacteria as the main bacterial class, Deinococcus- Thermus as the minor bacterial phyla, and Ascomycota as the major fungal phyla. Multivariate analysis revealed that several bacterial families and fungal classes correlated positively or negatively with plant species. PMID:24463576

  3. Sedimentary processes associated with sand and boulder deposits formed by the 2011 Tohoku-oki tsunami at Sabusawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Goto, Kazuhisa; Sugawara, Daisuke; Ikema, Satoko; Miyagi, Toyohiko

    2012-12-01

    This paper reports on the sedimentary processes of sand and boulder deposition at Sabusawa Island, Japan as a result of the 2011 Tohoku-oki tsunami. Boulders were composed of tuffaceous rocks and sourced from an earthquake-triggered slope failure as well as concrete fragments of seawall. They were scattered over the ground surface and did not form boulder ridges, although there was some local imbrication. The boulders were deposited on top of a sand layer indicating that the latter, possibly deposited from bed load, covered the ground surface first. This sand layer probably reduced friction allowing boulders to be transported more easily than might be expected across a hard ground with a high bottom friction. Sand deposits showed landward thinning and fining features, while the boulders showed a landward coarsening (tuffaceous boulders) or a landward fining (concrete boulders), indicating that large clasts were not necessarily scattered randomly but rather might have a clast size gradient with distance inland. These features are explained by the local topographic setting that constrained the directions of incoming and returning tsunami flows. Some clasts at the inland extent of the boulder field were covered by an upward fining sand layer. This feature suggests that the boulders were deposited prior to the suspended sands, with the latter subsequently laid down before the water level dropped below the top of the boulders. Such modern investigations of the sedimentary features of various sizes of grains and clasts immediately after a tsunami provide invaluable data for the reconstruction of inundation processes.

  4. Seasonal Variations of Low Molecular Weight Dicarboxylic Acids in Atmospheric Aerosols at Okinawa Islands, Japan

    NASA Astrophysics Data System (ADS)

    Nakaema, F.; Handa, D.; Tanahara, A.; Arakaki, T.

    2009-04-01

    Low molecular weight dicarboxylic acids are major fraction of water soluble organic compounds in the atmospheric aerosols. Recently, economy of East Asia grows up remarkably, and atmospheric aerosols discharged from this area have been transported to Japan. In this study, we collected aerosol at Cape Hedo (CH) and University of the Ryukyus(UR), and studied the distribution and origin of low molecule dicarboxylic acid. Aerosols were collected on a quartz filter with a high volume air sampler. Low molecular weight dicarboxylic acids extracted by pure water were derivatized to dibutyl esters by reactions with BF3/butanol and were measured by GC-FID. In many samples, oxalic acid showed the highest concentration. Concentration of oxalic acid, malonic acid, succinic acid and malic acid were strongly correlated between the two sampling sites. Oxalic acid occupied on the average 83% and 76% of all the dicarboxylic acid measured for CH samples and UR samples. It is suggested that the aerosols in Okinawa were affected by secondary photochemical reactions, not by the primary emissions from local sources. The seasonal variation of the dicarboxylic acids concentrations in CH and UR showed higher in spring and fall, and a lower in summer. From the back trajectory analysis, dicarboxylic acids concentrations showed higher when an air mass came from East Asia area, and showed lower when it came from Pacific Ocean.

  5. Properties of GPS noise at Japan islands before and after Tohoku mega-earthquake.

    PubMed

    Lyubushin, Alexey; Yakovlev, Pavel

    2014-01-01

    The field of 3-components GPS signals is analyzed for the network of 1203 stations at the Japanese islands from January 30 up to March 26, 2011. This time interval includes just over 40days of observation before the Tohoku mega-earthquake on March 11, 2011 (M?=?9.0) and nearly 16days of observation following this event. The signals from each station are three-component time series with time step 30minutes. We study the statistical properties of the random fluctuations of GPS signals before and after the seismic catastrophe after transition to increments. The values of wavelet-based spectral index for GPS noise components for each station were estimated separately for pieces of records before and after seismic event. The maps of the noise spectral index are constructed as the values for grid size of 50??50 nodes covering the region under study, based on information from 10 stations closest to each node. These maps clearly extract the region of future seismic catastrophe by relatively high noise spectral index. The using of principal components method distinguished this spatial anomaly more explicitly. These results support the hypothesis that statistical properties of random fluctuations of geophysical fields carry important information about earthquake preparation. PMID:25077067

  6. Tectonics and petroleum potential of sedimentary basins in the Bering, Okhotsk, Japan seas, and island arcs

    SciTech Connect

    Levin, L.E. )

    1993-09-01

    In this vast region located in the northwestern part of the Pacific rim, basins of two main genetic types possess petroleum potential. These two types are represented by basins of the recent active margin and basins of the transitional zone between analogs of the passive margin and the recent active margin. For basins of the active margin, the mean density of potential resources is estimated at 5000 MT/km[sup 2] or more. The total area of these basins is 324,000 km[sup 2] among which 120,000 km[sup 2] are in the Russian sector. Ultimate resources of hydrocarbons are estimated at 1.62 billing MT of oil equivalent. Basins of the zone, transitional from analogs of the passive margin to the recent active margin, are characterized by a number of factors favorable for petroleum occurrence. One of the important factors is the presence of rift trough and foredeeps that are potential sites for zones of oil and gas accumulation. The age of the rifts varies from the late Cretaceous through the Oligocene-Miocene in the Olyutorsky and Litke basins, to the Neogene in the Okhotsk Sea and Tatar-Japan basins. Only a small area of the rifts has been proven to contain zones of oil and gas accumulation. Based on the structural characteristics, the rifts are subdivided into oil-gas bearing, potentially oil-gas bearing, and nonprospective for hydrocarbon exploration. Potential hydrocarbon resources of basins of this type are estimated to be not less than 15.12 billion MT of oil equivalent including 9.2 billion MT in the Russian sector. New large zones of oil and gas accumulation are expected to be found both on the shallow shelf and in some deep-water basins such as in the Aleutian and Kuril basins.

  7. On the Fourth Diadema Species (Diadema-sp) from Japan

    PubMed Central

    Chow, Seinen; Kajigaya, Yoshikazu; Kurogi, Hiroaki; Niwa, Kentaro; Shibuno, Takuro; Nanami, Atsushi; Kiyomoto, Setuo

    2014-01-01

    Four long-spined sea urchin species in the genus Diadema are known to occur around the Japanese Archipelago. Three species (D. savignyi, D. setosum, and D. paucispinum) are widely distributed in the Indo-Pacific Ocean. The fourth species was detected by DNA analysis among samples originally collected as D. savignyi or D. setosum in Japan and the Marshall Islands and tentatively designated as Diadema -sp, remaining an undescribed species. We analyzed nucleotide sequences of the cytochrome oxidase I (COI) gene in the D. savignyi-like samples, and found all 17 individuals collected in the mainland of Japan (Sagami Bay and Kyushu) to be Diadema-sp, but all nine in the Ryukyu Archipelago (Okinawa and Ishigaki Islands) to be D. savignyi, with large nucleotide sequence difference between them (11.0%1.7 SE). Diadema-sp and D. savignyi shared Y-shaped blue lines of iridophores along the interambulacrals, but individuals of Diadema-sp typically exhibited a conspicuous white streak at the fork of the Y-shaped blue iridophore lines, while this feature was absent in D. savignyi. Also, the central axis of the Y-shaped blue lines of iridophores was approximately twice as long as the V-component in D. savignyi whereas it was of similar length in Diadema-sp. Two parallel lines were observed to constitute the central axis of the Y-shaped blue lines in both species, but these were considerably narrower in Diadema-sp. Despite marked morphological and genetic differences, it appears that Diadema-sp has been mis-identified as D. savignyi for more than half a century. PMID:25054386

  8. On the fourth Diadema species (Diadema-sp) from Japan.

    PubMed

    Chow, Seinen; Kajigaya, Yoshikazu; Kurogi, Hiroaki; Niwa, Kentaro; Shibuno, Takuro; Nanami, Atsushi; Kiyomoto, Setuo

    2014-01-01

    Four long-spined sea urchin species in the genus Diadema are known to occur around the Japanese Archipelago. Three species (D. savignyi, D. setosum, and D. paucispinum) are widely distributed in the Indo-Pacific Ocean. The fourth species was detected by DNA analysis among samples originally collected as D. savignyi or D. setosum in Japan and the Marshall Islands and tentatively designated as Diadema-sp, remaining an undescribed species. We analyzed nucleotide sequences of the cytochrome oxidase I (COI) gene in the "D. savignyi-like" samples, and found all 17 individuals collected in the mainland of Japan (Sagami Bay and Kyushu) to be Diadema-sp, but all nine in the Ryukyu Archipelago (Okinawa and Ishigaki Islands) to be D. savignyi, with large nucleotide sequence difference between them (11.0%1.7 SE). Diadema-sp and D. savignyi shared Y-shaped blue lines of iridophores along the interambulacrals, but individuals of Diadema-sp typically exhibited a conspicuous white streak at the fork of the Y-shaped blue iridophore lines, while this feature was absent in D. savignyi. Also, the central axis of the Y-shaped blue lines of iridophores was approximately twice as long as the V-component in D. savignyi whereas it was of similar length in Diadema-sp. Two parallel lines were observed to constitute the central axis of the Y-shaped blue lines in both species, but these were considerably narrower in Diadema-sp. Despite marked morphological and genetic differences, it appears that Diadema-sp has been mis-identified as D. savignyi for more than half a century. PMID:25054386

  9. A new marine interstitial Psammogammarus (Crustacea, Amphipoda, Melitidae) from Gura Ici Island, off western Halmahera (North Moluccas, Indonesia), and an overview of the genus

    PubMed Central

    Vonk, Ronald; Hoeksema, Bert W.; Jaume, Dami

    2011-01-01

    Abstract Psammogammarus wallacei sp. n. is described from the shallow marine interstitial of a sand and coral rubble beach on the Gura Ici islands (North Moluccas; Indonesia). This is the first record of this circum-tropical genus from SE Asia, with the geographically closest relative inhabiting the Ryukyu archipelago in Japan. The new species is highly distinctive by the display of sexual dimorphism on pleopod II, with the medial margin of the male proximal article of exopod provided with a comb of short, blunt curved spinules; no other representative of the genus is known to display sexually-dimorphic appendages aside of the gnathopods. The new species is also noteworthy by the outline of the palm margin of male gnathopod II, hardly excavated, and by showing a carpus broader than long. An overview of the genus Psammogammarus with 14 species to date is provided. PMID:21998551

  10. Phylogeography, Interaction Patterns and the Evolution of Host Choice in Drosophila-Parasitoid Systems in Ryukyu Archipelago and Taiwan

    PubMed Central

    2015-01-01

    Island biotas provide a great opportunity to study not only the phylogeographic patterns of a group of species, but also to explore the differentiation in their coevolutionary interactions. Drosophila and their parasitoids are exemplary systems for studying complex interaction patterns. However, there is a lack of studies combining interaction-based and molecular marker-based methods. We applied an integrated approach combining phylogeography, interaction, and host-choice behavior studies, with the aim to understand how coevolutionary interactions evolve in Drosophila-parasitoid island populations. The study focused on the three most abundant Drosophila species in Ryukyu archipelago and Taiwan: D. albomicans, D. bipectinata, and D. takahashii, and the Drosophila-parasitoid Leptopilina ryukyuensis. We determined mitochondrial COI haplotypes for samples representing five island populations of Drosophila and four island populations of L. ryukyuensis. We additionally sequenced parts of the autosomal Gpdh for Drosophila samples, and the ITS2 for parasitoid samples. Phylogenetic and coalescent analyses were used to test for demographic events and to place them in a temporal framework. Geographical differences in Drosophila-parasitoid interactions were studied in host-acceptance, host-suitability, and host-choice experiments. All four species showed species-specific phylogeographic patterns. A general trend of the haplotype diversity increasing towards the south was observed. D. albomicans showed very high COI haplotype diversity, and had the most phylogeographically structured populations, with differentiation into the northern and the southern population-group, divided by the Kerama gap. Differentiation in host suitability was observed only between highly structured populations of D. albomicans, possibly facilitated by restricted gene flow. Differentiation in host-acceptance in D. takahashii, and host-acceptance and host-choice in L. ryukyuensis was found, despite there being no differentiation in these two species according to molecular markers. Host choice assays show that L. ryukyuensis populations that have had more time to coevolve adapt their behavior to exploit the most suitable host – D. albomicans. L. ryukyuensis parasitoids on border ranges may, on the other hand, benefit from broader host-acceptance, that may facilitate adaptation to uncertain and variable environments. All results indicate that Drosophila-parasitoid populations in the Ryukyu archipelago and Taiwan have different evolutionary trajectories, and coevolve in a dynamic, complex, and local-specific way. PMID:26070158

  11. Modelling of wave propagation and attenuation in the Osaka sedimentary basin, western Japan, during the 2013 Awaji Island earthquake

    NASA Astrophysics Data System (ADS)

    Asano, Kimiyuki; Sekiguchi, Haruko; Iwata, Tomotaka; Yoshimi, Masayuki; Hayashida, Takumi; Saomoto, Hidetaka; Horikawa, Haruo

    2016-03-01

    On 2013 April 13, an inland earthquake of Mw 5.8 occurred in Awaji Island, which forms the western boundary of the Osaka sedimentary basin in western Japan. The strong ground motion data were collected from more than 100 stations within the basin and it was found that in the Osaka Plain, the pseudo velocity response spectra at a period of around 6.5 s were significantly larger than at other stations of similar epicentral distance outside the basin. The ground motion lasted longer than 3 min in the Osaka Plain where its bedrock depth spatially varies from approximately 1 to 2 km. We modelled long-period (higher than 2 s) ground motions excited by this earthquake, using the finite difference method assuming a point source, to validate the present velocity structure model and to obtain better constraint of the attenuation factor of the sedimentary part of the basin. The effect of attenuation in the simulation was included in the form of Q(f) = Q0(f/f0), where Q0 at a reference frequency f0 was given by a function of the S-wave velocity, Q0 = αVS. We searched for appropriate Q0 values by changing α for a fixed value of f0 = 0.2 Hz. It was found that values of α from 0.2 to 0.5 fitted the observations reasonably well, but that the value of α = 0.3 performed best. Good agreement between the observed and simulated velocity waveforms was obtained for most stations within the Osaka Basin in terms of both amplitude and ground motion duration. However, underestimation of the pseudo velocity response spectra in the period range of 5-7 s was recognized in the central part of the Osaka Plain, which was caused by the inadequate modelling of later phases or wave packets in this period range observed approximately 2 min after the direct S-wave arrival. We analysed this observed later phase and concluded that it was a Love wave originating from the direction of the east coast of Awaji Island.

  12. Pleistocene intraplate magmatism in the Goto Islands, SW Japan: Implications for mantle source evolution and regional geodynamics

    NASA Astrophysics Data System (ADS)

    Hoang, Nguyen; Uto, Kozo; Matsumoto, Aki; Itoh, Jun'ichi

    2013-08-01

    We present geochemical, Sr, Nd and Pb isotopic data for the youngest back-arc tholeiitic and alkali basalts in the southern tip of Goto Islands along the Taiwan-Shinji Folded Belt in northwestern Kyushu, SW Japan. The data are compared with those more-or-less contemporaneous back-arc basalts elsewhere in the region and interpreted accordingly. Our sampling loci included Ukujima (ca. 1 Ma), Ojikajima and Kamigoto (from 0.6 Ma to 0.14) and six locations in the Fukue island area (ages between 0.7 and 0.02 Ma). The Ukujima tholeiites show the highest SiO2 (ca. 52.5 wt%), FeO* (13 wt%), TiO2 (>2.5 wt%) and lowest MgO (4 wt%) and CaO (7.5 wt%) contents whereas the alkali Kamigoto and most Ojikajima magmas show lower SiO2 (48 wt%) and higher MgO (8.5 wt%) and CaO (11 wt%). The Ukujima tholeiites also show the least radiogenic lead with closely similar 87Sr/86Sr and 143Nd/144Nd ratios ranging between 0.7038 and 0.7042, and between 0.51280 and 0.51285, respectively. Mantle-normalized incompatible element distributions are of alkali basalt-type exhibiting, along with the major element, significant spatio-temporal variations. Regardless of such differences the younger basalts, as compared with older 6-15 Ma eruptive products in Hirado (and those in Kita-Matsuura), northeastward along the belt, are the least radiogenic. The 15 Ma volcanics were erupted during episodes of lithospheric extension and show effects of crustal contamination. The 6-9 Ma tholeiites and alkali basalts appeared as regional extension gave way to compression and show hybrids of depleted mid-ocean ridge basalt-like (N-MORB) mantle and heterogeneous EM2 (enriched mantle type 2) (Uto et al., 2004). As extension diminished, deeper asthenospheric sources were tapped producing a range of enriched mantle type 1 (EM1)-contaminated N-MORB-like magmas in the younger (<1 Ma) Ukujima, Ojikajima-Kamigoto and Fukue volcanoes. This composition is believed to present throughout East and Southeast Asian asthenosphere.

  13. Imaging and 2.5D Modeling of Receiver Functions from Deep Virtual Receivers in Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Takenaka, H.; Ueda, T.; Murakoshi, T.; Okamoto, T.

    2014-12-01

    Receiver function analysis is very useful tool to image the seismic velocity structures. We apply it to image seismic structure beneath Kyushu island, Japan. Kyushu region is characterized by active subduction of the Philippine Sea plate (PHS) beneath the Eurasian plate and many active volcanoes. In this study, we use teleseismic records from Hi-net seismic stations (borehole stations) and F-net stations (near-surface stations) in Kyushu, which are supplied by the NIED. Because most of these seismic stations are located at the top or in the sedimentary layer, the records may include strong effect of reverberation within the sedimentary layer, and this effect makes the image of the structure unclear. To overcome this problem, we exploit the modified S-wavevector receiver functions (SWV-RFs). The SWV-RFs are derived by deconvolving the upgoing S-wave component with the upgoing P-wave component of the records. Although it was originally proposed for surface records by Reading et al. (2003, GRL), we use Takenaka and Murakoshi's (2010) method in which we virtually move the seismic sensor at the surface or in the borehole down to the top of the basement layer and calculate the SWV-RFs at that location for suppressing the sedimentary layer effect. This method needs the structure model from the surface to the virtual sensor location. Here we apply the Integrated Velocity Structure Model by the Headquarters for Earthquake Research Promotion. We take several cross sections in Kyushu Island to map the calculated SWV-RFs. We then interpret the continental Moho and low velocity zones in the SWV-RFs. The Moho depth beneath Kyushu varies from 25 km to 33 km. We found two types of exceptional occurrence of 'inverted' Moho (IM): one is the top of sill-like low velocity zones just under active volcanoes, and the other is non-sill type events beneath fore-arc regions of northern Kyushu, which may be attributed to dehydration of PHS. The latter-type IM has been observed by Abe et al. (2013, JGR), while, to our knowledge, the former type IM have been imaged by us for the first time. We further model some SWVRF sections by the 2.5D finite-difference method [Takenaka and Okamoto, 2012, InTech]: we confirm that the assumed depths of Moho and sill-like low velocity zones in the simulation model are well reproduced in the simulated RF imaging results.

  14. Functions of an unreported "rocking-embrace" gesture between female Japanese Macaques (Macaca fuscata) in Kinkazan Island, Japan.

    PubMed

    Shimooka, Yukiko; Nakagawa, Naofumi

    2014-02-12

    Recently, research has focused on the effects of the concurrence of multimodal signals and their efficacy and meaning. We observed an unreported behaviour, a ventro-ventral "rocking-embrace" gesture that is always accompanied by lip smacking as the facial expression and sometimes by a girney call, in wild Japanese macaques (Macaca fuscata) living in Kinkazan Island, northern Japan. This study examined the form and contexts of the occurrence of such multimodal signals in order to elucidate its functions. Eighty-eight cases of rocking embrace were recorded during 183h of observation over 22days. Adult females were involved in all of the cases. Of the 71 cases between adult females in which behaviours prior to the rocking embrace could be identified, 13 cases were allogrooming interruptions, 11 were aggression, and 42 were approaches, most of which occurred between non-kin grooming partners. The rocking embrace was often followed by allogrooming. This suggests that rocking embraces occur under stressful conditions and may function to reduce tensions. This conclusion is consistent with the contexts and functions of lip smacking and girneys shown in previous studies. In contrast with lip smacking and girneys, neither a rocking embrace nor a ventro-ventral embrace (without rocking) between anoestrous adult females has been previously shown in Japanese macaques. In other macaque species, however, the latter gesture is often observed as an affiliative behaviour that immediately follows conflict; it functions to reconcile or as a greeting when it occurs immediately after an approach. Rocking embraces among the Kinkazan macaques occur in contexts similar to, and have a similar function to, the ancestral gesture of ventro-ventral embracing (which is hidden in Japanese macaques) and the ancestral display of lip smacking (which is still observed in Japanese macaques). The ventro-ventral embrace as a tactile signal might have been hidden since it was made redundant by the visual signal of lip smacking in ancestral macaques. PMID:24519610

  15. Sulfate reduction using methane in sediments beneath a bathyal ``cold seep'' giant clam community off Hatsushima Island, Sagami Bay, Japan

    NASA Astrophysics Data System (ADS)

    Masuzawa, Toshiyuki; Handa, Nobuhiko; Kitagawa, Hiroyuki; Kusakabe, Minoru

    1992-05-01

    Two sandy sediment cores (Cores D227-120 and D380) were collected from inside a deep-sea giant clam ( Calyptogena soyoae) community off Hatsushima Island, western Sagami Bay, central Japan (3559.9'N, 13913.6'E; 1160 m deep) and a muddy sediment core (Core D227-202) was obtained from outside the community by the submersible Shinkai 2000. The chloride concentration of the pore waters is constant vertically and sulfate reduction using sedimentary organic matter occurs in Core D227-202 (21 cm long). The chloride concentrations are lower by 7% at the 7.5-9 cm depth in Core D227-120 (9 cm long) and by 3% at the 11-12 cm depth in Core D380 (16 cm long) than those of the overlying bottom waters in the cores from inside of the community. Sulfate concentration decreases remarkably and dissolved inorganic carbon, alkalinity, ammonium-N, and hydrogen sulfide concentrations increase significantly with increasing depth in Core D380. ? 34S values of sulfate ions increase from +20.5 to +35.3 and ? 13C values of dissolved inorganic carbon decrease drastically from -7.0 to -45 with increasing depth from the top to the bottom of the core, although the ? 13C values of the organic carbon of the sediments are -23.7 0.9 in Core D380. These results indicate that sulfate reduction using methane is active within the sediments just beneath the living clams and that the hydrogen sulfide produced can be used by endosymbiotic sulfur oxidizing bacteria living in the gills of C. soyoae in the community.

  16. A Model for the Termination of the Ryukyu Subduction Zone against Taiwan A Triple Junction of Collision, Subduction/Separation and Subduction Boundaries

    NASA Astrophysics Data System (ADS)

    Wu, F. T.; Liang, W.; Lee, J. C.

    2006-12-01

    In the vicinity of Taiwan, the Philippine Sea plate moves in the direction of N50^{O}W to collide with the Eurasian continent and at the same time subducts toward the north along the Ryukyu subduction zone. The geometry of the junction between the Ryukyu subduction and Taiwan is obscured by intense deformation near the island. Based on tomographic velocity images for the subduction zone and relocated seismicity the junction is determined to be near the Longitudinal Valley at the latitude of about 23.7^{O}N, i.e., the northern part of the Coastal Range overlies the subduction zone. North of this latitude the subduction becomes deeper and only the portion of the Eurasian lithosphere that is in contact with the subduction zone is engaging in collision. Above the subduction zone the Eurasian plate undergoes stretching due to the shortening of the plate on the Taiwan side and the lack of shortening of the Eurasian plate above the subducting Philippine Sea plate. When the subducting Philippine Sea reaches the depths of the lower part of the lithosphere or asthenosphere then the Eurasian plate is no longer under compression and a bight in the surface structure is created. Adding to these actions is the opening of the Okinawa Trough and the resulting southward migration of the Ryukyu Trench. Because of the opening of Okinawa this junction is a dynamically changing triple junction that involves collision between about 23^{O}N and 23.7^{O}N, collision and separation, with normal and strike-slip motion along the boundary, to its north and subduction along the Ryukyu Trench. The triple junction migrates southward with time. The plate configuration in this junction resembles that in the eastern syntaxis of Himalaya where the Indian plate moves northwestward to collide along the Himalayan front and subducts under Northeastern India and Myanmar. While the Taiwan collision began about four million years the Indian collision has probably gone on for at least a few tens of million years. The Taiwan situation can provide a scenario of the earlier development of the Indian/Eurasian collision regime.

  17. Phosphorus and iron cycles during early diagenesis of Lake Kai-ike sediments, Kami-koshiki Island, southwest Japan

    NASA Astrophysics Data System (ADS)

    Iida, H.; Yamaguchi, K. E.; Oguri, K.

    2014-12-01

    A meromictic Lake Kai-ike is located on the northeastern margin of Kami-koshiki island, Japan. Permanent density stratification develops due to seawater infiltration through a gravel bar separating the lake from the ocean. The oxygenated surface water overlays a stagnant, saline, and anoxic deep water containing hydrogen sulfide. Purple sulfur bacteria (Chromatium sp.) inhabit the chemocline at 4.5m depth. At the lake bottom, green sulfur bacteria form microbial mat-like structures (Nakajima et al., 2003; Environ. Microbiol.). Such environment can be treated as a model for the past anoxic ocean, such as during Cretaceous OAEs (Oguri et al., 2003; Frontier Res. on Earth Evol.). A 25 cm-long KAI4 sediment core (Yamaguchi et al., 2010; Palaeo3) was used for two sequential extraction methods. SEDEX method (Ruttenberg, 1992; Limnol. Oceanogr.) was used for partitioning phosphorus-bearing species into Pabs (absorbed), PFe (Fe-bound), Pauth (authigenic), Pdet (detrital), and Porg (organic). Iron-bearing species were also divided into FeHCl (HCl-soluble), Fecarb (carbonate), Feox (oxide), Femag (magnetite), and Feresi (residue), following the method of Poulton et al. (2005; Chem. Geol.). At the uppermost part of KAI4 core, Porg was the most abundant P-bearing species (~90% of total P). The Porg content sharply decreased with increasing depth to 5cm. The second most abundant species was PFe; however, PFe and Feox contents remained constant throughout the whole depth. At sediment surface in present-day oxygenated ocean, Fe3+-(oxy)hydroxides trap phosphate diffusing from deeper-anoxic sediment, and the phosphate concentration in pore water becomes high enough to precipitate authigenic apatite (Slomp et al., 1996; J. Mar. Res.). In case of Lake Kai-ike, however, the amount of Fe3+-(oxy)hydroxides was small relative to that of Porg (PFe/Porg = ~0.1). We suggest that the excess phosphate not adsorbed on Fe3+-(oxy)hydroxides was diffused out to the overlying water mass, and the fraction enhanced the microbial activity. This positive feedback mechanism plays a significant role in maintaining anoxic environment in the bottom water.

  18. Interisland variegation of venom [Lys(49)]phospholipase A2 isozyme genes in Protobothrops genus snakes in the southwestern islands of Japan.

    PubMed

    Yamaguchi, Kazuaki; Chijiwa, Takahito; Yamamura, Takeshi; Ikeda, Naoki; Yatsui, Takayo; Hayama, Setsuko; Hattori, Shosaku; Oda-Ueda, Naoko; Ohno, Motonori

    2015-12-01

    Protobothrops tokarensis (Pt), a Crotalinae snake, inhabits only Takarajima and Kodakarajima islands of the Tokara Islands located in the immediate north of Amami-Oshima island of Japan. Kodakarajima P. tokarensis venom gland cDNA library gave four types of phospholipase A2 (PLA2) cDNAs encoding neutral [Asp(49)]PLA2, basic [Asp(49)]PLA2, highly basic [Asp(49)]PLA2, and [Lys(49)]PLA2. As the amino acid sequences encoded by their open reading frames (ORFs) were identical to those of PLA2, PLA-B, PLA-N, and BPI (a [Lys(49)]PLA2), respectively, from Amami-Oshima P. flavoviridis (Pf) venom, they were named PtPLA2, PtPLA-B, PtPLA-N, and PtBPI. Chromatography of P. tokarensis venom gave three PLA2 isozymes, PtPLA2, PtPLA-B, and PtBPI. However, BPII and BPIII ([Lys(49)]PLA2s) expressed in Amami-Oshima P. flavoviridis venom were not found in P. tokarensis venom. Genomic polymerase chain reaction (PCR) for P. tokarensis liver DNAs with the unique primers gave PtBPI gene. Notably it was found that LINE (long interspersed nuclear element)-1 fragment is inserted into second intron of PtBPI gene. The LINE-1 fragment may prevent duplication of PtBPI gene and thus formation of plural [Lys(49)]PLA2 genes in P. tokarensis genome. The interisland variegation of venom [Lys(49)]PLA2 isozyme genes in Protobothrops genus snakes in the southwestern islands of Japan is discussed. PMID:26335362

  19. Genetic and biological characterization of Muko virus, a new distinct member of the species Great Island virus (genus Orbivirus, family Reoviridae), isolated from ixodid ticks in Japan.

    PubMed

    Ejiri, Hiroko; Lim, Chang-Kweng; Isawa, Haruhiko; Kuwata, Ryusei; Kobayashi, Daisuke; Yamaguchi, Yukie; Takayama-Ito, Mutsuyo; Kinoshita, Hitomi; Kakiuchi, Satsuki; Horiya, Madoka; Kotaki, Akira; Takasaki, Tomohiko; Maeda, Ken; Hayashi, Toshihiko; Sasaki, Toshinori; Kobayashi, Mutsuo; Saijo, Masayuki; Sawabe, Kyoko

    2015-12-01

    Among the tick-borne orbiviruses (genus Orbivirus, family Reoviridae), 36 serotypes are currently classified within a single virus species, Great Island virus. In this study, we report the first characterization of a tick-borne orbivirus isolated from the tick Ixodes turdus in Japan, which we identified as a new member of the species Great Island virus. The virus isolate, designated Muko virus (MUV), replicated and induced cytopathic effects in BHK-21, Vero E6, and CCL-141 cells and caused high mortality in suckling mice after intracerebral inoculation. Full genome sequence analysis showed that MUV shared the greatest phylogenetic similarity with Tribe? virus in terms of the amino acid sequences of all viral proteins except for outer capsid protein 1 (OC1; VP4 of MUV). Analysis of genome segment 9 in MUV detected an uninterrupted open reading frame that overlaps with VP6 (Hel), which putatively encodes a molecular and functional equivalent of NS4 from Great Island virus. Our study provides new insights into the geographic distribution, genetic diversity, and evolutionary history of the members of the species Great Island virus. PMID:26350980

  20. Estimation of locations and migration of debris flows on Izu-Oshima Island, Japan, on 16 October 2013 by the distribution of high frequency seismic amplitudes

    NASA Astrophysics Data System (ADS)

    Ogiso, Masashi; Yomogida, Kiyoshi

    2015-06-01

    In the early morning on 16 October 2013, large debris flows resulted in over 30 people dead on Izu-Oshima Island, Japan, which were induced by heavy rainfall from the approaching Typhoon 1326 (Wipha). We successfully estimated the locations and migration processes of five large events of the debris flows, using the spatial distribution of high-frequency seismic amplitudes recorded by a seismic network on the island. The flows occurred on the western flank of the island, almost at the same place as the site where large traces of debris flows were identified after the disaster. During each event of debris flows, the estimated locations migrated downstream with increasing time, from the caldera rim of Miharayama volcano in the center of the island to its western side with a speed of up to 30 m/s. The estimated time series of source amplitudes are different from event to event, exhibiting a large variety of flow sequences while they seem to have repeated at a relatively narrow area over several tens of minutes. The present approach may be utilized for early detection and warning for prevention and reduction of the present type of disasters in the future.

  1. Japan: Shikoku Island

    Atmospheric Science Data Center

    2013-04-16

    ... to global climate change research, they must carefully test their understanding of the data under controlled conditions. During April ... D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. The MISR data were obtained from the NASA Langley ...

  2. Characterization of Heavy Metal Contents in the Bulk Atmospheric Aerosols Simultaneously Collected at Three Islands in Okinawa, Japan by X-ray fluorescence spectrometric method (XRF)

    NASA Astrophysics Data System (ADS)

    Oshiro, Y.; ITOH, A.; Azechi, S.; Somada, Y.; Handa, D.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

    2011-12-01

    We studied heavy metal contents of atmospheric aerosols using an X-ray fluorescence spectrometric method (XRF). The XRF method enables us to analyze heavy metal contents of bulk aerosols rapidly without any chemical pretreatments. We used an energy dispersive X-ray fluorescence spectrometer that is compact and portable. We prepared several different amounts of standard reference materials (NIES No.28) of Japanese National Institute of Environmental Studies on quartz filters for calibration curves. Then, we evaluated quantitative responses of XRF method by comparing with the metal contents determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after acid-digestion. Good linear relationships between X-ray intensity and amount of aerosol on filter were seen in the following 10 metals; Al, K, Ti, V, Fe, Ni, Rb, Ba, Pb and As. We then used XRF method to determine heavy metal contents in authentic atmospheric aerosols collected in Okinawa islands, Japan. Okinawa islands, consisting of many small islands, are situated east of Asian continent, and its location in Asian is well suited for studying long-range transport of air pollutants. Also, in Okinawa islands, maritime air mass prevails during summer, while Asian continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background clean air and can be compared with continental air mass which has been affected by anthropogenic activities such as industries and automobiles. Therefore, Okinawa region is suitable area for studying impacts of air pollutants from East Asia. We simultaneously collected bulk aerosol samples by using identical high-volume air samplers at 3 islands; Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS, Okinawa island), Kume island (ca. 160 km south-west of CHAAMS), and Minami-Daitou island (ca. 320 km south-east of CHAAMS). We report and discuss spatial and temporal distribution of heavy metals determined by the XRF method in the bulk atmospheric aerosols collected at the three islands during June 2008 to June 2010, and for CHAAMS during June 2008 to September 2011.

  3. Ligophorus abditus n. sp. (Monogenea: Ancyrocephalidae) and other species of Ligophorus Euzet & Suriano, 1977 infecting the flathead grey mullet Mugil cephalus L. in the Sea of Japan and the Yellow Sea.

    PubMed

    Dmitrieva, Evgenija V; Gerasev, Pavel I; Gibson, David I

    2013-06-01

    As a result of the re-examination of museum slides and new material of monogeneans collected from Mugil cephalus L. in the Sea of Japan, the estuary of a river which flows into the Sea of Japan, the Yellow Sea (off Zhifu, at the boundary of the Bohai Sea) and the East China Sea (off the Ryukyu Islands), five species of Ligophorus Euzet & Suriano, 1977 were identified, one of which is new. The known species are L. chabaudi Euzet & Suriano, 1977, L. cheleus Rubtsova, Balbuena & Sarabeev, 2007, L. domnichi Rubtsova, Balbuena & Sarabeev, 2007 and L. pacificus Rubtsova, Balbuena & Sarabeev, 2007, which are reported from the Yellow Sea; in addition, L. domnichi is reported for the first time from the East China Sea. Ligophorus abditus n. sp., from the Sea of Japan, differs from its most similar congeners, L. pacificus and L. domnichi, in the shapes of the dorsal anchors and the accessory piece of the male copulatory organ. A comparison of all of the species of Ligophorus recovered from M. cephalus in the Sea of Japan was carried out using Principal Component Analysis, and their distribution and origin are discussed. PMID:23673691

  4. First Report of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) Infections in Invasive Rodents from Five Islands of the Ogasawara Archipelago, Japan

    PubMed Central

    Tokiwa, Toshihiro; Hashimoto, Takuma; Yabe, Tatsuo; Komatsu, Noriyuki; Akao, Nobuaki; Ohta, Nobuo

    2013-01-01

    Background Angiostrongylus cantonensis (Chen, 1935) is a parasite of murid rodents and causative agent of human neuro-angiostrongyliasis. In 2011, the Ogasawara Islands in the western North Pacific were assigned a World Natural Heritage site status. The occurrence of A. cantonensis is well documented in the Chichijima, Hahajima, and Anijima Islands. However, the occurrence of A. cantonensis in the other islands of the Ogasawara Islands has not been reported. Methodology/Principal Findings Between March 2010 and July 2011, 57 Rattus norvegicus and 79 R. rattus were collected from 9 islands (the Hahajima group: Anejima, Imoutojima, Meijima, Mukohjima, and Hirajima; Chichijima group: Minamijima; Mukojima group: Nakoudojima and Yomejima; and Iwojima group: Iwojima). Adult nematodes were found in the pulmonary artery of 46 R. norvegicus collected in the 5 islands of the Hahajima group (Anejima, Meijima, Imoutojima, Hrajima, and Mukohjima Islands). These nematodes were identified by molecular analysis as A. cantonensis. Comparison of the mitochondrial DNA sequences confirmed that all the samples from the Ogasawara Islands shared only a single lineage of A. cantonensis, which has been previously detected in the Okinawa, Hawaii, and Brazil. Conclusions/Significance We describe new endemic foci of rat angiostrongyliasis in the Hahajima group (Anejima, Meijima, Imoutojima, Hirajima, and Mukohjima Islands) of the Ogasawara Islands. These findings indicate that the endemic foci of A. cantonensis are widely distributed in the Ogasawara Islands. Although human cases have not yet been reported in the Ogasawara Islands, the widespread detection of A. cantonensis could be of importance from the perspective of public health. PMID:23950989

  5. Coseismic deformation due to the 2011 Tohoku earthquake: influence of 3-D plate structure around Japan

    NASA Astrophysics Data System (ADS)

    Hashima, A.; Freed, A. M.; Becker, T. W.; Sato, H.; Okaya, D. A.; Suito, H.; Hatanaka, Y.; Matsubara, M.; Takeda, T.; Ishiyama, T.; Iwasaki, T.

    2013-12-01

    Beneath the Japan islands, the Pacific plate descends from the east and the Philippine sea plate descends from the south, causing interaction of two slabs at depth. The 2011 M9 Tohoku earthquake in northern Japan had a source region with a length of ~500 km and a width of ~200 km and forced broad lithospheric and mantle regions in the region to deform. Here, we investigate the effects of slab geometry and 3D heterogeneity on the inversion of inferred coseismic slip and the resulting broad coseismic deformation throughout the region. We construct a 3-D finite element model (FEM) to generate Green's functions for use in a coseismic inversion study that allows considering the influence of complex slab geometry as well as heterogeneities in elastic structure on inferred slip. We utilize the large, land-based Japan GPS array as well as seafloor geodetic constraints in the inversion. We are particularly interested in how coseismic seafloor constraints influence inversion results. Our FEM considers a region of 4500 km x 4900 km x 670 km, incorporating the Pacific and the Philippine sea slabs by interpolating models for the Tohoku region and the Nankai trough, as well as the Kuril, Ryukyu and Izu-Bonin arcs. The model region is divided into about 500,000 tetrahedral elements with average dimension ranging from 20-100 km. We also test the role of gravity on coseismic results, with initial results suggesting that gravitational loading is not an important factor because of the shallow dip of the upper Pacific slab.Our long-term objective is to study the influence of the Tohoku earthquake on evolution of stresses throughout Japan due to both coseismic and postseismic processes, the latter including afterslip and viscoelastic relaxation. An accurate accounting of coseismic slip is very important to such an endeavor.

  6. Petrology of Early Miocene volcanic rocks from Okushiri Island, Japan: geochemical characteristics of lithospheric mantle beneath the back-arc side of the NE Japan arc.

    NASA Astrophysics Data System (ADS)

    Sato, M.; Shuto, K.; Ishimoto, H.; Yagi, M.; Takazawa, E.

    2004-12-01

    The Sr and Nd isotopic studies on Tertiary to Quaternary basaltic rocks of the NE Japan arc have shown that isotopic characteristics of basaltic rocks found on the back-arc side of the NE Japan arc changed drastically from an undepleted isotopic signature (initial 87Sr/86Sr (SrI)=0.7040-0.7060 and initial 143Nd/144Nd (NdI)=0.51260-0.51284) to a depleted isotopic signature (SrI=0.7030-0.7040 and NdI=0.70284-0.51308) at around 15 Ma (Shuto et., 2004). This feature may have resulted from changes around 15 Ma in the isotopic compositions of the magma source beneath the back-arc side in the NE Japan arc due to the thinning of the undepleted subcontinental lithospheric mantle by upwelling of depleted asthenospheric mantle material during the opening of Japan Sea. Based on major and trace element data as well as SrI and NdI values for Early Miocene basaltic rocks from the back-arc side of the NE Japan arc, we examined geochemical characterization of the magma source (lithospheric mantle) for these basaltic rocks. Early Miocene (23-18 Ma) basalts and associated more felsic volcanic rocks form seven volcanic fields (Okushiri Is., Matsumae Pen., Fukaura, Oga Pen., Honjo, Atsumi and Sado Is.) delineating a 500 km-long array in the back-arc side of the NE Japan arc. In terms of major, trace element and Nd isotopic compositions, two groups of Early Miocene basalts can be distinguished. Group 1 is composed of tholeiitic basalts and alkali basalts, and is characterized by high TiO2 contents (1.5-2.5 %) and high (La/Yb)n ratios (>5.5), and high Zr/Y ratios (>6). These samples show the chondrite-normalized LREE-enriched patterns and have NdI values ranging from 0.51259 to 0.51282. Group 2 is composed of tholeiitic basalts, and is different from Group 1 by lower TiO2 contents (<1.5 %), lower (La/Yb)n ratios (<5) and lower Zr/Y ratios (<5.5). These samples show modelately LREE-enriched patterns and have NdI values ranging from 0.51250 to 0.51278. In contrast, Middle Miocene (after 15 Ma) basaltic rocks from the Niigata and Honjo areas in the back-arc side of the NE Japan arc have NdI values of 0.51286 to 0.51310, which are higher than those of Early Miocene basalts. These Middle Miocene samples are lower in TiO2 contents and (La/Yb)n and Zr/Y ratios than Early Miocene Group 1 samples, but partly overlap with Early Miocene Group 2 samples. The geochemical differences between Group 1 and 2 basalt magmas possibly originated from subcontinental lithospheric mantle may be due to differences in degrees of partial melting or heterogeneity of the mantle.

  7. The 3-D tectonic stress fields in and around Japan inverted from centroid moment tensor data of seismic events

    NASA Astrophysics Data System (ADS)

    Terakawa, Toshiko; Matsu'Ura, Mitsuhiro

    2010-12-01

    We can regard the occurrence of earthquakes as the partial release of tectonic stress by sudden brittle rupture. In the framework of linear elasticity, any indigenous source including earthquake rupture is represented by a moment tensor. The moment tensor is mathematically equivalent to the volume integral of stress release over the whole elastic region surrounding the source, and so we can quantitatively relate the centroid moment tensor (CMT) of seismic events with an unknown tectonic stress field. On the basis of such an idea and Bayesian statistical inference theory, we developed an inversion method to estimate the 3-D pattern of tectonic stress from CMT data. Applying the CMT data inversion method to 12,500 seismic events in and around Japan, we obtained precise 3-D tectonic stress patterns that illuminate the present-day (Quaternary) complex tectonic motion of Japanese islands. The stress pattern of the Kuril-Japan-Nankai arc is basically E-W compression, but the direction of intermediate principal stress changes from N-S (reverse faulting type) in northeast Japan to vertical (strike-slip faulting type) in southwest Japan. On the other hand, the stress pattern of the Ryukyu and Izu-Bonin back-arc regions is basically trench perpendicular tension (normal faulting type). In addition to these basic stress patterns governed by mechanical interaction between the Eurasian, North American, Pacific, and Philippine Sea plates, we can recognize several characteristic local stress patterns corresponding to the horizontal motion of the Kuril fore-arc sliver, the collision of the Izu Peninsula with the mainland of Japan, and the opening of the Beppu-Shimabara rift zone.

  8. Submarine counterpart of 7200 BP marine caldera formation in Kikai caldera in southern-off Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Ikegami, F.; Kiyokawa, S.; Oiwane, H.; Nakamura, Y.; Kameo, K.; Minowa, Y.; Kuratomi, T.

    2013-12-01

    Kikai caldera (Matsumoto, 1943) is a mostly submerged highly active caldera complex located in 40 km offshore from Kyushu Island. The caldera is considered to be the source of Akahoya tephra (K-Ah: Machida and Arai, 1978) which date was determined as 7200 cal. BP (Smith et al., 2013). The climactic ignimbrite of the eruption was Koya (K-Ky) pyroclastic density current (PDC), which extent was reached to the deep inland of Kyushu (Ono et al., 1982). K-Ky is known as a characteristic dilute PDC (Maeno and Taniguchi, 2007), though its mechanism to become dilute has been remained unknown due to the lack of the offshore geology. We conducted seismic reflection surveys in two survey cruises (KT-10-18 and KT-11-11) in 2010 and 2011 using a research vessel Tansei-maru of JAMSTEC (Japan Agency for Marine-Earth Science and Technology) at Kikai caldera. The sound source was a 150 cubic inches G-I gun with 10 seconds of shot interval, and a 48-channled streamer cable was used for acquisition. Totally 24 profiles were obtained with the speed of 4 knots. At the southern outskirts where Kikai Caldera is in contact with relatively deep basin, five sedimentary units consist of chaotic lower parts and stratified upper parts are identified. They are named C1-5 in descending order from the seafloor. We examined and defined those sequences through the intersection of the seismic profiles. The coverage area of the seismic profiles without shallow multiple reflections is 110 square km. C1 and C2 can be confirmed in wide area including other caldera margin and caldera infill basin. The thickness is about 100 m in most parts, however C2 dramatically increases it towards 500 m at the southwestern caldera rim. Estimated volume for the sequences are 12.1 cubic km (C1) and 14 cubic km (C2). The major feature of the C3 is the heavily truncated upper surface. Both upper and lower part of C3 is pinched out at the flanks, thus both its distribution and volume show less than a half of C1-2, as 45 square km / 5.5 cubic km. C4 and C5 are the lowermost recognizable sequences. Their chaotic lower parts have much more thickness of >200 m constantly in contrast with the other sequences. The likeliest origins of the sequences are pyroclastic flows from the recurring past large eruptions because of their significance and morphology. The coverage area of this time marks the small radial portion of 0-20 km from the caldera rim. It is unlikely that such large deposits are only at the small portion, therefore the exact total volumes must increase with the scale of the order towards hundreds of cubic km for each sequences. Maeno and Taniguchi (2007) estimated 10 and 20-35 cubic km for the climactic PDC units in 7200 BP eruption from onshore geology. Though we can assume C1 is the PDC deposits of 7200 BP eruption, there is still major discrepancy in volume. Therefore 7200 BP eruption must be far larger than the previously estimated. The cause of such gap is that climactic PDC dispersion in two different environments: onshore and submarine, may be deposited totally independent.

  9. Atmospheric mercury concentrations at two sites in the Kyushu Islands, Japan, and evidence of long-range transport from East Asia

    NASA Astrophysics Data System (ADS)

    Marumoto, Kohji; Hayashi, Masahiko; Takami, Akinori

    2015-09-01

    Continuous monitoring of atmospheric gaseous mercury at Fukuoka and Minamata in the Kyushu Islands, western Japan, was carried out from June 2012 to May 2013 to investigate the influence of long-range transport of mercury in the Asian region. Speciation data at Fukuoka indicated that approximately 99% of the atmospheric mercury was in the gaseous elemental form. The average concentration of gaseous elemental mercury (GEM) at Fukuoka was slightly higher than that of total gaseous mercury (TGM) at Minamata. Synchronous pollution events of higher concentrations of both GEM at Fukuoka and TGM at Minamata were frequently observed from late fall to early spring. We infer that these events occurred due to long-range transport of mercury rather than local, domestic emission sources because the two sites are far apart (about 150 km), and local sources would be unlikely to synchronously influence concentrations at both sites over such a long distance. The results of backward trajectory analyses indicated that these events occurred when air masses came from the Asian continent. In addition, the pollution events were often the result of cold fronts or migratory anticyclones that passed over the Kyushu Islands, often accompanied by descending cool and heavy air currents. Thus, these results indicate that, under specific climate conditions, higher concentrations of atmospheric mercury are transported to the Kyushu Islands from the Asian continent, and are evident in ground-based observations there.

  10. Influence of Asian outflow on Rishiri Island, northernmost Japan: Application of radon as a tracer for characterizing fetch regions and evaluating a global 3D model

    NASA Astrophysics Data System (ADS)

    Zhu, Chunmao; Yoshikawa-Inoue, Hisayuki; Matsueda, Hidekadzu; Sawa, Yosuke; Niwa, Yosuke; Wada, Akira; Tanimoto, Hiroshi

    2012-04-01

    Atmospheric 222Rn was monitored from December 2008 to November 2010 on Rishiri Island (45°07‧N, 141°12‧E), northernmost Japan. Seasonal 222Rn variation was characterized by high concentrations from November to February and low concentrations from May to July, caused by the alternation of continental and maritime fetch regions. 222Rn tracer and back trajectory cluster analyses indicated that the predominant continental fetch region was southeastern Siberia and northeastern China. 222Rn emitted from China and South Korea, whose economies are growing rapidly, did not significantly affect the Rishiri site. The major maritime fetch region was the Sea of Okhotsk and the Bering Sea. A global three-dimensional model (NICAM-TM) accurately simulated 222Rn concentrations on Rishiri Island and in the seasonal fetch regions. The time series of 222Rn data will make it possible to evaluate the sources and sinks of atmospheric greenhouse gases being monitored at Rishiri Island, which complements other sites in the Asia-Pacific rim region, and to validate model simulations used to examine trans-boundary air pollution.

  11. Seasonally resolved sea surface temperature variability over the past 435 years in the northwestern Pacific recorded in Porites coral in Kikai Island, Southern Japan

    NASA Astrophysics Data System (ADS)

    Kawakubo, Y.; Yokoyama, Y.; Suzuki, A.; Alibert, C.; Kinsley, L.; Eggins, S. M.

    2011-12-01

    The Little Ice Age (LIA) is the most recent climate anomaly. According to the hemispheric scale surface temperature reconstructions based on the proxy records in various places, LIA is characterized by the cooling period between 1400 and 1850. However, since these proxy records mainly depend on the terrestrial records in mid to high latitude in the northern hemisphere and the marine records are limited, there is still no consensus concerning its spatial pattern, timing and cause. In June 2009, we obtained a 435-year-long modern core from a coral reef in Kikai Island, Japan. The island is located on the eastern boundary of the East China Sea in the northwestern Pacific. This modern coral core can date back to the LIA. Thus, to better understand the LIA, we reconstructed seasonally resolved sea surface temperature (SST) over the past 435 years in the northwestern Pacific, where it is a lack of records during LIA, based on Sr/Ca ratio in coral skeleton in Kikai Island. We analyzed the skeletal elements using laser ablation inductively coupled plasma mass spectorometry (LA-ICP-MS). This is a very powerful tool to handle long-term records since it requires a relatively brief experimental time compared with the analysis using isotope dilution or thermal ionazation ICP-MS. Our SST reconstruction in Kikai Island during LIA showed cooler period before 1700 and a bit warmer period between 1700 and 1850 compared with the average after the LIA. Based on these results, we discuss the paleoceanographic conditions in the northwestern Pacific during the LIA.

  12. A 'Propagating' Active Across-Arc Normal Fault Shows Rupture Process of the Basement: the Case of the Southwestern Ryukyu Arc

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.; Shinjo, R.; Nakamura, M.; Kubo, A.; Doi, A.; Tamanaha, S.

    2011-12-01

    Ryukyu Arc is located on the southwestern extension of Japanese Island-arc towards the east of Taiwan Island along the margin of the Asian continent off China. The island-arc forms an arcuate trench-arc-backarc system. A NW-ward subduction of the Philippine Sea Plate (PSP)at a rate of 6-8 cm/y relative to the Eurasian Plate (EP) causes frequent earthquakes. The PSP is subducting almost normally in the north-central area and more obliquely around the southwestern area. Behind the arc-trench system, the Okinawa Trough (OT) was formed by back-arc rifting, where active hydrothermal vent systems have been discovered. Several across-arc submarine faults are located in the central and southern Ryukyu Arc. The East Ishigaki Fault (EIF) is one of the across-arc normal faults located in the southwestern Ryukyu Arc, ranging by 44km and extending from SE to NW. This fault was surveyed by SEABAT8160 multibeam echo sounder and by ROV Hyper-Dolphin in 2005 and 2008. The result shows that the main fault consists of five fault segments. A branched segment from the main fault was also observed. The southernmost segment is most mature (oldest but still active) and the northernmost one is most nascent. This suggests the north-westward propagation of the fault rupture corresponding to the rifting of the southwestern OT and the southward retreat of the arc-trench system. Considering that the fault is segmented and in some part branched, propagation might take place episodically rather than continuously from SE to NW. The ROV survey also revealed the rupture process of the limestone basement along this fault from the nascent stage to the mature stage. Most of the rock samples collected from the basement outcrop were limestone blocks (or calcareous sedimentary rocks). Limestone basement was observed to the west on the hanging wall far away from the main fault scarp. Then fine-grained sand with ripple marks was observed towards the main scarp. Limestone basement was observed on the main scarp and on the footwall. These suggest that basically the both sides are composed of the same material, that the whole study area is characterised by Ryukyu limestone exposure and that the basement was split by the across-arc normal fault. Coarse-grained sand and gravels/rubbles were observed towards and on the trough of the fault. On the main scarp an outcrop of limestone basement was exposed and in some part it was broken into rubbles. These facts suggest that crash of the basement due to rupturing is taking place repeatedly on the scarp and the trough. The observed fine-grained sand on the hanging wall might be the final product by the process of the crash of the limestone basement.

  13. Movement of shallow magmatic sources inferred from volcano-tectonic faults: An example from Shinjima Island nearby Sakurajima volcano, Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Y.; Haraguchi, T.; Toda, S.; Miki, D.; Imura, R.

    2006-12-01

    Uplift and subsidence due to magma movement involve complex fault system at the surface of a volcano. Conversely, mapping volcano-tectonic faults and surface deformation allows us to infer the feeding system of magma and eruption process in the past. Here we represent a case study of such deformation and a complex fault system associated with prehistoric and historic volcanic uplifts on and around Shinjima Island that is a small island of ~0.2 square meter located northeast of Sakurajima volcano, Kagoshima Bay, southwest Japan. Combining detail mapping of the faults and dislocation modeling, we reveal geometry, volume, and depth of the magma intrusion during the past eruptions that produced the current Shinjima landform. According to historical records, Shinjima Island was uplifted and emerged from bottom of the sea at the eruption of Sakurajima in 1779. Shinjima Island that is characterized by horst-and-graben structures caused by numerous E-W striking normal faults. The island is mainly composed of pyroclastic deposits, top of which exposes Moejima shell bed that consists of shell fossils yielded a radiocarbon age of 6,000 - 2,300 yr BP. Assuming the shells had been borne horizontally below the water level before the eruption, we applied the shell bed to a piercing point to estimate the fault vertical separation. We measured the height of the shell bed at 75 points along the coastline and then found the faults on both sides of the main graben vertically offset 15.9m, and 23.5m respectively. In addition to the surface mapping, we made E-W and N-S seismic reflection profiles across Shinjima Island. The N-S profile shows a structure that swells up the geologic units (pyroclastic deposits and andestic lava recovered from a deep borehole by Kyoto University) broadly between 200m and 350m in contrast to the narrow surface deformation. The profile suggests the fault displacements do not extend deeper than ~100m below the surface. We also made the 3D submarine topography using bathymetric charts around An'ei Islands which were newly formed during the 1779 eruption. The topography shows An'ei Islands including Shinjima are on the An'ei Plateau which size is about 3 by 5 km. To estimate the magma storage and movement at the 1779 eruption and the predecessors, we performed forward modeling to restore the surface deformation in elastic half-space. A complex model combining a point source inflation and dike intrusions approximately reproduces the current Shinjima landform. The model suggests that the island was uplifted by two-stage volcanic growth. The former is a wide-area bulging formed An'ei Plateau by a deep magma expansion. The latter is the solo uplift of Shinjima Island accompanied with a ridge-trough-ridge structure by a shallow dike intrusion.

  14. Observations of Methane Plumes East of Oki Island in the Sea of Japan, Carried Out by Hyogo Prefecture Fisheries Research Vessel Tajima

    NASA Astrophysics Data System (ADS)

    Aoyama, D.; Aoyama, S.

    2012-12-01

    Twice in June and once in August of 2012, observations of gas plumes east of Oki Island in the Sea of Japan, at depths from 800m to 1500m, were carried out using the quantitative echo sounder (KFC3000, Kaijo) and the echo sounder (FCV1500L, Furuno), installed on the Hyogo Prefecture fisheries research vessel Tajima of 199 tons. At the same time, CTD observations of water temperature and quality, and observations of the ocean floor via underwater camera were carried out for confirmation. This is also a good fishing area for beni-zuwai crab, and although the relationship is unclear, there are often populations of beni-zuwai crab near methane hydrate deposits, so it is likely there are methane hydrate deposits in this area.

  15. A 6.5-year continuous record of sea surface salinity and seawater isotopic composition at Harbour of Ishigaki Island, southwest Japan.

    PubMed

    Abe, Osamu; Agata, Seizen; Morimoto, Maki; Abe, Manabu; Yoshimura, Kei; Hiyama, Tetsuya; Yoshida, Naohiro

    2009-09-01

    We produced continuous records of sea surface salinity and isotopic composition from 1998 to 2004 at Ishigaki Island, southwest Japan, and found clear seasonal variations in salinity and oxygen isotopic composition and increasing trends of them after 1999. These increasing trends could be principally due to the decreasing difference between local precipitation (P) and evaporation (E), as a result of the reduction of horizontal vapour transport from adjacent oceans. When samples collected in heavy rainfall events were excluded, the average Deltadelta(18)O/Delta salinity slope was obtained as 0.31, 0.35 in summer and 0.28 in winter. Estimated E/P ratios based on the isotopic box model are in good agreement with the ratios of independently estimated E to observed P. PMID:20183236

  16. Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station Off-Hatsushima Island Observatory in Sagami Bay, Japan

    PubMed Central

    Kasaya, Takafumi; Mitsuzawa, Kyohiko; Goto, Tada-nori; Iwase, Ryoichi; Sayanagi, Keizo; Araki, Eiichiro; Asakawa, Kenichi; Mikada, Hitoshi; Watanabe, Tomoki; Takahashi, Ichiro; Nagao, Toshiyasu

    2009-01-01

    Sagami Bay is an active tectonic area in Japan. In 1993, a real-time deep sea floor observatory was deployed at 1,175 m depth about 7 km off Hatsushima Island, Sagami Bay to monitor seismic activities and other geophysical phenomena. Video cameras monitored biological activities associated with tectonic activities. The observation system was renovated completely in 2000. An ocean bottom electromagnetic meter (OBEM), an ocean bottom differential pressure gauge (DPG) system, and an ocean bottom gravity meter (OBG) were installed January 2005; operations began in February of that year. An earthquake (M5.4) in April 2006, generated a submarine landslide that reached the Hatsushima Observatory, moving some sensors. The video camera took movies of mudflows; OBEM and other sensors detected distinctive changes occurring with the mudflow. Although the DPG and OBG were recovered in January 2008, the OBEM continues to obtain data. PMID:22291563

  17. Spatial variations of the Kuroshio nutrient stream from the East China Sea to South of Japan

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-Hua; Guo, Xinyu; Long, Yu; Li, Bo

    2013-04-01

    Based on velocity calculated from hydrographic data obtained from 39 cruises during from 2000 to 2009 and nitrate concentration data observed from 1964 to 2011, we calculated nitrate flux (the product of velocity and nitrate concentration) and nitrate transport (integration of flux over a section) through 5 sections along the Kuroshio path from the East China Sea (Sections PN and TK) to south of Japan (Sections ASUKA and 137E). In addition, Section OK east of the Ryukyu Islands was also examined. The nitrate flux showed a subsurface maximum core with a value of 9, 10, 6, 11 and 11 mol/m^2/s at Sections PN, TK, OK, ASUKA, 137E, respectively. The depth of subsurface maximum core changes at five sections and was about 400, 500, 800, 500, and 400 m at Sections PN, TK, OK, ASUKA, 137E, respectively. The eastward nitrate transport was 171, 167, 351, 942, 1444 k mol/s at Sections PN, TK, OK, ASUKA, 137E, respectively. The difference between nitrate transport through Section ASUKA and the sum of transports through Sections TK and OK, as well as the difference of nitrate transport between Sections ASUKA and 137E, suggest that the Kuroshio recirculation south of Shikoku can significantly intensify the eastward nitrate transport by the Kuroshio and therefore play an important role in the nitrate transport in the Kuroshio region.

  18. Spatial changes of inter-plate coupling inferred from sequences of small repeating earthquakes in Japan

    NASA Astrophysics Data System (ADS)

    Igarashi, Toshihiro

    2010-10-01

    We extract sequences of small repeating earthquakes to clarify inter-plate coupling of subducting plates over a large area of the Japanese Islands. As a result, many sequences are detected at the Philippine Sea plate subducting from the Ryukyu trench and Pacific plate subducting from the Kuril-Japan trench. The average slip-rates and standard deviations estimated from the sequences show substantial spatial changes of inter-plate coupling. The large deviations of slip-rates correspond to the occurrence of episodic slips such as after-slips following large earthquakes. Constant slip-rates approaching the relative plate motion indicate weak coupling areas. Slip deficits and sparse distributions of repeating groups suggest locked areas. In the Nankai trough, deep low-frequency earthquakes in the transition zone and burst-type repeating sequences within plates have not been located in the downdip direction of groups with slow slip-rates. This suggests that the space-time characteristics of inter-plate coupling affected these seismic events.

  19. Avian haemosporidian parasites infection in wild birds inhabiting Minami-daito Island of the Northwest Pacific, Japan.

    PubMed

    Murata, Koichi; Nii, Ryosuke; Yui, Saori; Sasaki, Emi; Ishikawa, Satoshi; Sato, Yukita; Matsui, Shin; Horie, Sayaka; Akatani, Kana; Takagi, Masaoki; Sawabe, Kyoko; Tsuda, Yoshio

    2008-05-01

    Haemosporidian parasites infection among wild birds inhabiting Minami-daito Island was studied. Blood films from 183 birds representing 4 species of 4 families were examined microscopically. Avian haemosporidian parasites were detected in 3 species with an overall prevalence of 59.6%. None of the 30 Daito scops owls (Otus scops interpositus) examined were infected. Either Haemoproteus sp. or Plasmodium sp. infection was found in 14 of 31 (45.2%) Borodino islands white-eyes (Zosterops japonicus daitoensis). Plasmodium spp. were found in 94 of 102 (92.2%) bull-headed shrikes (Lanius bucephalus) and 1 of 20 (5%) tree sparrows (Passer montanus). PMID:18525175

  20. Seasonal variability of radon-derived fetch regions for Sado Island, Japan, based on 3 years of observations: 2002-2004

    NASA Astrophysics Data System (ADS)

    Chambers, Scott; Zahorowski, Wlodek; Matsumoto, Kiyoshi; Uematsu, Mitsuo

    Three years of hourly atmospheric radon measurements at Sado Island (Japan) are discussed and compared with corresponding measurements at Gosan (South Korea), and Hok Tsui (China). In conjunction with back trajectory analysis, Sado radon data are used to characterise the seasonal variability in fetch regions of air masses subject to extremes of terrestrial influence. In winter, fetch regions of air masses that have experienced the greatest terrestrial influence covered southern Siberia; in summer, the terrestrial fetch was dominated by Japan; throughout the remaining months the terrestrial fetch encompassed the Korean Peninsula and far eastern China. Summer radon data are then used to estimate the radon flux from central Honshu (23.5 mBq m -2 s -1), which varied regionally between 10.6 and 47.9 mBq m -2 s -1. The Sado radon record reported here completes a 4-site, multi-year dataset of hourly radon concentrations across East Asia and the central Pacific (spanning 16 of latitude), which constitutes a unique evaluation tool for transport and mixing schemes of atmospheric and chemical transport models.

  1. Analysis of electrical activity and seismicity in the natural time domain for the volcanic-seismic swarm activity in 2000 in the Izu Island region, Japan

    NASA Astrophysics Data System (ADS)

    Uyeda, S.; Kamogawa, M.; Tanaka, H.

    2009-02-01

    Seismicity and geoelectric potential changes, possibly associated with the seismic swarm activity in 2000 in the Izu Island region, Japan, are analyzed in the framework of the natural time ?, which has been recently introduced as an index of the kth event ? = k/N, where N is the total number of events. The Izu 2000 swarm activity lasted for about 2 months with some 7000 shocks with magnitude M ? 3 and five M ? 6 shocks, and was preceded by a pronounced electrical activity with innumerable signals that started 2 months prior to the swarm onset. It is shown, first, that the seismicity subsequent to the electrical activity approaches to a critical stage a few days before the occurrence of the first M ? 6 shock and, second, that the electrical signals also have the properties characteristic to the critical stage. Despite the big differences in time scale and numbers of electric signals and earthquakes, these features are found similar to those in Greece. The present results suggest that both in Greece and Japan, the electrical activity as well as the subsequent seismicity may have a self-similar structure and exhibits similar dynamic evolution toward critical stage.

  2. Evaluation of Mn and Fe in coral skeletons ( Porites spp.) as proxies for sediment loading and reconstruction of 50 yrs of land use on Ishigaki Island, Japan

    NASA Astrophysics Data System (ADS)

    Inoue, Mayuri; Ishikawa, Daisaku; Miyaji, Tsuzumi; Yamazaki, Atsuko; Suzuki, Atsushi; Yamano, Hiroya; Kawahata, Hodaka; Watanabe, Tsuyoshi

    2014-06-01

    Manganese (Mn) and iron (Fe) concentrations were measured in coral skeletons ( Porites spp.) collected from the Todoroki River on Ishigaki Island, Japan, to reconstruct the history of land use in the river catchment area. We prepared (1) five bulk samples to investigate the present spatial distribution and (2) micro-samples from two long cores to study the temporal variability of sediment loading from the Todoroki River. The existing state of the elements Mn and Fe in bulk coral skeleton samples was examined by a chemical cleaning experiment. The results of the experiment suggested that Fe was not incorporated into the crystal lattice of the coral skeleton but that Mn was incorporated, as previously reported. The bulk sample data, with and without chemical cleaning, indicated that the spatial distribution of both elements in corals collected along a sampling line from the river mouth toward the reef crest was complex and most likely reflected salinity changes and the amount of suspended particulate matter. The temporal variation of Mn and Fe, in particular the variation of baseline/background levels, mainly reflected the history of land development on Ishigaki Island. In addition, Mn showed clear seasonal variability that appeared to be controlled by a combination of temperature, primary productivity, and precipitation. The results of the present study suggest that Mn may be a useful proxy for river discharge or biological activity depending on local marine conditions, if the specific behavior of Mn at the coral growth site is known.

  3. Photochemical Formation of Fe(II) and Peroxides in Coastal Seawater Collected around Okinawa Island, Japan - Impact of Red Soil Pollution

    NASA Astrophysics Data System (ADS)

    Okada, K.; Nakajima, H.; Higuchi, T.; Fujimura, H.; Arakaki, T.; Taira, H.

    2003-12-01

    In a study to elucidate the impacts of red soil pollution on the oxidizing power of seawater, photochemical formation of Fe(II) and peroxides was studied in seawaters collected around Okinawa Island, Japan. The northern part of Okinawa Island suffers from red soil pollution which is caused mainly by land development such as pineapple farming and the construction of recreational facilities. We studied photochemical formation of peroxides and Fe(II) in the same seawater samples because the reaction between HOOH and Fe(II) forms hydroxyl radical (OH radical), the most potent environmental oxidant. Photochemical formation of Fe(II) was fast and reached steady-state in 30 minutes of simulated sunlight illumination and the steady-state Fe(II) concentrations were about 80% of total iron concentrations. Photochemical formation of peroxides was relatively slow and formation kinetics varied, depending on the initial peroxide concentrations. Because photochemical formation of peroxides was faster and total iron concentrations in the red soil polluted seawater were higher, red soil polluted seawater is expected to have greater oxidizing power than seawater that is not polluted with red soil.

  4. Trace element accumulation in short-tailed albatrosses (Diomedea albatrus) and black-footed albatrosses (Diomedea nigripes) from Torishima Island, Japan

    NASA Astrophysics Data System (ADS)

    Shinsuke, T.; Tokutaka, I.; Takashi, K.; Miyako, T.; Fumio, S.; Nariko, O.

    2003-05-01

    Concentrations of 19 trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Hg, Tl, and Pb) were determined in liver, kidney, muscle, feather and stomach content of short-tailed albatross and feather of black-footed albatross from Torishima Island, Japan. For most of the elements, concentrations in liver and kidney were higher than those in muscle and feather, whereas concentrations of Ga, Sr and Ba were highest in feather of short-taled albatross. Metal concentrations in tissues of short-tailed albatross were within the range of those reported for albatrosses from other locations. Concentrations of Cr, Mn, Hg and Pb were relatively low in the tissues of short-tailed albatross, indicating less contamination by those metals in this species of Torishima Island. No significant differences were observed in metal concentrations in feather between short-tailed albatross and black-footed albatross. To our knowledge, this is the first report on the trace element accumulation in tissues of short-tailed albatross.

  5. Interannual variations of the occurrence of epipelagic fish in the diets of the seabirds breeding on Teuri Island, northern Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Deguchi, Tomohiro; Watanuki, Yutaka; Niizuma, Yasuaki; Nakata, Akifumi

    2004-05-01

    The diets of breeding seabirds can be a good monitor of marine environmental changes. From 1984 to 2001 we monitored the diets of black-tailed gulls ( Larus crassirostris) (“surface foragers”), rhinoceros auklets ( Cerorhinca monocerata) (“epipelagic divers”), and Japanese cormorants ( Phalacrocorax filamentotus) (“bottom divers”) that breed on Teuri Island at the northern boundary of the Tsushima Warm current in the Sea of Japan/East Sea. Between 1984 and 1987, both the gulls and the auklets foraged on the sardine ( Sardinops melanostictus), but after 1992, they switched to the anchovy ( Engraulis japonica). This change might reflect the collapse of the sardine stock in the late 1980s. In the 1990s, the year-to-year variations of the percentage of anchovy in the diets of the three seabird species showed similar trends: High in 1994 and 1998-2001; and low in 1992-1993 and 1995-1997. The estimated stock size of the anchovy population in the Tsushima Current area was positively correlated with the percentage of mass of anchovy in the seabirds’ diets. Thus, the short-term annual changes of the total anchovy availability, which might reflect SST or the volume transport of Tsushima Current, possibly affected the seabirds diets on this island.

  6. Asymmetric seasonal march from autumn to the next spring in East Asia (Toward interdisciplinary education on the climate systems and the "seasonal feeling" such as around the Japan Islands area)

    NASA Astrophysics Data System (ADS)

    Kato, Kuranoshin; Kato, Haruko; Sato, Sari; Akagi, Rikako; Haga, Yuichi; Miyake, Shoji

    2014-05-01

    There are many steps of seasonal transitions in East Asia, greatly influenced by the considerable phase differences of seasonal cycle among the Asian monsoon subsystems, resulting in the variety of "seasonal feeling" around the Japan Islands. For example, the "wintertime pressure pattern" begins to prevail already from November due to the seasonal development of the Siberian Air mass and the Siberian High, although the air temperature around the Japan Islands is still rather higher than in midwinter. On the other hand, since the southward retreat of the warm moist air mass in the western Pacific area delays rather greatly to the advances of those northern systems. Thus it would be interesting to re-examine the whole seasonal cycle around the Japan Islands at the view point of how the phase differences among seasonal marches of the Asian monsoon subsystems affect the variety of the seasonal cycle there, together with their effects on the "seasonal feeling". As such, the present study will examine the asymmetric seasonal march from autumn to the next spring through midwinter around the Japan Islands as an interesting example, and will also report the joint activity with music, and so on, toward the development of an interdisciplinary study plan on such topics for the students in junior high school, high school and the faculty of education of the university. The wintertime weather pattern, i.e., precipitation in the Japan Sea side and clear day in the Pacific side of the Japan Islands, prevails from early November to early March, reflected by the seasonal cycle of the Siberian Air Mass and the Siberian High. However, the air temperature shows the minimum from late January to early February around the Japan Islands. In other words, although the dominant weather patterns around November and in early March are nearly the same as each other, air temperature is still lower in early March (early spring). In spite of that, the solar radiation is rather stronger in early March. Comparison of "seasonal feeling" expressed in the Japanese classic poems called "Wa-Ka", the Japanese school songs, and so on, between those seasons was also made, referring to the asymmetric seasonal march as just mentioned above. We would like to introduce also the results of the trial of the class at Kurashiki-Seiryo High School or Faculty of Education of Okyama University. We should note that the present joint activity might also contribute to providing the study materials for the cultural understanding, which is one of the important elements for the ESD (Education for Sustainable Development).

  7. Sapporo, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The city of Sapporo on the northernmost of the Japanese Home Island of Hokkaido (43.5N, 141.5E), host to the 1986 Winter Olympic Games is situated along the margin of a large valley which extends across the island from the Sea of Japan to the Pacific Ocean. The Valley is largely cultivated (the lighter green of the cultivated land distinguishes it from the gray urban development of Sapporo), but much of the island remains heavily forested.

  8. Could a Sumatra-like megathrust earthquake occur in the south Ryukyu subduction zone?

    NASA Astrophysics Data System (ADS)

    Lin, Jing-Yi; Sibuet, Jean-Claude; Hsu, Shu-Kun; Wu, Wen-Nan

    2014-12-01

    A comparison of the geological and geophysical environments between the Himalaya-Sumatra and Taiwan-Ryukyu collision-subduction systems revealed close tectonic similarities. Both regions are characterized by strongly oblique convergent processes and dominated by similar tectonic stress regimes. In the two areas, the intersections of the oceanic fracture zones with the subduction systems are characterized by trench-parallel high free-air gravity anomaly features in the fore-arcs and the epicenters of large earthquakes were located at the boundary between the positive and negative gravity anomalies. These event distributions and high-gravity anomalies indicate a strong coupling degree of the intersection area, which was probably induced by a strong resistance of the fracture features during the subduction. Moreover, the seismicity distribution in the Ryukyu area was very similar to the pre-seismic activity pattern of the 2004 Sumatra event. That is, thrust-type earthquakes with a trench-normal P-axis occurred frequently along the oceanward side of the mainshock, whereas only a few thrust earthquakes occurred along the continentward side. Therefore, the aseismic area located west of 128E in the western Ryukyu subduction zone could have resulted from the strong plate locking effect beneath the high gravity anomaly zone. By analogy with the tectonic environment of the Sumatra subduction zone, the occurrence of a potential Sumatra-like earthquake in the south Ryukyu arc is highly likely and the rupture will mainly propagate continentward to fulfill the region of low seismicity (approximately 125 E to 129 E; 23 N to 26.5 N), which may generate a hazardous tsunami.

  9. Improving the seismic imaging in the southern Ryukyu subduction system by using multiple attenuation methods

    NASA Astrophysics Data System (ADS)

    Lyu, Ci-Jhu; Kuo-Chen, Hao; McIntosh, Kirk; Wu, Francis; Liu, Char-Shine

    2015-04-01

    The southern Ryukyu subduction system is at the boundary where the Philippine sea plate subducts northwestward beneath the Eurasian plate near the Taiwan orogen. In previous studies, the boundary where the PSP subducts northward beneath the EP have no clear answers due to a lack of high-resolution crustal-scale geophysical constraints. We want to know the Moho boundary. We analyze in this study the dynamics of SRA system with TAIGER program of 2009, multi-channel marine seismic reflection (MGL0906_23, MGL0906_28, MGL0906_26A, MGL0906_13, MGL0906_18N). Data area covers about 30,000 km2. Shots are spaced every 50 m, hydrophones are spaced every 12.5 m, and CDP spacing is 6.25 m. Recording length is 15 s. Signal of the source is low frequencies (20Hz~60Hz), which can penetrate the shallow sediments and reflex signal of the deep crust. Because multiple can affect the deep structure signals. Therefore, we use a variety of methods to remove multiple effects, and increase Moho signals. In this study, we use four ways to remove the multiple. (1) Increases CDP spacing. (2)Deconvolution. (3) Surface Related Multiple Elimination (SRME). (4)Radon Transform multiple attenuation. From the TAIGER marine reflection data. The shallow structure are Huatung Basin, Yeyama Accretionary Prism, Forearc Basin and Ryukyu Arc (from south to north), respectively. We discover a lot of transform fault zone, and account these stress related with shear zone of Ryukyu subduction system. The deep structure, the crust of PSP velocity is about 5~7 km/s, the PSP Moho velocity is 7.5 km/s. In multichannel reflection seismic, the PSP Moho deep is about 15~20 km under the seabed. Keywords: multiple; Moho boundary; subduction zone; southern Ryukyu Arc (SRA)

  10. Temporal changes of genetic population structure and diversity in the endangered Blakiston's fish owl (Bubo blakistoni) on Hokkaido Island, Japan, revealed by microsatellite analysis.

    PubMed

    Omote, Keita; Nishida, Chizuko; Takenaka, Takeshi; Masuda, Ryuichi

    2012-05-01

    The Blakiston's fish owl (Bubo blakistoni) population on Hokkaido Island, Japan, decreased to less than one hundred individuals over the last century due to habitat disruption by human activity. Although the ongoing conservation management has slightly restored the population, it remains endangered. In order to assess the genetic variation and population structure of the Blakiston's fish owl in Hokkaido, we genotyped eight microsatellite loci on 120 individuals sampled over the past three decades. The genotype data set showed low levels of genetic variation and gene flow among the geographically isolated five subpopulations. Comparative analysis of past and current populations indicated that some alleles shared by past individuals had been lost, and that genetic variation had declined over the last three decades. The result suggests that the genetic decline may have resulted from inbreeding and/or genetic drift due to bottlenecks in the Hokkaido population. The present study provides invaluable genetic information for the conservation and management of the endangered Blakiston's fish owl in Hokkaido. PMID:22559963

  11. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    NASA Astrophysics Data System (ADS)

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-01

    Radioactive fission product 131I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, 134Cs and 137Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBqm-3 in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of 134Cs and 137Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ngm-3) variation of stable cesium (133Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  12. Analysis of early bacterial communities on volcanic deposits on the island of Miyake (Miyake-jima), Japan: a 6-year study at a fixed site.

    PubMed

    Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Nanba, Kenji; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Ohta, Hiroyuki

    2012-01-01

    Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. Collected samples were acidic (pH 3.0-3.6), did not utilize any organic substrates in ECO microplate assays (Biolog), and harbored around 106 cells (g dry weight)(-1) of autotrophic Fe(II) oxidizers by most-probable-number (MPN) counts. Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, and the Leptospirillum groups I, II and III were found to be abundant in the deposits by clone library analysis of bacterial 16S rRNA genes. The numerical dominance of Acidithiobacillus ferrooxidans was also supported by analysis of the gene coding for the large subunit of the form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Comparing the 16S rRNA gene clone libraries from samples differing in age, shifts in Fe(II)-oxidizing populations seemed to occur with deposit aging. The detection of known 16S rRNA gene sequences from Fe(III)-reducing acidophiles promoted us to propose the acidity-driven iron cycle for the early microbial ecosystem on the deposit. PMID:22075623

  13. Analysis of Early Bacterial Communities on Volcanic Deposits on the Island of Miyake (Miyake-jima), Japan: a 6-year Study at a Fixed Site

    PubMed Central

    Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Nanba, Kenji; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Ohta, Hiroyuki

    2012-01-01

    Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. Collected samples were acidic (pH 3.0–3.6), did not utilize any organic substrates in ECO microplate assays (Biolog), and harbored around 106 cells (g dry weight)−1 of autotrophic Fe(II) oxidizers by most-probable-number (MPN) counts. Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, and the Leptospirillum groups I, II and III were found to be abundant in the deposits by clone library analysis of bacterial 16S rRNA genes. The numerical dominance of Acidithiobacillus ferrooxidans was also supported by analysis of the gene coding for the large subunit of the form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Comparing the 16S rRNA gene clone libraries from samples differing in age, shifts in Fe(II)-oxidizing populations seemed to occur with deposit aging. The detection of known 16S rRNA gene sequences from Fe(III)-reducing acidophiles promoted us to propose the acidity-driven iron cycle for the early microbial ecosystem on the deposit. PMID:22075623

  14. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    SciTech Connect

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-15

    Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  15. systematics of island arc crustal amphibolite migmatites from the Asago body of the Yakuno Ophiolite, Japan: a field evaluation of some model predictions

    NASA Astrophysics Data System (ADS)

    Pu, Xiaofei; Brophy, James G.; Tsujimori, Tatsuki

    2014-09-01

    The two most commonly invoked processes for generating silicic magmas in intra-oceanic arc environments are extended fractional crystallization of hydrous island arc basalt magma or dehydration melting of lower crustal amphibolite. Brophy (Contrib Mineral Petrol 156:337-357, 2008) has proposed on theoretical grounds that, for liquids >~65 wt% SiO2, dehydration melting should yield, among other features, a negative correlation between rare earth element (REE) abundances and increasing SiO2, while fractional crystallization should yield a positive correlation. If correct, the REE-SiO2 systematics of natural systems might be used to distinguish between the two processes. The Permian-age Asago body within the Yakuno Ophiolite, Japan, has amphibolite migmatites that contain felsic veins that are believed to have formed from dehydration melting, thus forming an appropriate location for field verification of the proposed REE-SiO2 systematics for such a process. In addition to a negative correlation between liquid SiO2 and REE abundance for liquids in excess of ~65 % SiO2, another important model feature is that, at very high SiO2 contents (75-76 %), all of the REE should have abundances less than that of the host rock. Assuming an initial source amphibolite that is slightly LREE-enriched relative to the host amphibolites, the observed REE abundances in the felsic veins fully support all theoretical predictions.

  16. Continuous measurement of CO2 flux through the snowpack in a dwarf bamboo ecosystem on Rishiri Island, Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Zhu, Chunmao; Nakayama, Momoko; Yoshikawa Inoue, Hisayuki

    2014-09-01

    To investigate the dynamics and environmental drivers of CO2 flux through the winter snowpack in a dwarf bamboo ecosystem (Hokkaido, northeast Japan), we constructed an automated sampling system to measured CO2 concentrations at five different levels in the snowpack, from the base to the upper snow surface. Using a gas diffusion approach, we estimated an average apparent soil CO2 flux of 0.26 μmol m-2 s-1 during the snow season (December-April); temporally, the CO2 flux increased until mid-snow season, but showed no clear trend thereafter; late-season snow-melting events resulted in rapid decreases in apparent CO2 flux values. Air temperature and subnivean CO2 flux exhibited a positive linear relationship. After eliminating the effects of wind pumping, we estimated the actual soil CO2 flux (0.41 μmol m-2 s-1) to be 54% larger than the apparent flux. This study provides new constraints on snow-season carbon emissions in a dwarf bamboo ecosystem in northeast Asia.

  17. Is heterostyly rare on oceanic islands?

    PubMed Central

    Watanabe, Kenta; Sugawara, Takashi

    2015-01-01

    Heterostyly has been considered rare or absent on oceanic islands. However, there has been no comprehensive review on this issue. Is heterostyly truly rare on oceanic islands? What makes heterostyly rare on such islands? To answer these questions, we review the reproductive studies on heterostyly on oceanic islands, with special emphasis on the heterostylous genus Psychotria in the Pacific Ocean as a model system. Overall, not many reproductive studies have been performed on heterostylous species on oceanic islands. In Hawaiian Psychotria, all 11 species are thought to have evolved dioecy from distyly. In the West Pacific, three species on the oceanic Bonin and Lanyu Islands are distylous (Psychotria homalosperma, P. boninensis and P. cephalophora), whereas three species on the continental Ryukyu Islands show various breeding systems, such as distyly (P. serpens), dioecy (P. rubra) and monoecy (P. manillensis). On some other Pacific oceanic islands, possibilities of monomorphy have been reported. For many Psychotria species, breeding systems are unknown, although recent studies indicate that heterostylous species may occur on some oceanic islands. A shift from heterostyly to other sexual systems may occur on some oceanic islands. This tendency may also contribute to the rarity of heterostyly, in addition to the difficulty in colonization/autochthonous evolution of heterostylous species on oceanic islands. Further investigation of reproductive systems of Psychotria on oceanic islands using robust phylogenetic frameworks would provide new insights into plant reproduction on oceanic islands. PMID:26199401

  18. Very exceptional cases of VLF/LF ionospheric perturbations for deep oceanic earthquakes offshore the Japan island

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiroki; Hayakawa, Masashi

    2015-12-01

    It is so far believed that ionospheric perturbations as detected by subionospheric VLF/LF (very low frequency/low frequency) propagation, are generated above and around the earthquake (EQ) epicenter. This paper presents very rare cases, which are in complete contrast to the above fact. We have found that in extremely rare cases when EQs happened (i) in the Pacific Ocean or (ii) offshore the Soya cape (Hokkaido) both with very large depths (300-400 km), corresponding ionospheric perturbations take place far away from the EQ epicenter and above the regions with considerable seismic intensity at the time of each EQ. Two EQs happened in the Torishima area of Izu islands (magnitude ?7 and depth ?400 km), and corresponding seismic intensity was observed in the Tokyo and Ibaraki districts. Our VLF data have indicated that the ionospheric perturbation takes place over such regions with high seismic intensity. Another group is two EQs (magnitude ?5) offshore the Soya cape of Hokkaido, and the spatial distribution of seismic intensity at the time of each EQ is just around Aomori prefecture. VLF data have indicated the ionospheric perturbations taken place over the same Aomori area, which is in complete coincidence with the spatial distribution of seismic intensity. As a conclusion, these exceptional examples are, in principle, very similar to the concept of 'selectivity' (or sensitive zone) of geoelectric measurement by the Greek group, and we try to interpret these cases in the context of lithosphere-atmosphere-ionosphere coupling.

  19. Giant Subaqueous Pyroclastic-Flow Deposits Revealed: Sedimentological Revision of the Holocene Outcrops of Izu-Oshima Island, Japan

    NASA Astrophysics Data System (ADS)

    Hemmi, R.; Yoshida, S.; Nemoto, Y.; Kotake, N.

    2010-12-01

    The early-to-middle Holocene outcrops of Izu-Oshima island, 100 km SSW of Tokyo, comprise sand- to gravel-size pyroclasts, and exhibit undulating layered structures, with each wavelet typically measuring 5-10 m high. These outcrops were traditionally interpreted as exemplary subaerial "ash-fall" deposits in volcanology textbooks (e.g. Schmincke 2006). Our detailed sedimentological analyses, however, have revealed that it is of pyroclastic density-current origin, the majority of which formed in shallow-marine settings. The present study focuses on the outcrops along the western coast of the Island, where the three-dimensional architecture of the outcrops is superbly exposed, and the existing archaeological framework provides a reliable chronostratigraphic control. The outcrops contain abundant compound bedforms, where small bedforms (dunes/antidunes) occur within the larger bedforms. The compound bedforms exhibit four-fold hierarchy (ranks 1 to 4), and bedforms for each scale display dominantly upstream-accreting geometry. The largest scale (Rank 1) of these bedforms show wavy parallel-bedding geometry (each wavelet typically measuring 5-10 m high and 50-100 m wide). We interpreted the large-scale architecture as sediment waves (gigantic antidunes) similar to the one reported from the shallow-marine deposits associated with AD 79 Mt. Vesuvius eruptions (Milia et al. 2008). Moreover, we have identified crustacean burrows and other trace fossils indicative of a nearshore shallow-marine environment. The pervasive occurrence of these fossils throughout the outcrops and abundant water-escape structures also suggests their subaqueous origin. On the other hand, evidence of subaerial deposition (e.g., paleosols and rootlets) or subaerial reworking (e.g., lahar) is absent, except for some spots on several regional unconformities that divide 10’s-m-thick sediment-wave deposits. On some of these unconformities, ribbon- to fan-shaped lava and/or ancient human-dwelling sites (5.0-7.5 ka) are locally present. These observations suggest that the deposition of the pyroclastic and lava flow occurred near the coastline, with rapid fluctuations of relative sea level. Earlier workers suggested that these outcrops were “subaerial ash-fall” deposits, with each dm-thick layer representing a small eruption that occurred at about 150-year interval from 20 ka to 5 ka, with the total number of eruptions reaching or possibly exceeding 100 (Tazawa 1980). However, we suggest that these layers form several 10’s-m-thick unconformity-bounded units (sediment waves). Together with the abundant shallow-marine trace fossils, we believe that these outcrops are of subaqueous pyroclastic-flow origin, recording less frequent but much bigger catastrophic eruptions than previously thought. Without recognizing the stratal packaging patterns on the 2-D/3-D vertical cross-sections, these outcrops can easily be mistaken for ash-fall deposits, and the magnitude of eruptions can be vastly underestimated.

  20. Detection and location of shallow very low frequency earthquakes along the Nankai trough and the Ryukyu trench

    NASA Astrophysics Data System (ADS)

    Asano, Y.; Matsuzawa, T.; Obara, K.

    2013-12-01

    We have investigated spatiotemporal distribution of shallow very low frequency earthquakes (VLFEs) along the Nankai trough and the Ryukyu trench. Three component seismograms recorded at broadband stations of the NIED F-net were analyzed by using waveform-correlation and back-projection techniques after processing a band-pass filter (0.02 to 0.05 Hz). Here we used known VLFEs and regular interplate earthquakes near the trench axis as template events. Time series of cross-correlation function (CC) at each station was calculated from continuous waveform data and triggered seismograms of template events with a length of 180 s. Assuming surface wave propagation with a velocity of 3.8 km/s, CCs are back-propagated onto possible origin times and horizontal locations. We obtained VLFE epicenters by performing a grid search in time and space domains with spacing of 1 s and 0.025 degrees, respectively, to maximize the averaged CCs from all stations. At first, we choose grid points with averaged CCs larger than 0.5. If these grid points have similar origin times within 180 s, we assume that these grid points reflect a same event and choose the VLFE candidate having the largest averaged CC. If some grid points are detected in the same time window from different template events, we choose the VLFE candidate with the largest averaged CC from grid points located within 100 km from the template event. VLFEs were finally identified by removing regular earthquakes listed in the JMA catalogue from all candidates. As a result of the analysis for data from October, 2009 to February, 2010, two episodes of VLFE activity were detected. One episode was located east of the M6.8 interplate earthquake which occurred on October 30, 2009 along the Ryukyu trench. The VLFE seismicity was quite active just after the M6.8 earthquake and had been smoothly decreasing with the elapsed time. Such time dependent seismicity may be related to the post-seismic slip following the M6.8 earthquake. Another episode was detected mainly in Hyuga-nada along the Nankai trough. This episode started on January 24, 2010 in east off Tanegashima Island, migrated northward along the strike of the subducting plate, then reached Hyuga-nada on January 31. Travel distance of migration is at least 100 km and the migration velocity is about 10 km/day. The VLFE seismicity was reactivated from February 12, then migrated eastward and continued in Ashizuri-misaki-oki until the end of February. Such a large scale migration is quite similar to that of non-volcanic tremor and deep very low-frequency earthquakes coincident with slow slip events in the deeper extension of the seismogenic zone along Nankai subduction zone. This suggests that possible slow slip events associated with VLFEs in this area can exist even in the shallower extension of the seismogenic zone.

  1. Okinawa, Japan: Geologic Battleground

    NASA Astrophysics Data System (ADS)

    Waymack, S. W.; Carrington, M. P.; Harpp, K. S.

    2005-12-01

    One of our main goals as instructors, particularly in introductory courses, is to impart students with an appreciation of how geology has influenced the course of human events. Despite the apparent accessibility of such topics, communicating this in a lively, relevant, and effective way often proves difficult. We use a series of historical events, the Pacific island hopping campaign of WWII, to engage students in an active, guided inquiry exercise to explore how terrain and the underlying geology of an area can shape historical events. Teams of students are assigned the role of planning either the defense or occupation of Okinawa Island, in the Ryukyu arc, in a theoretical version of the 1945 conflict. Students are given a package of information, including geologic and topographic maps, a list of military resources available to them at the time, and some historical background. Students also have access to "reconnaissance" images, 360o digital panoramas of the landscape of Okinawa, keyed to their maps. Each team has a week to plan their strategies and carry out additional research, which they subsequently bring to the table in the form of a written battle plan. With an instructor as arbiter, teams alternate drawing their maneuvers on a map of the island, to which the other team then responds. This continues one move at a time, until the instructor declares a victor. Throughout the exercise, the instructor guides students through analysis of each strategic decision in light of the island's structure and topography, with an emphasis on the appropriate interpretation of the maps. Students soon realize that an understanding of the island's terrain literally meant the difference between life and death for civilians and military participants alike in 1945. The karst landscape of Okinawa posed unique obstacles to both the Japanese and the American forces, including difficult landing sites, networks of natural caves, and sequences of hills aligned perpendicular to the length of the island and to American troop movement. This unique topography forced innovative tactics ranging from reverse slope defense to "blowtorch and corkscrew" offense in response. During this exercise, students apply their map-reading and interpretation skills, as well as their critical analysis abilities; the historical context, in turn, provides motivation to refine those skills. Sun Tzu wrote that all warfare is based on deception. What we hope to communicate to students with this activity is that much of warfare, and, more broadly, the way humans interact with the world, is inherently and undeniably based on geology.

  2. Paleoclimate Reconstruction during the 17th to 18th Century Using Fossil Coral Tsunami Boulders from Ishigaki Island, the Ryukyus, Japan

    NASA Astrophysics Data System (ADS)

    Tsuzuki, K.; Yokoyama, Y.; Seki, A.; Kawakubo, Y.; Araoka, D.; Suzuki, A.

    2014-12-01

    Little Ice Age (LIA) which lasted during approximately 1450 to 1850 (e.g. Grove, 1988) is known as naturally occurring climate fluctuation, so knowing LIA in detail is necessary to improve climate models. Instrumental records can only extend back to about 100 years in many areas, thus paleoclimate records are reconstructed using proxies in tree rings, sediments and so force. However there are differences in reconstructed timings and magnitudes of LIA occurred in each area (Overpack et al., 1997), and most of the records are based mainly on terrestrial proxies such as tree ring records, whereas only limited numbers of marine records are available (Mann et al., 2008). Coral skeletal climatology is a useful tool to reconstruct marine paleoclimate records in tropics and subtropics. Hermatypic corals, Porites spp. have aragonite skeletons and they have annual bands, which are suitable to reconstruct high-resolution paleoclimate in seasonal scale by measuring chemical compositions. Skeletal Sr/Ca ratio in Porites spp. has been widely used as a reliable proxy of SST (Sea Surface Temperature). However, corals grow for approximately several decades to 200 years, hence it is difficult to reconstruct LIA paleoclimate using living corals. Cobb et al. (2003) used fossil corals casted on shore by storms to reconstruct millennial scale paleoclimate. There are fossil coral boulders in the eastern coast of Ishigaki Island, Ryukyus, Japan. These fossil coral boulders were casted on shore by paleo Tsunami events, thus they are called "Tsunami boulders" (Araoka et al., 2010). Fossil corals used by Cobb et al. have 30-90-year records while some large Tsunami boulders have multi-centennial continuous records. In this study, we reconstruct paleo SST using the Tsunami boulder from Ishigaki Island. The boulder has 185 years of annual banding. U-series dating shows the boulder was moved on shore at Meiwa earthquake in 1771. We measure Sr/Ca ratio using LA-HR-ICPMS (Laser Ablation High Resolution Inductively Coupled Plasma Mass Spectrometry) to reconstruct paleo SST during LIA (Kawakubo et al., 2014). LA-HR-ICPMS enables us to measure the long coral core rapidly. Our result shows SST variation in 17th-18th century in this area and SST declined in around 1700. This result reveals the response of Little Ice Age in the northwestern Pacific.

  3. Northeast Coast, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The northeast coast of Hokkaido and Kunashir Island, Japan (44.0N, 143.0E) are seen bordered by drifting sea ice. The sea ice has formed a complex pattern of eddies in response to surface water currents and winds. Photos of this kind aid researchers in describing local ocean current patterns and the effects of wind speed and direction on the drift of surface material, such as ice floes or oil. Kunashir is the southernmost of the Kuril Islands.

  4. Amplitude Comparison of Teleseismic P-Wave Phases from the Japan Subduction Zone and the South Sandwich Islands recorded at Uturuncu Volcano, Bolivia

    NASA Astrophysics Data System (ADS)

    Farrell, A. K.; McNutt, S. R.; West, M. E.

    2012-12-01

    Uturuncu volcano (22 15' S, 67 12'W) has been shown to be inflating at a rate of 1-1.5 cm per year by a satellite geodetic survey from May 1996-present. This inflation is centered just southwest of the volcano's summit and at a depth of 15-17 km. This may be caused by the injection of magma into the system. Seismic studies performed as part of the multi-university PLUTONS project can help constrain the location and nature of this inflation. By looking at how teleseismic peak-to-peak waveform amplitudes (velocities in nm/s) vary across the network, we can begin to pinpoint the size and location of attenuating zones beneath the edifice. Analysis of 5 P-wave phases from 4 earthquakes with origins in the Japan subduction zone (NW of the network, ~155 distant) shows a consistent 'shadow zone' of decreased amplitudes in a 13.6 by 33.3 km zone to the SE of the summit. Observations from two teleseismic events originating in the South Sandwich Islands (~45 distant) show similar effects although the geometry differs with respect to individual stations. We expect this trend to hold true for events originating to the NE and SW of the volcano, which would indicate a zone of decreased amplitude in the same region SE of the summit. The attenuation of P-waves that would otherwise be of uniform amplitude could be the result of some ray paths traveling through a shallow, low-velocity and highly attenuating zone of either magma/mush, highly fractured rock, or some other cause. This attenuating zone may be located at or near the center of the inflation zone, and physical processes associated with it could well be closely related to the observed inflation.

  5. Culture-Dependent and -Independent Characterization of Microbial Communities Associated with a Shallow Submarine Hydrothermal System Occurring within a Coral Reef off Taketomi Island, Japan?

    PubMed Central

    Hirayama, Hisako; Sunamura, Michinari; Takai, Ken; Nunoura, Takuro; Noguchi, Takuro; Oida, Hanako; Furushima, Yasuo; Yamamoto, Hiroyuki; Oomori, Tamotsu; Horikoshi, Koki

    2007-01-01

    Microbial communities in a shallow submarine hydrothermal system near Taketomi Island, Japan, were investigated using cultivation-based and molecular techniques. The main hydrothermal activity occurred in a craterlike basin (depth, ?23 m) on the coral reef seafloor. The vent fluid (maximum temperature, >52C) contained 175 ?M H2S and gas bubbles mainly composed of CH4 (69%) and N2 (29%). A liquid serial dilution cultivation technique targeting a variety of metabolism types quantified each population in the vent fluid and in a white microbial mat located near the vent. The most abundant microorganisms cultivated from both the fluid and the mat were autotrophic sulfur oxidizers, including mesophilic Thiomicrospira spp. and thermophilic Sulfurivirga caldicuralii. Methane oxidizers were the second most abundant organisms in the fluid; one novel type I methanotroph exhibited optimum growth at 37C, and another novel type I methanotroph exhibited optimum growth at 45C. The number of hydrogen oxidizers cultivated only from the mat was less than the number of sulfur and methane oxidizers, although a novel mesophilic hydrogen-oxidizing member of the Epsilonproteobacteria was isolated. Various mesophilic to hyperthermophilic heterotrophs, including sulfate-reducing Desulfovibrio spp., iron-reducing Deferribacter sp., and sulfur-reducing Thermococcus spp., were also cultivated. Culture-independent 16S rRNA gene clone analysis of the vent fluid and mat revealed highly diverse archaeal communities. In the bacterial community, S. caldicuralii was identified as the predominant phylotype in the fluid (clonal frequency, 25%). Both bacterial clone libraries indicated that there were bacterial communities involved in sulfur, hydrogen, and methane oxidation and sulfate reduction. Our results indicate that there are unique microbial communities that are sustained by active chemosynthetic primary production rather than by photosynthetic production in a shallow hydrothermal system where sunlight is abundant. PMID:17921273

  6. A five-year observation of atmospheric metals on Ulleung Island in the East/Japan Sea: Temporal variability and source identification

    NASA Astrophysics Data System (ADS)

    Kang, Jeongwon; Choi, Man-Sik; Yi, Hi-Il; Song, Yun-Ho; Lee, Dongyup; Cho, Ju-Hye

    2011-08-01

    We investigated seasonal characteristics (concentration, enrichment factors, and correlation coefficients) of chemical constituents, including sources for sea salt-corrected metals (Al, Fe, K, Ca, Mg, S, As, Cd, Co, Cu, Li, Mn, Mo, Ni, Pb, Sn, Sr, Ti, V, and Zn), in 334 aerosol samples collected during October 2003-October 2008 at Ulleung Island in the southern East/Japan Sea. High Al concentrations were found in spring (geometric means of 1.23 and 1.28 μg m -3 in March and April, respectively) due to Asian dust (yellow sand) originating from northeastern China. The dust mineral transport by strong winds resulted in a change of metal composition showing soil-dominated condition. In the rainy period (June-September), the aerosol metal concentrations and composition were influenced largely by wet deposition and the summer monsoon, together with anthropogenic aerosol transport. The correlation coefficients in the summer period (July and August) showed a positive correlation of Al with K ( r = 0.74) and As ( r = 0.63), probably reflecting anthropogenic-originated Al coming from coal burning. In autumn (October and November) and winter (December and January), mixed sources of soil and anthropogenic-originated aerosols were pronounced by the development of northwesterly winds from the Asian continent. Especially, the soil-originated proportion was relatively higher in autumn than in winter when the anthropogenic-originated aerosols from heating fuels predominated. Anthropogenic As, Sn, Mo, Zn, Pb, and Cd between low- and high-dust periods that had similar air-mass movements in spring were at similar concentrations, but higher in the air masses including eastern China trajectories and/or slow movement at lower height during high-dust periods.

  7. Three-dimensional resistivity modelling of grounded electrical-source airborne transient electromagnetic (GREATEM) survey data from the Nojima Fault, Awaji Island, south-east Japan

    NASA Astrophysics Data System (ADS)

    Allah, Sabry Abd; Mogi, Toru; Ito, Hisatoshi; Jymori, Akira; Yuuki, Youichi; Fomenko, Elena; Kiho, Kenzo; Kaieda, Hideshi; Suzuki, Koichi; Tsukuda, Kazuhiro

    2014-08-01

    An airborne electromagnetic (AEM) survey using the grounded electrical-source airborne transient electromagnetic (GREATEM) system was conducted over the Nojima Fault on Awaji Island, south-east Japan, to assess GREATEM survey applicability for studying coastal areas with complex topographic features. To obtain high-quality data with an optimised signal-to-noise ratio, a series of data processing techniques was used to acquire the final transient response curves from the field survey data. The 1D inversion results were feasible in that the horizontal resistivity contrast was not much higher than the true contrast, but they were not reasonable in that the horizontal resistivity values were greatly changed. To circumvent this problem, we performed numerical forward modelling using a finite-difference staggered-grid method (Fomenko and Mogi, 2002) adding a finite-length electrical dipole source routine to generate a three-dimensional (3D) resistivity structure model from GREATEM survey data of the Nojima Fault area. The 3D model was based on an initial model consisting of two adjacent onshore and offshore layers of different conductivity such that, a highly conductive sea of depth (10-40 m) is placed on top of a uniform half-space, assuming the presence of topographic features on the inland side. We examined the fit of the magnetic transient responses between field data and 3D forward-model computed data, the latter were convolved with the measured system response of the corresponding dataset. The inverted 3D resistivity structures showed that the GREATEM system has the capability to map underground resistivity structures as deep as 500 m onshore and offshore. The GREATEM survey delineated how seawater intrudes on the landside of the fault and indicated that the fault is a barrier to seawater invasion.

  8. A pilot study of tele-anaesthesia by virtual private network between an island hospital and a mainland hospital in Japan.

    PubMed

    Miyashita, Tetsuya; Mizuno, Yusuke; Sugawara, Yo; Nagamine, Yusuka; Koyama, Yukihide; Miyazaki, Tomoyuki; Uchimoto, Kazuhiro; Iketani, Yasuhiro; Tojo, Kentaro; Goto, Takahisa

    2015-03-01

    We studied the use of tele-anaesthesia between Sado General Hospital (SGH) located on Sado Island and Yokohama City University Hospital (YCUH) located in mainland Japan. The two sites were connected via a virtual private network (VPN). We investigated the relationship between the bandwidth of the VPN and both the frame rate and the delay time of the tele-anaesthesia monitoring system. The tool used for communication between the two hospitals was free videoconferencing software (FaceTime), which can be used over Wi-Fi connections. We also investigated the accuracy of the commands given during teleanaesthesia: any commands from the anaesthetist at the YCUH that were not carried out for any reason, were recorded in the anaesthetic records at the SGH. The original frame rate and data rate at the SGH were 5 fps and approximately 18 Mbit/s, respectively. The frame rate at the transmission speeds of 1, 5 and 20 Mbit/s was 0.6, 1.6 and 5.0 fps, respectively. The corresponding delay time was 12.2, 4.9 and 0.7 s. Twenty-five adult patients were enrolled in the study and tele-anaesthesia was performed. The total duration of anaesthesia was 37 hours. All 888 anaesthetic commands were completed. There were 7 FaceTime disconnections, which lasted for 10 min altogether. Because no commands needed to be given during the FaceTime disconnection, the telephone was not used. The anaesthesia assistance system might form part of the solution to medical resource shortages. PMID:25488187

  9. Rapid sedimentation of iron oxyhydroxides in an active hydrothermal shallow semi-enclosed bay at Satsuma Iwo-Jima Island, Kagoshima, Japan

    NASA Astrophysics Data System (ADS)

    Kiyokawa, Shoichi; Ueshiba, Takuya

    2015-04-01

    Hydrothermal activity is common in the fishing port of Nagahama Bay, a small semi-enclosed bay located on the southwest coast of Satsuma Iwo-Jima Island (38 km south of Kyushu Island, Japan). The bay contains red-brown iron oxyhydroxides and thick deposits of sediment. In this work, the high concentration and sedimentation rates of oxyhydroxide in this bay were studied and the sedimentary history was reconstructed. Since dredging work in 1998, a thickness of ~ 1.0-1.5 m of iron oxyhydroxide-rich sediments has accumulated on the floor of the bay. To estimate the volume of iron oxyhydroxide sediments and the amount discharged from hydrothermal vents, sediment traps were operated for several years and 13 sedimentary core samples were collected to reconstruct the 10-year sedimentary history of Nagahama Bay. To confirm the timing of sedimentary events, the core data were compared with meteorological records obtained on the island, and the ages of characteristic key beds were thus identified. The sedimentation rate of iron oxyhydroxide mud was calculated, after correcting for sediment input from other sources. The sediments in the 13 cores from Nagahama Bay consist mainly of iron oxyhydroxide mud, three thick tephra beds, and a topmost thick sandy mud bed. Heavy rainfall events in 2000, 2001, 2002, and 2004-2005 coincide with tephra beds, which were reworked from Iwo-Dake ash deposits to form tephra-rich sediment. Strong typhoon events with gigantic waves transported outer-ocean-floor sediments and supplied quartz, cristobalite, tridymite, and albite sands to Nagahama Bay. These materials were redeposited together with bay sediments as the sandy mud bed. Based on the results from the sediment traps and cores, it is estimated that the iron oxyhydroxide mud accumulated in the bay at the relatively rapid rate of 33.3 cm/year (from traps) and 2.8-4.9 cm/year (from cores). The pore water contents within the sediment trap and core sediments are 73%-82% and 47%-67%, respectively. The estimated production of iron oxyhydroxide for the whole fishing port from trap cores is 142.7-253.3 t/year/5000 m2. From sediment cores, however, the accumulation of iron oxyhydroxide sediments on the sea floor is 39-95 t/year/5000 m2. This finding indicates that the remaining 63%-73% of iron was transported out to sea from Nagahama Bay. Even with a high rate of iron oxyhydroxide production, the sedimentation rate of iron oxyhydroxides in the bay is considerably higher than that observed in modern deep-ocean sediments. This example of rapid and abundant oxyhydroxide sedimentation might provide a modern analog for the formation of iron deposits in the geological record, such as ironstones and banded iron formations.

  10. Tetrodotoxin and Its Analogues in the Pufferfish Arothron hispidus and A. nigropunctatus from the Solomon Islands: A Comparison of Their Toxin Profiles with the Same Species from Okinawa, Japan.

    PubMed

    Puilingi, Clyde Gorapava; Kudo, Yuta; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2015-09-01

    Pufferfish poisoning has not been well documented in the South Pacific, although fish and other seafood are sources of protein in these island nations. In this study, tetrodotoxin (TTX) and its analogues in each organ of the pufferfish Arothron hispidus and A. nigropunctatus collected in the Solomon Islands were investigated using high resolution LC-MS. The toxin profiles of the same two species of pufferfish from Okinawa, Japan were also examined for comparison. TTXs concentrations were higher in the skin of both species from both regions, and relatively lower in the liver, ovary, testis, stomach, intestine, and flesh. Due to higher TTX concentrations (51.0 and 28.7 g/g at highest) detected in the skin of the two species from the Solomon Islands (saxitoxin was <0.02 g/g), these species should be banned from consumption. Similar results were obtained from fish collected in Okinawa, Japan: TTX in the skin of A. hispidus and A. nigropunctatus were 12.7 and 255 g/g, respectively, at highest, and saxitoxin was also detected in the skin (2.80 g/g at highest) and ovary of A. hispidus. TTX, 5,6,11-trideoxyTTX (with its 4-epi form), and its anhydro forms were the most abundant, and 11-oxoTTX was commonly detected in the skin. PMID:26343722

  11. Tetrodotoxin and Its Analogues in the Pufferfish Arothron hispidus and A. nigropunctatus from the Solomon Islands: A Comparison of Their Toxin Profiles with the Same Species from Okinawa, Japan

    PubMed Central

    Gorapava Puilingi, Clyde; Kudo, Yuta; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2015-01-01

    Pufferfish poisoning has not been well documented in the South Pacific, although fish and other seafood are sources of protein in these island nations. In this study, tetrodotoxin (TTX) and its analogues in each organ of the pufferfish Arothron hispidus and A. nigropunctatus collected in the Solomon Islands were investigated using high resolution LC-MS. The toxin profiles of the same two species of pufferfish from Okinawa, Japan were also examined for comparison. TTXs concentrations were higher in the skin of both species from both regions, and relatively lower in the liver, ovary, testis, stomach, intestine, and flesh. Due to higher TTX concentrations (51.0 and 28.7 µg/g at highest) detected in the skin of the two species from the Solomon Islands (saxitoxin was <0.02 µg/g), these species should be banned from consumption. Similar results were obtained from fish collected in Okinawa, Japan: TTX in the skin of A. hispidus and A. nigropunctatus were 12.7 and 255 µg/g, respectively, at highest, and saxitoxin was also detected in the skin (2.80 µg/g at highest) and ovary of A. hispidus. TTX, 5,6,11-trideoxyTTX (with its 4-epi form), and its anhydro forms were the most abundant, and 11-oxoTTX was commonly detected in the skin. PMID:26343722

  12. An Attempt at Captive Breeding of the Endangered Newt Echinotriton andersoni, from the Central Ryukyus in Japan.

    PubMed

    Igawa, Takeshi; Sugawara, Hirotaka; Tado, Miyuki; Nishitani, Takuma; Kurabayashi, Atsushi; Islam, Mohammed Mafizul; Oumi, Shohei; Katsuren, Seiki; Fujii, Tamotsu; Sumida, Masayuki

    2013-01-01

    Anderson's crocodile newt (Echinotriton andersoni) is distributed in the Central Ryukyu Islands of southern Japan, but environmental degradation and illegal collection over the last several decades have devastated the local populations. It has therefore been listed as a class B1 endangered species in the IUCN Red List, indicating that it is at high risk of extinction in the wild. The species is also protected by law in both Okinawa and Kagoshima prefectures. An artificial insemination technique using hormonal injections could not be applied to the breeding of this species in the laboratory. In this study we naturally bred the species, and tested a laboratory farming technique using several male and female E. andersoni pairs collected from Okinawa, Amami, and Tokunoshima Islands and subsequently maintained in near-biotopic breeding cages. Among 378 eggs derived from 17 females, 319 (84.4%) became normal tailbud embryos, 274 (72.5%) hatched normally, 213 (56.3%) metamorphosed normally, and 141 (37.3%) became normal two-month-old newts; in addition, 77 one- to three-year-old Tokunoshima newts and 32 Amami larvae are currently still growing normally. Over the last five breeding seasons, eggs were laid in-cage on slopes near the waterfront. Larvae were raised in nets maintained in a temperature-controlled water bath at 20 C and fed live Tubifex. Metamorphosed newts were transferred to plastic containers containing wet sponges kept in a temperature-controlled incubator at 22.5 C and fed a cricket diet to promote healthy growth. This is the first published report of successfully propagating an endangered species by using breeding cages in a laboratory setting for captive breeding. Our findings on the natural breeding and raising of larvae and adults are useful in breeding this endangered species and can be applied to the preservation of other similarly wild and endangered species such as E. chinhaiensis. PMID:26479528

  13. Intraplate volcanism influenced by distal subduction tectonics at Jeju Island, Republic of Korea

    NASA Astrophysics Data System (ADS)

    Brenna, Marco; Cronin, Shane J.; Kereszturi, Gbor; Sohn, Young Kwan; Smith, Ian E. M.; Wijbrans, Jan

    2015-01-01

    The drivers behind the inception of, and the variable, pulsatory eruption rates at distributed intraplate volcanic fields are not well understood. Such broad areas of monogenetic volcanism cover vast areas of the world and are often heavily populated. Reliable models to unravel their behaviour require robust spatio-temporal frameworks within the fields, but an analysis of the potential proximal and distal regional volcano-tectonic processes is also needed. Jeju Island (Republic of Korea) is a volcanic field that has been extensively drilled and dated. It is also located near one of the world's best-studied tectonic plate boundaries: the subduction zone in southwestern Japan, which generates the Ryukyu and SW Japan arcs. A new set of 40Ar/39Ar ages collected from cores penetrating the entire Jeju eruptive pile, along with geochemical information, is used to construct a temporal and volumetric model for the volcano's growth. The overall pattern indicates inception of volcanism at ~1.7 Ma, with an initial 1.2 Myr of low-rate activity, followed by over an order of magnitude rise over the last 0.5 Myr. The magma flux at Jeju correlates well with increased extension rates in the arc/backarc region. In particular, we infer that the increased trenchward mantle flow, caused by the greater rollback of the Philippine Sea Plate, activated pre-existing shear weaknesses in the mantle beneath Jeju, resulting in mantle upwelling and decompression melting that caused a change in compositions and an increase in eruption rates at Jeju. Thus, the volcanic activity of an intraplate field system can be modulated by regional subduction processes occurring more than 650 km away. This model may explain the frequent observation of pulsatory behaviour seen in many monogenetic volcanic fields worldwide that lie within 1,000 km of subduction zones.

  14. A new species of fiddler crab from the Ogasawara (Bonin) Islands, Japan, separated from the widely-distributed sister species Uca (Paraleptuca) crassipes (White, 1847) (Crustacea: Decapoda: Brachyura: Ocypodidae).

    PubMed

    Shih, Hsi-Te; Komai, Tomoyuki; Liu, Min-Yun

    2013-01-01

    A new species of fiddler crab (Brachyura: Ocypodidae), Uca boninensis sp. nov., is described from the Ogasawara (Bonin) Islands, Japan. The new species has previously been identified with the widely distributed U. crassipes (White, 1847), from which it differs by having a slightly differently shaped carapace, and relatively stouter male first gonopods (G1). The recognition of the new species is also supported by differences in the mitochondrial cytochrome oxidase I (COI) and control region (CR) genes. U. boninensis sp. nov., appears to be endemic to the Ogasawara Islands, and as the only known population is small, urgent conservation measures are needed for its protection. Our study brings the total number of the Japanese fiddler crab species to 12. PMID:25113474

  15. Activated Very Low Frequency Earthquakes By the Slow Slip Events in the Ryukyu Subduction Zone

    NASA Astrophysics Data System (ADS)

    Nakamura, M.; Sunagawa, N.

    2014-12-01

    The Ryukyu Trench (RT), where the Philippine Sea plate is subducting, has had no known thrust earthquakes with a Mw>8.0 in the last 300 years. However, the rupture source of the 1771 tsunami has been proposed as an Mw > 8.0 earthquake in the south RT. Based on the dating of tsunami boulders, it has been estimated that large tsunamis occur at intervals of 150-400 years in the south Ryukyu arc (RA) (Araoka et al., 2013), although they have not occurred for several thousand years in the central and northern Ryukyu areas (Goto et al., 2014). To address the discrepancy between recent low moment releases by earthquakes and occurrence of paleo-tsunamis in the RT, we focus on the long-term activity of the very low frequency earthquakes (VLFEs), which are good indicators of the stress release in the shallow plate interface. VLFEs have been detected along the RT (Ando et al., 2012), which occur on the plate interface or at the accretionary prism. We used broadband data from the F-net of NIED along the RT and from the IRIS network. We applied two filters to all the raw broadband seismograms: a 0.02-0.05 Hz band-pass filter and a 1 Hz high-pass filter. After identification of the low-frequency events from the band-pass-filtered seismograms, the local and teleseismic events were removed. Then we picked the arrival time of the maximum amplitude of the surface wave of the VLFEs and determined the epicenters. VLFEs occurred on the RA side within 100 km from the trench axis along the RT. Distribution of the 6670 VLFEs from 2002 to 2013 could be divided to several clusters. Principal large clusters were located at 27.1-29.0N, 25.5-26.6N, and 122.1-122.4E (YA). We found that the VLFEs of the YA are modulated by repeating slow slip events (SSEs) which occur beneath south RA. The activity of the VLFEs increased to two times of its ordinary rate in 15 days after the onset of the SSEs. Activation of the VLFEs could be generated by low stress change of 0.02-20 kPa increase in Coulomb failure stress. The strain in the plate interface where the VLFEs occur frequently would be released by small change in stress. Cluster of the VLFEs is complementally to the historical tsunami source area and locked area. Continuous activity of VLFEs would release the stress patchily in the plate interface and give the constraint to the maximum size of large thrust earthquakes.

  16. Distribution of Non-Locus of Enterocyte Effacement Pathogenic Island-Related Genes in Escherichia coli carrying eae from Patients with Diarrhea and Healthy Individuals in Japan ?

    PubMed Central

    Narimatsu, Hiroshi; Ogata, Kikuyo; Makino, Yoshihiro; Ito, Kenitiro

    2010-01-01

    The relationship to diarrhea of genes located on the pathogenicity islands (PAI) other than the locus of enterocyte effacement (LEE) was investigated. Enteropathogenic Escherichia coli (EPEC), the retention of espC on the EspC PAI, the OI-122 genes (efa1/lifA, nleB), the phylogenetic marker gene yjaA, and the bundle-forming pilus gene bfpA on the EPEC adherence factor (EAF) plasmid were studied. E. coli strains carrying the intimin gene (eae) without the Shiga toxin gene, isolated from patients with diarrhea (n = 83) and healthy individuals (n = 38) in Japan, were evaluated using PCR. The genotypes of eae and espC were identified by heteroduplex mobility assay (HMA). The proportions of strains isolated from individuals with and without diarrhea that carried these genes were as follows: bfpA, 13.3 and 7.9%, respectively; espC, 25.3 and 36.8%; efa1/lifA, 32.5 and 13.2%; nleB, 63.9 and 60.5%; yjaA, 42.2 and 55.3%. Statistical significance (P < 0.05) was achieved only for efa1/lifA. The proportion of strains lacking espC and carrying efa1/lifA was higher for patient-derived strains (30.1%) than for strains from healthy individuals (13.2%), but the difference was not significant. Strains carrying both espC and efa1/lifA were rare (2 strains from patients). Statistical analyses revealed significant relationships between espC and yjaA and between efa1/lifA and nleB, as well as significant inverse relationships between espC and efa1/lifA and between efa1/lifA and yjaA. espC was found in eae HMA types a1, a2, and c2, whereas efa1/lifA was found in types b1, b2, and c1. In addition, 6 polymorphisms of espC were found. The espC, yjaA, efa1/lifA, and nleB genes were mutually dependent, and their distributions were related to eae type, findings that should be considered in future epidemiological studies. PMID:20844211

  17. Discovery of a bird-parasitic fly, Carnus orientalis (Diptera: Carnidae), in Japan, with bionomic remarks and a key to Carnus species.

    PubMed

    Iwasa, Mitsuhiro; Sakamoto, Hironori; Asahi, Kento

    2014-03-01

    A bird-parasitic fly, Carnus orientalis Maa, 1968, is recorded for the first time from Japan, and it is taxonomically reexamined on the basis of specimens collected in Okinawa Prefecture. Adult flies were found from nestlings of Ryukyu scops owl (Otus elegans Cassin, 1852), which is a new host for C. orientalis. Bionomic remarks regarding C. orientalis are presented, and akey to the world species of Carnus is also provided. PMID:24724300

  18. Japan Nuclear Fuel, Ltd.

    SciTech Connect

    1992-08-01

    Just over a month ago, on July 1, Japan Nuclear Fuel Industries (JNFI) and Japan Nuclear Fuel Services (JNFS) merged to form the integrated nuclear fuel cycle company, Japan Nuclear Fuel, Ltd. (JNFL). The announcement in mid-January that the country`s two major fuel cycle firms intended to merge had long been anticipated and represents one of the most significant restructuring events in Japan`s nuclear industry. The merger forming JNFL was a logical progression in the evolution of Japan`s fuel cycle, bringing complementary technologies together to encourage synergism, increased efficiency, and improved community relations. The main production facilities of both JNFI and JNFS were located near the village of Rokkashomura, on the northern end of the main island of Honshu, and their headquarters were in Tokyo. The former JNFS was responsible for spent fuel reprocessing and also was building a high-level waste (HLW) management facility. The former JNFI focused on uranium enrichment and low-level waste (LLW) disposal. It was operating the first stage of a centrifuge enrichment plant and continuing to construct additional capacity. These responsibilities and activities will be assumed by JNFL, which now will be responsible for all JNFI and JNFS operations, including those at Rokkashomura.

  19. Two Types of Spatio-Temporal Distribution of Large Earthquakes during Holocene; A Case Study for Active Faults in Island Arc of Northeast Japan

    NASA Astrophysics Data System (ADS)

    Mizumoto, T.; Imaizumi, T.; Otsuki, K.; Kagohara, K.

    2006-12-01

    Northeast Japan is one of the most typical island arc-trench systems which is under EW-trending horizontal compression since ca. 3 Ma-DThe elastic thin layer of upper crust was buckled initially with wavelength of about 50 km, and eventually thrust faults were developed near the inflection line of these crustal folds. The hanging walls have been grown as mountainous regions, while Quaternary sedimentary basins have been formed on the footwalls. Mountain range along the Quaternary volcanic front (Ou Backbone Range) and the uplift zone in the back-arc region (Dewa Hill) are anticlinoriums associated with thrust planes dipping mountain-ward. Kitakami lowland between Kitakami Mountain Ranges (Non-volcanic outer arc) and Ou Backbone Range, Yokote, Yamagata, Nagai, and Yonezawa inter-mountain basins between Ou Backbone Range and Dewa Hill, and Shonai Plain on the west of Dewa Hill are synclinoliums, which have been subsided by the vertical load of hanging walls of thrust faults. There are two types for the relation for the pair of uplifting and subsiding region and thrust faults. One is the case where they are bounded by thrust faults on both sides, for an example, Ou Backbone Range between Kitakami lowland and Yokote inter-mountain basin. Other is the case where thrust faults are developed only on one side, for examples, west-dipping thrust fault zones between Ou Backbone range and Fukushima Basin- Sendai Plain, between Yamagata inter-mountain basin and Dewa Hill, and between Nagai-Yonezawa inter- mountain basins and Dewa Hill. We concentrated our study only on the Holocene events, because it is easier for us to obtain precise data on the timing of seismic events and the amount of vertical displacement per single event. We combined the data from field observations on fault scarplets on the Holocene terraces of different ages with the much data from the previous trench excavation surveys. As a result we found that all these active thrust faults show the recurrence intervals of 2,000 to 4,000 years, and seismic fault slips per single event of 1.5 to 2.0 m, at most 3.5 m. All data on seismic events were plotted on the time-space grids. The resolution of time limit is shorter than 1,000 years. This analysis revealed two types of time-space trends for seismic events. One is concerned with the case where uplift zones are bounded by thrust faults on both sides. We found in this case that large earthquakes with slip of about 2 m occurred alternatively on the two fault zones with time interval of 1,500 to 2,000 years. Other is concerned with the case where one-sided faults between mountainous zones and lowland zones are arranged linearly but discontinuously. Once anyone of the fault segments became active, they tend to have been active nearly simultaneously, probably due to seismic triggering.

  20. Deep Structure of the Fold-and-Thrust Belt in the Tenpoku Area, Northern Hokkaido Island, Japan, Revealed by Reprocessing of Seismic Reflection Data From the 1990 MITI Geophysical Explorations.

    NASA Astrophysics Data System (ADS)

    Yokokura, T.; Miyazaki, T.; Kano, N.

    2005-12-01

    The Tenpoku area, the northern part of Hokkaido island, Japan, is believed to have hydrocarbon potential in the thick Cretaceous-Tertiary sediments. Ministry of International Trade and Industry (MITI, present Ministry of Economy, Trade and Industry) and some private companies have conducted many geological and geophysical explorations and test drillings in this area. These surveys have revealed that some anticlines (e.g. Horonobe and Toyotomi anticlines) and faults (e.g. Ohmagari and Horonobe faults) exist in the mountainous area and that a large sedimentary basin extends from the west of the mountainous area to the Japan Sea. The area shows a fold-and-thrust belt structure of west vergence. There is an active Sarobetsu flexural zone in the eastern end of the sedimentary basin. The flexural zone is believed to have become active since the middle Pliocene. In this way, overall geological structure down to around 5km in depth is well known, while there is few information about the deeper part. Japan National Oil Corporation (present Japan Oil, Gas and Metals National Corporation (JOGMEC)) conducted seismic reflection surveys in this area in 1990 on consignment from MITI. Part of the seismic reflection data was acquired by using dynamite and has long two-way traveltime of 18sec. As the seismic data may provide us deeper information on this fold-and-thrust belt, we tried to reprocess the data with permission by JOGMEC. As a result, we found that two low-angle east-dipping thrusts extend to around 10km in depth, which are related to the Ohmagari fault and Sarobetsu flexural zone. Beneath these thrusts, some other east-dipping thrusts also exist which may be related to micro-earthquake activity of this area.

  1. Elucidation of Environmental Fate of Artificial Sweetener, Aspartame by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Reaction By-Products Presentation type:Poster Section:Ocean Sciences Session:General Contribution Authors:Takashi Teraji (1) Takemitsu Arakaki (2) AGU# 10173629 (1) Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0123, Japan (a4269bj@yahoo.co.jp), (2) Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0123, Japan (arakakit@sci.u-ryukyu.ac.jp)

    NASA Astrophysics Data System (ADS)

    Teraji, T.; Arakaki, T.

    2011-12-01

    Use of artificial sweeteners in drinks and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. In particular, we focused on the fate of aspartame by determining its bimolecular rate constants with hydroxyl radicals at various pH and temperature conditions and reaction by-products. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far was (2.6±1.2)×109 M-1 s-1 at pH = 3.0. Little effect was seen by changing the temperatures between 15 and 40 °C. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, which could be regarded as zero. We will report reaction rate constants at different pHs and reaction by-products which will be analyzed by GC-MS. We will further discuss the fate of aspartame in the coastal environment.

  2. Japan Smoke

    Atmospheric Science Data Center

    2013-04-16

    ... Smoke Plume from Industrial Fires in Miyagi Prefecture, Japan     View larger image ... aftermath of the massive earthquake that struck northeastern Japan at 2:46 p.m. local time on March 11, 2011, and its subsequent tsunami, ...

  3. The Effects of Climate Change and Globalization on Mosquito Vectors: Evidence from Jeju Island, South Korea on the Potential for Asian Tiger Mosquito (Aedes albopictus) Influxes and Survival from Vietnam Rather Than Japan

    PubMed Central

    Jeong, Ji Yeon; Yoo, Seung Jin; Koh, Young-Sang; Lee, Seogjae; Heo, Sang Taek; Seong, Seung-Yong; Lee, Keun Hwa

    2013-01-01

    Background Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. Methods and Results In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. Conclusion Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs. PMID:23894312

  4. Japan Today.

    ERIC Educational Resources Information Center

    Erickson, Andrea M.

    1985-01-01

    A teacher who traveled to Japan on a Japan Institute for Social and Economic Affairs (JISEA) travel-study fellowship talks about the many problems facing Japan today, including resource scarcity and concern about global conflict. Characteristics of the Japanese people are also discussed. (RM)

  5. AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan

    NASA Astrophysics Data System (ADS)

    Okuno, Mitsuru; Nakamura, Toshio; Geshi, Nobuo; Kimura, Katsuhiko; Saito-Kokubu, Yoko; Kobayashi, Tetsuo

    2013-01-01

    Radiocarbon dating using accelerator mass spectrometry (AMS) was performed on numerous wood trunks from pumiceous deposits along the Nagata, Isso and Miyanoura rivers on the northern side of Yakushima Island, 60 km south of Kyushu Island. The obtained 14C dates were around 6.5 ka BP, which, in combination with the geological characteristics of the pumiceous deposits indicates that these specimens were buried during the Kikai-Akahoya (K-Ah) eruption from the Kikai caldera. However, the fact that they are not charred suggests that the origin of these deposits are not pyroclastic flows. Fourteen taxa (Pinus subgen. Diploxylon, Tsuga, Cryptomeria, Chamaecyparis, Myrica, Castanea, Castanopsis, Quercus subgen. Cyclobalanopsis, Trochodendron, Phellodendron, Lagerstroemia, Rhododendron, Myrsine and Symplocos) were identified through anatomical characteristics. This is the first discovery of forest species on the Yakushima Island before the devastating eruption.

  6. Interdisciplinary approaches to better understand the past tsunamis -Case study of the 1771 Meiwa Tsunami, Japan-

    NASA Astrophysics Data System (ADS)

    Goto, K.

    2012-12-01

    It is important to know frequency and magnitude of past tsunamis over hundred to thousand years to better understand the risk from low-frequency large tsunamis. Historical documents, archeological evidence, and sediments laid down by tsunamis in coastal environments are useful for understanding the past tsunamis. Among them, tsunami geology has become a subject of great interest since the March 11, 2011 Tohoku-oki tsunami, Japan. This is because the 2011 tsunami was suspected as a recurrence of the AD869 Jogan tsunami, which was well known based on the geological and historical evidence. Our newly acquired geological data on the 2011 tsunami however, suggest that previous estimates of the Jogan tsunami have probably been underestimated [Goto et al., 2011]. This suggests that more interdisciplinary research is needed to better understand the historical and prehistoric tsunamis. As an example of the interdisciplinary research to better understand the past tsunami, here I review the studies of the AD1771 Meiwa Tsunami and its predecessors that struck the southern Ryukyu Islands, Japan. Reliable historical documents suggest run-up heights of up to 30 m for this tsunami [e.g. Goto et al., 2010], which are well supported by the archeological evidence as well as local traditions. Moreover, the displacement of specific coral boulders by the tsunami is also described in detail. Geological studies and numerical modeling of the boulder transport by the tsunami further revealed that many coral boulders of several hundred tons were deposited by the tsunami [e.g. Goto et al., 2010]. Based on such researches, the source model for the tsunami was estimated by the high-resolution numerical modeling, although it remains still controversial. Our study suggests that all available historical, geological, and archaeological data should be collected to better estimate the historical and prehistoric tsunami source model. The field evidences are still increasing for the 1771 Meiwa Tsunami and this event is a good example to test whether historical (or even prehistoric) tsunami source model can be estimated accurately using various evidences obtained from interdisciplinary studies.

  7. A novel cluster of mariner-like elements belonging to mellifera subfamily from spiders and insects: implications of recent horizontal transfer on the South-West Islands of Japan.

    PubMed

    Yamada, Kaori; Kawanishi, Yuichi; Yamada, Akinori; Tokuda, Gaku; Gurung, Raj Deep; Sasaki, Takeshi; Nakajima, Yumiko; Maekawa, Hideaki

    2014-04-01

    Mariner-like elements (MLEs) have been isolated from various eukaryotic genomes and they are divided into 15 subfamilies, including main five subfamilies: mauritiana, cecropia, mellifera/capitata, irritans, and elegans/briggsae. In the present study, MLEs belonging to mellifera subfamily were isolated from various spiders and insects (Hymenoptera and Lepidoptera) inhabiting the South-West Islands of Japan and neighboring regions. MLEs isolated from 15 different species formed a distinct novel cluster in mellifera subfamily. MLEs obtained from three different species [i.e., the bee Amegilla senahai subflavescens (Amsmar1), the wasp Campsomeris sp. (Casmar1), and the swallowtail butterfly Pachliopta aristolochiae (Paamar1)] contained an intact open reading frame that encoded a putative transposase. These transposases exhibited high similarity of 97.9% among themselves. In case of Casmar1, the presence of an intact ORF was found in high frequencies (i.e., 11 out of 12 clones). In addition, these transposases also showed the presence of a terminal inverted repeat-binding motif, DD(34)D and two highly conserved amino acid motifs, (W/L)(I/L)PHQL and YSP(D/N)L(A/S)P. These two motifs differed from previously known motifs, WVPHEL and YSPDLAP. MLEs isolated from these three different species may have been inserted into their genomes by horizontal transfer. Furthermore, the presence of an intact ORF suggests that they are still active in habitats along these isolated islands. PMID:24723149

  8. A model for the termination of the Ryukyu subduction zone against Taiwan: A junction of collision, subduction/separation, and subduction boundaries

    USGS Publications Warehouse

    Wu, F.T.; Liang, W.-T.; Lee, J.-C.; Benz, H.; Villasenor, A.

    2009-01-01

    The NW moving Philippine Sea plate (PSP) collides with the Eurasian plate (EUP) in the vicinity of Taiwan, and at the same time, it subducts toward the north along SW Ryukyu. The Ryukyu subduction zone terminates against eastern Taiwan. While the Ryukyu Trench is a linear bathym??trie low about 100 km east of Taiwan, closer to Taiwan, it cannot be clearly identified bathymetrically owing to the deformation related to the collision, making the location of the intersection of the Ryukyu with Taiwan difficult to decipher. We propose a model for this complex of boundaries on the basis of seismicity and 3-D velocity structures. In this model the intersection is placed at the latitude of about 23.7??N, placing the northern part of the Coastal Range on EUP. As PSP gets deeper along the subduction zone it collides with EUP on the Taiwan side only where they are in direct contact. Thus, the Eurasian plate on the Taiwan side is being pushed and compressed by the NW moving Philippine Sea plate, at increasing depth toward the north. Offshore of northeastern Taiwan the wedge-shaped EUP on top of the Ryukyu subducting plate is connected to the EUP on the Ryukyu side and coupled to the NW moving PSP by friction at the plate interface. The two sides of the EUP above the western end of the subduction zone are not subjected to the same forces, and a difference in motions can be expected. The deformation of Taiwan as revealed by continuous GPS measurements, geodetic movement along the east coast of Taiwan, and the formation of the Hoping Basin can be understood in terms of the proposed model. Copyright 2009 by the American Geophysical Union.

  9. Species-specific responses of corals to bleaching events on anthropogenically turbid reefs on Okinawa Island, Japan, over a 15-year period (1995-2009).

    PubMed

    Hongo, Chuki; Yamano, Hiroya

    2013-01-01

    Coral bleaching, triggered by elevated sea-surface temperatures (SSTs) has caused a decline in coral cover and changes in the abundances of corals on reefs worldwide. Coral decline can be exacerbated by the effects of local stressors like turbidity, yet some reefs with a natural history of turbidity can support healthy and resilient coral communities. However, little is known about responses of coral communities to bleaching events on anthropogenically turbid reefs as a result of recent (post World War II) terrestrial runoff. Analysis of region-scale coral cover and species abundance at 17-20 sites on the turbid reefs of Okinawa Island (total of 79 species, 30 genera, and 13 families) from 1995 to 2009 indicates that coral cover decreased drastically, from 24.4% to 7.5% (1.1%/year), subsequent to bleaching events in 1998 and 2001. This dramatic decrease in coral cover corresponded to the demise of Acropora species (e.g., A. digitifera) by 2009, when Acropora had mostly disappeared from turbid reefs on Okinawa Island. In contrast, Merulinidae species (e.g., Dipsastraea pallida/speciosa/favus) and Porites species (e.g., P. lutea/australiensis), which are characterized by tolerance to thermal stress, survived on turbid reefs of Okinawa Island throughout the period. Our results suggest that high turbidity, influenced by recent terrestrial runoff, could have caused a reduction in resilience of Acropora species to severe thermal stress events, because the corals could not have adapted to a relatively recent decline in water quality. The coral reef ecosystems of Okinawa Island will be severely impoverished if Acropora species fail to recover. PMID:23565291

  10. Species-Specific Responses of Corals to Bleaching Events on Anthropogenically Turbid Reefs on Okinawa Island, Japan, over a 15-year Period (19952009)

    PubMed Central

    Hongo, Chuki; Yamano, Hiroya

    2013-01-01

    Coral bleaching, triggered by elevated sea-surface temperatures (SSTs) has caused a decline in coral cover and changes in the abundances of corals on reefs worldwide. Coral decline can be exacerbated by the effects of local stressors like turbidity, yet some reefs with a natural history of turbidity can support healthy and resilient coral communities. However, little is known about responses of coral communities to bleaching events on anthropogenically turbid reefs as a result of recent (post World War II) terrestrial runoff. Analysis of region-scale coral cover and species abundance at 1720 sites on the turbid reefs of Okinawa Island (total of 79 species, 30 genera, and 13 families) from 1995 to 2009 indicates that coral cover decreased drastically, from 24.4% to 7.5% (1.1%/year), subsequent to bleaching events in 1998 and 2001. This dramatic decrease in coral cover corresponded to the demise of Acropora species (e.g., A. digitifera) by 2009, when Acropora had mostly disappeared from turbid reefs on Okinawa Island. In contrast, Merulinidae species (e.g., Dipsastraea pallida/speciosa/favus) and Porites species (e.g., P. lutea/australiensis), which are characterized by tolerance to thermal stress, survived on turbid reefs of Okinawa Island throughout the period. Our results suggest that high turbidity, influenced by recent terrestrial runoff, could have caused a reduction in resilience of Acropora species to severe thermal stress events, because the corals could not have adapted to a relatively recent decline in water quality. The coral reef ecosystems of Okinawa Island will be severely impoverished if Acropora species fail to recover. PMID:23565291

  11. Application of Satellite Geodesy in Analyzing the Accelerated Movement of the Back-arc Rifting in the Izu Bonin Islands, Japan

    NASA Astrophysics Data System (ADS)

    Arisa, D.; Heki, K.

    2014-12-01

    The Izu-Bonin islands lies along the convergent boundary between the subducting Pacific plate (PA) and the overriding Philippine Sea plate (PH) in the western Pacific. Nishimura (2011) found that the back-arc rifting goes on behind the Izu arc by studying the horizontal velocities of GNSS stations on the Izu islands. Here we show that this rifting has accelerated in 2004 using GNSS data at Aogashima, Hachijoujima, and Mikurajima stations. The back-arc rifting behind the Izu islands can be seen as the increasing distance between stations in the Izu-Bonin islands and stations located in the stable part of PH. We found that their movement showed clear acceleration around the third quarter of 2004. Obtaining the Euler vector of the PH is necessary to analyzed the movement of each stations relative to the other stations on the same plate. The analyzing of GPS timeseries leads us to one initial conclusion that some accelerated movement started to occur in the third quarter of 2004. This event was closely related to the earthquake on May 29, 2004 in Nankai Trough and September 5, 2004 earthquake near the triple junction of Sagami Trough. The analyzing process help us to understand that this accelerated movement was not the afterslip of any of these earthquakes, but it was triggering these area to move faster and further than it was. We first rule out the best possible cause by constraining the onset time of the accelerated movement, and correlating it with the earthquakes. May 29, 2004 earthquake (M6.5) at the PA-PH boundary clearly lacked the jump which should mark the onset of the eastward slow movement. Moreover, additional velocity vectors do not converge to the epicenter, and onset time that minimizes the post-fit residual is significantly later than May. We therefore conclude that accelerated movement started in 2004 was not due to the afterslip of interplate earthquake in May 29. On the next step we found that the onset time coincides with the occurrence of September 5, 2004 We found that the accelerated movement vectors of these islands are almost parallel with each other, and perpendicular to the rift axis. We hypothesize that the seismic wave radiated from the epicenter of this earthquake dynamically triggered the acceleration of the back arc opening in the Izu Arc.

  12. Explaining unusual winter lightning in Japan

    NASA Astrophysics Data System (ADS)

    Shindo, Takatoshi; Ishii, Masaru; Williams, Earle

    2011-11-01

    Third International Symposium on Winter Lightning; Sapporo, Japan, 15-16 June 2011 Japan's meteorological setting in winter is unusual: It is an island in a relatively warm sea frequently overswept by colder air from Siberia. This sets up appreciable atmospheric instability in the fringe of the land adjacent to the Sea of Japan. Heavy snowstorms overlap the edge of the island and produce extraordinarily energetic lightning flashes that initiate from points on the ground (known as ground-to-cloud (GC) strokes) and wreak havoc on power lines and, more recently, wind turbines. These troublesome and costly conditions set the stage for the third in a series of conferences on winter lightning.

  13. Rifting Process and Geomorphic Development of the Okinawa Tough, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Sato, T.; Arai, K.; Inoue, T.; Matsumoto, D.

    2012-12-01

    The Ryukyu Island Arc extends from Kyushu to Taiwan, a distance of 1,200 km, along the Ryukyu Trench where the Philippine Sea Plate is subducting beneath the Eurasian Plate. The Okinawa Trough, a back arc basin has formed behind the Ryukyu Island Arc in late Pliocene to early Pleistocene. The research cruises of GH11 (from 14 July to 15 August, 2011) and GH12 (from 20 to 30 July, 2012) were carried out around the Okinawa Trough. More than 3,600 miles multi channel high-resolution seismic profiles were acquired during these cruises by the GI-gun (Generator 250 cu inch and Injector 105 cu. inch) systems with 16ch digital streamer cable. As a result, two unconformities and three depositional sequence divided by the unconformities are recognized in the trough. The lower and the midlle sequence are tilted and blocked by many normal faults, on the other hand the upper one is not tilted and shows the pattern of onlap fill. From this result, the upper sequence started to deposit after start of the rifting. Additionally, internal reflection of the upper sequence shows the cyclic activities of the rifting. The position of the rifting axis was revealed based on dip of the normal faults. As a result, rifting axis shows echelon arrangement and the displacement of the faults are varied with the segment of the arrangement. The location of the segment boundaries is correlated with geometrical boundary of the adjacent slope. Steep slope with incised valley is distributed in southwestern part where the displacement of the normal fault is large, on the other hand, gentle slope without incised valley is distributed in northeastern part where the displacement is small. This difference of the displacement strongly controls the geometry of the adjacent slope.

  14. Bathymetric patterns of meiofaunal abundance and biomass associated with the Kuril and Ryukyu trenches, western North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Itoh, Makoto; Kawamura, Kiichiro; Kitahashi, Tomo; Kojima, Shigeaki; Katagiri, Hideki; Shimanaga, Motohiro

    2011-01-01

    The abundance and biomass of metazoan meiofauna and their relationships with environmental factors [chloroplastic pigment equivalents (CPE) and sediment characteristics] were studied quantitatively around and within the Kuril Trench (560-7090 m) and the Ryukyu Trench (1290-7150 m), which are located in eutrophic and oligotrophic regions, respectively, of the western North Pacific. Faunal abundance and biomass, as well as the CPE content of sediments, were considerably higher in the Kuril region than in the Ryukyu region. In both cases, CPE tended to decrease with water depth, but relatively high values were found in the deepest areas, suggesting that organic matter has accumulated in both trenches. Meiofaunal abundance and biomass were lower than expected from sediment CPE values at hadal stations below 6000 m. Differences in the density and biomass of meiofauna between these two trenches appeared to reflect differences in overall ocean productivity above them. When the analysis was restricted to each region, however, no association was found between the abundance and biomass of meiofauna and food availability. Furthermore, the factors regulating the bathymetric patterns in these meiofaunal parameters appeared to differ between the two trenches.

  15. Tokyo, Japan

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Tokyo, (35.5N, 140.0E) the capital city of Japan, Tokyo Bay and the neighboring cities of Yokohama, Kawasaki and Chiba are seen in this view of Japan. This great international seaport facility covers almost all of the bayfront and is home to over thirty million people.

  16. A possible factor controlling fault behavior of reverse fault zone along the island arc - Heterogeneity of crustal structure in the Ou backbone range, NE Japan

    NASA Astrophysics Data System (ADS)

    Aoyagi, Y.; Kimura, H.; Abe, S.

    2014-12-01

    We report crustal structure in the Ou backbone range, NE Japan by a seismic tomography analysis using the campaigned micro-earthquake observation data and discuss a role of the heterogeneity to control active fault behavior. In the present, a lot of N-S striking active faults dominated by dip-slip are found along the backbone range in the E-W compressive stress perpendicular to the arc. Some large (~M7) crustal earthquakes of reverse faulting has occurred under the backbone range in the last century. On the other hand, it is known that the NE Japan arc used to be pulled away from the Asian continent by back arc rifting in the middle Miocene. Consequently many normal faults along the arc and some strike slip faults oblique to the arc had been initially formed in this stage. Some of the ancient normal faults are seemed to reactivate as reverse faults in the present E-W compression. We carried out a dense arrayed micro-earthquake observation with 30 temporary stations in the Ou backbone range during 2011-2012. A seismic tomography analysis using the acquired data with the surrounding seismic network clearly shows heterogeneity of the velocity structure. The results indicate 1) a remarkable heterogeneity (discontinuity) in NW-SE direction along the strike slip faults oblique to the arc, 2) an apparent change of the distribution and the activity of the present reverse faults across the discontinuity, 3) a good correspondence between the end of the source area of the large earthquakes in this century and the discontinuity. We discuss a possibility that the present fault behavior is controlled by the heterogeneous structure formed by the ancient faults.

  17. Dutch surgery in Japan.

    PubMed

    van Gulik, Thomas M; Nimura, Yuji

    2005-01-01

    An isolation policy was adopted in feudal Japan from 1639 to 1853 owing to the fear of foreign influence. During those 200 years of isolation, all foreigners were withheld from the country with the exception of the Dutch, who were permitted to establish a trading post on a small island in the Bay of Nagasaki, called Decima. Western culture and science reached the Japanese exclusively through the Dutch on Decima. Health care on Decima was provided by Dutch barber-surgeons, who introduced Western surgical practice in Japan. Official interpreters were the only Japanese allowed on Decima. It was from among these interpreters that the first Japanese surgeons arose who, having mastered the Dutch language, translated several Dutch anatomic and surgical texts. Genpaku Sugita translated a Dutch anatomy textbook into Japanese, which was completed in 1774. This book, entitled Kaitai Shinsho [New Book on Anatomy], was the first Western scientific monograph to be translated entirely into Japanese. Several Dutch surgical schools were founded through which Dutch surgery, known in Japan as "surgery of the red-haired" was propagated. According to the custom of the surgical guilds in Holland, certificates were granted to Japanese apprentices who had completed their training in Dutch surgery. About 60 Dutch surgeons had served on Decima up to 1850, providing the basis for surgery to develop in Japan. Among them, Philipp Franz von Siebold was an exceptional scholar who also had a great impact in making Japanese culture known to the Western world. PMID:15599736

  18. Genetic diversity and differentiation of the Ryukyu endemic frog Babina holsti as revealed by mitochondrial DNA.

    PubMed

    Tominaga, Atsushi; Matsui, Masafumi; Nakata, Katsushi

    2014-02-01

    We surveyed the genetic diversity and genetic differentiation of an endangered frog, Babina holsti, endemic to Okinawajima and Tokashikijima Islands of the Ryukyus, to elucidate its divergence history and obtain basic data for its conservation. Genetic differentiation between the two island lineages is moderate (3.1% p-distance in the cyt b gene). This result suggests that the two island lineages have been isolated between the late Pliocene and the middle Pleistocene and have never migrated between the current northern part of Okinawajima and Tokashikijima Islands, which were once connected in the late Pleistocene glacial age. On Okinawajima Island, the southernmost sample was constituted by a unique haplotype, without considerable genetic distance from haplotypes detected from northern samples. This unique haplotype composition in the southernmost sample would have resulted from the restricted gene flow between the southernmost population and the other populations in Okinawajima Island. Furthermore, the absence of genetic diversity within the southernmost sample indicates that this population has recently experienced population size reduction, possibly by predation pressure from an introduced mongoose, which is more abundant in the southern part than in the northern part of the island. Lower genetic diversity in the Tokashikijima sample implies a small effective population size for mitochondrial DNA (mtDNA) in B. holsti on the island. Immediate conservation measures should be taken for the populations from the southernmost range in Okinawajima and Tokashikijima. PMID:24521314

  19. First records of interstitial leptocytherids (Crustacea, Ostracoda): two new species and a redescription of Callistocythere ventricostata Ruan & Hao, 1988 collected from the Okinawa Islands, southern Japan.

    PubMed

    Ha, Tran Manh; Tsukagoshi, Akira

    2015-01-01

    Two new and one known species belonging to the genus Callistocythere of the family Leptocytheridae from interstitial environments of the Okinawa Islands are fully described. Callistocythere intermedia sp. nov. is regarded as belonging to the C. japonica group, and Callistocythere ryukyuensis sp. nov. belongs to the C. minor group (these groups were established by Hanai 1957 based on carapace morphology). The redescribed Callistocythere ventricostata Ruan & Hao, 1988 clearly differs from known leptocytherid species in the morphologies of the carapace and the male copulatory organ. The habitats of C. intermedia sp. nov. and C. ryukyuensis sp. nov. are found along the shoreline zone and the mid to high tide levels of the littoral zone, respectively, and C. ventricostata is found from the shoreline to the sub-tidal zone. These species are the first global records of interstitial leptocytherids. PMID:26623759

  20. Insecticide-degrading Burkholderia symbionts of the stinkbug naturally occupy various environments of sugarcane fields in a Southeast island of Japan.

    PubMed

    Tago, Kanako; Okubo, Takashi; Itoh, Hideomi; Kikuchi, Yoshitomo; Hori, Tomoyuki; Sato, Yuya; Nagayama, Atsushi; Hayashi, Kentaro; Ikeda, Seishi; Hayatsu, Masahito

    2015-01-01

    The stinkbug Cavelerius saccharivorus, which harbors Burkholderia species capable of degrading the organophosphorus insecticide, fenitrothion, has been identified on a Japanese island in farmers' sugarcane fields that have been exposed to fenitrothion. A clearer understanding of the ecology of the symbiotic fenitrothion degraders of Burkholderia species in a free-living environment is vital for advancing our knowledge on the establishment of degrader-stinkbug symbiosis. In the present study, we analyzed the composition and abundance of degraders in sugarcane fields on the island. Degraders were recovered from field samples without an enrichment culture procedure. Degrader densities in the furrow soil in fields varied due to differences in insecticide treatment histories. Over 99% of the 659 isolated degraders belonged to the genus Burkholderia. The strains related to the stinkbug symbiotic group predominated among the degraders, indicating a selection for this group in response to fenitrothion. Degraders were also isolated from sugarcane stems, leaves, and rhizosphere in fields that were continuously exposed to fenitrothion. Their density was lower in the plant sections than in the rhizosphere. A phylogenetic analysis of 16S rRNA gene sequences demonstrated that most of the degraders from the plants and rhizosphere clustered with the stinkbug symbiotic group, and some were identical to the midgut symbionts of C. saccharivorus collected from the same field. Our results confirmed that plants and the rhizosphere constituted environmental reservoirs for stinkbug symbiotic degraders. To the best of our knowledge, this is the first study to investigate the composition and abundance of the symbiotic fenitrothion degraders of Burkholderia species in farmers' fields. PMID:25736865

  1. Insecticide-Degrading Burkholderia Symbionts of the Stinkbug Naturally Occupy Various Environments of Sugarcane Fields in a Southeast Island of Japan

    PubMed Central

    Tago, Kanako; Okubo, Takashi; Itoh, Hideomi; Kikuchi, Yoshitomo; Hori, Tomoyuki; Sato, Yuya; Nagayama, Atsushi; Hayashi, Kentaro; Ikeda, Seishi; Hayatsu, Masahito

    2015-01-01

    The stinkbug Cavelerius saccharivorus, which harbors Burkholderia species capable of degrading the organophosphorus insecticide, fenitrothion, has been identified on a Japanese island in farmers’ sugarcane fields that have been exposed to fenitrothion. A clearer understanding of the ecology of the symbiotic fenitrothion degraders of Burkholderia species in a free-living environment is vital for advancing our knowledge on the establishment of degrader-stinkbug symbiosis. In the present study, we analyzed the composition and abundance of degraders in sugarcane fields on the island. Degraders were recovered from field samples without an enrichment culture procedure. Degrader densities in the furrow soil in fields varied due to differences in insecticide treatment histories. Over 99% of the 659 isolated degraders belonged to the genus Burkholderia. The strains related to the stinkbug symbiotic group predominated among the degraders, indicating a selection for this group in response to fenitrothion. Degraders were also isolated from sugarcane stems, leaves, and rhizosphere in fields that were continuously exposed to fenitrothion. Their density was lower in the plant sections than in the rhizosphere. A phylogenetic analysis of 16S rRNA gene sequences demonstrated that most of the degraders from the plants and rhizosphere clustered with the stinkbug symbiotic group, and some were identical to the midgut symbionts of C. saccharivorus collected from the same field. Our results confirmed that plants and the rhizosphere constituted environmental reservoirs for stinkbug symbiotic degraders. To the best of our knowledge, this is the first study to investigate the composition and abundance of the symbiotic fenitrothion degraders of Burkholderia species in farmers’ fields. PMID:25736865

  2. Rare Earth Element - SiO2 systematics of island arc lower crust amphibolite migmatite from Yakuno Ophiolite, SW Japan: a field evaluation of some model predictions

    NASA Astrophysics Data System (ADS)

    Pu, X.; Brophy, J. G.; Tsujimori, T.

    2011-12-01

    It is widely recognized that the two end member processes for the generation of felsic magma are fractional crystallization of basaltic magma and partial melting of middle to lower crust. Brophy (2008) proposed a model that can potentially distinguish these two processes (Brophy, 2008). The model predicts that for magma with SiO2 content over 60%, the correlation between REE and SiO2 is positive for fractional crystallization and negative for partial melting. A set of migmatites from the Asago body of the Yakuno ophiolite have been selected to test the validity of this model. The Asago body is reported to represent a Permian age lower oceanic island arc crust (Suda, 2004). The host rock is cpx-bearing amphibolite that has been metamorphosed to granulite facies. Field observation suggests that the silicic melts were produced by the partial melting of the host rock. Mafic amphibolites consisit mainly of pargasitic hornblende, clinopyroxene, plagioclase, and ilmenite, with subordinate amounts of secondary actinolite, clinozoisite, and titanite. The original felsic melt mainly includes plagioclase and quartz, and the plagioclase has been saussuritized. The SiO2 content ranges from 43% to 51% for mafic amphibolite and from 61% to 78% for the felsic melt. The major element data are similar to those obtained from experimental studies of amphibolite partial melting under similar P-T conditions (Beard&Lofgren, 1991; Rushmer, 1991). On chondrite-normalized spider diagram, the host amphibolites display large positive Ba and negative Nb, consistent with island an arc setting. The chondrite-normalized REE diagram shows typical island arc basaltic patterns with LREE abundance ranging from 30 to 80 and HREE from 15 to 20. The patterns are generally smooth with moderate LREE enrichment. Compared to the host amphibolites, the intermediate partial melts display similarly smooth patterns but slightly higher overall abundances. Meanwhile, the patterns for higher silicic partial melts (> 73% SiO2) display lower overall abundances, steeper profiles with pronounced enrichment in LREE and a concave-upward curve at the depleted HREE end. The REE abundances in the partial melts were divided by the average REE abundance of the mafic host rocks, thus yielding a parameter equivalent to Cl/Co. , For the partial melts, the Cl/Co-SiO2 systematics are consistent with the predicted model in the aspects below: 1) the Cl/Co values of the rare earth elements in melt (SiO2>~60%) steadily decrease with increasing SiO2 content; 2) The Cl/Co ratio for the samples of about 60% SiO2 concentration decreases from LREE to HREE; 3) The rate of the Cl/Co decrement (the slope of the diagram) becomes smaller from LREE to HREE gradually. Thus, all the model predictions are supported by the Yakuno migmatite samples.

  3. Sumisu Volcano, Izu-Bonin Arc, Japan: Site of a Rhyolitic Caldera-Forming Eruption From a Small Open-Ocean Island

    NASA Astrophysics Data System (ADS)

    Fiske, R. S.; Tani, K.; Tamura, Y.; Naka, J.; Shukuno, H.; Kido, Y.

    2005-12-01

    Sumisu submarine caldera, an 8 x 10 km Crater Lake type structure along the front of the Izu-Bonin arc, was the site of a 30-60 ka eruption that introduced 50-70 km3 of rhyolite tephra into open-ocean environment. A manned submersible, two ROVs, a DeepTow camera system, and dredge samples (augmented by newly acquired single-channel seismic profiles and SeaBeam mapping) were used to study the caldera and surrounding areas. Caldera-wall studies show that pre-caldera eruptions built a complex of overlapping submarine dacitic and basaltic cones that formed an edifice 40 x 25 km in diameter; its summit grew above sea level to form an island about 200 m high. The caldera-forming eruption likely began on this island and sent a Plinian column high into the air. We interpret that prodigious rates of tephra fallback overwhelmed the Sumisu area, forming huge rafts of floating pumice and forcing large volumes of hot, proximal fallback debris beneath sea level-- generating gravity flows of quenched pumice that traveled downslope along the sea floor. The caldera rim, currently 100-400 m below sea level, is mantled by thin and discontinuous deposits of syn-caldera pumice showing no evidence of heat retention. Ocean currents apparently eroded most proximal pumice away (especially during periods of late Pleistocene sea-level lowering), and the caldera rim is locally mantled by lag lithics. ODP Leg 126 cores in the Sumisu Rift, atop the Rift's east margin, and on the forearc slope, show the sea floor south and southeast to be underlain by non-welded pumice deposits 10-20 m thick. Geochemical data point to Sumisu as the source of these distal deposits, rather than the nearby arc-front centers of Minami Sumisu or Torishima-indicating that the Sumisu pumice gravity flows traveled for distances of at least 70 km. Post-caldera edifice instability resulted in the collapse of a 15 degree sector of the east caldera rim and the formation of spectacular thin-skin slumps that ring much of the edifice.

  4. New particle formation and growth associated with East-Asian long range transportation observed at Fukue Island, Japan in March 2012

    NASA Astrophysics Data System (ADS)

    Seto, Takafumi; Kim, Seyoung; Otani, Yoshio; Takami, Akinori; Kaneyasu, Naoki; Fujimoto, Toshiyuki; Okuyama, Kikuo; Takamura, Tamio; Hatakeyama, Shiro

    2013-08-01

    Time-resolved data for size distribution, number concentration and chemical composition of atmospheric aerosols were taken from March 9 to 16, 2012 during Fukue Site Atmospheric Aerosol Observation Campaign (128.7E, 32.8N) organized by ASEPH (Impacts of Aerosols in East Asia on Plants and Human Health) project. A scanning mobility particle sizer was employed to continuously measure the particle size distribution from 14 nm to 670 nm and the total number concentration of particles (>3 nm) was measured by a condensation particle counter. Very large amount of polluted air mass transportation (PM2.5 > 65 ?g m-3) was observed on March 11, associated with a sudden increase in particle number concentration having a mobility diameter from 100 to 300 nm. The transported air mass contained anthropogenic pollutants such as sulfate (>20 ?g m-3), nitrate (>15 ?g m-3) and black carbon (>3 ?g m-3). Typical new particle formation and growth events were also observed on March 12-13. The onset of particle formation and nucleation bursts was identified at around noon and it is considered that these were nucleated species near the island area. It was found that some new particle formation events were associated with the long range transportation of polluted air mass from East Asian region.

  5. Recognition of `cryptochron' in the polarity subchron C3Ar: Palaeomagnetic results of the Late Miocene lava sequence from Noma Peninsula (Kyushu Island), Japan

    NASA Astrophysics Data System (ADS)

    Otofuji, Yo-ichiro; Zaman, Haider; Shimoda, Makiko; Aihara, Kazuyoshi; Kani, Munemoto; Yokoyama, Masahiko; Ikeda, Satoru; Ahn, Hyeon-Seon; Wada, Yutaka

    2013-04-01

    This study presents a newly discovered geomagnetic excursion in the andesitic lava sequence of the Kamegaoka Mountain (3121'N, 13013'E), Noma Peninsula, Kyushu Island. About 170 oriented samples were collected from 13 consecutive lava flows, covering an area from mountain top to sea shore. Thermal and alternating field demagnetizations of the studied samples generally revealed a univectorial magnetization, however, two components structure with minor viscous overprints is also observed in some samples. Remanent magnetization is generally unblocked between 560 and 590 C, indicating magnetite as dominant remanence carrier. Reversed polarity directions are detected in the bottom and uppermost parts of the sequence, whereas anomalous directions with positive inclination are observed in the middle part of the sequence. This newly discovered anomalous palaeomagnetic direction, named as Noma excursion (C3Ar-1), has a well-defined K-Ar age of 6.66 0.45 Ma. Comparison with the geomagnetic polarity timescale allow us to place this event within the polarity subchron C3Ar, in which no such cryptochron has been observed before by high resolution ODP study of the sedimentary cores. The virtual geomagnetic poles estimated for the studied lava sequence moved from Antarctica to Kamchatka Peninsula (60N), swung back to New Guinea equatorial region and then followed a path to Antarctica again. These poles followed a swath between the 90E and 140E longitudes, which are almost identical to one of the preferred longitudinal bands for transitional poles at the times of polarity reversals and excursions in the Brunhes and Matuyama chrons. According to this study, this preferred pathway may have started prior to 6.7 Ma. If properly emphasized, identification of Noma excursion in the studied lava flows can facilitate more such discoveries in the Late Miocene.

  6. Tsunami Recurrences in the Ryukyu Arc-trench System: Geological Records in the Jinshan Coastal Plain of North Taiwan

    NASA Astrophysics Data System (ADS)

    Yu, N. T.; Yen, J. Y.; Lin, L. H.; Liu, J. H.

    2014-12-01

    Active continental margin like the Ryukyu arc-trench system poses high tsunami risk, which however remains poorly assessed due to the sparse historic records and geological studies. In order to better understand the tsunami risk in northern Taiwan of the southernmost Ryukyu active margin, borehole cores of the Jinshan Coastal Plain were investigated for the tsunami deposits of 1867 event and possibly its precursors. Based on facies characteristics, two decimeter-thick marine event sand beds are identified intercalated with the fluvial gravelly deposit that has been accumulated in a microtidal barred estuary over the past millennium. Distributed all over the coastal plain except the coastal sand spits, the fluvial deposit are predominantly sourced from the Pleistocene arc andesite, and thus commonly reddish in color due to the high iron content. The marine beds are rich in quartz sand and granule, whitish gray in color, and rounded to subangular in grain shape, indicating a sediment source from the coastal sand spits which receive longshore drift from the nearby rocky coasts dominated by the Oligocene and Miocene quartzose sandstone and mudstone. The facies succession of marine bed is characterized by erosion base, planar lamination, normal grading, soft-sediment deformation, and variations in magnetic susceptibility, Si, K, Ti, and Fe. The succession reflects the sedimentary processes from incoming wave erosion, rapid marine deposition, backflow reworking, and suspension fall-out. The marine beds are traceable landward based on the facies characteristics and C14 dating over a distance up to two kilometers before thinning out and grading into carbonaceous mud. According to the C14 dating, the two marine beds are linked to the 1867 tsunami and an earlier event in the late 17th century. Based on their ages and distributions, the two event beds further suggest two marine incursions of similar extant in an approximate recurrence interval of ~170 yr.

  7. Structure of the Ryukyu Subduction Zone at its Western end: Slab Buckling, Double Seismic Layer, and the Effect of Dehydration

    NASA Astrophysics Data System (ADS)

    Chou, H.; Kuo, B.; Hung, S.; Chiao, L.; Wu, Y.; Zhao, D.

    2004-12-01

    Network data of Taiwan and Japan were integrated to illuminate the collision-oblique subduction complex in a region within 100 km of the island's coast, which has been poorly resolved by either single network. We relocated 4814 events applying a series of 1-D velocity model inversion and double difference method. These processes reduce the variance of traveltime residuals by about 70% with respect to each network value. The relocated seismicity delineates better the curving of the trench-forarc system toward the island and the 15--20 km apart double seismogenic layer (DSL) within the slab of the subducted Philippine Sea Plate in the depth range of 30-70 km. Not revealed before is the seismicity distribution that clearly defines bulging of the slab near its western end continuing from 50 km depth to 90 km. The overall geometry and the focal mechanisms suggest that the slab buckles against the Eurasian plate under lateral compression while subducting obliquely toward the continent. Tomographic inversion of the data set further reduces variance by 61%. The images reveal that much of the DSL is punctuated by low velocity anomalies (LVA) on the upper layer. We propose two hypotheses to explain the buckling-DSL-LVA combination, based on a previous notion that the DSL results from lateral compression. It could be that diabase and olivine present different creep rheology for crust and mantle causing the double layer, and that dehydration of hydrous minerals triggers melting that lowers the seismic velocity. Lateral compression could have thickened the typical oceanic crust to accommodate the at least 15 km gap for DSL. Or, a non-basaltic section of crust, thick and low in velocity, is subducted, which causes the 15--20 km separated double layer and the low anomalies in tomography. Subduction of a buoyant segment of crust has various implications for the dynamics of this subduction-collision junction.

  8. Estimation of photosynthesis and calcification rates at a fringing reef by accounting for diurnal variations and the zonation of coral reef communities on reef flat and slope: a case study for the Shiraho reef, Ishigaki Island, southwest Japan

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Nakamori, T.

    2009-03-01

    Seven coral reef communities were defined on Shiraho fringing reef, Ishigaki Island, Japan. Net photosynthesis and calcification rates were measured by in situ incubations at 10 sites that included six of the defined communities, and which occupied most of the area on the reef flat and slope. Net photosynthesis on the reef flat was positive overall, but the reef flat acts as a source for atmospheric CO2, because the measured calcification/photosynthesis ratio of 2.5 is greater than the critical ratio of 1.67. Net photosynthesis on the reef slope was negative. Almost all excess organic production from the reef flat is expected to be effused to the outer reef and consumed by the communities there. Therefore, the total net organic production of the whole reef system is probably almost zero and the whole reef system also acts as a source for atmospheric CO2. Net calcification rates of the reef slope corals were much lower than those of the branching corals. The accumulation rate of the former was approximately 0.5 m kyr-1 and of the latter was ~0.7-5 m kyr-1. Consequently, reef slope corals could not grow fast enough to keep up with or catch up to rising sea levels during the Holocene. On the other hand, the branching corals grow fast enough to keep up with this rising sea level. Therefore, a transition between early Holocene and present-day reef communities is expected. Branching coral communities would have dominated while reef growth kept pace with sea level rise, and the reef was constructed with a branching coral framework. Then, the outside of this framework was covered and built up by reef slope corals and present-day reefs were constructed.

  9. Japan: Tsunami

    Atmospheric Science Data Center

    2013-04-16

    ... tsunami triggered by the March 11, 2011, magnitude 8.9 earthquake centered off Japan's northeastern coast about 130 kilometers (82 ... inland from the eastern shoreline is visible in the post-earthquake image. The white sand beaches visible in the pre-earthquake view are ...

  10. Japan: Land of the Rising Sun. A Twelve Day Unit of Study for Fourth Grade Students.

    ERIC Educational Resources Information Center

    Craycraft, Kenneth; Winters, Norm

    This unit of study on Japan contains the following content areas: Unit Focus/Motivation; Islands of Japan; Living on an Island; Buildings; Economics; Transportation; and Culminating Activities. The objectives of the unit include knowledge, skills, and attitudes. Suggested activities for each of the content areas are offered and explained to assist

  11. Boron isotopic composition of fumarolic condensates from some volcanoes in Japanese island arcs

    NASA Astrophysics Data System (ADS)

    Nomura, Masao; Kanzaki, Tadao; Ozawa, Takejiro; Okamoto, Makoto; Kakihana, Hidetake

    1982-11-01

    Boron samples from 40 fumarolic condensates from volcanoes in the Ryukyu arc (Satsuma Iwo-jima and Shiratori Iwo-yama) and the North-east Japan arc (Usu-shinzan, Showa-shinzan, Esan and Issaikyo-yama) all have 11B /10B ratios close to 4.07. Higher values, from 4.09 to 4.13, were only observed in condensates from volcanoes in the southernmost end of the North-east Japan arc (Nasu-dake), the northern part of the Izu-Bonin arc (Hakone), and the North Mariana arc (Ogasawara Iwo-jima). These higher values suggest geological interaction of the magmas with sea-water enriched in 11B.

  12. Cenozoic rift tectonics of the Japan Sea

    SciTech Connect

    Kimura, K.

    1988-08-01

    The Japan Sea is one of the back-arc basins in trench-arc systems bordering the western Pacific. Recent paleomagnetic works suggest the Japan Sea opened during early to middle Miocene. Radiometric and microfossil ages of the Cenozoic onland sequences in the Japanese Islands elucidate the rift tectonics of the Japan Sea. The rifting history is summarized as follows: nonmarine volcanic formations of prerift stage before 50 Ma, rift-onset unconformity at 40 Ma, nonmarine volcanic formations of synrift stage 20-33 Ma, breakup unconformity 19 Ma showing the opening of the Japan Sea, marine volcanic and sedimentary formations of synrift stage 14.5-18 Ma, beginning of regional subsidence 14.5 Ma corresponding to the end of the Japan Sea opening, marine sedimentary formations of postdrift stage after 14.5 Ma. Rifting is not limited to the synrift stage but is continued to the syndrift stage. Rifting led to a horst-and-graben structure. Thus, the Cenozoic onland sequences in the Japanese Islands are suited for a study of rift tectonics because the sequences were subaerially exposed by the late Miocene-Holocene island-arc tectonics. Rift tectonics cannot be studied as easily in most Atlantic-type passive margins.

  13. Tokyo, Japan

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Tokyo, (35.5N, 140.0E) one of the most densely populated regions on Earth, and capital of Japan, is seen through the clouds. The city is at the north end of Edo Bay and Yokohama, partially cloud covered, is along the bay's western margin. The gray patches are close-packed urban urban areas and the brown valleys along the eastern side of the bay are cultivatedd, mostly rice. Although the Imperial Palace is obscured, many other features may be seen.

  14. Ryukyuan Culture.

    ERIC Educational Resources Information Center

    Trafton, Terry

    The Ryukyu Islands of Japan, of which Okinawa is the best known, possess a lengthy history and a sophisticated cultural background, an exploration of which helps to shed light on this area and on mainland Japan. This document is an exposition of Ryukuan culture. Divided into eight sections, the areas covered include: (1) Historical perspective;

  15. Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Cities mingle with rugged hills and a dormant volcano in this image of Hokkaido, Japan. This three-dimensional image comes from observations made by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite on July 23, 2006. The view is toward the north and slightly east. Green indicates vegetation; beige and gray indicate bare ground, paved surfaces, or buildings; and dark blue indicates water. The water body at the top of the image is the Pacific Ocean. Now dormant, Mount Yotei is a stratovolcano--a symmetrical cone composed of alternating layers of hardened lava, solidified ash, and volcanic rocks ejected in previous eruptions. It reaches a height of 1,898 meters (6,227 feet), and its summit sports a 700-meter- (2,297-foot-) wide crater. Snow often caps this volcano, but in this summertime shot, the volcano's summit is snow-free. The volcano is also known as Ezo-Fuji for its resemblance to Mount Fuji. As angular patches of gray and beige indicate, urban areas surround the volcano, most notably the city of Kutchan to the northwest. Even when volcanoes remain active, people often settle close to them, drawn by benefits of good soil and mild climates that appear to outweigh the risks. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  16. American Influence on Okinawan Culture before 1972.

    ERIC Educational Resources Information Center

    Trafton, Terry

    The Ryukyu Islands form a chain stretching from the southernmost point of mainland Japan to the northern tip of Taiwan. The largest and most important of these islands is Okinawa. This paper documents the influence of other nations and cultures upon the Okinawan culture, and focuses upon U.S. cultural influence. In the mid-nineteenth century,

  17. Shallow very low frequency earthquakes off the Pacific coast of Tohoku, Japan

    NASA Astrophysics Data System (ADS)

    Matsuzawa, T.; Asano, Y.; Obara, K.

    2012-12-01

    Activities of shallow very low frequency earthquakes (VLFEs) have been reported around the trench axis of the off-Tokachi region, and the Nankai and the Ryukyu subduction zone around the Japan Islands (e.g., Obara and Ito, 2005; Asano et al., 2008; Ando et al., 2012). In NIED, epicenters of seismic sources including VLFEs are routinely located by an array analysis technique using Hi-net high-sensitivity accelerometers (Asano et al., 2008). Some of the epicenters are also located off the Pacific coast of Tohoku, Japan. However, these events are not fully examined, as most of these sources have been thought to arise from regular earthquakes and microseisms, and the number of events is much smaller than those in the previously reported region. In this study, we aim to detect VLFEs in the off-Tohoku region with a waveform correlation analysis. We examined waveforms of the events detected by the array analysis in the off-Tohoku region. Some of events are very similar to pre-known shallow VLFEs, which are dominant around the frequency of 0.05 Hz and have no clear signals in the high frequency band (above 1 Hz). We successfully estimated CMT solutions of some of these events, using F-net broadband seismometers and Hi-net high-sensitivity accelerometers. The result shows that these events are reverse-fault-type Mw~3.5 earthquakes, and located around the depth of the subducting plate interface. As a typical dominant frequency of regular earthquakes with similar magnitude and close hypocenter is several Hz, these events are considered as shallow VLFEs. To reveal the activity of the off-Tohoku VLFEs, other VLFEs were detected by a waveform correlation analysis using a template event. We selected two VLFEs as template events in the central and southern off-Tohoku region. Averaged cross correlation values for template events were calculated using broadband seismograms at surrounding F-net stations which are bandpass-filtered between 0.02 to 0.1 Hz. Finally, we visually checked the waveforms with the averaged correlation coefficient over 0.3, and detected VLFEs which are not attributed to near- or far-field earthquakes, microseisms, and other noise. We applied this technique to the period from 2005 to 2011, and detected clustered activity of VLFEs in the central and southern off-Tohoku region. Before the occurrence of the 2011 Tohoku earthquake, five and six VLFEs were detected in the central and southern clusters, respectively. After the 2011 Tohoku earthquake, no and 41 VLFEs were detected in the central and southern clusters, respectively. The activated VLFEs after the Tohoku earthquake may be caused by the stress accumulation of the slip or afterslip of the Tohoku earthquake, as the VLFEs in the southern cluster are located at the rim of large slip area of the Tohoku earthquake. VLFEs in the central cluster are located in the large slip area of M9 earthquake, and at the northern rim of the aftershock area of M7.3 off-Sanriku earthquake on 9 March 2011. This implies that the VLFE region can behave as a part of large slip area in an extraordinarily large earthquake.

  18. Phylogeny and Differentiation of Wide-Ranging Ryukyu Kajika Frog Buergeria japonica (Amphibia: Rhacophoridae): Geographic Genetic Pattern Not Simply Explained by Vicariance Through Strait Formation.

    PubMed

    Tominaga, Atsushi; Matsui, Masafumi; Eto, Koshiro; Ota, Hidetoshi

    2015-06-01

    To investigate geographic genetic structures and taxonomic relationships among isolated populations of Buergeria japonica, occurring very widely in various habitats of the Ryukyu Archipelago and Taiwan, we conducted phylogenetic and demographic analyses among individuals from various localities, representing their entire distributional ranges. Buergeria japonica is genetically greatly differentiated and comprises three major clades (the Southern Taiwan [ST] clade, the Northern Taiwan + Southern Ryukyu [NT/SR] clade, and the Central + Northern Ryukyu [CR/NR] clade), each of which seems to represent independent species. The first divergence in the species is estimated to have occurred in the middle to late Miocene in areas of current Taiwan, then eastern periphery of the Asian continent. Split of the ST and the remaining clades, and subsequent divergence between the NT/SR and the CR/NR clades in the latter, indicate consecutive south to north vicariant diversifications. However, these vicariances are not always associated with formation of significant barriers such as deep straits. Less but still prominently diverged subclades (the Amami + Tokara [AM/TK] and the Okinawa [ON] subclades) in the CR/NR clade were recognized in spite of the absence of an intervening deep strait. Contrariwise, individuals from Amami and Tokara Groups formed the AM/TK subclade in spite of the presence of the intervening Tokara Gap (a long-standing deep tectonic strait). Furthermore, in the AM/TK subclade, low but definite genetic divergence was found between the Northern Amami + Tokara (NAM/TK) lineage and the Southern Amami (SAM) lineage. Estimated divergence time and gene flow rate within the NAM/TK lineage indicate that this species reached northern Tokara from the south by overseas dispersal over the Tokara Gap long after its formation, but not by more recent artificial transportation. This overseas dispersal would have been facilitated by its more frequent occurrence around coastal habitats than other frogs. PMID:26003978

  19. Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood

    ERIC Educational Resources Information Center

    Rappleye, Jeremy

    2015-01-01

    This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In…

  20. Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood

    ERIC Educational Resources Information Center

    Rappleye, Jeremy

    2015-01-01

    This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In

  1. Canary Islands

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This easterly looking view shows the seven major volcanic islands of the Canary Island chain (28.0N, 16.5W) and offers a unique view of the islands that have become a frequent vacation spot for Europeans. The northwest coastline of Africa, (Morocco and Western Sahara), is visible in the background. Frequently, these islands create an impact on local weather (cloud formations) and ocean currents (island wakes) as seen in this photo.

  2. Seismology in Ryukyu arc, Japan reveals the distribution and orientation of serpentine minerals suggesting convection and low viscosity of forearc mantle

    NASA Astrophysics Data System (ADS)

    Nagaya, T.; Walker, A.; Wookey, J. M.; Kendall, M.; Wallis, S.

    2014-12-01

    Refining available estimates of the amount, distribution and alignment of serpentinite in the forearc wedge is needed to develop a better understanding of the seismic anisotropy, strength and fluid transport in this region. Mantle dominantly consists of olivine. However, petrological studies and thermal modeling of convergent margins predict that olivine will be replaced by hydrous mineral phases in fluid-rich and relatively cold forearc mantle. The dominant hydrous mineral will be antigorite. Lower seismic velocities (Vp < ~8 km/s and Vs < ~4 km/s) and higher Vp/Vs values (> ~1.8) of serpentine minerals than those of olivine are commonly used as to detect the distribution of antigorite and estimate its proportion compared to olivine. However, antigorite is highly anisotropic and this anisotropy can disguise the presence of antigorite in seismic tomography; the apparent Vp/Vs ratio of antigorite can vary from 1.2-3.4 (Vp = 5.6-8.9 km/s and Vs = 2.5-5.1 km/s) depending on the propagation path of the seismic wave relative to the crystal orientation. Here, we take advantage of this anisotropy and perform an analysis of seismic anisotropy that takes into account ray path measured above the forearc mantle of the Rykuyu arc subduction zone. The measured shear wave splitting delay time above this subduction zone is very large, suggesting the presence of aligned antigorite. Comparing the results of modeling to observed shear wave splitting for both local-S and teleseismic SKS phases, we conclude that the mantle wedge consists of 65 % antigorite and that the antigorite must be aligned along the subducting slab in the deepest part of the wedge but aligned vertically at intermediate depths. This distribution of different orientations strongly suggests the presence of convective mantle flow in the forearc mantle. Physical modeling of the dynamics of the mantle wedge shows that a bulk long-term viscosity of less than 1019 Pa s is required to maintain this large-scale flow. This analysis reveals the presence of otherwise invisible antigorite bearing domains, allows an estimate of the volume percent of serpentinite in the forearc mantle to be made and indicates the pattern of large scale induced flow in this domain.

  3. Intraspecific variations in carbon-isotope and oxygen-isotope compositions of a brachiopod Basiliola lucida collected off Okinawa-jima, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Takayanagi, Hideko; Asami, Ryuji; Abe, Osamu; Miyajima, Toshihiro; Kitagawa, Hiroyuki; Sasaki, Keiichi; Iryu, Yasufumi

    2013-08-01

    This study presents intraspecific variations in carbon-isotope (?13C) and oxygen-isotope (?18O) compositions of nine specimens of a subtropical brachiopod, Basiliola lucida, collected west of Okinawa-jima, Ryukyu Islands, southwestern Japan. The ?13C values of samples collected along the maximum growth axis (ontogenetic samples) from two modern and seven older (pre-1945 cal AD) shells show no seasonal changes. The modern shells, which were collected from comparable depths, have similar ?13C values that fall within the range of calcite precipitated in isotopic equilibrium with ambient seawater (equilibrium calcite) (?13CEC values), and their mean ?13C values are 1.1-1.6 less than those from the older shells. This decrease in ?13C values is similar in magnitude to the decreases in atmospheric CO2 and the oceanic dissolved inorganic carbon at the sea surface in recent years (13C Suess effect), suggesting that the effect can even be detected at water depths of 200-300 m in the subtropical northwestern Pacific Ocean. The ?18O values fluctuate within a narrow range (0.26-0.41) with no seasonal changes, and they exhibit small (0.14-0.51) offsets from those of equilibrium calcite (?18OEC values). A statistically significant negative linear relationship is established between seawater temperature and mean ?18O values of the nine shells, but the slope (-0.31/C) is steeper than those of equilibrium calcite (-0.23/C) and other calcareous organisms (-0.15 to -0.26/C). The cross-plots of the ?13C and ?18O values suggest that the degree of the vital effect varies among individuals in this species. The ?13C and ?18O values of B. lucida are potentially useful for reconstructing the ?13C and ?18O evolution of ancient oceans, because both values show small intraspecific variations, the former is identical to the ?13CEC values, and the latter shows small within-shell variations and small, nearly constant offsets from the ?18OEC values.

  4. Intraspecific Variation of Eysarcoris guttigerus (Hemiptera: Pentatomidae) in Japanese Southwest Population Based on Mitochondrial DNA.

    PubMed

    Yamaji, Takuya; Ishikawa, Tadashi; Nomura, Masashi

    2016-01-01

    The white-spotted globular bug Eysarcoris guttigerus (Thunberg) (Hemiptera: Pentatomidae) is widely distributed in East Asia and the Pacific region. In Japan, the species is found in grassy or composite weeds in the western area of the main islands and Ryukyu Islands of Japan. One notable characteristic of the Eysarcoris genus is the two white spots on the scutellum. This is not the case with the Ishigaki Island population, however, which sports red spots instead of white, suggesting that intraspecific variation exists in the species. Therefore, we investigated intraspecific variation in E. guttigerus using mitochondrial NADH dehydrogenase subunit 2 (ND2), cytochrome oxidase subunit 1 (CO1), cytochrome b (Cytb), tRNA-Serine (tRNA(ser)), NADH dehydrogenase subunit 1 (ND1), and 16S ribosomal RNA (16SrRNA) genes from 13 populations of Japan. The obtained maximum likelihood phylogenetic tree was divided into three groups-Group 1: Mainland, Group 2: Central Ryukyu Islands (Okinawa-Amamioshima Islands), and Group 3: South Ryukyu Islands (Ishigaki Island). The Ishigaki population was significantly separated from the other populations with consistent differences in spot color. The estimated period of divergence between the Ishigaki population and the other populations was consistent with the period of formation of the Kerama Gap in the Ryukyu arc. Thus, the process of formation of the Kerama Gap may have influenced the intraspecific variation of E. guttigerus. PMID:26798143

  5. Intraspecific Variation of Eysarcoris guttigerus (Hemiptera: Pentatomidae) in Japanese Southwest Population Based on Mitochondrial DNA

    PubMed Central

    Yamaji, Takuya; Ishikawa, Tadashi; Nomura, Masashi

    2016-01-01

    The white-spotted globular bug Eysarcoris guttigerus (Thunberg) (Hemiptera: Pentatomidae) is widely distributed in East Asia and the Pacific region. In Japan, the species is found in grassy or composite weeds in the western area of the main islands and Ryukyu Islands of Japan. One notable characteristic of the Eysarcoris genus is the two white spots on the scutellum. This is not the case with the Ishigaki Island population, however, which sports red spots instead of white, suggesting that intraspecific variation exists in the species. Therefore, we investigated intraspecific variation in E. guttigerus using mitochondrial NADH dehydrogenase subunit 2 (ND2), cytochrome oxidase subunit 1 (CO1), cytochrome b (Cytb), tRNA-Serine (tRNAser), NADH dehydrogenase subunit 1 (ND1), and 16S ribosomal RNA (16SrRNA) genes from 13 populations of Japan. The obtained maximum likelihood phylogenetic tree was divided into three groups—Group 1: Mainland, Group 2: Central Ryukyu Islands (Okinawa-Amamioshima Islands), and Group 3: South Ryukyu Islands (Ishigaki Island). The Ishigaki population was significantly separated from the other populations with consistent differences in spot color. The estimated period of divergence between the Ishigaki population and the other populations was consistent with the period of formation of the Kerama Gap in the Ryukyu arc. Thus, the process of formation of the Kerama Gap may have influenced the intraspecific variation of E. guttigerus. PMID:26798143

  6. Earthquakes along the Ryukyu-Kyushu Arc: Strain segmentation, lateral compression, and the thermomechanical state of the plate interface

    NASA Astrophysics Data System (ADS)

    Kao, Honn; Chen, Wang-Ping

    1991-12-01

    We systematically determined the focal depths and mechanisms of 49 large to moderate-sized earthquakes (mb?5.4) that occurred along the Ryukyu-Kyushu arc since 1963 by inverting the waveforms and amplitudes of P and SH wave trains at teleseismic distances. The results are sufficiently precise to delineate seismogenic structures near the plate interface in detail, revealing features not predicted by plate kinematics. In contrast to previous studies of this arc and those along other subduction zones, shallow seismicity along the plate interface is systematic, showing two distinct layers of activities. The second layer of seismicity is delineated by a few earthquakes that occurred at depths between 50 and 65 km, some 10-20 km directly beneath the seismogenic portion of the interplate thrust zone. These earthquakes indicate lateral compressional strain within the subducted slab as their P axes are subparallel to the local strike of the arc, not perpendicular to the arc as one would expect from the direction of plate convergence. The occurrence of these events cannot be accounted for by membrane stress due to the geometry of the subducted slab. To our knowledge, similar earthquakes occurred only beneath the northern Indoburman ranges and along the Banda arc where subducted slabs, as part of the Indian plate, are being dragged northward with their northern edges bumping into east-west trending collision zones nearby. By drawing an analogy between the tectonic settings of these three regions, we interpret events beneath the plate interface along the Ryukyu-Kyushu arc as a consequence of ongoing collision between the Philippine Sea plate and Eurasia near Taiwan. The interplate thrust zone is largely aseismic down to a depth of approximately 30 km. A large number of earthquakes showing low-angle thrust faulting commence at this depth and are accompanied by two events that show antithetic thrust faulting at a slightly shallower depth of 20-25 km. These observations suggest that the strength of the plate interface increases significantly below the depth of proximately 255 km. Based upon available heat flow measurements between the trench axis and the volcanic arc, we estimated the temperature field and magnitude of shear traction along the interplate thrust zone, the deepest interplate earthquakes (40-50 km) correspond to temperatures of approximately 730-980C, comparable to the limiting temperature of intraplate mantle earthquakes (800C) and that of intermediate- and deep-focus earthquakes at Wadati-Benioff zones (potential temperature 900K). Therefore, the cessation of seismicity in general is probably controlled by similar temperature conditions regardless of the tectonic settings of source regions. The magnitude of shear traction along the seismogenic portion (40-50 km depth) of the interplate thrust zone seems to be of the order of 100 MPa which, in turn, implies a low average coefficient of friction of only 0.100.05, considerably less than those observed for laboratory specimens. The inception of intermediate-focus earthquakes within the subducted slab is at a depth of about 100 km. Whereas shallow earthquakes show no apparent variations along the entire arc, intermediate-depth earthquakes indicate downdip extension along the northern end of the arc near Kyushu but abruptly change to downdip compression along the rest of the arc. All available evidence indicates that this is a spatial pattern unrelated to earthquake cycles. At the moment, tectonic interpretation of such a distinct strain segmentation along the arc is enigmatic. Without the presence of clear discontinuities in the age of the subducted slab, the sudden switch in the strain field of the slab is difficult to explain by the continuously varying rate of subduction along the arc. In any case, this pattern of strain segmentation requires the presence of a major accommodation structure, such as a tear fault, in the subducted slab near the Tokara channel. Appendix is available with entire article on microfiche. Order from American Geophysical Union,

  7. Introductory Overview of Stone Heritages in Japan

    NASA Astrophysics Data System (ADS)

    Kato, Hirokazu; Oikawa, Teruki; Fujita, Masayo; Yokoyama, Shunji

    2013-04-01

    As one contribution to 'Global Heritage Stone Resources' (GHSR), some stone heritages in Japan, which are nominated in the interim list, are briefly introduced. The geology of Japanese Islands where are the one of the most active areas in the history of the Earth, is very complicated. Therefore Japanese Islands consist of various kinds of minerals and rocks. Some of them were used to make stone implements and accessories. Japanese people also used to the best possible advantage to built tombstone, gate, pavement ,and the basement and wall of the large building such as temples, shrines, castles and modern buildings. 1. Stone Heritages of Pre-historical age: In the late Pleistocene and the early Holocene, ancient Japanese used obsidian cooled rapidly from rhyolitic magma.to make small implements and accessories. For example, Shirataki, Hokkaido (north island) is the largest place producing obsidian in Japan where Paleolithic people made arrowhead, knives and so on. Another example, Jade yielded in Itoigawa City, Japan Sea coast of central Japan, was made in the metamorphic rock about five hundred million years ago. Itoigawa area is only one place where jade is abundantly produced in Japan. Ancient people had been already collected and processed to ornaments although it is very hard and traded in wide area more than several thousand years ago. 2. Stone Heritages of Historical age: 2.1 Archaeological remains: In the Kofun (old mound) period (250 to 538 AD), stone burial chambers were used for old mounds to preserve against the putrefaction and to protect from the theft. For example, Ishibutai Kofun ("ishi" means "stone" and "butai" means "stage") in Nara old capital city, southwest Japan, is the largest known megalithic structure made of granite in Japan. 2.2 Stone walls of some typical castles Stones used is because of not only the rich reserves of rocks but also restriction of transportation. Osaka (second biggest city) castle, are composed of Cretaceous granite exceeding over 500,000 in number and the largest block is 108 ton in weight. Stoens of Hikone Castle came from Paleogene Koto Rhyolite. Edo (old Tokyo, biggest city, central Japan) castle ,Imperial Palace at present, Stones are late Quaternary andesite of Hakone Volcanic Products whose quarrying places are more than 100km far from Edo.They were transported by ships and manpower on land .

  8. Academic Libraries in Japan

    ERIC Educational Resources Information Center

    Cullen, Rowena; Nagata, Haruki

    2008-01-01

    Academic libraries in Japan are well resourced by international standards, and support Japan's internationally recognized research capability well, but there are also ways in which they reflect Japan's strong bureaucratic culture. Recent changes to the status of national university libraries have seen a new interest in customer service, and…

  9. Academic Libraries in Japan

    ERIC Educational Resources Information Center

    Cullen, Rowena; Nagata, Haruki

    2008-01-01

    Academic libraries in Japan are well resourced by international standards, and support Japan's internationally recognized research capability well, but there are also ways in which they reflect Japan's strong bureaucratic culture. Recent changes to the status of national university libraries have seen a new interest in customer service, and

  10. Galapagos Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of the Galapagos Islands was acquired on March 12, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The Galapagos Islands, which are part of Ecuador, sit in the Pacific Ocean about 1000 km (620 miles) west of South America. As the three craters on the largest island (Isabela Island) suggest, the archipelago was created by volcanic eruptions, which took place millions of years ago. Unlike most remote islands in the Pacific, the Galapagos have gone relatively untouched by humans over the past few millennia. As a result, many unique species have continued to thrive on the islands. Over 95 percent of the islands' reptile species and nearly three quarters of its land bird species cannot be found anywhere else in the world. Two of the more well known are the Galapagos giant tortoise and marine iguanas. The unhindered evolutionary development of the islands' species inspired Charles Darwin to begin The Origin of Species eight years after his visit there. To preserve the unique wildlife on the islands, the Ecuadorian government made the entire archipelago a national park in 1959. Each year roughly 60,000 tourists visit these islands to experience what Darwin did over a century and a half ago. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  11. 3-D Seismogenic Stress Fields in and around Japan, Inferred from the CMT Data Inversion

    NASA Astrophysics Data System (ADS)

    Terakawa, T.; Matsu'Ura, M.

    2007-12-01

    We developed a robust inversion method to estimate the pattern of the stress fields related to earthquake generation (seismogenic stress fields) from the centroid moment tensors (CMT) of seismic events by using Akaike's Bayesian information criterion (ABIC). The CMT solution of a seismic event is conventionally defined by the surface integral of 2-D moment tensor density over a rupture area. Applying Gauss' divergence theorem, we can transform the surface integral of 2-D moment tensor density into the volume integral of stress release over a finite elastic region surrounding the dynamic rupture area. The volume integral representation of CMT is more essential than the surface integral representation, because dynamic rupture growth is controlled by energy flow into the rupture zone from the surrounding region storing elastic strain energy. Since the occurrence of an earthquake releases some part of the seismogenic stress field around its hypocenter, we can relate CMT data with the seismogenic stress field with the volume integral representation. We represent the CMT of a seismic event by a weighted volume integral of the true but unknown seismogenic stress field. The weighting function is taken to be a 3-D Gaussian-type distribution with its peak at the hypocenter and variance proportional to the two- thirds power of the seismic moment. Representing each component of the seismogenic stress field by the superposition of a finite number of 3-D basis functions, we obtain a set of linear observation equations to be solved for the expansion coefficients (model parameters). We introduce prior constraint on the roughness of the seismogenetic stress field and combine it with observed data to construct a Bayesian model with a hierarchic flexible structure controlled by hyper-parameters. The optimum values of the hyper-parameters are objectively determined from observed data by minimizing ABIC. Given the optimum values of the hyper-parameters, we can obtain the best estimates of model parameters by using a maximum likelihood algorithm. We applied the inversion method to observed CMT data in and around Japan (the NIED Moment Tensor Catalogue, 1997.1.31-2007.1.31) to reveal the 3-D patterns of seismogenic stress fields associated with plate subduction. We compared the stress patterns in the northeast Japan arc and the Ryukyu arc. In both regions the stress patterns in the shallow part of the oceanic plates and the descending slabs are characterized by normal and reverse faulting with strikes parallel to the trench axes, respectively. However, the stress patterns in the back- arc regions are quite different from each other: reverse faulting in the northeast Japan arc and normal faulting in the Ryukyu arc. The difference in the stress pattern results from the difference in the tectonic loading mechanism.

  12. Can GRACE detect winter snows in Japan?

    NASA Astrophysics Data System (ADS)

    Heki, Kosuke

    2010-05-01

    Current spatial resolution of the GRACE (Gravity Recovery and Climate Experiment) satellites is 300-400 km, and so its hydrological applications have been limited to continents and large islands. The Japanese Islands have width slightly smaller than this spatial resolution, but are known to show large amplitude seasonal changes in surface masses due mainly to winter snow. Such loads are responsible for seasonal crustal deformation observed with GEONET, a dense array of GPS (Global Positioning System) receivers in Japan (Heki, 2001). There is also a dense network of surface meteorological sensors for, e.g. snow depths, atmospheric pressures, etc. Heki (2004) showed that combined effects of surface loads, i.e. snow (predominant), atmosphere, soil moisture, dam impoundment, can explain seasonal crustal deformation observed by GPS to a large extent. The total weight of the winter snow in the Japanese Islands in its peak season may reach ~50 Gt. This is comparable to the annual loss of mountain glaciers in the Asian high mountains (Matsuo & Heki, 2010), and is above the detection level of GRACE. In this study, I use GRACE Level-2 Release-4 data from CSR, Univ. Texas, up to 2009 November, and evaluated seasonal changes in surface loads in and around the Japanese Islands. After applying a 350 km Gaussian filter and a de-striping filter, the peak-to-peak change of the water depth becomes ~4 cm in northern Japan. The maximum value is achieved in February-March. The region of large winter load spans from Hokkaido, Japan, to northeastern Honshu, which roughly coincides with the region of deep snow in Japan. Next I compiled snow depth data from surface meteorological observations, and converted them to loads using time-dependent snow density due to compaction. By applying the same spatial filter as the GRACE data, its spatial pattern becomes similar to the GRACE results. The present study suggests that GRACE is capable of detecting seasonal mass changes in an island arc not wider than a few hundreds of kilometers. References: Heki, K., Seasonal modulation of interseismic strain buildup in Northeastern Japan driven by snow loads, Science, 293, 89-92, 2001. Heki, K., Dense GPS array as a new sensor of seasonal changes of surface loads, AGU Monograph, 150, 177-196, 2004. Matsuo, K. and K. Heki, Time-variable ice loss in Asian high mountains from satellite gravimetry, Earth Planet. Sci. Lett., doi:10.1016/j.epsl.2009.11.053, 2010.

  13. Onekotan Island, Kurile Chain, Russia as seen from STS-59

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The narrow end of Onekotan Island is to the north by northeast. This is one of several volcanic islands extending south by southwest between the southern tip of Kamchatka and Japan. The exposure was stopped down to provide extremely fine detail in the totally snow-covered landscape, at the same time making the dark sea look completely black.

  14. Akpatok Island

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Akpatok Island lies in Ungava Bay in northern Quebec, Canada. Accessible only by air, Akpatok Island rises out of the water as sheer cliffs that soar 500 to 800 feet (150 to 243 m) above the sea surface. The island is an important sanctuary for cliff-nesting seabirds. Numerous ice floes around the island attract walrus and whales, making Akpatok a traditional hunting ground for native Inuit people. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on January 22, 2001. Image provided by the USGS EROS Data Center Satellite Systems Branch

  15. Strawberry Species of Iturup and Sakhalin Islands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A plant collecting expedition to Iturup (known in Japan as Etorofu) and Sakhalin Islands, Sakhalin Territory, Russian Federation, occurred between 21 July and 12 September 2003. Strawberries, Fragaria L., were observed and collected. Japanese and Russian flora have described two diploid (2n = 2x = ...

  16. Island Hopping

    ERIC Educational Resources Information Center

    Bennett, Gayle

    2009-01-01

    At some institutions, it may feel as though faculty live on one island and advancement staff on another. The islands form part of an archipelago, and they exchange ambassadors and send emissaries occasionally, but interactions are limited. It may even seem as though the two groups speak different languages, deal in different currencies, and abide

  17. Metal Concentrations in the Liver and Stable Isotope Ratios of Carbon and Nitrogen in the Muscle of Silvertip Shark (Carcharhinus albimarginatus) Culled off Ishigaki Island, Japan: Changes with Growth

    PubMed Central

    Endo, Tetsuya; Kimura, Osamu; Ohta, Chiho; Koga, Nobuyuki; Kato, Yoshihisa; Fujii, Yukiko; Haraguchi, Koichi

    2016-01-01

    We analyzed Hg, Cd, Zn, Cu and Fe concentrations in liver samples as well as the Hg concentration and stable isotope ratios of carbon and nitrogen (δ13C and δ15N) in muscle samples from silvertip sharks (Carcharhinus albimarginatus) in Japan. Muscular and hepatic Hg concentrations increased with increased body length. However, these increases were more prominent in the liver than in the muscle samples, and appeared to occur after maturation. Hepatic Zn and Cu concentrations decreased during the growth stage, and then increased concomitantly thereafter with increases in Cd burden. Hepatic Fe concentration from males increased proportionally with increases in body length, whereas no increase was observed in samples from females, probably due to the mother-to-embryo transfer of Fe. The δ13C values tended to decrease with increases in body length, whereas no decrease in the δ15N values was observed. PMID:26859569

  18. Metal Concentrations in the Liver and Stable Isotope Ratios of Carbon and Nitrogen in the Muscle of Silvertip Shark (Carcharhinus albimarginatus) Culled off Ishigaki Island, Japan: Changes with Growth.

    PubMed

    Endo, Tetsuya; Kimura, Osamu; Ohta, Chiho; Koga, Nobuyuki; Kato, Yoshihisa; Fujii, Yukiko; Haraguchi, Koichi

    2016-01-01

    We analyzed Hg, Cd, Zn, Cu and Fe concentrations in liver samples as well as the Hg concentration and stable isotope ratios of carbon and nitrogen (?13C and ?15N) in muscle samples from silvertip sharks (Carcharhinus albimarginatus) in Japan. Muscular and hepatic Hg concentrations increased with increased body length. However, these increases were more prominent in the liver than in the muscle samples, and appeared to occur after maturation. Hepatic Zn and Cu concentrations decreased during the growth stage, and then increased concomitantly thereafter with increases in Cd burden. Hepatic Fe concentration from males increased proportionally with increases in body length, whereas no increase was observed in samples from females, probably due to the mother-to-embryo transfer of Fe. The ?13C values tended to decrease with increases in body length, whereas no decrease in the ?15N values was observed. PMID:26859569

  19. Game Development Toolkit for Business People in Japan

    ERIC Educational Resources Information Center

    Shirai, Hiroaki; Tanabu, Motonari; Terano, Takao; Kuno, Yasushi; Suzuki, Hisatoshi; Tsuda, Kazuhiko

    2003-01-01

    This article describes the authors' experience of developing a business gaming course for business people in Japan. The course that was developed consists of (a) simple gaming experiments among multiple students using ALEXANDER ISLANDS, a tiny business game on the World Wide Web; (b) lectures to make the students understand the core concepts of…

  20. Seismicity of the Earth 1900-2007, Japan and Vicinity

    USGS Publications Warehouse

    Rhea, Susan; Tarr, Arthur C.; Hayes, Gavin P.; Villaseñor, Antonio; Benz, Harley

    2010-01-01

    This map shows details of Japan and vicinity not visible in an earlier publication, U.S. Geological Survey Scientific Investigations Map 3064. Japan and its island possessions lie across four major tectonic plates: Pacific plate, North America plate; Eurasia plate; and Philippine Sea plate. The Pacific plate is subducted into the mantle, beneath Hokkaido and northern Honshu, along the eastern margin of the Okhotsk microplate, a proposed subdivision of the North America plate (Bird, 2003). Farther south, the pacific plate is subducted beneath volcanic islands along the eastern margin of the Philippine Sea plate. This 2,200 km-long zone of subduction of the Pacific plate is responsible for the creation of the deep offshore Ogasawara and Japan trenches as well as parallel chains of islands and volcanoes, typical of the Circumpacific island arcs. Similarly, the Philippine Sea plate is itself subducting under the Eurasia plate along a zone, extending from Taiwan to southern Honshu, that comprises the Ryuku Islands and the Nansei-Shonto trench.

  1. Outdoor Education in Japan.

    ERIC Educational Resources Information Center

    Hoshino, Tosio

    1986-01-01

    Discusses reasons for lack of outdoor education programs in Japan. Emphasizes importance of establishing outdoor education to recover traditional Japanese appreciation of nature. Examines Occidental and Oriental views of nature. Describes an innovative outdoor education program in Japan based on rice cultivation. (LFL)

  2. Devon Island

    Atmospheric Science Data Center

    2013-04-17

    article title:  Mars Researchers Rendezvous on Remote Arctic Island   ... each summer since 1999, researchers from NASA's Haughton-Mars Project and the Mars Society reside at this "polar desert" location to study the geologic and ...

  3. Diurnal variations in H2O2, O3, PAN, HNO3 and aldehyde concentrations and NO/NO2 ratios at Rishiri Island, Japan: potential influence from iodine chemistry.

    PubMed

    Kanaya, Yugo; Tanimoto, Hiroshi; Matsumoto, Jun; Furutani, Hiroshi; Hashimoto, Shigeru; Komazaki, Yuichi; Tanaka, Shigeru; Yokouchi, Yoko; Kato, Shungo; Kajii, Yoshizumi; Akimoto, Hajime

    2007-04-15

    The presence of iodine chemistry, hypothesized due to the overprediction of HO(2) levels by a photochemical box model at Rishiri Island in June 2000, was quantitatively tested against the observed NO/NO(2) ratios and the net production rates of ozone. The observed NO/NO(2) ratios were reproduced reasonably well by considering the conversion of NO to NO(2) by IO, whose amount was calculated so as to reproduce the observed HO(2) levels. However, the net production rates of ozone were calculated to be negative when such high mixing ratios of IO were considered, which was inconsistent with the observed buildup of ozone during daytime. These results suggest that iodine chemistry may not be the sole mechanism for the reduced mixing ratios of HO(2), or that "hot spots" for iodine chemistry were present. Diurnal variations in the mixing ratios of HCHO, CH(3)CHO, peroxy acetyl nitrate (PAN) and HNO(3) observed during the study are presented along with the simulated ones. The box model simulations suggest that the effect of iodine chemistry on these concentrations is small and that important sources of CH(3)CHO and sinks of PAN are probably missing from our current understanding of the tropospheric chemistry mechanism. PMID:17306859

  4. Euschoengastia suzukii (Acari: Trombiculidae): A new species of chigger mite collected from soil samples in the nest burrows of streaked shearwater in Japan.

    PubMed

    Takahashi, Mamoru; Fukaya, Hajime; Takahashi, Hisae

    2005-07-01

    Euschoengastia suzukii Takahashi, Fukaya & Takahashi is described and illustrated. The type material was collected from soil samples in the nest burrows of the sea bird streaked shearwater, Calonectris leucomelas (Temminck), living on Mikurajima Island in Tokyo; Oomorijima Island, Oki, Shimane Prefecture; and Awashima Island, Niigata Prefecture, in Japan, indicating that C. leucomelas is the main parasitic host of E. suzukii new species. PMID:16119540

  5. Groundwater contamination in Japan

    NASA Astrophysics Data System (ADS)

    Tase, Norio

    1992-07-01

    Problems on groundwater contamination in Japan are briefly summarized in this paper. Although normal physical conditions in Japan restrict the possibilities of groundwater contamination, human activities are threatening groundwater resources. A survey by the Environment Agency of Japan showed nationwide spreading of organic substances, such as trichloroethylene as well as nitrogen compounds. Synthetic detergents have also been detected even in rural areas and in deep confined aquifers, although their concentrations are not as high. Public awareness of agrichemical or pesticides abuse, especially from golf courses, is apparent. Other problems such as nitrate-nitrogen, leachate from landfills, and the leaking of underground storage tanks are also discussed.

  6. Space communications in Japan

    NASA Astrophysics Data System (ADS)

    Mori, T.

    This paper outlines some of the planned satellite comunication projects in Japan over the next 5-7 years. In addition, Japanese space development policies are set out along with a historic review of the development of artificial satellites.

  7. Teaching Materials on Japan.

    ERIC Educational Resources Information Center

    Wojtan, Linda, Ed.

    1984-01-01

    This annotated listing of resource materials for teaching elementary and secondary students about Japan describes videotapes, a film series, an activity booklet, a computer program, and units of study. (RM)

  8. Phylogeny, hybridization, and life history evolution of Rhinogobius gobies in Japan, inferred from multiple nuclear gene sequences.

    PubMed

    Yamasaki, Yo Y; Nishida, Mutsumi; Suzuki, Toshiyuki; Mukai, Takahiko; Watanabe, Katsutoshi

    2015-09-01

    Rhinogobius fishes (Gobiidae) are distributed widely in East and Southeast Asia, and represent the most species-rich group of freshwater gobies with diversified life histories (i.e., amphidromous, fluvial, and lentic). To reveal their phylogenetic relationships and life history evolution patterns, we sequenced six nuclear and three mitochondrial DNA (mtDNA) loci from 18 species, mainly from the mainland of Japan and the Ryukyu Archipelago. Our phylogenetic tree based on nuclear genes resolved three major clades, including several distinct subclades. The mtDNA and nuclear DNA phylogenies showed large discordance, which strongly suggested mitochondrial introgression through large-scale interspecific hybridization in these regions. On the basis of the molecular dating using geological data as calibration points, the hybridization occurred in the early to middle Pleistocene. Reconstruction of the ancestral states of life history traits based on nuclear DNA phylogeny suggests that the evolutionary change from amphidromous to freshwater life, accompanied by egg size change, occurred independently in at least three lineages. One of these lineages showed two life history alterations, i.e., from amphidromous (small egg) to fluvial (large egg) to lentic (small egg). Although more inclusive analysis using species outside Japan should be further conducted, the present results suggest the importance of the life history evolution associated with high adaptability to freshwater environments in the remarkable species diversification in this group. Such life history divergences may have contributed to the development of reproductive isolation. PMID:25929788

  9. OTEC research in Japan

    NASA Astrophysics Data System (ADS)

    Kamogawa, H.

    1980-06-01

    The OTEC research in Japan carried out since 1970 is described. Design and cost estimates of the model 100 MW OTEC plants, two OTEC power loop experiments, and the development of new heat exchangers have been completed. Evaluation of OTEC thermal resources and the assessment of the OTEC concept as a power system have been made. However, these activities are still in the early stage, and a large amount of work is needed before OTEC power plants can contribute to Japan's energy demands.

  10. Japan's nuclear power tightrope

    SciTech Connect

    Cross, M.

    1991-04-01

    This paper reports that early in February, just as Japan's nuclear energy program was regaining a degree of popular support after three years of growing opposition, an aging pressurized-water reactor at Mihama in western Japan sprang a leak in its primary cooling system. The event occasioned Japan's first nontest use of an emergency core-cooling system. It also elicited a forecast of renewed public skepticism about nuclear power form the Ministry of International Trade and Industry (MITI), the Government body responsible for promoting and regulating Japan's ambitious nuclear power program. Public backing for this form of energy has always been a delicate flower in Japan, where virtually every school child visits the atomic bomb museums at Hiroshima and Nagasaki. Yet the country, which imports 80 percent of its energy and just about all its oil, is behind only the United States, France, and the Soviet Union in installed nuclear capacity. In fiscal 1989, which started in April, Japan's 39 nuclear power stations accounted for 25.5 percent of electricity generated - the largest contribution - followed b coal and natural gas. Twelve more plants are under construction.

  11. IMPACTS OF DIOXIN EMISSIONS FROM THE SHINKAMPO INCINERATOR TO THE U.S. NAVAL AIR FACILITY AT ATSUGI, JAPAN

    EPA Science Inventory

    The United States Naval Air Facility at Atsugi, Japan (NAF Atsugi) is located in the Kanto Plain area on the island of Honshu, Japan. Directly to the south of the facility, in the Tade River Valley, was the Shinkampo Incinerator Complex (SIC). The Incinerator is no longer in op...

  12. A morphological review of the Cuora flavomarginata complex (Testudines: Geoemydidae)

    USGS Publications Warehouse

    Ernst, C.H.; Laemmerzahl, A.F.; Lovich, J.E.

    2008-01-01

    A reevaluation of the morphometric and color pattern differences within the Asiatic box turtle, Cuora flavomarginata sensu latu, was conducted in view of determining the taxonomic position of the three currently recognized subspecies: C. f. flavomarginata (Taiwan), C. f. sinensis (southern mainland China), and C. f. evelynae (Ryukyu Islands, Japan). Recent analyses indicate that the allopatric population of C. f. evelynae is the most divergent of the three taxa and shares little possibility for gene exchange with the other two populations. In contrast, the populations of C. f. flavomarginata and C. f. sinensis share many characters. We recommend the recognition of the Ryukyu population as a full species, C. evelynae.

  13. A new insight on magma generation environment beneath Jeju (Cheju) volcanic island

    NASA Astrophysics Data System (ADS)

    Shin, Y.; CHOI, K.; Koh, J.; Yun, S.; Nakamura, E.; Na, S.

    2011-12-01

    We present a Moho undulation model from gravity inversion that gives a new insight on the magma generation environment beneath Jeju (Cheju) volcanic island, Korea. The island is an intra-plate volcanic island located behind Ryukyu Trench, the collisional boundary between Eurasian plate and Philippine plate. Jeju island is a symmetrical shield volcano of oval shape (74 km by 32 km) whose peak is Hallasan (Mt. Halla: 1950m). The landform, which is closely related to the volcanism, can be divided topographically into the lava plateau, the shield-shaped Halla volcanic edifice and the monogenetic cinder cones, which numbers over 365. The basement rock mainly consists of Precambrian gneiss, Mesozoic granite and volcanic rocks. Unconsolidated sedimentary rock is found between basement rock and lava. The lava plateau is composed of voluminous basaltic lava flows, which extend to the coast region with a gentle slope. Based on volcanic stratigraphy, paleontology and geochronology, the Jeju basalts range from the early Pleistocene to Holocene in age. The mean density of the island is estimated to be very low, 2390 kg/cubic cm from gravity data analysis, which reflects the abundant unconsolidated pyroclastic sediments below the surface lava. The mean Moho depth is estimated to be 29.5 km from power spectral density of gravity anomaly, which means it has continental crust. It is noticeable that the gravity inversion indicates the island is developed above and along a swelled-up belt (ridge), several hundred meters higher than the surrounding area. The structure is also shows positive correlation with high magnetic anomaly distribution that could indicate existence of volcanic rocks. We interpret the Moho structure has a key to the magma generation: 1) the high gravity anomaly belt is formed by folding/buckling process under compressional environment, 2) it causes decrease of pressure beneath the lithosphere along the belt, and 3) it accelerates melting of basaltic magma in addition to the hot thermal structure widely distributed behind the collisional boundary.

  14. Anatahan Island

    Atmospheric Science Data Center

    2013-04-19

    ... Snorkelers around this island are likely to encounter the fish Achilles Tang and the Moorish Idol (Acanthurus achilles and Zanclus ... Terra circles the Earth in the same orbit as Landsat 7, flying at an altitude of about 700 kilometers above the Earth's surface. ...

  15. Island Panoramic

    USGS Multimedia Gallery

    A panoramic view taken from an island in the Yellowstone River.  Upstream is to the right side of the picture while downstream is to the left.  The middle of the picture looks straight across to the descending right bank. ...

  16. Unzen Volcano, Japan

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This is a space radar image of the area around the Unzen volcano, on the west coast of Kyushu Island in southwestern Japan. Unzen, which appears in this image as a large triangular peak with a white flank near the center of the peninsula, has been continuously active since a series of powerful eruptions began in 1991. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 93rd orbit on April 15, 1994. The image shows an area 41.5 kilometers by 32.8 kilometers (25.7 miles by 20.3 miles) that is centered at 32.75 degrees north latitude and 130.15 degrees east longitude. North is toward the upper left of the image. The radar illumination is from the top of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (vertically transmitted and received); green represents the average of L-band and C-band (vertically transmitted and received); blue represents the C-band (vertically transmitted and received). Unzen is one of 15 'Decade' volcanoes identified by the scientific community as posing significant potential threats to large local populations. The city of Shimabara sits along the coast at the foot of Unzen on its east and northeast sides. At the summit of Unzen a dome of thick lava has been growing continuously since 1991. Collapses of the sides of this dome have generated deadly avalanches of hot gas and rock known as pyroclastic flows. Volcanologists can use radar image data to monitor the growth of lava domes, to better understand and predict potentially hazardous collapses.

    Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI).

  17. Numerical earthquake model of the 20 April 2015 southern Ryukyu subduction zone M6.4 event and its impact on seismic hazard assessment

    NASA Astrophysics Data System (ADS)

    Lee, Shiann-Jong

    2015-12-01

    The M6.4 earthquake that took place on the 20 April 2015 off the shore of eastern Taiwan was the largest event in the vicinity of Taiwan during 2015. The mainshock was located in the southern Ryukyu subduction zone, which is the interface between the Philippine Sea Plate and the Eurasian Plate. People in Taipei experienced strong ground shaking for more than 40 s, even though the epicenter was located more than 150 km away. In order to understand the origin of ground motions from this earthquake and how it caused such strong shaking in Taipei, a numerical earthquake model is analyzed, including models of source rupture and wave propagation. First, a joint source inversion was performed using teleseismic body wave and local ground motion data. Source inversion results show that a large slip occurred near the hypocenter, which rapidly released seismic energy in the first 2 s. Then, the rupture propagated toward the shallow fault plane. A large amount of seismic energy was released during this rupture stage that slipped for more than 8 s before the end of the rupture. The estimated stress drop is 2.48 MPa, which is consistent with values for subduction zone earthquakes. Forward simulation using this inverted source rupture model and a 3D seismic velocity model based on the spectral-element method was then performed. Results indicate that the strong ground motion in Taipei resulted from two factors: (1) the Taipei basin amplification effect and (2) the specific source radiation pattern. The results of this numerical earthquake model imply that future subduction zone events that occur in offshore eastern Taiwan are likely to cause relatively strong ground shaking in northern Taiwan, especially in the Taipei metropolitan area.

  18. Cultural Astronomy in Japan

    NASA Astrophysics Data System (ADS)

    Renshaw, Steven L.

    While Japan is known more for its contributions to modern astronomy than its archaeoastronomical sites, there is still much about the culture's heritage that is of interest in the study of cultural astronomy. This case study provides an overview of historical considerations necessary to understand the place of astronomy in Japanese society as well as methodological considerations that highlight traditional approaches that have at times been a barrier to interdisciplinary research. Some specific areas of study in the cultural astronomy of Japan are discussed including examples of contemporary research based on interdisciplinary approaches. Japan provides a fascinating background for scholars who are willing to go beyond their curiosity for sites of alignment and approach the culture with a desire to place astronomical iconography in social context.

  19. Occupational asthma in Japan

    PubMed Central

    2012-01-01

    Research into occupational asthma (OA) in Japan has been led by the Japanese Society of Occupational and Environmental Allergy. The first report about allergic OA identified konjac asthma. After that, many kinds of OA have been reported. Cases of some types of OA, such as konjac asthma and sea squirt asthma, have been dramatically reduced by the efforts of medical personnel. Recently, with the development of new technologies, chemical antigen-induced asthma has increased in Japan. Due to advances in anti-asthma medication, control by medical treatment tends to be emphasized and the search for causative antigens seems to be neglected. Furthermore, we do not have a Japanese guideline for diagnosis and management of OA. This article discusses the current state of OA in Japan. PMID:22872819

  20. Streamlined Island

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-514, 15 October 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a streamlined island in Marte Vallis, a large outflow channel system that crosses the 180oW meridian between the Elysium and Amazonis regions of Mars. The flow patterns on the floor of Marte Vallis might be the remains of lava flows or mud flows. Marte is the Spanish word for Mars. Most of the largest valleys on the red planet are named for 'Mars' in various languages. This island is located near 21.8oN, 175.3oW. The picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  1. Phylogeographic Study of Whip Scorpions (Chelicerata: Arachnida: Thelyphonida) in Japan and Taiwan.

    PubMed

    Karasawa, Shigenori; Nagata, Satomi; Aoki, Jun-ichi; Yahata, Kensuke; Honda, Masanao

    2015-08-01

    Whip scorpions (Thelyphonida), comprising an order in the class Arachnida, are distributed from tropical to temperate zones. Two species occur exclusively in Japan and Taiwan, but the border of their distributional ranges is ambiguous in the Central Ryukyus (Japan). We collected new specimens from the Central Ryukyus and revealed that the border of distribution of the two species lies between the Central and Southern Ryukyus, i.e., the Kerama Gap. Moreover, the estimated divergence time (15.8 Mya) of the two species, based on the mitochondrial COI gene, was older than the recently estimated time (1.55 Mya) of formation of the Kerama Gap. These results highlight the risks of a priori assumption solely on the basis of geological data for applying it as a calibration point to some terrestrial animals in this region. Typopeltis stimpsonii was genetically divided into four lineages, two of which turned out to be endemic to the Okinawa Islands. All specimens from the main island of Japan and Shikoku were in one lineage, which was also found in the Amami Islands and Hachijojima Island. This suggests that these specimens may have been dispersed by human activity. Typopeltis crucifer included five genetic lineages. Species collected from Ishigakijima and Iriomotejima Islands were genetically diversified not between the borders of these islands but within Ishigakijima Island. This study also suggests that phylogenetic diversity of the species in the Southern Ryukyus have increased through two times of invasions from Taiwan. PMID:26245222

  2. Seasonal and spatial variation of atmospheric 210Pb and 7Be deposition: features of the Japan Sea side of Japan.

    PubMed

    Yamamoto, Masayoshi; Sakaguchi, Aya; Sasaki, Keiichi; Hirose, Katsumi; Igarashi, Yasuhito; Kim, Chang Kyu

    2006-01-01

    Monthly depositional fluxes of (210)Pb and (7)Be at Tatsunokuchi, Japan which faces the Japan Sea were studied over a 12-year period from 1991 to 2002. The data were compared with the spatial variability of these fluxes at Taejon in Korea and at 11 other sites in Japan from Ishigaki of the southern islands of Okinawa to Wakkanai of the northern end of Hokkaido over a 2-year period from 2000 to 2001. The monthly depositions of both (210)Pb and (7)Be at Tatsunokuchi revealed very similar seasonal variations with a single peak; both depositions were high in winter and low in summer. This phenomenon was found to be not transient but stationary. The deposition of these nuclides was much greater on the Japan Sea side of Japan than on the Pacific Ocean side. The cause for high deposition of (210)Pb and (7)Be in winter might be explained by a combination of a series of the following processes: blowing out of air masses with a high (210)Pb concentration near the surface layer over the continent by strong winter monsoons, additional flow of cold air masses with high (7)Be concentration at high latitude, well-mixing with generation of ascending current and convection clouds over the Japan Sea, and heavy snowfalls accompanying them. PMID:16181712

  3. Seismic Reflection Profiling across the Northeast Japan arc

    NASA Astrophysics Data System (ADS)

    Abe, S.; Tokuyama, H.; Arai, R.

    2002-12-01

    A series of crustal movements took place over a vast area approximately 18 million years (Ma) ago, expanding the Japan Sea and giving rise to fields formed by crustal extension. It was in these fields that the Japanese islands were formed from a part that had separated from the Eurasian continent. The formation of the Japanese islands was accompanied by large-scale igneous activity. Approximately 3 Ma ago, the Japanese islands had a stress field that changed into a compression field, which still remains today. In an attempt to find (1) differences between the respective developmental histories of geological structures on the Japan Sea side and those on the Pacific Ocean side and (2) the structural boundary between the two groups of geological structures, we conducted a seismic reflection survey along the 41st parallel of the north latitude (at the northern tip of the Northeast Japan arc). In acoustic data recorded along the survey line, we observed up to five stratigraphic successions of strata. To establish a correspondence between the acoustically observed successions and geological successions, we used the drilling operations data. Of the acoustically observed five stratigraphic successions (Unit I to Unit V), Unit IV and layers at shallower depths matched strata formed during or after the Miocene era. According to our data on deformation of sedimentary strata, faulting resulted in deformed sedimentary strata on the Japan sea side during the Miocene era, and it has maintained the deformation until the present. This deformation of sedimentary strata was traced from the Japan sea side to the western side of the extended sea area of the Natsudomari peninsula inside Mutsu Bay. In contrast, the eastern side of the Natsudomari peninsula exhibited unobstructed sedimentary structures that were formed during and after the Miocene era. We traced these smooth sedimentary structures to the Pacific Ocean side.

  4. Black brant from Alaska staging and wintering in Japan

    USGS Publications Warehouse

    Derksen, Dirk V.; Bollinger, K.S.; Ward, David H.; Sedinger, J.S.; Miyabayashi, Y.

    1996-01-01

    Black brant (Branta bernicla nigricans) nest in colonies in arctic Canada, Alaska, and Russia (Derksen and Ward 1993, Sedinger et al. 1993). Virtually the entire population stages in fall at Izembek Lagoon near the tip of the Alaska Peninsula (Bellrose 1976) before southward migration (Dau 1992) to winter habitats in British Columbia, Washington, Oregon, California, and Baja California (Subcommittee on Black Brant 1992). A small number of black brant winter in Japan, Korea, and China (Owen 1980). In Japan 3,000–5,000 brant of unknown origin stop over in fall, and a declining population (<1,000) of birds winter here, primarily in the northern islands (Brazil 1991, Miyabayashi et al. 1994). Here, we report sightings of brant in Japan that were marked in Alaska and propose a migration route based on historical and recent observations and weather patterns.

  5. Display of historical and hypothetical tsunami on the coast of Sakhalin Island

    NASA Astrophysics Data System (ADS)

    Kostenko, Irina; Zaytsev, Andrey; Kurkin, Andrey; Yalciner, Ahmet

    2014-05-01

    Tsunami waves achieve the coast of the Sakhalin Island and their sources are located in the Japan Sea, in the Okhotsk Sea, in Kuril Islands region and in the Pacific Ocean. Study of tsunami generation characteristics and its propagation allows studying display of the tsunami on the various parts of the island coast. For this purpose the series of computational experiments of some historical tsunamis was carried out. Their sources located in Japan Sea and Kuril Islands region. The simulation results are compared with the observations. Analysis of all recorded historical tsunami on coast of Sakhalin Island was done. To identify the possible display of the tsunami on the coast of Sakhalin Island the series of computational experiments of hypothetical tsunamis was carried out. Their sources located in the Japan Sea and in the Okhotsk Sea. There were used hydrodynamic sources. There were used different parameters of sources (length, width, height, raising and lowering of sea level), which correspond to earthquakes of various magnitudes. The analysis of the results was carried out. Pictures of the distribution of maximum amplitudes from each tsunami were done. Areas of Okhotsk Sea, Japan Sea and offshore strip of Sakhalin Island with maximum tsunami amplitudes were defined. Graphs of the distribution of maximum tsunami wave heights along the coast of the Sakhalin Island were plotted. Based on shallow-water equation tsunami numerical code NAMI DANCE was used for numerical simulations. This work was supported by ASTARTE project.

  6. Nuclear Power in Japan.

    ERIC Educational Resources Information Center

    Powell, John W.

    1983-01-01

    Energy consumption in Japan has grown at a faster rate than in any other major industrial country. To maintain continued prosperity, the government has embarked on a crash program for nuclear power. Current progress and issues/reactions to the plan are discussed. (JN)

  7. Japan's electronic packaging technologies

    NASA Astrophysics Data System (ADS)

    Tummala, Rao R.; Pecht, Michael

    1995-02-01

    The JTEC panel found Japan to have significant leadership over the United States in the strategic area of electronic packaging. Many technologies and products once considered the 'heart and soul' of U.S. industry have been lost over the past decades to Japan and other Asian countries. The loss of consumer electronics technologies and products is the most notable of these losses, because electronics is the United States' largest employment sector and is critical for growth businesses in consumer products, computers, automobiles, aerospace, and telecommunications. In the past there was a distinction between consumer and industrial product technologies. While Japan concentrated on the consumer market, the United States dominated the industrial sector. No such distinction is anticipated in the future; the consumer-oriented technologies Japan has dominated are expected to characterize both domains. The future of U.S. competitiveness will, therefore, depend on the ability of the United States to rebuild its technological capabilities in the area of portable electronic packaging.

  8. [Films: China and Japan].

    ERIC Educational Resources Information Center

    Gumport, Roberta H.

    The history of filmmaking in China and Japan and film usage in teaching are considered in this document. Pointing out how films describe historical context and culture, the document also describes various techniques of film making. Films in China were heavily influenced by western models and have tended to be tools of the power structure, as

  9. Japan's electronic packaging technologies

    NASA Technical Reports Server (NTRS)

    Tummala, Rao R.; Pecht, Michael

    1995-01-01

    The JTEC panel found Japan to have significant leadership over the United States in the strategic area of electronic packaging. Many technologies and products once considered the 'heart and soul' of U.S. industry have been lost over the past decades to Japan and other Asian countries. The loss of consumer electronics technologies and products is the most notable of these losses, because electronics is the United States' largest employment sector and is critical for growth businesses in consumer products, computers, automobiles, aerospace, and telecommunications. In the past there was a distinction between consumer and industrial product technologies. While Japan concentrated on the consumer market, the United States dominated the industrial sector. No such distinction is anticipated in the future; the consumer-oriented technologies Japan has dominated are expected to characterize both domains. The future of U.S. competitiveness will, therefore, depend on the ability of the United States to rebuild its technological capabilities in the area of portable electronic packaging.

  10. Photovoltaics in Japan

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1985-01-01

    Report surveys status of research and development on photovoltaics in Japan. Report based on literature searches, private communications, and visits by author to Japanese facilities. Included in survey are Sunshine Project, national program to develop energy sources; industrial development at private firms; and work at academic institutions.

  11. Film Resources on Japan.

    ERIC Educational Resources Information Center

    Michigan Univ., Ann Arbor. Audio-Visual Education Center.

    Sixteen millimeter motion pictures dealing with Japan are listed alphabetically by title and annotated. Length of film, whether color or black and white, and name of producer or distributor is given for each, and a subject index is provided. Films produced before 1960, "sponsored" films, and 35 mm filmstrips are listed without annotations. A list

  12. Japan's aging society.

    PubMed

    Miyajima, H

    1993-01-01

    This article concerns the consequences of current demographic aging in Japan. The emphasis is on the responsibilities of government to deal with the problems posed by an aging society and the increasing social and economic needs of a growing number of elderly people. PMID:12288894

  13. Political Corruption in Japan.

    ERIC Educational Resources Information Center

    Reed, Steven R.; And Others

    1996-01-01

    Provides an overview of political corruption and its place in Japanese culture and society. Discusses recent scandals and efforts at political reform. These efforts are moving Japan from a "boss-patronage" system to a "civic-culture." Includes a table of post-war Japanese prime ministers and corruption scandals. (MJP)

  14. Advanced composites in Japan

    NASA Technical Reports Server (NTRS)

    Diefendorf, R. Judd; Hillig, William G.; Grisaffe, Salvatore J.; Pipes, R. Byron; Perepezko, John H.; Sheehan, James E.

    1994-01-01

    The JTEC Panel on Advanced Composites surveyed the status and future directions of Japanese high-performance ceramic and carbon fibers and their composites in metal, intermetallic, ceramic, and carbon matrices. Because of a strong carbon and fiber industry, Japan is the leader in carbon fiber technology. Japan has initiated an oxidation-resistant carbon/carbon composite program. With its outstanding technical base in carbon technology, Japan should be able to match present technology in the U.S. and introduce lower-cost manufacturing methods. However, the panel did not see any innovative approaches to oxidation protection. Ceramic and especially intermetallic matrix composites were not yet receiving much attention at the time of the panel's visit. There was a high level of monolithic ceramic research and development activity. High temperature monolithic intermetallic research was just starting, but notable products in titanium aluminides had already appeared. Matrixless ceramic composites was one novel approach noted. Technologies for high temperature composites fabrication existed, but large numbers of panels or parts had not been produced. The Japanese have selected aerospace as an important future industry. Because materials are an enabling technology for a strong aerospace industry, Japan initiated an ambitious long-term program to develop high temperature composites. Although just starting, its progress should be closely monitored in the U.S.

  15. Country Profiles. Japan.

    ERIC Educational Resources Information Center

    Muramatsu, Minoru

    This occasional paper on Japan is one of a series setting forth the nature, scope, and accomplishments of population activities in specified countries. Here, an overview is given of population characteristics and growth patterns, the relationship of population growth to socioeconomic development, and the history of population concerns and…

  16. Globalization and Education in Japan

    ERIC Educational Resources Information Center

    Ohkura, Kentaro; Shibata, Masako

    2009-01-01

    In this paper, the authors contend that globalization in Japan is the gradual process in which Japan's positioning of "self" within international relations, which had formerly been dominated by the West, has changed. Accordingly, Japan's relationships with the West and the rest of the world, for example, Asia, have also been reviewed and modified.…

  17. Globalization and Education in Japan

    ERIC Educational Resources Information Center

    Ohkura, Kentaro; Shibata, Masako

    2009-01-01

    In this paper, the authors contend that globalization in Japan is the gradual process in which Japan's positioning of "self" within international relations, which had formerly been dominated by the West, has changed. Accordingly, Japan's relationships with the West and the rest of the world, for example, Asia, have also been reviewed and modified.

  18. 21 CFR 186.1555 - Japan wax.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Japan wax. 186.1555 Section 186.1555 Food and....1555 Japan wax. (a) Japan wax (CAS Reg. No. 8001-39-6), also known as Japan tallow or sumac wax, is a... succedanea (Japan, Taiwan, and Indo-China), R. vernicifera (Japan), and R. trichocarpa (China,...

  19. Folly Island Tidal Lines

    USGS Multimedia Gallery

    Lines of debris from tidal action on Folly Island.Folly Island, a preserve owned by the Maine Coast Heritage Trust, is about 7 acres. It is located in Bartlett Narrows, along the western coast of Mount Desert Island....

  20. Folly Island Tidal Lines

    USGS Multimedia Gallery

    Lines of debris from tidal action on Folly Island. Folly Island, a preserve owned by the Maine Coast Heritage Trust, is about 7 acres. It is located in Bartlett Narrows, along the western coast of Mount Desert Island....

  1. New observations at Iwo-Jima caldera, Volcano Islands, Japan

    NASA Astrophysics Data System (ADS)

    Ukawa, U. M.; Fujita, E.; Hill, D.; Kobayashi, T.; Lowenstern, J.; Newhall, C.

    2003-04-01

    Small phreatic eruptions on opposite sides of Iwo-Jima in September and October 2001 marked the beginning of several changes in this largely submarine caldera and trapdoor resurgence of its floor. The northern part of Motoyama, roughly the center of the caldera floor, has risen >120 m in the past 420 years at an average rate of ˜25 cm/y; uplift in the past year has been substantially faster. The main cause of uplift at Iwo-Jima is fresh, episodic(?) magma influx into a reservoir whose top is ˜ 2 km below the caldera floor. Despite roughly 10 million m3/y apparent magma influx, degassing seems to minimize magmatic eruptions.

  2. The Effect of Island-Island Interaction on Coarsening of Strained Islands

    NASA Astrophysics Data System (ADS)

    Liu, Feng

    2003-07-01

    We review recent studies on the effect of stress/strain-induced island-island interaction on coarsening of strained islands. For coarsening of strained 2D islands, there always exists a stable island size against coarsening. When coarsening proceeds via only mass transport between islands, the interaction broadens the island size distribution, leading to a power-law dependence of island size uniformity on island number density. When coarsening proceeds via island migration in addition to mass transport between islands, the interaction can effectively direct island motion through island edge diffusion, leading to self-assembly of a close-packing array of 2D islands with improved size uniformity. For coarsening of strained 3D islands, a stable island size against coarsening may only exist if a stress/strain induced island edge energy dominates over island surface energy. The island-island interaction then modifies the size of stable islands, driving it to increase exponentially with increasing film coverage.

  3. [Gambling disorder in Japan].

    PubMed

    Tanabe, Hitoshi

    2015-09-01

    Gambling disorder is a psychiatric disorder characterized by persistent and recurrent problematic gambling behavior, associated with impaired functioning, reduced quality of life, and frequent divorce and bankruptcy. Gambling disorder is reclassified in the category Substance-Related and Addictive Disorders in the DSM-5 because its clinical features closely resemble those of substance use disorders, and gambling activates the reward system in brain in much the same way drugs do. Prevalence of gambling disorder in Japan is high rate because of slot machines and pachinko game are very popular in Japan. The author recommend group psychotherapy and self-help group (Gamblers Anonymous), because group dynamics make them accept their wrongdoings related to gambling and believe that they can enjoy their lives without gambling. PMID:26394523

  4. Scientific ballooning in Japan

    NASA Astrophysics Data System (ADS)

    Makino, Fumiyoshi

    Activities in scientific ballooning in Japan during 1998-1999 are reported. The total number of scientific balloons flown in Japan in 1998 and 1999 was sixteen, eight flights in each year. The scientific objectives were observations of high energy cosmic electrons, air samplings at various altitudes, monitoring of atmospheric ozone density, Galactic infrared observations, and test flights of new type balloons. Balloon expeditions were conducted in Antarctica by the National Institute of Polar Research, in Russia, in Canada and in India in collaboration with foreign countries' institutes to investigate cosmic rays, Galactic infrared radiation, and Earth's atmosphere. There were three flights in Antarctica, four flights in Russia, three flights in Canada and two flights in India. Four test balloons were flown for balloon technology, which included pumpkin-type super-pressure balloon and a balloon made with ultra-thin polyethylene film of 3.4 ?m thickness.

  5. DPAL activities in Japan

    NASA Astrophysics Data System (ADS)

    Endo, Masamori; Wani, Fumio

    2015-02-01

    Activities on diode pumped alkali laser (DPAL) in Japan is reviewed. We have started alkali laser works in 2011, and currently, we are the only players in Japan. Our interests are application oriented, and it is not only defense but also industrial. DPAL is a good candidate as a source of remote laser machining, thanks to its scalability and extremely good beam quality. We are studying on scientific and engineering problems of Cs DPAL with a small-scale apparatus. A commercial diode laser with volume Bragg grating outcoupler is used to pump the gain cell longitudinally. A 6.5 W continuous-wave output with optical to optical efficiency of 56% (based on the absorbed power) has been achieved. Numerical simulation codes are developed to understand the physics of DPAL and to help future developments.

  6. Island Formation: Constructing a Coral Island

    ERIC Educational Resources Information Center

    Austin, Heather; Edd, Amelia

    2009-01-01

    The process of coral island formation is often difficult for middle school students to comprehend. Coral island formation is a dynamic process, and students should have the opportunity to experience this process in a synergistic context. The authors provide instructional guidelines for constructing a coral island. Students play an interactive role…

  7. Island Formation: Constructing a Coral Island

    ERIC Educational Resources Information Center

    Austin, Heather; Edd, Amelia

    2009-01-01

    The process of coral island formation is often difficult for middle school students to comprehend. Coral island formation is a dynamic process, and students should have the opportunity to experience this process in a synergistic context. The authors provide instructional guidelines for constructing a coral island. Students play an interactive role

  8. Tohoku, Japan Tsunami Sets us West Coast Into Ringing

    NASA Astrophysics Data System (ADS)

    Barberopoulou, A.; Legg, M. R.; Gica, E.; Legg, G.

    2011-12-01

    Tsunamis can last a long time compared to the geophysical events that generate them. The Tohoku, Japan tsunami of March 11, 2011 was an extreme event that continued to disturb the Pacific Ocean for many days following its initiation. Historically Japan was considered a source of low tsunami wave energy for the US West Coast. However, damage in California from the last great Japan tsunami was second to that suffered during the 1964 Alaska earthquake. Computer animations of the catastrophic Japan tsunami and other recent significant tsunamis combined with seismological techniques help to identify multiple paths of tsunami waves refracted and reflected by complex bathymetry across the Pacific Ocean basin. Using recent large tsunamigenic earthquakes we demonstrate that the long duration and damage noticed during the last great Japan tsunami in the farfield is a result of several factors. Waveguides acting as tsunami lenses and mirrors, including continental margins, direct the tsunami wave energy to diverse locations around the ocean basin; directionality affected by islands and seamounts, large reflections off of South America, bathymetric features far and near the area of impact and shelf geometry may delay and further amplify the main tsunami energy. This has direct implications on the prediction of tsunami impacts since the US West Coast appears to receive maximum waves much later than first wave arrivals.

  9. Terrorism in Japan.

    PubMed

    Asai, Yasufumi; Arnold, Jeffrey L

    2003-01-01

    Although the 1995 Tokyo subway sarin attack probably was the most widely reported terrorist event in Japan to date (5,500 injured, 12 dead), the country has suffered numerous other large terrorism-related events in recent decades, including bombings of the headquarters of Mitsubishi Heavy Industries in Tokyo in 1974 (207 injured, 8 dead), the Hokkaido Prefectural Government office building in Sapporo in 1976 (80 injured, 2 dead), and the Yosakoi-Soran Festival in Sapporo in 2000 (10 injured, none dead). Japan also has experienced two other mass-casualty terrorist events involving chemical releases, including the 1994 Matsumoto sarin attack (600 injured, 7 dead) and the 1998 Wakayama arsenic incident (67 injured, 4 dead). Until 1995, emergency management in Japan focused on planning and preparedness at the local level for the frequent disasters caused by natural events. Since that time, substantial progress has been made in advancing emergency planning and preparedness for terrorism-related events, including the designation of disaster centers in each prefecture, the implementation of several education and training programs for nuclear, biological, and chemical terrorism, and the establishment of a national Anti terrorism Office within the Ministry of Health, Labor, and Welfare. PMID:15074491

  10. 2012/13 abnormal cold winter in Japan associated with Large-scale Atmospheric Circulation and Local Sea Surface Temperature over the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Ando, Y.; Ogi, M.; Tachibana, Y.

    2013-12-01

    On Japan, wintertime cold wave has social, economic, psychological and political impacts because of the lack of atomic power stations in the era of post Fukushima world. The colder winter is the more electricity is needed. Wintertime weather of Japan and its prediction has come under the world spotlight. The winter of 2012/13 in Japan was abnormally cold, and such a cold winter has persisted for 3 years. Wintertime climate of Japan is governed by some dominant modes of the large-scale atmospheric circulations. Yasunaka and Hanawa (2008) demonstrated that the two dominant modes - Arctic Oscillation (AO) and Western Pacific (WP) pattern - account for about 65% of the interannual variation of the wintertime mean surface air temperature of Japan. A negative AO brings about cold winter in Japan. In addition, a negative WP also brings about cold winter in Japan. Looking back to the winter of 2012/13, both the negative AO and negative WP continued from October through December. If the previous studies were correct, it would have been extremely very cold from October through December. In fact, in December, in accordance with previous studies, it was colder than normal. Contrary to the expectation, in October and November, it was, however, warmer than normal. This discrepancy signifies that an additional hidden circumstance that heats Japan overwhelms these large-scale atmospheric circulations that cool Japan. In this study, we therefore seek an additional cause of wintertime climate of Japan particularly focusing 2012 as well as the AO and WP. We found that anomalously warm oceanic temperature surrounding Japan overwhelmed influences of the AO or WP. Unlike the inland climate, the island climate can be strongly influenced by surrounding ocean temperature, suggesting that large-scale atmospheric patterns alone do not determine the climate of islands. (a) Time series of a 5-day running mean AO index (blue) as defined by Ogi et al., (2004), who called it the SVNAM index. For reference, the conventional AO index is shown by the gray line. (b) a 5-day running mean WP index, (c) area-averaged Surface Air Temperature anomalies in Japan, (d) Air Temperature anomalies, (e) heat flux anomalies, and (f) Sea Surface Temperature anomalies. The boxed area on the Sea of Japan indicates the area in which the (d)-(f) indexes were calculated.

  11. Hawaiian Island Archipelago

    NASA Technical Reports Server (NTRS)

    1988-01-01

    In this view of the entire Hawaiian Island Archipelago (21.0N, 157.0W), the islands perturb the prevailing northeastewrly winds producing extensive cloud wakes in the lee of the islands. The atmospheric haze within the wake is a result of the near continuous eruptions of Kilauea volcano on the southeast coast of the big island of Hawaii.

  12. Hawaiian Island Archipelago

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The entire Hawaiian Island Archipelago (21.5N, 158.0W) is seen in this single view. The islands are a favorite international resort and tourist attraction drawing visitors from all over the world to enjoy the tropical climate, year round beaches and lush island flora. Being volcanic in origin, the islands' offer a rugged landscape and on the big island of Hawaii, there is still an occasional volcanic eruption of lava flows and steam vents.

  13. The graying of Japan.

    PubMed

    Martin, L G

    1989-07-01

    Japan's rapidly aging population has become a top policy issue, especially as the increasing costs of pensions and medical care are debated. With the highest life expectancy on earth, the Japanese potentially face long periods of retirement, as well as the possibility of long periods of disability. Although family support of the elderly is thought to have been strong traditionally, the recent decline in co-residence with children is 1 indication that the way support is given may be changing. This issue is of particular concern to the government, which wants to avoid any greater responsibility for the elderly than is necessary given the dramatic population aging yet to come. The government is also encouraging employers to provide more employment opportunities for the elderly at the same time that it is trying to raise the eligibility age for the receipt of public pensions. There is resistance on the part of employers, however, because wages and retirement allowances in Japan are positively related to length of employment. Furthermore, it is not clear whether elderly Japanese of the future will be as willing to work, if they learn to enjoy increased leisure early in their careers. Nevertheless, it is unlikely that population aging will lead to Japan's economic decline. Although the savings rate may decline somewhat, restructuring of the economy and continued overseas investment should keep the economy growing in the long run. Important in both the care of the frail elderly and the continued growth of the economy will be the roles played by middle-aged Japanese women. PMID:12282193

  14. Astrogeodetic geoid of Japan

    NASA Technical Reports Server (NTRS)

    Ganeko, Y.

    1976-01-01

    Three kinds of astrogeodetic geoid maps for Japan are presented: one referred to the global (18, 18) geoid of the 1973 Smithsonian Standard Earth (III) (SE III), referred to the best-fitting ellipsoid of SE III, and one referred to the reference ellipsoid of the Tokyo datum. Interpolations of the deflection of the vertical are carried out by a least squares estimation method. The geoid height differences obtained are compared with solutions of satellite-derived station positions. Good agreement is found in a comparison with Doppler tracking stations.

  15. Ijime in Japan.

    PubMed

    Ogura, Masayoshi; Okada, Kaori; Hamada, Shoko; Asaga, Reiko; Honjo, Shuji

    2012-01-01

    This paper reviews the problem of ijime in Japan from a variety of perspectives, primarily through studies conducted in this country. The term ijime is not uniform in concept, open to different interpretations given the disparity in definitions among different circles, making precise assessment of the actual conditions difficult. Such being the case, what is needed is further study on the mechanisms and actual state of ijime accounting for the flow of the times, and compilation of research to enable the creation of ever more effective modes of prevention and intervention. PMID:22909914

  16. 21 CFR 186.1555 - Japan wax.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Japan wax. 186.1555 Section 186.1555 Food and... Substances Affirmed as GRAS § 186.1555 Japan wax. (a) Japan wax (CAS Reg. No. 8001-39-6), also known as Japan... fruits of the oriental sumac, Rhus succedanea (Japan, Taiwan, and Indo-China), R. vernicifera...

  17. 21 CFR 186.1555 - Japan wax.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Japan wax. 186.1555 Section 186.1555 Food and... Substances Affirmed as GRAS § 186.1555 Japan wax. (a) Japan wax (CAS Reg. No. 8001-39-6), also known as Japan... fruits of the oriental sumac, Rhus succedanea (Japan, Taiwan, and Indo-China), R. vernicifera...

  18. Overview of DRAGON-Japan in 2012

    NASA Astrophysics Data System (ADS)

    Sano, I.; Holben, B. N.; Mukai, S.; Sugimoto, N.; Hatakeyama, S.; Schafer, J. S.; Eck, T. F.; Nishizawa, T.; Takemura, T.; Takamura, T.; Teruyuki, N.; Nakajima, T. Y.; Takami, A.; Kaneyasu, N.; Goto, M.; Hiraki, T.; Iguchi, N.; Kenny, P.; Kouzai, K.; Kuji, M.; Muramatsu, K.; Nakata, M.; Okada, Y.; Sadanaga, Y.; Sorokin, M.; Tohno, S.; Toyazaki, Y.; Kim, J.; Li, Z.

    2012-12-01

    The AERONET (AErosol RObotic NETwork) is an on-going project since early 1990s. The 400 sun/sky radiometers are sparsely deployed and provide us with the information of aerosol properties over the world. In summer of 2011, the first DRAGON field campaign was made in Washington, D.C./Baltimore metropolitan area, where about 40 AERONET Cimel instruments were set according to small square grid boxes. Thus it has been shown that the detail scale observations are useful to investigate the local influence of aerosols and validation of high resolution satellite product such as newly developed 3 km x 3 km aerosol product from MODIS. The second DRAGON project is done in East Asia because this region emits huge amount of anthropogenic gases and aerosols. The emission influences not only local atmosphere near the origin but also out of Asian continent by long range transportation. The aim of DRAGON-Japan is as follows: 1: retrieval of optical properties of trans-boundary aerosols, 2: detection of aerosols over megacity, 3: investigation of the influence to local aerosols by inbound aerosols from continent. During the DRAGON-Asia (March-May, 2012), AERONET instruments were set sparsely from Fukue Island (in the East China Sea) to Osaka (in the middle of Japan) as well as 2ch-LIDAR system. As for megacity region, dense sun/sky radiometer network was made by using nine instruments at Mt. Rokko (840 m/asl.), Mt. Ikoma (640 m/asl.), Kobe, North-Osaka, South-Osaka, Central-Osaka, East-Osaka (simply named by Osaka in AERONET web), Nara, and Kyoto. The following results on AOT (Aerosol optical thickness at a wavelength of 500 nm: AERONET Level 1.5) have been driven from the measurements : 1: Fukue Island provides the highest value as 0.56, 2: in respect of urban cities; 0.42 at Fukuoka, 0.42~0.47 over Osaka area, and 0.39 at Kyoto or Nara, 3: in the remote place; 0.33~0.35 at Nishiharima, Noto or Shirahama, 4: the difference between AOT values at mountain (ex. Mt. Rokko, Mt. Ikoma) and those at sea level takes the value of about 0.1. It is drawn from the above facts that the influence of inbound aerosols to total one is really high in western part of Japan.

  19. Comparison of Helmert and rigorous orthometric heights over Japan

    NASA Astrophysics Data System (ADS)

    Odera, Patroba Achola; Fukuda, Yoichi

    2015-12-01

    The local vertical datum in Japan is based on the Helmert's approximation of mean gravity along the plumbline. However, determination of a rigorous orthometric height requires that the integral-mean value of gravity along the plumbline between the geoid and the Earth surface has to be known precisely. An attempt has been made to obtain rigorous orthometric heights at 816 GPS/levelling points distributed over four main islands of Japan (Hokkaido, Honshu, Shikoku and Kyushu) by applying corrections to the Helmert orthometric heights. The corrections to Helmert orthometric heights are evaluated from the differences between the integral-mean gravity and the approximate mean gravity along the plumbline. The corrections to Helmert orthometric heights vary from -30.9 cm to 0.0 cm with a mean value of -0.4 cm and standard deviation of 1.7 cm. An improved high-resolution gravimetric geoid model covering four main islands of Japan from our previous study is used to compare the consistency of the two height systems to a regionally defined gravimetric geoid model. The standard deviation of the differences between gravimetric and GPS/levelling geoid undulations is 7.5 cm, when Helmert orthometric heights are used. The standard deviation of the differences between gravimetric and GPS/levelling geoid undulations reduces to 7.3 cm, when rigorous orthometric heights are used. This indicates that rigorous orthometric heights are more consistent with the gravimetric geoid model than Helmert orthometric heights.

  20. Strong Quake Strikes Japan

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-03-01

    As Eos was about to go to press, a powerful earthquake with a preliminary estimated magnitude of 8.9 shook the northeast coast of Japan on 11 March at 05:46:23 UTC. It is the largest known earthquake along the Japan Trench subduction zone since 869 A.D. or earlier, Brian Atwater, geologist with the U.S. Geological Survey (USGS), told Eos. The quake's magnitude would place it fifth in terms of any earthquake magnitude worldwide since at least 1900, according to information from the USGS Earthquake Hazards Program. The amount of energy released in the quake—which occurred 130 kilometers east of Sendai, Honshu, at a depth of 24.4 kilometers—was equivalent to the energy from 30 earthquakes the size of the 1906 quake in San Francisco, Calif., according to David Applegate, USGS senior science advisor for earthquake and geologic hazards. He said the economic losses from the shaking are estimated to be in the tens of billions of dollars.

  1. Women of courage. Japan.

    PubMed

    1996-02-01

    JOICFP President Shidzue Kato was influenced by and friends with Margaret Sanger from their initial meeting in 1920 to Sanger's death in 1966. Bruce Alfred is currently directing and producing a 90-minute documentary film about Sanger and her pioneering work in promoting the development and use of family planning. Once completed in the Spring of 1997, the film will be broadcast nationally in the US on Public Television. It is being produced with support from the National Endowment for the Humanities and several private foundations. Alfred interviewed Kato for three hours to gain insight into the life and legacy of Margaret Sanger. Sanger inspired Kato to make birth control her life's work. Kato spoke about how the prewar, pronatalist Japanese government allowed Sanger to visit Japan in 1922 only on the condition that she not speak about birth control. This official opposition and the subsequent reaction, however, actually fueled interest in Sanger and her message, and caused her ideas to become widely known among the Japanese public. While in Japan, Sanger did manage to discuss family planning, but in English in a closed meeting. Oddly enough, the government honored Sanger after the second World War with the highest award presented to non-Japanese. Kato noted how unfortunate it was that Sanger died in 1966 without witnessing the realization of the UNFPA. PMID:12290713

  2. Use of microbial analysis to evaluate denitrification in the karstic aquifer of Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Yasumoto, J.

    2014-12-01

    Denitrification, a microbial process in the nitrogen cycle, is a facultative respiratory pathway in which nitrate (NO3-), nitrite (NO2-), nitric oxide (NO), and nitrous oxide (N2O), successively, are reduced to nitrogen gas (N2). This study explores the use of microbial analysis to evaluate the processes involved in nitrate attenuation in groundwater. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) is used to identify denitrifiers based only on their 16SrRNA gene sequences, and Real-Time PCR analysis is used to quantify nitrite reducing genes (nirK and nirS), this suggest that a new methods for detecting denitrification activity by comparing the gene dosage that has been detected by RT-PCR and the value of the δ15NNO3- and δ18ONO3-. This study focuses on a zone of significant NO3- attenuation occurring at underground dam catchment area in the karstic Ryukyu limestone aquifer, which is located southern part of Okinawa, Japan. As a result of microbial analysis, the bacteria were detected at all observation points which have been reported to have denitrification ability. And it has been confirmed that the bacteria has a gene nirS which is related to denitrification. In addition, many bacteria related to denitrification have been extracted from suspended solids more than from groundwater in the aquifer. And, the correlation was high between nirK /nirS gene dosage that has been detected by RT-PCR and the value of the δ15N and δ18O; therefore, this study demonstrates the effectiveness of using Real-Time PCR analysis for providing insights into the processes affecting nitrate attenuation in ground water.

  3. Model analysis of seasonal variation of PM2.5 across Japan and its reginal-scale transport in East Asia

    NASA Astrophysics Data System (ADS)

    Ikeda, Kohei; Yamaji, Kazuyo; Kanaya, Yugo; Taketani, Fumikazu; Pan, Xiaole; Komazaki, Yuichi; Kurokawa, Jun-ichi; Ohara, Toshimasa

    2013-04-01

    In Japan, an atmospheric environmental standard for PM2.5 was newly introduced in September 2009. According to one year of data observed at ambient air quality monitoring stations in Japan main islands in fiscal 2010, PM2.5 concentrations exceed the environmental standard at the large part of monitoring stations. In particular, concentration levels at almost all the monitoring stations in the western part of Japan exceed the standard value. Besides Japan main islands, PM2.5 concentrations monitored at Fukue Island, a remote island in the most western part of Japan and close to the Asian continent, clearly exceeds the short-term standard value. These results suggest that regional-scale transport in East Asia affects the spatial and temporal variations of PM2.5 across Japan. To investigate seasonal variations of PM2.5 and estimate the influence of trans-boundary air pollution in East Asia, we performed emission sensitivity simulations for the full year 2010 by using a chemical transport model (Weather Research and Forecasting model /Community Multi-scale Air Quality model). The source regions in East Asia were divided into six areas: Japan, Korean Peninsula, northeast China, central north China, central south China, and south China. In each sensitivity simulation, the anthropogenic emission was reduced by 20% in each source region. The sensitivity of each source region was obtained by taking the difference of simulated PM2.5 concentration between each sensitivity and base run. The model generally well reproduces the seasonal variation pattern of PM2.5 concentrations across Japan; in the western part of Japan, PM2.5 concentration decreases in summer, whereas it increases during summer in the eastern part of Japan. However, the absolute concentrations were underestimated by the model in the entire Japan throughout the year. We estimated the relative contributions from each source region to annual mean PM2.5 concentrations in Japan. The contribution of domestic pollution is estimated at about 30% except the major urban areas. The contribution from central north China accounts for 30-40% of PM2.5 in western Japan, and for 20-30% in eastern Japan. Central south has the relative contribution of 10-15% in western Japan. The contribution from northeastern China accounts for about 30% in northern Japan. The contribution from the Korean Peninsula is estimated at about 10% in western Japan.

  4. Teaching Elementary Students about Japan

    ERIC Educational Resources Information Center

    Fitzhugh, William P.

    This paper presents a study unit on Japan for elementary students which can be adapted for any level. Lessons include: (1) "Video Traveling Activities To Accompany Students on Their Journey to Japan"; (2) "Travel Brochure"; (3) "Discovering Culture by Using a Realia Kit"; (4) "Comparative Geography Using the Five Fundamental Themes of Geography";…

  5. Higher Education Studies in Japan

    ERIC Educational Resources Information Center

    Kaneko, Motohisa

    2010-01-01

    The rapid development of higher education in the postwar period has given rise to various problems, and higher education studies in Japan have developed in response to them. What have been the major issues, and how did academic research respond to them, in postwar Japan? This article delineates an outline of higher education studies in general,…

  6. Continuing Engineering Education in Japan.

    ERIC Educational Resources Information Center

    Oshima, Keichi; Yamada, Keiichi

    1985-01-01

    Discusses: (1) the current status of continuing engineering education (CEE) in Japan; (2) characteristics of CEE in enterprises; and (3) future issues of CEE in Japan. Indicates that ways of improving CEE include increasing the role of universities, promoting creativity and education of elites, and re-education of middle- and advanced-aged

  7. [Buddhist mummies in Japan].

    PubMed

    Morimoto, I

    1993-08-01

    The mummy of priest Kochi (preserved at Saishoji Temple, Teradomari, Niigata Pref.) has become famous, since it appeared in the book "Snow Country Tales" written by Bokushi Suzuki in 1841 (Fig. 1). In a country of high humidity, such as Japan, the belief that mummification could not, and did not, exist would not be altogether unfounded, but rather more a matter of common sense. There are two dozen Buddhist mummies in this country. It was not known until 1961 that a reliable source of artificial mummification has existed in Japan. The Japanese Buddhist mummies, apart from those of the Fujiwara family, a powerful clan of northeast Japan in the 12th century, dated mostly from the 17th to the 19th century as given in Table 1. Three principal types of mummification described by Vreeland, Jr. and Cockburn (1980) could be identified in the Japanese Buddhist mummies: type I, natural mummification; type II, intentional natural; and type III, artificial. Matsumoto (1990) classified the mummies into four groups, based on their ideological backgrounds: group A, mummies of the priests having faith in the Amitabha (the Supreme Buddha presiding over the Pure Land in the West); group B, sokushin-butsu mummies of the priests belonging to the Shingon sect of Japanese Buddhism founded by Kukai (Kobo-daishi); group C, nyujo mummies of the priests having faith in the Maitreya (the Buddha presiding over the Pure Land in the North, or the Buddha of the future); and group D, other mummies. These mummies of groups A, B, C and D are respectively listed in Table 2. Previous papers have shown that the mummies of the groups A, C and D belonged to the mummification of type I (natural mummification) or type II (intentional natural), whereas those of only the group B were of type III (artificial). The mummies of groups A to D were given as follows. a) Mummies of group A. The four mummies of the Fujiwara family in the Amitabha faith (preserved at Chusonji Temple, Hiraizumi, Iwate Pref.), which were laid in daisies for Buddhist images at golden Konjikido, a model of the Western Pure Land of Amitabha, did not bear any evidence of Ainu character in their physical traits. Of these, the mummy of Yasuhira Fujiwara, of which the head and neck were severely injured by swords, showed that it had been decapitated. This decapitated head had suffered mutilations: i.e. a long iron nail had been driven into the forehead, and the both auricles and the nose had been cut off.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8237299

  8. Nature of the Moho in Japan and Kamchatka

    NASA Astrophysics Data System (ADS)

    Iwasaki, Takaya; Levin, Vadim; Nikulin, Alex; Iidaka, Takashi

    2013-04-01

    The Kamchatka peninsula and the islands of Japan are located along the eastern margin of the Asian continent. The natures of the Moho in these areas have been studied for decades, with a variety of geophysical methods, including active and passive seismic methods, gravity and other techniques. The Moho and the upper mantle structures in the NE Japan and SE Japan Arcs have been investigated well both from active and passive seismic source studies. The Moho depth in the NE Japan is ranging from 30 to 40 km. Almost parallel to the present volcanic front, there exists a belt of deep Moho (34-36 km) with a lower Pn velocity (7.5-7.7 km/s). Amplitude analysis of the PmP phase indicates that the Moho beneath the NE Japan Arc is not a simple velocity contrast, but rather a gradual transition. Toward the backarc side, remarkable crustal thinning is recognized. Actually, the Moho depth decreases from 35 km beneath the central part of NE Japan to 18 km beneath the Sea of Japan. This thinning is evident in the upper crust, while the lower crust remains constant in thickness. This may be explained by the continuous magmatic underplating beneath the rifted crust or deformation under a simple shear mode, allowing the lower crustal thickness to remain unchanged. The Moho in the SW Japan Arc is also at a depth of 30-40 km. The Pn velocity is 7.7-7.8 km/s, slightly higher than that in the NE Japan, although this value was mostly sampled in the eastern half of the SW Japan Arc where the recent volcanic activity has been less effective. Fluids expelled from the subducted oceanic lithosphere (the PHS plate) play an important role in controlling the structure of the mantle wedge. As these fluids leak into the mantle wedge they induce serpentinization there, transforming original mantle materials to those of lower velocity and higher Vp/Vs. The crustal thinning of the SW Japan Arc is characterized by notable decrease in upper crustal thickness, which is similar to the case of the NE Japan Arc. The Moho and uppermost mantle structures beneath the southern part of the Kamchatka have a lot of similarities to those beneath the NE Japan Arc. Earlier DSS investigations and converted wave analyses show that Moho is situated at a depth of 38-40 km along the east coast of Kamchatka, that is beneath the volcanic front, but decreases to about 32 km near the west coast. Moho depth values based on modern receiver function methodology are also ranging from 31 to over 38 km. Moho is a fairly simple boundary under the western coast of Kamchatka, while in the Central Kamchatka Depression and especially along the eastern coast it is likely gradational. Uppermost mantle material beneath the Moho is complex, with additional impedance contrasts that are likely anisotropic in their properties being present under the entire Kamchatka peninsula. The dominant anisotorpy-inducing fabric varies from site to site along the west coast, but is almost universally trench-normal along the east coast. The seismic velocities beneath Kamchatka are very low (7.4-7.8 km/s for P-wave and 4.1-4.2 km/s for S wave). Also, gradual structural change is recognized around the Moho beneath the active volcanoes. These features are quite similar to those in NE Japan Arc.

  9. Constraints on the Moho in Japan and Kamchatka

    NASA Astrophysics Data System (ADS)

    Iwasaki, Takaya; Levin, Vadim; Nikulin, Alex; Iidaka, Takashi

    2013-12-01

    This review collects and systematizes in one place a variety of results which offer constraints on the depth and the nature of the Moho beneath the Kamchatka peninsula and the islands of Japan. We also include studies of the Izu-Bonin volcanic arc. All results have already been published separately in a variety of venues, and the primary goal of the present review is to describe them in the same language and in comparable terms. For both regions we include studies using artificial and natural seismic sources, such as refraction and reflection profiling, detection and interpretation of converted-mode body waves (receiver functions), surface wave dispersion studies (in Kamchatka) and tomographic imaging (in Japan). The amount of work done in Japan is significantly larger than in Kamchatka, and resulting constraints on the properties of the crust and the uppermost mantle are more detailed. Japan and Kamchatka display a number of similarities in their crustal structure, most notably the average crustal thickness in excess of 30 km (typical of continental regions), and the generally gradational nature of the crust-mantle transition where volcanic arcs are presently active.

  10. Nutrition in the Great East Japan Earthquake Disaster.

    PubMed

    Amagai, Teruyoshi; Ichimaru, Satomi; Tai, Mayumi; Ejiri, Yutaka; Muto, Atsushi

    2014-10-01

    The Great East Japan Earthquake Disaster (GEJED) struck the northeast region of Honshu, the main island of Japan, on March 11, 2011. This mega-disaster claimed more than 15,000 lives, with approximately 3000 later deaths being disaster related. The GEJED consisted of a mega-earthquake, tsunami, and nuclear accident. Survivors living in temporary shelters might have received insufficient levels of vitamins, with the exception of vitamin B1, which appeared to be overestimated, and excess levels of sodium. However, scientific data collection and surveys following the GEJED were extremely limited. This experience highlights the need to prepare an emergency nutrition assessment system for optimal nutrition in future disasters. PMID:25606634

  11. Disaster Nutrition in the Great East Japan Earthquake Disaster.

    PubMed

    Amagai, Teruyoshi; Ichimaru, Satomi; Tai, Mayumi; Ejiri, Yutaka; Muto, Atsushi

    2014-07-23

    The Great East Japan Earthquake Disaster (GEJED) struck the northeast region of Honshu, the main island of Japan, on March 11, 2011. This mega-disaster claimed more than 15,000 lives, with approximately 3000 later deaths being disaster related. The GEJED consisted of a mega-earthquake, tsunami, and nuclear accident. Survivors living in temporary shelters might have received insufficient levels of vitamins, with the exception of vitamin B1, which appeared to be overestimated, and excess levels of sodium. However, scientific data collection and surveys following the GEJED were extremely limited. This experience highlights the need to prepare an "emergency nutrition assessment" system for optimal nutrition in future disasters. PMID:25057050

  12. Tectonics and volcanism in the Sado-Pohang Belt from 20 to 14 Ma and opening of the Yamato Basin of the Japan Sea

    NASA Astrophysics Data System (ADS)

    Shimazu, Mitsuo; Yoon, Sun; Tateishi, Masaaki

    1990-09-01

    Tertiary volcanism around the Japan Sea is closely related to the opening of the Japan Sea. Paleogene to early Middle Miocene formations in the Pohang-Yangnam area of the Korean Peninsula mainly consist of volcanic rocks that are stratigraphically and petrographically similar to similar age rocks on the Japan Sea side of the Japanese Islands, especially those of Sado Island. We propose that all these early Cenozoic rocks formed part of a single tectonic-volcanic belt called Sado-Pohang Belt. It is inferred that this belt was located on the south side of the Yamato Ridge in Paleogene time. After the Japan Basin opened, the Yamato Basin opened during Early Miocene to the early Middle Miocene time and part of the Sado-Pohang Belt migrated southward. The tectonics of the Sado-Pohang Belt is considered to support the hypothesis of the two-stage opening of the Japan Sea.

  13. A high-resolution gravimetric geoid model for Japan from EGM2008 and local gravity data

    NASA Astrophysics Data System (ADS)

    Odera, Patroba Achola; Fukuda, Yoichi; Kuroishi, Yuki

    2012-05-01

    A high-resolution geoid model covering the four main islands of Japan has been developed on a 1 by 1.5 arc-minute grid from EGM2008 and terrestrial gravity data. The Stokes-Helmert scheme in a modified form is applied for the determination of the geoid using an empirically-determined optimal spherical cap, and Kriging is used for gridding the residual gravity anomalies. In comparison with the previous geoid model for Japan (JGEOID2008), there is a slight improvement in the standard deviation from 8.44 cm to 8.29 cm. It is noted that although the determined gravimetric geoid model represents the geoid over Japan fairly well, there is still a need for more gravity data especially in the northern parts of Japan.

  14. Barrier Island Hazard Mapping.

    ERIC Educational Resources Information Center

    Pilkey, Orrin H.; Neal, William J.

    1980-01-01

    Describes efforts to evaluate and map the susceptibility of barrier islands to damage from storms, erosion, rising sea levels and other natural phenomena. Presented are criteria for assessing the safety and hazard potential of island developments. (WB)

  15. Overwash on Assateague Island

    USGS Multimedia Gallery

    Overwash on Assateague Island. Overwash occurs when waves overtop the main sand dune and redistribute the sand along new patterns. Overwash has contributed to the gradual movement of Assateague Island to the south....

  16. Future Change of Snow Water Equivalent over Japan

    NASA Astrophysics Data System (ADS)

    Hara, M.; Kawase, H.; Kimura, F.; Fujita, M.; Ma, X.

    2012-12-01

    Western side of Honshu Island and Hokkaido Island in Japan are ones of the heaviest snowfall areas in the world. Although a heavy snowfall often brings disaster, snow is one of the major sources for agriculture, industrial, and house-use in Japan. Even during the winter, the monthly mean of the surface air temperature often exceeds 0 C in large parts of the heavy snow areas along the Sea of Japan. Thus, snow cover may be seriously reduced in these areas as a result of the global warming, which is caused by an increase in greenhouse gases. The change in seasonal march of snow water equivalent, e.g., snowmelt season and amount will strongly influence to social-economic activities. We performed a series of numerical experiments including present and future climate simulations and much-snow and less-snow cases using a regional climate model. Pseudo-Global-Warming (PGW) method (Kimura and Kitoh, 2008) is applied for the future climate simulations. MIROC 3.2 medres 2070s output under IPCC SRES A2 scenario and 1990s output under 20c3m scenario used for PGW method. The precipitation, snow depth, and surface air temperature of the hindcast simulations show good agreement with the AMeDAS station data. In much-snow cases, The decreasing rate of maximum total snow water equivalent over Japan due to climate change was 49%. Main cause of the decrease of the total snow water equivalent is the air temperature rise due to global climate change. The difference in the precipitation amount between the present and the future simulations is small.

  17. Falkland Islands, UK

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Falkland Islands (52.0S, 58.5W) was taken with a dual camera mount. Compare this scene with STS048-109-043 to analyze the unique properties of each film type. Seldom seen cloud free, the Falkland Islands lie off the southern coast of Argentina. The cold Falklands Ocean Current keeps the islands chilly, ideal for sheep herding and fishing, the two main industries. Colonies of seals and penguins also thrive on the islands.

  18. Island of Timor, Indonesia

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This almost totally cloud free, photo of the island of Timor, Indonesia (9.0S, 125.0E) illustrates the volcanic origin of the over 1500 islands of Indonesia. Close examination of the photo reveals several eroded volcanoes on the Island of Timor and several of the adjacent islands. The linear alignment of the volcanoes, as seen from space, indicates the edges of the tectonic plates of the Earth's crust where volcanic activity is most common.

  19. Arctic ice islands

    SciTech Connect

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  20. Diomede Islands, Bering Straight

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Diomede Islands consisting of the western island Big Diomede (also known as Imaqliq, Nunarbuk or Ratmanov Island), and the eastern island Little Diomede (also known as Krusenstern Island or Inaliq), are two rocky islands located in the middle of the Bering Strait between Russia and Alaska. The islands are separated by an international border and the International Date Line which is approximately 1.5 km from each island; you can look from Alaska into tomorrow in Russia. At the closest land approach between the United States, which controls Little Diomede, and Russia, which controls Big Diomede, they are 3 km apart. Little Diomede Island constitutes the Alaskan City of Diomede, while Big Diomede Island is Russia's easternmost point. The first European to reach the islands was the Russian explorer Semyon Dezhnev in 1648. The text of the 1867 treaty finalizing the sale of Alaska uses the islands to designate the border between the two nations.

    The image was acquired July 8, 2000, covers an area of 13.5 x 10.8 km, and is located at 65.8 degrees north latitude, 169 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  1. Bouvet Island near Antarctica

    Atmospheric Science Data Center

    2013-04-16

    ... island presents an obstacle to the westerly winds, and wake patterns in the cloud layers are visible downstream of the island's location. ... tip of Antarctica but could not circumnavigate or land upon the island due to severe weather. Steep cliffs surrounding most sides ...

  2. Overwash on Assateague Island

    USGS Multimedia Gallery

    Overwash on Assateague Island. When waves wash over the main sand dune on the island, that creates a phenomenon called overwash, where the sand is moved along the path of the wave. Overwash has contributed to the gradual movement of Assateague Island to the south....

  3. Winter weather in Japan controlled by large-scale atmospheric and small-scale oceanic phenomena

    NASA Astrophysics Data System (ADS)

    Ando, Y.; Ogi, M.; Tachibana, Y.; Kodera, K.; Yamazaki, K.

    2014-12-01

    The important components of atmospheric circulation in the winter over the Northern Hemisphere are the Arctic Oscillation (AO) and Western Pacific (WP) pattern. Although in general negative AO and WP phases cause Siberia, East Asia, and Japan to be abnormally cold, Japan was relatively warm in October 2012 even though both the AO and WP were strongly negative. The temperature of the Sea of Japan reached a high in October 2012, and it was found that heating by these very warm waters, despite the small size of the Sea of Japan, overwhelmed the cooling effect of the strongly negative AO and WP in October. Linear regression analyses except the forcing of atmospheric circulations showed that Japan tends to be warm in years when the Sea of Japan is warm. Consequently, the temperature over Japan is statistically controlled by interannual variations of small-scale oceanic phenomena as well as by large-scale atmospheric patterns. Previous studies have ignored such small-scale oceanic influences on island temperatures.

  4. Improvement of the geoid model over Japan using integral formulae and combination of GGMs

    NASA Astrophysics Data System (ADS)

    Odera, Patroba Achola; Fukuda, Yoichi

    2014-12-01

    An improved high-resolution gravimetric geoid model covering the four main islands of Japan (Hokkaido, Honshu, Shikoku, and Kyushu) was developed on a 1 1.5 arc-minute grid from EGM2008, GOCO02S/EGM2008, and terrestrial gravity data. A modified form of the Stokes-Helmert scheme was applied for the determination of the geoid using an empirically determined optimal spherical cap size. Handling of the topographical effects on gravity was accomplished using the integral formulae of Martinec and Van?ek, which were found to be more suitable for geoid modeling over Japan than the classical formulae. EGM2008 was used in Hokkaido, Honshu, and Kyushu Islands, whereas a combination of GOCO02S and EGM2008 was used in Shikoku Island and its immediate surroundings. The global geopotential models (GGMs) used in this study were chosen based on our earlier evaluation of the performance of EGM2008- and GOCE-related GGMs in Japan. In comparison with the previous geoid model for Japan, our new model shows an improvement in the standard deviation from 8.3 to 7.5 cm.

  5. Teaching about Japan in the Elementary School.

    ERIC Educational Resources Information Center

    Cogan, John J.

    1981-01-01

    Focuses on ideas for teaching about Japan which elementary school classroom teachers can use to supplement a textbook unit on Japan. Suggestions are intended to allow for reflection by students on their own culture, as well as the culture of Japan. Topics are children's perceptions of Japan and the Japanese, developing a geographical perspective,

  6. The Social Sciences in Japan

    ERIC Educational Resources Information Center

    Watanuki, Joji

    1975-01-01

    This article relates a brief historical background of social sciences in Japan, the institutional framework of social science education and research, and major issues and perspectives for the development of the social scinces. (ND)

  7. Japan's launch vehicles

    NASA Astrophysics Data System (ADS)

    Kuroda, Y.; Hara, N.

    The development of Japan's Mu series scientific research launch vehicles, and N and H series practical applications vehicles, is described. The three-stage M-3C features a second-stage radio inertial guidance system. The evolution to the M-3S includes a first-stage TVC and Solid Motor Roll Control device, and eight 310-m strap-on boosters (SOB's). The M-3SII developed to launch an interplanetary satellite for the 1986 Halley's Comet apparition, employs two 735-mm SOB's and a microprocessor digitalized flight control system, and can put a 770 kg satellite into low earth orbit. The N-1 is a three-stage radio-guided vehicle using first and second stage liquid engines, a solid motor third stage, three SOB's, and having the capability to launch a 145 kg geostationary satellite. N-II improvements include a 350 kg geostationary payload capacity, nine SOB's, and an inertial guidance system. The H-1 planned for 1987 has a 550 kg geostationary payload capacity and a domestically developed cryogenic engine. The H-II planned for 1992 will be capable of launching a two-ton geostationary satellite, or LOX/LH2 plural satellites simultaneously. It will be powered by a single 95-ton thrust LE-7 main engine.

  8. Gluten ataxia in Japan.

    PubMed

    Nanri, Kazunori; Mitoma, Hiroshi; Ihara, Masafumi; Tanaka, Nobuyuki; Taguchi, Takeshi; Takeguchi, Masafumi; Ishiko, Tomoko; Mizusawa, Hidehiro

    2014-10-01

    Gluten ataxia, a type of cerebellar ataxia caused by exposure to gluten in sensitive patients, has been considered common in the USA and Europe, and rare in Asia. We measured anti-deamidated gliadin peptide (DGP) antibody levels in 49 patients with cerebellar ataxia, excluding those with multiple system atrophy, hereditary spinocerebellar ataxia, or cancer, as well as those who were receiving oral administration of phenytoin. Anti-DGP antibody was positive in eight (16.3%) patients, five of these patients were positive only for IgA, one was positive for both IgG and IgA, and two were positive only for IgG antibody. Intravenous immunoglobulin was administered to five of the eight patients, and was markedly effective in one, moderately effective in two, and ineffective in two. Steroid therapy was administered to four patients, but none had an apparent response. Ataxia symptoms improved in one patient treated with a gluten-free diet only. Although it had been thought to be extremely rare in Asia, we speculate that more than 10% of cerebellar ataxia patients in Japan currently have gluten ataxia; therefore, measuring anti-DGP antibody or anti-gliadin antibody in cerebellar ataxia patients in Asia is important. PMID:24997752

  9. Illegal migrant laborers in Japan.

    PubMed

    Spencer, S A

    1992-01-01

    "The purpose of this article is to describe the problem of illegal labor migration into Japan. It begins with a view of the current situation of illegal laborers in Japan--their numbers, their legal status, and their working and living conditions. The principal issues affecting the development of Japanese policy toward illegal foreign laborers are then discussed, and finally some alternatives are considered." Data are from a variety of published sources and concern the period 1984-1989. PMID:12317591

  10. Clean coal technologies in Japan

    SciTech Connect

    Yoshida, Ryoichi

    1997-11-01

    Coal provided 16.1% (116.3 million tons) of the energy for Japan in FY 1992. According to the long-term energy supply and demand outlook in Japan, prepared and revised in June 1994 by the Advisory Committee for Energy, it is estimated that coal will provide 16.4% (130 million tons) of the energy in 2000 and 15.4% (134 million tons) in 2010, and that coal demand will increase. Japan imports one-third of the amount of international coal trade and depends heavily on overseas coals. In FY 1993, Japan imported 112 million tons of overseas coals and depended on foreign countries for about 94% of coal used. Coal provides about 30% of the energy for the world. Owing to the stable supply of coal and its economic efficiency for the middle and long term, technologies for coal utilization such as clean coal conversion, including liquefaction, gasification, etc., and efficient combustion processes are being developed in Japan as the chief substitute for petroleum to reduce the excessive dependence on petroleum. Clean coal technologies being developed in Japan will spread widely throughout the world and are expected to create sustainable growth while solving energy and environmental issues.

  11. High definition systems in Japan

    NASA Technical Reports Server (NTRS)

    Elkus, Richard J., Jr.; Cohen, Robert B.; Dayton, Birney D.; Messerschmitt, David G.; Schreiber, William F.; Tannas, Lawrence E., Jr.; Shelton, Duane

    1991-01-01

    The successful implementation of a strategy to produce high-definition systems within the Japanese economy will favorably affect the fundamental competitiveness of Japan relative to the rest of the world. The development of an infrastructure necessary to support high-definition products and systems in that country involves major commitments of engineering resources, plants and equipment, educational programs and funding. The results of these efforts appear to affect virtually every aspect of the Japanese industrial complex. The results of assessments of the current progress of Japan toward the development of high-definition products and systems are presented. The assessments are based on the findings of a panel of U.S. experts made up of individuals from U.S. academia and industry, and derived from a study of the Japanese literature combined with visits to the primary relevant industrial laboratories and development agencies in Japan. Specific coverage includes an evaluation of progress in R&D for high-definition television (HDTV) displays that are evolving in Japan; high-definition standards and equipment development; Japanese intentions for the use of HDTV; economic evaluation of Japan's public policy initiatives in support of high-definition systems; management analysis of Japan's strategy of leverage with respect to high-definition products and systems.

  12. 21 CFR 186.1555 - Japan wax.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Japan wax. 186.1555 Section 186.1555 Food and Drugs... Substances Affirmed as GRAS § 186.1555 Japan wax. (a) Japan wax (CAS Reg. No. 8001-39-6), also known as Japan... fruits of the oriental sumac, Rhus succedanea (Japan, Taiwan, and Indo-China), R. vernicifera...

  13. Contraception in Japan.

    PubMed

    Marsumoto, S

    1969-01-01

    In a 1967 survey 72 percent of informants were either practicing contraception or had done so in the past. As the sale of oral contraceptives and IUDs is illegal in Japan other methods were used, mostly condoms or the safe period. However, studies relating to oral contraceptives and IUDs have been authorized. A committee established in 1960 gave the opinion in 1964 that oral contraceptives were effective and not seriously harmful. A doctor's prescription and supervision were recommended. In 1966 the Endocrine Committee of the Japanese Society of Obstetrics and Gynecology reported results among 1513 women treated in hospital clinics with oral contraceptives. Side-effects were found in 10 percent during 15,778 cycles. Among 859 women who discontinued medication after 12 cycles or more, menstruation took longer than 34 days to appear in 50 percent but became regular later. Among 3037 women pregnancy rate was .4 percent per 100 women years on combined therapy and .68 percent on sequential therapy. Although the Ota ring had been used for 30 years, its sale was prohibited in 1936 because of possible harmful effects. Insertion of an IUD is lawful only when done by a docter for the purpose of scientific study. However in 1967 IUDs were used by 6.1 percent of all contraceptors. They have been inserted by about 80 percent of gynecologists. Expulsions have been more frequent with Lippes loop B than with the Ota ring, the same for the ring and the C loop. Perforation of the uterus has been reported in 15 cases (presumably due to faulty insertion), ectopic pregnancy in 38 cases, and cases of cervical pregnancy, placenta praevia, and placenta accreta have been reported with conception while retaining an IUD. Fertility after removal is well-maintained and ovarian function of long-term IUD users is normal. Endometrial histology showed only local pressure effects from an IUD and of 1058 women with an IUD in place vaginal smears were similar to controls. Of 10 cervical carcinomas none was considered to have started in the area of contact with an Ota ring and a single case of carcinoma of the body of the uterus was thought to have been present before IUD insertion. Abortion has been used as a major form of birth control. Reported induced abortions reached a maximum in 1955 with 1,170,000; in 1966, 808,000. Reported numbers do not reflect the true incidence; in recent years 1.4 million abortions are believed to have been performed. In 1964 an induced abortion was performed for every 2 registered birth. A 1967 survey showed that 12.2 percent of wives who did not use contraceptives had resorted to induced abortion, while wives with current or past experience with contraception had abortion rates of 40.9 percent and 44.1 percent respectively. Serious complications from induced abortion have been uncommon in Japan. PMID:12331996

  14. Mt. Fuji, Japan

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] Click on image to view the movie

    The nearly perfectly conical profile of Fuji soars 3,776 meters (12,388 feet) above sea level on southern Honshu, near Tokyo. The highest mountain in Japan, Fuji is the country's most familiar symbol. The summit of this graceful, dormant volcano is broken by a crater 610 meters (2,000 feet) in diameter. The crater is ringed by eight jagged peaks. The five Fuji Lakes lie on the northern slopes of the mountain, all formed in the wake of lava flows. Mirrored in the still waters of Kawaguchi-ko, the most beautiful of the five lakes, is a reflection of Fuji. Part of Fuji-Hakone-Izu National Park, Fuji last erupted for a two-month period starting in November 1707, covering Tokyo, some 100 kilometers (60 miles) away, with a layer of ash. According to legend, Fuji arose from the plain during a single night in 286 BC. Geologically, the mountain is much older than this.

    Considered sacred by many, Fuji is surrounded by temples and shrines. Thousands of pilgrims climb the mountain each year as part of their religious practice, hoping to reach the summit by dawn to watch the sunrise. This animated fly-by was created by draping visible and near infrared image data over a digital topography model, created from ASTER's stereo bands. The spatial resolution of both the image and topography is 15 m. The image is centered at 35.3 degrees north latitude, 138.7 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. Quo Vadis, Japan. [Status of Japan's Nuclear Power Program

    SciTech Connect

    Not Available

    1993-08-01

    A pile of plutonium - 1.4 tonnes in all - was on board Japanese nuclear transport ship Akatsuki Maru when it left France on November 8, 1992 for Japan. Alongside it were Greenpeace's hostile and ever-vigilant boats and the great swells of public protest from around the world. Transports like this are likely to follow. But more to the tune of 30 to 40 tonnes of plutonium cargo is expected from the Japanese spent fuel that is separated at European reprocessing plants. Both Japanese utilities and governmental agencies have agreed that plutonium is to be fabricated into mixed oxide fuel (MOX) before being returned to Japan. But in the meantime, critics are accusing Japan of being one of the greatest threats to international safety. After the Akatsuki Maru spectacle, the Japanese civil nuclear program is awash in criticism and can not escape the watchful eye of the international community. Now, with Japan's parliamentary elections over and a review of its nuclear program just around the corner, the question is: Quo vadis, Japan

  16. Plate tectonics and crustal deformation around the Japanese Islands

    NASA Technical Reports Server (NTRS)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  17. Ainu as a Heritage Language of Japan: History, Current State and Future of Ainu Language Policy and Education

    ERIC Educational Resources Information Center

    Teeter, Jennifer Louise; Okazaki, Takayuki

    2011-01-01

    Ainu is the heritage language of the indigenous people of present-day southern Sakhalin, the Kurile Islands, present-day Hokkaido, and northeastern Honshu (mainland Japan). The UNESCO Interactive Atlas of the World's Languages in Danger (2009) considered the Ainu language critically endangered with only 15 speakers remaining. This article

  18. Ainu as a Heritage Language of Japan: History, Current State and Future of Ainu Language Policy and Education

    ERIC Educational Resources Information Center

    Teeter, Jennifer Louise; Okazaki, Takayuki

    2011-01-01

    Ainu is the heritage language of the indigenous people of present-day southern Sakhalin, the Kurile Islands, present-day Hokkaido, and northeastern Honshu (mainland Japan). The UNESCO Interactive Atlas of the World's Languages in Danger (2009) considered the Ainu language critically endangered with only 15 speakers remaining. This article…

  19. Japan lagging in reproductive rights.

    PubMed

    1994-12-01

    Japan is one of only 11 of the world's countries that have not authorized the oral contraceptive pill for contraceptive purposes, noted Margaret Catley-Carlson, president, Population Council. Catley-Carlson made her comments on the low-dose pill at a special lecture meeting in Tokyo on October 14 where she served as guest speaker. The meeting was organized by the Japan Family Planning Association (JFPA) in cooperation with the Family Planning Federation of Japan (FPFJ), and JOICFP. It was attended by medical experts, parliamentarians, representatives of non-governmental organizations (NGOs) and the media. During her lecture, Catley-Carlson noted the emphasis on women's empowerment and reproductive health and rights for women made in the World Population Program of Action adopted at the recent International Conference on Population and Development (ICPD) in Cairo. She emphasized that NGOs have an important role to play in realizing the goals of the program of action. Widening the choice of contraceptives, an important reproductive health issue, is the responsibility of the service providers including NGOs, she added. Noting the relatively high rate of induced abortion in Japan, Catley-Carlson commented that the lack of access to the low-dose pill is not desirable from the perspective of reproductive health and rights. She called for widening the choice of contraceptives in Japan to include the low-dose pill and a wider selection of IUDs to promote reproductive health. PMID:12288242

  20. Ober's Island, One of the Review Islands on Rainy Lake, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Ober's Island, One of the Review Islands on Rainy Lake, bounded on the south by The Hawk Island and on the north by The Crow Island. These islands are located seven miles east of Ranier, Minnesota, three miles west of Voyageur National Park, and one mile south of the international border of the United States of America and Canada. The legal description of Mallard Island is Lot 6, Section 19, T-17-N, R-22-W, Koochiching County, Minnesota, Ranier, Koochiching County, MN

  1. Back-arc Mantle Evolution inferred from Peridotite Xenotlishs from the Japan Sea

    NASA Astrophysics Data System (ADS)

    Morishita, T.; Ichiyama, Y.; Tamura, A.; Arai, S.

    2014-12-01

    Peridotite xenoliths are recovered in basaltic to andesitic lavas from several localities in the Japan Sea, a Miocene back-arc basin of the Western Pacific region. These peridotites are classified into two groups: two-pyroxene peridotitess and dunite-wehrlite groups. Although slight chemical modifications are observed in these peridotite samples, two-pyroxene peridotite group has retained their original residual mantle geochemical signatures left after partial melting. The dunite-wehrlite group is, on the other hand, probably formed by extensive interaction of the two-pyroxene peridotite group. We examined trace element characteristics of clinopyroxene in these xenoliths. Light REE-depleted clinopyroxenes that are usually interpreted as a simple residual mantle after anhydrous partial melting are similar to those of abyssal peridotite recovered from mid-ocean ridges and back-arc basins. Other samples show LREE-enriched patterns that are residues after influx melting caused by hydrous melt/supercritical fluids released from the subducted slab at high pressure conditions. The geotectonic and geochemical variations of the peridotite xenoliths from the Japan Sea (Shirabeshi Seamount, Seifu Seamount and Oshima-Oshima Island) suggest that the mantle beneath the Japan Sea are suffered from hydrous to anhydrous melting as the Japan Sea forms. This is consistent with the geochemical and isotopic results from Miocene basaltic rocks formed during opening of the Japan Sea (Sato et al., Jour. Petrol., 2013). The Japan Sea peridotite xenoliths also shed lights on the origin of ophiolites.

  2. FBIS report. Science and technology: Japan, April 10, 1996

    SciTech Connect

    1996-04-10

    ;Partial Contents: Biotechnology (Japan: Japan`s RITE Introduces Biotech Projects, Japan: Pharmacia Biotech Develops Detection Method for Point Mutation); Energy (Japan: New Catalyst for Synthesis Gas Reduces Energy Needs, Japan: Major Company Activities for Promotion of Wind Power Generation, Japan: Waste Power Generation System in Saitama Draws Much Attention); Environment (Japan: AIST`s NIMC To Develop Efficient Decomposition Method for Waste Using Super-Critial Water, Japan: Kyoei Co. Develops High Temperature Fusion Furnace for Industrial Waste Treatment, Japan: Air Dry Cleaning for Recycling Chemically Contaminated Plastic Sheets); Microelectronics (Japan: Toshiba Corp. DEC To jointly Develop LSI for ATM); Science and Technology Policy (Japan`s MITI To Begin Electronic Commerce Experiment Project); Technology Transfer (Japan: Nissho Iwai Delivers Cleaner Plant to Russia`s Energiya, Japan: Energy Agency Transfers Coal Fired Power Generation Technology to Indonesia); Telecommunications (Japan`s MPT Releases Study Report on Advanced Information Technologies).

  3. Hydrologic data for Block Island, Rhode Island

    USGS Publications Warehouse

    Burns, Emily

    1993-01-01

    This report was compiled as part of a study to assess the hydrogeology and the quality and quantity of fresh ground water on Block Island, Rhode Island. Hydrologic data were collected on Block Island during 1988-91. The data are pre- sented in illustrations and tables. Data collec- ted include precipitation, surfae-water, ground- water, lithologic, and well-construction and dis- charge information. Precipitation data include total monthly precipitation values from 11 rain gages and water-quality analyses of 14 precipi- tation samples from one station. Surface-water data include water-level measurements at 12 ponds, water-quality data for five ponds, and field specific-conductance measurements at 56 surface- water sites (streams, ponds, and springs). Ground- water data include water-level measurements at 159 wells, water-quality data at 150 wells, and field specific-conductance data at 52 wells. Lithologic logs for 375 wells and test borings, and construc- tion and location data for 570 wells, springs, and test borings are included. In addition, the data set contains data on water quality of water samples, collected by the Rhode Island Department of Health during 1976-91, from Fresh and Sands Ponds and from wells at the Block Island Water Company well field north of Sands Pond.

  4. Levels and distribution of polybrominated diphenyl ethers and organochlorine compounds in sea turtles from Japan.

    PubMed

    Malarvannan, Govindan; Takahashi, Shin; Isobe, Tomohiko; Kunisue, Tatsuya; Sudaryanto, Agus; Miyagi, Toshihiko; Nakamura, Masaru; Yasumura, Shigeki; Tanabe, Shinsuke

    2011-01-01

    Three species of sea turtles (green, hawksbill and loggerhead turtles) stranded along the coasts or caught (by-catch) around Ishigaki Island and Kochi, Japan were collected between 1998 and 2006 and analyzed for six organohalogen compounds viz., PBDEs, PCBs, DDTs, CHLs, HCHs and HCB. The present study is the first and foremost to report the occurrence of organohalogen compounds in the sea turtles from Japan. Among the compounds analyzed, concentrations of PCBs, DDTs and CHLs were the highest in all the turtle samples. PBDEs were ubiquitously present in all the turtle species. Comparing with the other two species, concentrations of organohalogens in green turtle were relatively low and decreasing trend in the concentrations were noted with increasing carapace length. Concentrations of OCs in sea turtles from the coasts of Ishigaki Island and Kochi were relatively low as compared to those from other locations in the world. PMID:21377171

  5. 10Be concentrations of Red soils in Southwest Japan and its possibility of dating

    NASA Astrophysics Data System (ADS)

    Maejima, Y.; Matsuzaki, H.; Nakano, C.

    2004-08-01

    10Be concentrations of six Red soils distributed in Southwest Japan ranged from 0.8 × 108 to 2.7 × 109 atoms g-1, and minimum absolute ages were estimated by inventory of meteoric 10Be. The results are follows: Red soils on Toyota derived from granite (⩽25 ka), Kashii derived from Tertiary shale (⩽24 ka), Akiyoshidai derived from limestone (⩽110 ka), Okinawa Island derived from Kunigami gravel bed (⩽9 ka) and Ogasawara Island derived from agglomerate and Boninite (⩽22 and ⩽7 ka) were obtained, respectively. Soil age except with Akiyoshidai indicated younger age. It suggested that the loss of 10Be from the soil was caused by leaching of 10Be or by soil erosion, and 10Be is susceptible to leaching out from these Red soils under the humid climate condition such as Southwest Japan.

  6. Exceedances of air quality standard level of PM2.5 in Japan caused by Siberian wildfires

    NASA Astrophysics Data System (ADS)

    Ikeda, Kohei; Tanimoto, Hiroshi

    2015-10-01

    We revisited long-term observations of PM2.5 at ground-based stations in Japan during 2001-2012 to examine possible impacts of Siberian wildfires on regional air quality. Exceedances of Japans air quality standard for daily mean concentration (35 ?g m-3) were observed several times at Rishiri Island in northern Japan in the spring of 2003 and 2008 when intense wildfires occurred in Siberia. Satellite observations showed that aerosols and CO originating from biomass burning were transported from Siberia toward Japan. The regional chemical transport model also demonstrated that the PM2.5 enhancements during high PM2.5 days (>35 ?g m-3) were attributed to Siberian wildfires, suggesting that the contribution from Siberian biomass burning had a critical impact on exceedances of air quality standard level. The monthly (May) and annual mean PM2.5 concentrations in 2003 were about twice and 20% higher, respectively, than those of the long-term average at Rishiri Island, where the influence of Siberian wildfires was the largest in Japan. Except for 2003 and 2008, a high PM2.5 day due to Siberian wildfires was not identified. Although Siberian biomass burning does not affect the air quality standard of PM2.5 for the years without strong fires, it causes exceedance of the air quality standard level when intense fires occur.

  7. Stewart Head from Folly Island

    USGS Multimedia Gallery

    Stewart Head, as seen from Folly Island. Folly Island, a preserve owned by the Maine Coast Heritage Trust, is about 7 acres. It is located in Bartlett Narrows, along the western coast of Mount Desert Island. ...

  8. The educational system in Japan

    NASA Technical Reports Server (NTRS)

    Spearman, M. L.

    1986-01-01

    The rapid economic growth of Japan since World War II has resulted in Japan becoming a reference point for developing nations and the West. This remarkable growth results from a combination of factors, one of which has been unyielding attention to education in order to cultivate the human talent necessary to provide the productivity for economic growth. The Japanese education system emphasizes quality of instruction and rewards hard work. Some of the principles of the system are outlined together with a summary of the content of the curriculum, the quantity and quality of instruction, and the influence of culture and environment.

  9. Japan starts two more reactors

    SciTech Connect

    Not Available

    1993-01-01

    Hokuriku Electric Power Company's first operating reactor, Shika 1, reached initial criticality on November 20. Construction on the 513-MWe BWR began in 1987, when the plant originally was called the Noto reactor. The name was changed in December 1988 to Shika, a name more familiar to local residents. The unit is Japan's 44th operating reactor and is scheduled to begin commercial operation in July 1993. Japan's 45th reactor reached initial criticality on December 2. Chubu Electric Power Company's Hamaoka 4, a 1,045-MWe BWR, is scheduled for pre-trial operation in February 1993, and full commercial operation in September.

  10. Island Natural Science School.

    ERIC Educational Resources Information Center

    Toronto Board of Education (Ontario).

    Prepared for students in grade six attending the Island Natural Science School, Toronto, Ontario, Canada, this booklet offers information and suggests activities in the areas of ecology, conservation, natural resources, and outdoor recreation. Introductory material describes island lore, its formation and significant features, followed by units of

  11. Barnacles on Folly Island

    USGS Multimedia Gallery

    Barnacles on a rock on Folly Island. Barnacles are crustaceans, related to lobsters and crabs, that often live in tidal zones. Once they become adults, they anchor themselves to a hard surface and filter feed. Folly Island, a preserve owned by the Maine Coast Heritage Trust, is about 7 acres. It is ...

  12. Islands in a Storm.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1995-01-01

    Smith Island in the Chesapeake Bay is actually a group of three islands: Ewell, Rhodes Point, and Tylerton. Dwindling enrollment jeopardizes the community's two schools that contain grades one through seven. The school board believes they can give the sixth and seventh graders at Ewell and Tylerton a better education on the mainland. (MLF)

  13. Basaltic island sand provenance

    SciTech Connect

    Marsaglia, K.M. . Dept. of Geological Sciences)

    1992-01-01

    The Hawaiian Islands are an ideal location to study basaltic sand provenance in that they are a series of progressively older basaltic shield volcanoes with arid to humid microclimates. Sixty-two sand samples were collected from beaches on the islands of Hawaii, Maui, Oahu and Kauai and petrographically analyzed. The major sand components are calcareous bioclasts, volcanic lithic fragments, and monomineralic grains of dense minerals and plagioclase. Proportions of these components vary from island to island, with bioclastic end members being more prevalent on older islands exhibiting well-developed fringing reef systems and volcanic end members more prevalent on younger, volcanically active islands. Climatic variations across the island of Hawaii are reflected in the percentage of weathered detritus, which is greater on the wetter, northern side of the island. The groundmass of glassy, basaltic lithics is predominantly black tachylite, with lesser brown sideromelane; microlitic and lathwork textures are more common than holohyaline vitric textures. Other common basaltic volcanic lithic fragments are holocrystalline aggregates of silt-sized pyroxene or olivine, opaque minerals and plagioclase. Sands derived from alkalic lavas are texturally and compositionally indistinguishable from sands derived from tholeiitic lavas. Although Hawaiian basaltic sands overlap in composition with magmatic arc-derived sands in terms of their relative QFL, QmPK and LmLvLs percentages, they are dissimilar in that they lack felsic components and are more enriched in lathwork volcanic lithic fragments, holocrystalline volcanic lithic fragments, and dense minerals.

  14. Channel Islands rare plants

    USGS Publications Warehouse

    McEachern, K.

    1999-01-01

    Database contains information on 65 rare plant taxa on six islands from archive searches and field surveys, including population location, size and extent 1920-1999, population and habitat conditions, census data, phenological information, associated species. USGS-BRD, Channel Islands Field Station, Ventura, CA.

  15. Back to Treasure Island

    ERIC Educational Resources Information Center

    Shriki, Atara

    2011-01-01

    In this article, the author presents the Treasure Island problem and some inquiry activities derived from the problem. Trying to find where pirates buried a treasure leads to a surprising answer, multiple solutions, and a discussion of problem solving. The Treasure Island problem is an example of an inquiry activity that can be implemented in

  16. Rhode Island Seafloor

    USGS Multimedia Gallery

    This photograph is of the seafloor on the Rhode Island coast and shows a skate on a fine-grained, likely silty or muddy seafloor. This photograph was collected to support research and management activities (e.g., wind farms and fisheries) along the Rhode Island inner continental shelf....

  17. Marine and Island Ecology.

    ERIC Educational Resources Information Center

    Stephens, Lawrence J.; And Others

    1988-01-01

    Describes an ecology course which provides students with an opportunity to observe aquatic and terrestrial life in the Bahamas. States that students learn scientific methodology by measuring physical and chemical aspects of the island habitats. Provides information on the island, course description and objectives, transportation, facilities, and

  18. Eocene Paleolatitude of the Kitakami Massif in Northeastern Japan

    NASA Astrophysics Data System (ADS)

    Hoshi, H.; Hayakawa, K.

    2011-12-01

    The geologic basement of the Japan Arc consists primarily of rocks formed by subduction-related processes. Mesozoic to Cenozoic accretionary complexes are the vast majority of the subduction-related products, but there are also many fragments of ancient continents or volcanic islands or seamounts of different sizes, characterized by lithologies and geologic histories distinct from surrounding rocks. The South Kitakami Massif in northeastern Japan is typical of those allochthonous units. Early paleomagnetic studies demonstrated that the sedimentary rocks of the South Kitakami Massif have completely been remagnetized by intrusion of Cretaceous plutons. Recently, shallow paleomagnetic inclinations were reported from early Cretaceous and early Paleogene volcanic rocks of the Northern Kitakami Massif, leading to an interpretation that the whole Kitakami Massif was located at low latitude in the Cretaceous to early Paleogene. Here we present new paleomagnetic results from the Northern Kitakami Massif. Dacite dikes of Eocene age (ca. 44 Ma) and baked country rocks were sampled at 16 sites. The dikes possess vertical or subvertical intrusion surfaces, suggesting little or no significant tectonic tilt. We obtained for the first time an Eocene reliable paleomagnetic direction for the Kitakami massif; a positive baked contact test proves the primary nature of remanence. A suggestion that pre-Miocene rocks of northeastern Japan have completely been remagnetized can be eliminated. The mean direction is characterized by a westerly declination, indicating large counterclockwise rotation. Miocene rotational motion of the northeastern Japan Arc associated with backarc opening can account for this westerly direction. The mean inclination is statistically indistinguishable from that expected at the present latitude of the studied area, indicating little or no significant latitudinal motion. This finding provides a constraint on the suspected northward motion; the Kitakami Massif has not suffered latitudinal motion since at least Eocene time.

  19. Superconducting magnet development in Japan

    SciTech Connect

    Yasukochi, K.

    1983-05-01

    The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb/sub 3/Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting ..mu.. meson channel and ..pi.. meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration.

  20. Aerial Measuring System in Japan

    SciTech Connect

    Lyons, C., Colton, D. P.

    2012-05-01

    The U.S. Department of Energy National Nuclear Security Agencys Aerial Measuring System deployed personnel and equipment to partner with the U.S. Air Force in Japan to conduct multiple aerial radiological surveys. These were the first and most comprehensive sources of actionable information for U.S. interests in Japan and provided early confirmation to the government of Japan as to the extent of the release from the Fukushima Daiichi Nuclear Power Generation Station. Many challenges were overcome quickly during the first 48 hours; including installation and operation of Aerial Measuring System equipment on multiple U.S. Air Force Japan aircraft, flying over difficult terrain, and flying with talented pilots who were unfamiliar with the Aerial Measuring System flight patterns. These all combined to make for a dynamic and non-textbook situation. In addition, the data challenges of the multiple and on-going releases, and integration with the Japanese government to provide valid aerial radiological survey products that both military and civilian customers could use to make informed decisions, was extremely complicated. The Aerial Measuring System Fukushima response provided insight in addressing these challenges and gave way to an opportunity for the expansion of the Aerial Measuring Systems mission beyond the borders of the US.

  1. Japan's Eco-School Programme

    ERIC Educational Resources Information Center

    Mori, Masayuki

    2007-01-01

    Since 1997, several ministries in Japan have collaborated on an eco-school programme, which applies to both newly constructed and renovated school buildings, in an effort to make its schools more environmentally friendly. The programme equips school buildings with ecological features such as photovoltaic cells, solar thermal collectors, other new

  2. Direct Broadcasting Satellites in Japan.

    ERIC Educational Resources Information Center

    Maeda, Jiro

    The development and use of broadcasting satellites in Japan are discussed in this paper. The paper describes the medium-scale experimental broadcasting satellite, YURI, launched by NASA in 1978, and reports that experiments with YURI in the areas of basic technologies in the broadcasting satellite system, experiments on satellite control…

  3. The Japan of Today, 1982.

    ERIC Educational Resources Information Center

    Ministry of Foreign Affairs, Tokyo (Japan).

    Following an introduction which discusses the history and geography of Japan, this book focuses on topics related to this country's government, economy, social conditions, and cultural life. Topics related to government include: constitution and emperor; legislature; executive power; judiciary system; foreign relations; and defense. Topics related

  4. Japan Studies Association Journal, 2001.

    ERIC Educational Resources Information Center

    Reichel, Philip L., Ed.

    2001-01-01

    This journal presents new perspectives and materials on Japan that are engaging, relatively jargon-free, and shaped so that their usefulness in a college classroom is readily apparent. The journal represents an example of the potential for genuine scholarship that lies within interdisciplinary studies. Articles grouped under the topic of "Minority

  5. Japan and America: Culture Counts.

    ERIC Educational Resources Information Center

    Cooney, Barry D.

    1989-01-01

    Cultural distinctions in the approach to social relationships, access to information, personal motivation, and hierarchy make Japan an effective economic power. U.S. business can learn from the Japanese ways to create more information-based organizations, think in global terms, foster links between business and education, and develop internal

  6. Teaching and Learning in Japan.

    ERIC Educational Resources Information Center

    Rohlen, Thomas P., Ed.; LeTendre, Gerald K., Ed.

    The essays gathered in this volume are united by the common goal of understanding teaching and learning in Japan as it actually occurs. The essays seek to answer questions about the actual conduct of learning in different settings and at different points in the life cycle. This volume explores the expectations and associations found in specific…

  7. Teaching and Learning in Japan.

    ERIC Educational Resources Information Center

    Rohlen, Thomas P., Ed.; LeTendre, Gerald K., Ed.

    The essays gathered in this volume are united by the common goal of understanding teaching and learning in Japan as it actually occurs. The essays seek to answer questions about the actual conduct of learning in different settings and at different points in the life cycle. This volume explores the expectations and associations found in specific

  8. Direct Broadcasting Satellites in Japan.

    ERIC Educational Resources Information Center

    Maeda, Jiro

    The development and use of broadcasting satellites in Japan are discussed in this paper. The paper describes the medium-scale experimental broadcasting satellite, YURI, launched by NASA in 1978, and reports that experiments with YURI in the areas of basic technologies in the broadcasting satellite system, experiments on satellite control

  9. Japan Studies Association Journal, 1998.

    ERIC Educational Resources Information Center

    Speaker, Richard B., Jr., Ed.; Kawada, Louise Myers, Ed.

    1998-01-01

    This journal presents new perspectives and materials on Japan that are engaging, relatively jargon-free, and shaped so that their usefulness in a college classroom is readily apparent. The journal represents an example of the potential for genuine scholarship that lies within interdisciplinary studies. Articles are divided among three thematic…

  10. Innovative shotcreting system in Japan

    SciTech Connect

    Okada, Takashi

    1995-12-31

    Robotization of shotcreting has advanced remarkably in Japan in a short span of time for the purpose of avoiding exposure of human workers to adverse conditions. This paper provides an overview of various devices used in shotcreting and discusses the development of improved systems which ensure higher safety and larger productivity.

  11. Japan's Eco-School Programme

    ERIC Educational Resources Information Center

    Mori, Masayuki

    2007-01-01

    Since 1997, several ministries in Japan have collaborated on an eco-school programme, which applies to both newly constructed and renovated school buildings, in an effort to make its schools more environmentally friendly. The programme equips school buildings with ecological features such as photovoltaic cells, solar thermal collectors, other new…

  12. Teaching about Japan: Lessons and Resources.

    ERIC Educational Resources Information Center

    Bernson, Mary Hammond, Ed.; Wojtan, Linda S., Ed.

    This document is a revised and updated version of two publications: "Modern Japan: An Idea Book for K-12 Teachers" and "Resources for Teaching About Japan." These lesson plans were developed by teachers who participated in a summer institute on Japan, sponsored by the East Asia Resource Center at the Jackson School of International Studies,

  13. 75 FR 38119 - Polychloroprene Rubber From Japan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... from Japan (38 FR 33593). Following five-year reviews by the Department of Commerce (``Commerce'') and... imports of polychloroprene rubber from Japan (64 FR 47765, September 1, 1999). Following second five-year... antidumping duty finding on imports of polychloroprene rubber from Japan (70 FR 44893). The Commission is...

  14. AGU Expresses Condolences to People of Japan

    NASA Astrophysics Data System (ADS)

    McPhaden, Michael J.; McEntee, Christine W.

    2011-03-01

    AGU president Mike McPhaden and executive director/chief executive officer Chris McEntee sent the following letter to Gaku Kimura, president of the Japan Geoscience Union, conveying sympathy and condolences to the people of Japan following the devastating earthquake and tsunami that hit Japan on 11 March.

  15. Economics in Japan: A Curriculum Project.

    ERIC Educational Resources Information Center

    Lindfors, Burton R.

    Intended for use with students in grades 9-12, this collection of materials dealing with economics in Japan is based on and prepared from experiences and information gathered by a U.S.-Japan study trip. Materials focus on: (1) underlying values important to contemporary Japanese society, (2) Japan's rise from an "occupied country" (1945-1951) to

  16. Japan Resource Catalogue: A Guide for New England Educators.

    ERIC Educational Resources Information Center

    Barsh, Adele L., Ed.

    This catalog of instructional resources for teaching about Japan provides annotated entries under three main headings: Japan Resources (resources that are specific to Japan); General Resources (materials that are Japan-related but not Japan-specific); and Organizations. Japan Resources, which includes the major portion of the materials, lists 110

  17. Ober's Island: The Mallard Ober's Island, One of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Ober's Island: The Mallard - Ober's Island, One of the Review Islands on Rainy Lake, bounded on the south by The Hawk Island and on the north by The Crow Island. These islands are located seven miles east of Ranier, Minnesota, three miles west of Voyageur National Park, and one mile south of the international border of the United States of America and Canada. The legal description of Mallard Island is Lot 6, Section 19, T-17-N, R-22-W, Koochiching County, Minnesota, Ranier, Koochiching County, MN

  18. Japan`s refiner/marketers headed for major shakeout

    SciTech Connect

    1996-08-26

    Japan`s downstream oil industry is in a state of crisis and headed for a major shakeout. The major catalyst for this was a dramatic deregulation step during April 1996 that allowed refined petroleum product imports by non-refiners. The move, together with a sharp drop in refining margins, falling retail gasoline prices, and a service station sector on the brink of collapse, are all leading to massive changes in the way the country`s refiners and marketers do business. This paper reviews the collapse of corporate profits during this period of deregulation; the development of a new price system geared toward bringing the prices of gasoline, fuel oil, and kerosene into line with each other to offset the fall in gasoline prices; and industry restructuring including mergers, acquisitions, and marketing consolidation. The paper then makes predictions on the outcome of these changes on the Japanese oil industry.

  19. Threatened Pollination Systems in Native Flora of the Ogasawara (Bonin) Islands

    PubMed Central

    ABE, TETSUTO

    2006-01-01

    Background and Aims Various alien species have been introduced to the Ogasawara Islands (Japan). A survey was made investigating whether the native pollination systems fit an island syndrome (biasing the flora to dioecy, with subdued, inconspicuous flowers) and whether alien species have disrupted the native pollination network. Methods Flower visitors and floral traits were determined in the field (12 islands) and from the literature. Associations among floral traits such as sexual expression, flower colour and flower shape were tested. Key Results Among the 269 native flowering plants, 747?% are hermaphroditic, 130?% are dioecious and 71?% are monoecious. Classification by flower colour revealed that 360?% were white, 216?% green and 138?% yellow. Woody species (trees and shrubs) comprised 365?% of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 667?% of the observed species on satellite islands where the native pollination networks are preserved. In contrast to the situation on the satellite islands, introduced honeybees were the most dominant pollinator (visiting 601?% of observed species) on the two main islands, Chichi-jima and Haha-jima, and had spread to satellite islands near Chichi-jima Island. Conclusions The island syndrome for pollination systems in the Ogasawara Islands was evident in a high percentage of dioecious species, the subdued colour of the native flora and solitary flower visitors on satellite islands. The shape and colour adaptations of several flowers suggested native pollination niches for long-proboscis moths and carpenter bees. However, the domination and expansion of introduced honeybees have the potential for disruption of the native pollination network in the two main, and several satellite, islands of the Ogasawara Islands. PMID:16790463

  20. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  1. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that

  2. Water resources in the Japanese Islands

    NASA Astrophysics Data System (ADS)

    Takagi, T.

    2005-12-01

    Due to its limited land area and limited range of natural resources (particularly fuel), Japan has developed a highly efficient economy in terms of resource utilization. This also applies to water resources. For sustainable use of water resources in the Japanese Islands, integrated and unified analyses of the data of groundwater by the nation and local governments have been needed. Land area of the Japanese Islands is 377,000 square kilometers, which is equivalent to the area of the state of Montana, but extends for 3,600 kilometers along the margin of the Eurasian continent. Mountainous areas separated by isolated, narrow plains make up 80 % of the land area. Due to the topography of Japan, rivers are generally short with steep grades, the longest being only 367 kilometers in length. Average annual precipitation is 1,600 millimeters but is highly seasonal. The annual water demand was approximately 87 billion cubic meters during the past 25 years, which represents 21 % of the total usable water. The water demand for agriculture makes up 66 % of the total water demand, and 96 % of the water for agricultural uses is used for the irrigation of rice paddies. Municipal and industrial uses make up 15.4 and 18.9 % of the demand, respectively (as of 2000). Nearly 80 % of the water used by industry in recycled. Approximately 87 % of the water demand is supplied from surface water with the rest from ground water. Because of its mountainous topography, the extent of individual aquifers is far smaller than in United States. Groundwater basins in the Japanese Islands are classified into the following six types: plain type (thick Quaternary strata); basin type (intermontane terraces and fans; hill type (highly eroded old volcanoes); volcano type (permeable lava and pyroclasitc flows comprising Quaternary strato volcanoes); pyroclastic type (thick tuff associated with large caldera formations); and limestone type (limestone blocks with karsts). Of the above types, the only major groundwater aquifers are the plain type (e.g., Kanto plain) and the volcano type (e.g., Mount Fuji). Ground water usage in 1998 was divided between 28 % domestic, 31 % industrial, and 23 % agricultural, and 18 % other. In the Japanese Islands, due to the small drainage areas of rivers, limited storage volume of aquifers, and variable seasonal and annual precipitation, droughts are common in some regions. Excessive pumping of groundwater in the 1950s to 1970s caused local land subsidence and salt water intrusion.

  3. Deformation of erosive and accretive forearcs during subduction of migrating and non-migrating aseismic ridges: Results from 3-D finite element models and application to the Central American, Peruvian, and Ryukyu margins

    NASA Astrophysics Data System (ADS)

    Zeumann, Stefanie; Hampel, Andrea

    2015-09-01

    Subduction of aseismic oceanic ridges causes considerable uplift and deformation of the upper plate and may lead, for example, to the indentation of the forearc, the formation of marine terraces, or distinct fault patterns in the upper plate. Depending on the orientation of the ridge relative to the plate convergence direction, the ridge may either be stationary or migrate along the margin. Here we use three-dimensional numerical models to investigate the tectonic evolution of forearcs affected by ridge subduction. In different experiments, we distinguish between migrating/non-migrating ridges and accretive/erosive margins, respectively. Our results reveal that displacement and strain fields above migrating and non-migrating ridges are asymmetric with respect to the ridge axis unless both ridge and plate convergence direction are perpendicular to the trench. As the asymmetric deformation pattern shifts along the margin through time, uplift caused by the underthrusting ridge is followed by subsidence when the ridge crest passed by, and regions initially experiencing shortening may subsequently undergo extension and vice versa. If the forearc comprises an accretionary prism, the ridge-induced reentrant is larger than those in models with erosive forearcs and strain localizes in the frontal part of the wedge. Additional models with a setup adjusted to the Cocos and Gagua Ridges provide constraints on the onset of their subduction at the Central American and Ryukyu margins at ~2 Ma and 1 Ma, respectively. Displacement and strain fields from a model for the Nazca Ridge collision zone show good agreement with geological data from marine terraces and Quaternary faulting.

  4. DUPAL anomaly in the Sea of Japan: Pb, Nd, and Sr isotopic variations at the eastern Eurasian continental margin

    USGS Publications Warehouse

    Tatsumoto, M.; Nakamura, Y.

    1991-01-01

    Volcanic rocks from the eastern Eurasian plate margin (southwestern Japan, the Sea of Japan, and northeastern China) show enriched (EMI) component signatures. Volcanic rocks from the Ulreung and Dog Islands in the Sea of Japan show typical DUPAL anomaly characteristics with extremely high ??208/204 Pb (up to 143) and enriched Nd and Sr isotopic compositions (??{lunate}Nd = -3 to -5, 87Sr 86Sr = ~0.705). The ??208/204 Pb values are similar to those associated with the DUPAL anomaly (up to 140) in the southern hemisphere. Because the EMI characteristics of basalts from the Sea of Japan are more extreme than those of southwestern Japan and inland China basalts, we propose that old mantle lithosphere was metasomatized early (prior to the Proterozoic) with subduction-related fluids (not present subduction system) so that it has been slightly enriched in incompatible elements and has had a high Th/U for a long time. The results of this study support the idea that the old subcontinental mantle lithosphere is the source for EMI of oceanic basalts, and that EMI does not need to be stored at the core/ mantle boundary layer for a long time. Dredged samples from seamounts and knolls from the Yamato Basin Ridge in the Sea of Japan show similar isotopic characteristics to basalts from the Mariana arc, supporting the idea that the Yamato Basin Ridge is a spreading center causing separation of the northeast Japan Arc from Eurasia. ?? 1991.

  5. Seismic-induced water waves by the March 2011 Japan earthquake

    NASA Astrophysics Data System (ADS)

    Lin, L.; Liang, W.; Liang, M.; Huang, N.

    2011-12-01

    On March 11, 2011, the Mw 9.0 Tohoku earthquake caused unusual water waves in many harbors. After about 10 minutes, significant changes in sea level were observed in the coastal regions of Taiwan. The event also induced seismic surface waves of ~7 cm displacement. The effects of earthquake on water bodies were examined in Taiwan, Japan and Russia. Results show the effect is more amplified at the islands than in the continental area. Other dominant features from this analysis are the roughly 20-40 cm amplitude, period of 2-5 minutes oscillations and ~20 cm amplitude of tsunami waves at the Orchid island of Taiwan. The superposition of two waves estimates the amplitude of roughly 40 cm at the island but has two different source mechanisms. Therefore, the real tsunami is overestimate and the arrival time for tsunami wave groups need to be adjusted. This study will focus on the forced waves caused by the passing of seismic waves.

  6. Harmonizing national with international standards in Japan

    SciTech Connect

    Hohki, Keiichi; Hammons, T.J.

    1996-05-01

    This paper presents a Japanese engineer`s view on harmonization of global standards as the key factor in maintaining and promoting free trade. Japan is endowed with almost no natural resources, and, for this reason, Japan must rely on international trade to sustain its standard of living. Japan fully recognizes that the maintenance and promotion of mutually beneficial free trade is indispensable for cooperation in an international society, and is essential for Japan`s survival. It is very clear that the promotion of the international harmonization of standards is the key factor in the maintenance and promotion of free trade. And Japan is one of the countries most eagerly hoping for its realization. The authors focus on three issues concerning the international harmonization of Japanese standards: (1) Efforts Japan has made for the harmonization of Japanese standards with international ones; (2) natural or tectonic circumstances unique to Japanese standards; and (3) relationship between standard harmonization and international trade.

  7. Small islands adrift

    NASA Astrophysics Data System (ADS)

    Petherick, Anna

    2015-07-01

    With the charismatic former president of the Maldives, Mohamed Nasheed, behind bars on a widely derided terrorism charge, Anna Petherick asks whether small island states can really make themselves heard in Paris.

  8. Christmas Island birds returning

    NASA Astrophysics Data System (ADS)

    Six months after their mass exodus, birds are beginning to return to Christmas Island. Roughly 17 million birds, almost the entire adult bird population, either perished or fled their mid-Pacific atoll home last autumn, leaving behind thousands of nestlings to starve (Eos, April 5, 1983, p. 131). It is believed that the strong El Nio altered the ecology of the surrounding waters and forced the birds to flee. Christmas Island is the world's largest coral atoll.Ocean and atmosphere scientists are unsure of future directions for the El Nio conditions and cannot now predict what will happen to the birds in the coming months, said Ralph W. Schreiber, curator of ornithology at the Natural History Museum of Los Angeles County in California. Heisthe ornithologist who discovered the disappearance. The recovery of the bird populations depends on the food supply in the waters surrounding the island. The island's birds feed exclusively on small fish and squid.

  9. Island Watershed Activity.

    ERIC Educational Resources Information Center

    Benson, Rod

    2003-01-01

    Describes a 90-minute "Island Watershed" activity to help earth science students understand the concept of the water cycle. Introduces a surface waters unit appropriate for students in grades 7-10. Includes watershed project guidelines. (Author/KHR)

  10. Belcher Islands, Canada

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Belcher Islands are an archipelago in Hudson Bay in Canada, belonging to the territory of Nunavit. The hamlet of Sanikiluaq is on the north coast of Flaherty Island. Over 1500 islands make up the archipelago. The folded sedimentary and volcanic rocks making up the islands are Proterozoic in age between 0.5 and 2.5 billion years old.

    The image mosaic was acquired 18 September 2006, covers an area of 45.7 x 113.3 km, and is located near 56.1 degrees north latitude, 79.4 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. Commencement of Geoparks, Geology day and International Earth Science Olympiad, IYPE in Japan

    NASA Astrophysics Data System (ADS)

    Tsukuda, Eikichi; Kodama, Kisaburo; Miyazaki, Teruki

    2010-05-01

    The GSJ is the main supporting organization of IYPE Japan, which is an implementation body of IYPE in Japan, serving as its secretariat. During the IYPE triennial activity, the GSJ has been supporting development of Geparks, establishment of "the Geology Day" and the Earth Science Olympiad activities with some academic societies, and has distributed geological maps with IYPE logo. The GSJ also established an outreach network "Geo-networks Tsukuba" as a local legacy of the IYPE, and has managed it with a local government, research organizations, nonprofit corporations and local media to increase geological and environmental literacy of public, especially among young people. The GSJ-AIST has also contributed internationally to IYPE by joining two international projects, OneGeology and the CCOP Book project. Geoparks in Japan are characterized by following features. The Japanese Islands and the surrounding seas are situated in the area of unique geologic features; the place where several tectonic plates meet and collide. This causes earthquakes and volcanic activities, and makes Japan one of most dynamic areas on the earth. The dynamics of the earth bring about not only geological hazards but also a lot of blessings. In August of 2009, three Geoparks, the Toya Caldera and Usu Volcano Geopark, the Itoigawa Geopark and the Unzen Volcanic Area Geopark, were accepted to join the Global Geopark Network from Japan for the first time. Since its launch in 2006, the GSJ has been playing a major role in promoting Geoparks in Japan together with Geological Society of Japan. The GSJ hosts the Japan Geopark Committee (JGC) for quality evaluation, serving as the information center of Geoparks in Japan. The Geology Day of Japan (10th of May) has been set up by the academic societies for geology in Japan and GSJ in 2007. The Geology Day is expected to provide the chances for the public to enjoy field trips and excursions and to understand the importance of geo-diversity. The Day commemorates the first publication of the geological map of Japan on 10th of May in 1878. A total of fifty-nine geology-related organizations including natural museums and academic societies have joined the eighty nine events for Geology Day all over Japan in 2009. After the great success of 1st Iinternational Earth Science Olympiad(IESO) in Korea (2007), 2nd Philippines (2008) and 3rd Taiwan (2009), 6th IESO was decided to be held in Japan (2012). We also expect great success of 4th IESO in Indonesia and 5th IESO in Italy. Earth science communities in Japan including Societies, Universities, and Research Institutes take present-day environmental crisis seriously and throw strong messages to young people for saving the earth. Under such circumstances, IESO provides wonderful chances to think of the earth, to make friendships among worldwide participants and to understand each other. We, earth science communities in Japan, promise strongly to support 6th IESO in Tsukuba, Japan (2012) and then to organize this event efficiently. Through the triennial activity of IYPE we all learned the importance of international cooperation and public outreach.

  12. Another setback for women. Japan.

    PubMed

    1996-08-01

    The Japanese government delivered a blow to women's groups by postponing legalization of low-dose oral contraceptives (OCs). Japan is unique among industrialized nations in refusing to allow its women access to OCs or to other effective methods such as the medicated IUD, or other hormone-based methods. Only nonmedicated IUDs are available to Japanese women. While the diaphragm is legal, a lack of demand for this method caused Japanese companies to stop producing it, and imported supplies are not yet available. Approximately 80% of couples rely on the male condom, which does not allow women any independent control over their fertility and which is likely to be misused. Indeed, 25.9% of married women in Japan have had an induced abortion, and, in 1995, there were 343,024 abortions and less than 1.2 million live births. Activists believe that the abortion rate would drop if the OC were available. PMID:12347291

  13. Japan's research on gaseous flames

    NASA Technical Reports Server (NTRS)

    Niioka, Takashi

    1995-01-01

    Although research studies on gaseous flames in microgravity in Japan have not been one-sided, they have been limited, for the most part, to comparatively fundamental studies. At present it is only possible to achieve a microgravity field by the use of drop towers, as far as gaseous flames are concerned. Compared with experiments on droplets, including droplet arrays, which have been vigorously performed in Japan, studies on gaseous flames have just begun. Experiments on ignition of gaseous fuel, flammability limits, flame stability, effect of magnetic field on flames, and carbon formation from gaseous flames are currently being carried out in microgravity. Seven subjects related to these topics are introduced and discussed herein.

  14. Fruit harvesting robots in Japan

    NASA Astrophysics Data System (ADS)

    Kondo, N.; Monta, M.; Fujiura, T.

    We have developed harvesting robots for tomato /1/, petty-tomato, cucumber /2/ and grape /3/ in Japan. These robots mainly consist of manipulators, end-effectors, visual sensors and traveling devices. These mechanisms of the robot components were developed based on the physical properties of the work objects. The robots must work automatically by themselves in greenhouses or fields, since we are considering for one operator to tend several robots in the production system. The system is modeled after Japanese agriculture which is commonly seen to produce many kinds of crops in greenhouses and in many small fields intensively. Bioproduction in space is somewhat similar to the agricultural system in Japan, because few operators have to work in a small space. Employing robots for bioproduction in space is considered desirable in near future. The following is a description of the harvesting robots.

  15. Melville Island, Australia

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Melville Island, just off the coast of Darwin, Northern Territory, Australia (11.5S, 131.0E) is a sparsely inhabited tropical island with heavy woodland concentrations. The widespread and prominant smoke plumes were most likely set to renew pasture under open canopy woodland. Soil erosion is almost non- existant as can be seen by the clear and clean river flow. The offshore sediments are coastal current borne deposits from King Sound to the west.

  16. Eviota nigramembrana, a new dwarfgoby from the Western Pacific (Teleostei: Gobiidae).

    PubMed

    Greenfield, David W; Suzuki, Toshiyuki

    2013-01-01

    Eviota nigramembrana is described from the Ryukyu Islands, Japan and also recorded from the Philippine Islands. It belongs to the cephalic sensory-pore system pattern group I (complete), has a dorsal/anal fin-ray formula of 8/8, 5th pelvic-fin ray absent, some lower pectoral-fin rays branched, five dark internal bands between anal-fin origin and caudal fin, no distinct marking on pectoral-fin base, dark internal rectangular mark above midline of ural centrum, a light spinous dorsal fin, and black pigment on the opercular membrane. PMID:26046191

  17. Marketing medical devices in Japan.

    PubMed

    Ohashi, J

    1998-01-01

    The control of medical devices in Japan has recently undergone significant changes as the country brings its systems into line with those of the United States and Europe. This article discusses pre-market approval, quality system requirements and post-market surveillance. Many technical issues have been harmonized but language is likely to continue to be a barrier to trade. Details of information services that are available to foreign manufacturers and importers are supplied. PMID:10176143

  18. Japan Atomic Energy Research Institute

    SciTech Connect

    Seki, M.; Yoshida, H.; Nakamura, T.; Watanabe, H.; Kudo, H. )

    1990-03-01

    The Japan Atomic Energy Research Institute (JAERI) organizes many fusion nuclear technology research and development activities. JAERI is also involved in the design of next-step machines such as the International Thermonuclear Experimental Reactor (ITER) and the Fusion Experimental Reactor (FER). In this paper, research using relatively large facilities are discussed, such as tritium technology, high heat flux technology, fusion neutronics, and breeding material research.

  19. Relationship of the crustal structure and its deformation from arc to back-arc basin in the eastern Japan Sea deduced from the seismic survey

    NASA Astrophysics Data System (ADS)

    Sato, Takeshi; No, Tetsuo; Miura, Seiichi; Kodaira, Shuichi; Sato, Hiroshi

    2015-04-01

    The Japan Sea is a back-arc basin in the northwestern Pacific. Based on geophysical, geological, and petrological results, it is suggested that the opening of the Japan Sea was initiated by crustal rifting and the separation of Japan Island arcs from the Asian continent in the Early Oligocene, followed by the ocean floor spreading in the Late Oligocene (e.g., Tamaki et al., 1992). After 3.5 Ma, the crustal shortening by a strong compression occurred in the eastern margin (e.g., Sato, 1994). In the eastern margin, because of the extension associated with the opening of the Japan Sea and this shortening, the deformation such as active faults and folds formed have developed and large earthquakes with magnitudes-7 class repeatedly occurred (e.g., Okamura et al., 2007). The Japan Sea has a unique setting in terms of the connection between the back-arc basin opening and the crustal deformation. However, we have little information concerning with a crustal structure formed by the back-arc opening in the margin and the deformation. To obtain the information, we have been carrying out active-source seismic surveys using ocean bottom seismographs (OBSs) and multi-channel streamer system (MCS) to cover the eastern margin of the Japan Sea. The obtained results show a difference in crustal structures between the northern and the southern parts of the eastern Japan Sea. In the northern part from the arc to the back-arc basin, the crust is divided into three types; the rifted island arc crust, the thicker oceanic crust and the oceanic crust, based on the comparison of the P-wave velocity distribution and the crustal thickness of a typical oceanic crust (White et al., 1992) and of the northeastern Japan Island arc crust (Iwasaki et al., 2001). On the other hand, the southern part from the arc to the back-arc basin has two crustal types, which are the rifted island arc crust and the thicker oceanic crust. In the northern part, the deformation is distributed in a structural boundary between the rifted island arc crust and the thicker oceanic crust, and in the rifted island arc crust. On the contrary, in the southern part, the deformation is only distributed in the rifted island arc crust.

  20. Investigations of The Structure of Mesoscale Convective Systems Over The Sea of Japan

    NASA Astrophysics Data System (ADS)

    Mezrin, M. Yu.; Starokoltsev, E. V.; Fujiyoshi, Yasushi

    Under the Joint Research Agreement between the Central Aerological Observatory of the Russian Federal Service for Hydrometeorology and Environmental Monitoring, Russia (CAO) and Japan Science and Technology Corporation, Japan (JST), investigations of the structure and formation/development mechanisms of mesoscale convective systems in the Sea of Japan area were carried out in January- February 2001 from board a Russian research aircraft IL-18. The aircraft was equipped with navigation and research instruments to investigate diverse atmospheric and cloud parameters, including instrumentation to study turbulent transport of moisture, heat, etc. The meteorological situation was characterized by a surge of cold, dry continental air to the rear of a cold front (i.e., from Siberia to the open surface of the Sea of Japan). Horizontal measurements were made during flights at altitudes of 100, 500, 1500, and 3000 m, between Vladivistok, Russia, and Sado Island of Japan. As a result of the investigations of turbulent moisture transport at a 100-m level, mesostructure features of the transport were observed having a horizontal scale of about 30 km and an amplitude of about 0.100 g/m2s. The shape and magnitude of such features repeated at a 500-m level, their position shifting windward with time. This phenomenon was evidently caused by cylindrical convection, whose spatial structure showed in the arrangement of cloud streets formed at a 1500-m level. Satellite pictures of the cloud streets were used.

  1. My continuing efforts toward the eradication of the vaccine-preventable diseases from Japan.

    PubMed

    Togashi, Takehiro

    2011-10-26

    When compared to the Western countries, unfortunately, the progress toward the eradication of vaccine-preventable diseases in Japan has been relatively slow and hampered by some problems inherent to Japan. Concerning this, I have been working on the vaccine-preventable diseases, that is, measles, influenza, Haemophilus influenzae, and Streptcoccus pneumoniae infections. My first work was to produce monoclonal antibodies against measles virus proteins, and by using these antibodies, I established the immunofluorescent measles virus detection system in tissue samples. I constructed the 'Hokkaido measles-zero strategy' to eliminate measles from Hokkaido prefecture, the northernmost island of Japan, within 5 years since 2001 with very kind efforts of pediatricians in Hokkaido and those who are engaged in political activities. Coworkers and I established the disease entity of influenza-associated encephalopathy. And finally, I worked as a member of some groups that accumulated the basic data on the occurrence of bacterial meningitis in Japan and urged the government to introduce the H. influenzae type b conjugate vaccine and the pediatric 7-valent pneumococcal conjugate vaccine in Japan. I would like to express many thanks to all of my colleagues for their contributions to these achievements. PMID:21802468

  2. Aerial measuring system in Japan.

    PubMed

    Lyons, Craig; Colton, David

    2012-05-01

    The U.S. Department of Energy/National Nuclear Security Administration's (DOE/NNSA) Aerial Measuring System (AMS) deployed personnel and equipment to partner with the U.S. Forces in Japan (USFJ) to conduct multiple aerial radiological surveys. These were the first and most comprehensive sources of actionable information for U.S. interests in Japan and provided early confirmation to the Government of Japan as to the extent of the release from the Fukushima Daiichi Nuclear Power Plant. Many challenges were overcome quickly during the first 48 h, including installation and operation of Aerial Measuring System equipment on multiple USFJ aircraft, flying over difficult terrain, and flying with USFJ pilots who were unfamiliar with the Aerial Measuring System flight patterns. These factors combined to make for a programmatically unanticipated situation. In addition to the challenges of multiple and ongoing releases, integration with the Japanese government to provide valid aerial radiological survey products that both military and civilian customers could use to make informed decisions was extremely complicated. The Aerial Measuring System Fukushima response provided insight into addressing these challenges and gave way to an opportunity for the expansion of the Aerial Measuring System's mission beyond the borders of the U.S. PMID:22469929

  3. Effects of island geometry in postdeposition island growth

    NASA Astrophysics Data System (ADS)

    Tataru, Oana; Family, Fereydoon; Amar, Jacques G.

    2000-11-01

    The results of kinetic Monte Carlo simulations of a realistic model of postdeposition island growth that takes into account the spatial extent of islands are presented. Simulations were carried out on one- and two-dimensional substrates for different values of the critical island size i and were compared with previous results for a point-island model. The use of a realistic island geometry results in enhanced island aggregation and coalescence. This leads to an increase in the average island size S as well as the exponent z describing the dependence of S on coverage. The shape of the island-size distribution for i=3 also changes dramatically due to the existence of ``magic'' islands.

  4. Continuous measurements of perfluorocarbons at remote monitoring stations in Japan

    NASA Astrophysics Data System (ADS)

    Saito, T.; Yokouchi, Y.; Mukai, H.

    2007-12-01

    In order to determine the trends and regional sources in East Asia, continuous measurements of halocarbons including perfluorocarbons (PFCs), powerful greenhouse gases, has been performed by fully-automated preconcentration/gas chromatograph/mass spectrometer at remote monitoring stations at Hateruma island (24.1 N, 123.8 E) since 2004 and Cape Ochiishi (43.1 N, 145.3 E) since 2006 in Japan. The measurements show that the background concentrations of PFCs in 2007 were 3.7 ppt for PFC-116, 0.5 ppt for PFC-218, and 1.3 ppt for PFC-318. As for PFC-116, slight increasing trend was observed at Hateruma. Enhanced concentration above the baseline were occasionally observed in air masses which had passed over urban areas such as Shanghai, Taipei, and Tokyo, suggesting great anthropogenic emission there, while the frequency of the enhancements were relatively low compared to those of hydrofluorocarbons.

  5. FBIS report. Science and technology: Japan, December 3, 1996

    SciTech Connect

    1996-12-03

    Contents (selected articles): Japan: Nissan To Use Nickel-Hydrogen Battery in EV; Japan: Takii To Commercialize Cauliflower-Broccoli Hybrid; Japan: Kawasaki Steel Improves Recovery of Metals from Furnace Residue; Japan: Japan`s NEC Corp. To Develop Cost-Effective Photodection Chip; Japan: Japanese Companies Establish Research Association to Develop 16-gigabit DRAMS; Japan: Safe Operation of Nuclear Power Plants, Actual Achievements; Japan: Future for Nuclear Fuel Recycle as a Result of Monju Accident; Japan: Superconducting Magnet System Using No Liquid Helium; Japan: Hitachi`s MULTI Network Security Technologies; Japan: Defense Bureau Chief Tokita Interviewed; Japan: DRC Executive on GSDF, High Technology; and Japan: Retired Admiral on Post-Cold War MSDF Strategy.

  6. A revision of the Australian species of Trimma (Actinopterygii, Gobiidae), with descriptions of six new species and redescriptions of twenty-three valid species.

    PubMed

    Winterbottom, Richard; Hoese, Douglass F

    2015-01-01

    The gobiid genus Trimma currently contains 75 valid species, with another 20-30 known but undescribed species. There are 29 species in Australian waters (six undescribed). This paper describes the six new species, and provides redescriptions of most of the 23 previously described species known from the region, as well as a key for all the species. The six new species are: T. insularum (endemic to Cocos (Keeling) Islands), T. kitrinum (Fiji to Great Barrier Reef), T. meristum (Cape York to the Bismark Archipelago and Fiji), T. pentherum (Great Barrier Reef to Fiji and the South-West Islands of Palau), T. readerae (Australia to Japan), and T. xanthum (Palau to Fiji, Great Barrier Reef to Christmas Island). The following 23 species have been recorded from Australian waters, and most are redescribed here: T. anaima (Comores to Fiji), T. annosum (Maldives to the Phoenix Islands, Taiwan to the southern Great Barrier Reef), T. benjamini (southern Vietnam to the Marshall Islands, Samoa and southern Barrier Reef), T. caesiura (Ryukyus through the Marshall Islands to Samoa and Elizabeth Reef on the Lord Howe Rise), T. capostriatum (New Caledonia to eastern Australia and Papua New Guinea), T. maiandros (Java to the Ryukyus, Marshalls to Great Barrier Reef), T. emeryi (Comores to Ryukyus and Samoa), T. fangi (western South China Sea through to the Solomons), T. flavatrum (Ryukyu Islands to Western Australia and Samoa), T. hoesei (Chagos Archipelago, central Indian Ocean to Palau and Solomons), T. lantana (Australia, Solomons, northern New Guinea, South-West Islands of Palau), T. macrophthalmus (Ryukyu Islands to Cocos (Keeling) Islands and Samoa), T. milta (Taiwan to Western Australia, Society Islands and Hawaii), T. nasa (Sumbawa, Indonesia to Fiji), T. necopinum (northern tip of Cape York to Sydney), T. nomurai (Japan to northern Australia and New Caledonia), T. okinawae (western Thailand to Japan and the Phoenix Islands, north-west Australia to the Great Barrier Reef), T. preclarum (Palau to Fiji, Great Barrier Reef), T. stobbsi (Maldives to New Caledonia), T. striatum (Maldives to Palau, to northern Australia), T. taylori (Red Sea to Hawaii and Society Islands), T. tevegae (Red Sea to Ryukyu Islands, Marshall Islands to Samoa), and T. unisquame (Comores to Hawaii and Easter Island). PMID:25781853

  7. FBIS report. Science and technology: Japan, February 20, 1996

    SciTech Connect

    1996-02-20

    ;Partial Contents: Energy (Japan: MHI Discovers Maritime Photo Plankton that Produces Ethanol from CO2, Japan: Tokyo Electric Power Co.`s PAFC Development); Telecommunications (Japan: Report on 1st Asian Telecommunications Industry Exchange, Japan: MPT Reports Test Evaluation Results for PHS); Defense Industries (Japan: Expert on Shipbuilding, Welding Technology, Japan: Komatsu R&D Chief on Dream of Ground Robots; Japan: Defense Simulator Series, Part 7: Torpedo Simulator).

  8. FBIS report. Science and technology: Japan, May 7, 1996

    SciTech Connect

    1996-05-07

    ;Partial Contents: Japan: FH1 Aerospace Division Executive on UAV R&D; JapaN: MHI Delivers First F-2 Flight Test Model; Nuclear Technologies; Japan: Nuclear Material Research in Cross-Over Research Project; Japan: MITI To Subsidize Development of Cryptography; Defense Industries; Japan: JADI Announces FY96 Major Events Schedule; Japan: Rollout Ceremony Held for First OH-X Flight Test Model; and Japan: KHI Weapons Designer OH-X Development.

  9. Interim report on the 2008 Southern and the Central Japan Alps Transect (SCAT)

    NASA Astrophysics Data System (ADS)

    Komada, N.; Murata, K.; Hayakawa, M.; Tsumura, N.; Kano, K.; Sato, T.; Miyauchi, T.; Kojima, S.; Iwasaki, T.; Ikeda, Y.; Sato, H.; Hirata, N.; Abe, S.; Miyake, Y.; Otsuka, T.; Yamakita, S.; Fukahata, Y.; Kawamoto, K.; Kaneda, H.; Panayotopoulos, Y.; Hashima, A.; Ito, T.; Kawanaka, T.; Mizohata, S.; Abe, S.; Takahashi, A.

    2009-12-01

    The N-trending Japan Alps runs across the central part of the E-trending Japanese Island arc forming the three major mountain ranges, the Northern, the Central, and the Southern Alps. The eastern merge of the Japan Alps corresponding nearly to the Itoigawa-shizuoka Tectonic Line (ISTL), one of the major faults in Japan. As the Japan Alps also constructs a structural high, it has been believed for a long time that the Alps has been growing by the subduction of the eastern belt of the Japanese island arc beneath the western belt along the ISTL. However. recent deep seismic reflection studies have revealed that the ISTL is not composed of a single fault, but of three different segments: the E-dipping northern thrust, the high-angle central(belt-lateral), the w-dipping southern thrust. Three lines of evidence inevitably bring us to re-examine and re-establish the formative process of the Japan Alps. Sato, et al. (2004) shows that the formation of the Northern Alps has been associated with opening of the Japan Sea in Middle Miocene, and the successive structural inversion. On the contrary, the formation of the Central and Southern is still controversial because of no seismic reflection study from the southern segment of the ISTL to the Central Alps through the more-than-2000m-asl Southern Alps. Thus, the 2008 Southern and the Central Japan Alps Transect (SCAT) was conducted based on the following specifications; seismic line: 90km receiver interval: 50m (total receiver points: 1700) source: Flat basin area: 4 Vibroseises 100m interval Mountainous route : 4 Vibroseises 1km interval and 4 dynamite shot (30 - 50kg) Our preliminary processing reveals: (1) Major thrusts have been formed beneath the Southern Alps by the subduction of the Philippine Sea Plate with the collision of Izu arc. (2) The activity of these thrusts have produced the uplift and growth of the Southern Alps. (3) The uplift of the Central Alps has been probably caused by a significant thrust, the Ina valley thrust generated from the subhorizontal detachment occurring at about 10km depth widely in the Central Japan.

  10. Japan's hidden youths: mainstreaming the emotionally distressed in Japan.

    PubMed

    Borovoy, Amy

    2008-12-01

    One of the most talked-about social issues in Japan in recent years has been the problem of the nation's purportedly one million "hidden" youths, known as hikikomori (literally, "the withdrawn"). Most observers agree that the category of hikikomori encompasses a wide range of problems and provocations. The fact that these various dilemmas lead to the shared outcome of shutting oneself away at home is the point of departure here. The article explores the spheres of mental health care, education and family, focusing on the reluctance to highlight underlying psychological dimensions of hikikomori and the desire on the part of schools and families to "mainstream" Japanese children, accommodating as many as possible within standardized public education. Hikikomori can perhaps be seen as a manifestation of Japanese democracy, in which the good society is imagined as cohesive, protective and secure, rather than one in which the individual can freely exercise the right to be different. Schools, families and the sphere of mental health care have focused on producing social inclusion but have discouraged citizens from being labeled as "different" -- even when such a distinction might help them. The dearth of facilities and discourse for caring for the mentally ill or learning disabled is, in many respects, the darker side of Japan's successes. Those who cannot adjust are cared for through the institutions of families, companies and various other spheres that offer spaces to rest and to temporarily "drop out"; however, the expectation is that rest will eventually lead to a re-entry into mainstream society. Often the psychological problem or disability that led to the problem goes unnamed and untreated (hikikomori, psychiatry, special education, youth, family, Japan). PMID:18818992

  11. Impact Materials of Takamatsu Crater in Japan

    NASA Astrophysics Data System (ADS)

    Miura, Y.; Okamoto, M.; Fukuchi, T.

    1995-09-01

    Shocked quartz materials have been found in Japanese K.T boundary (Hokkaido) and mountains of middle main-islands of Japan, though there are few direct evidence of "natural circular structure" on the surface in Japan. However circular structure has been recently found as a buried crater(up to 150m deep) [1] which is ca. 4km in diameter with -10 mgal of Bouguer gravity anomaly from surrounding Rhyoke granitic region of the southern part of Takamatsu City, Kagawa Prefecture, northeast Shikoku, Japan [1,2,3]. Two boring cores of 300m deep near small mountains inside the crater could not reach the bottom of the crater so far. From model calculation of the negative gravity anomaly, the Takamatsu crater shows deep basin structure up to 1.4km. If the Takamatsu crater is considered to be only impact crater, it is difficult to discuss only surface materials on the crater. But anomalous minerals are found only around small volcanic intrusions inside the crater, which the mixed minerals are clearly different with those of other volcanic intrusions of the Yashima and Goshikidai outside the crater [1,2,3]. The small volcanic intrusions are not origin of large Takamatsu crater, because the small volcanic intrusions are found on whole areas of Kagawa Prefecture. Major different activity of the small intrusions inside the crater is to bring the brecciated materials of the interior (esp. crater sediments). The xenolith materials around only volcanic intrusion of andesite are divided into the following four major mineral materials:(a) round pebble fragments from the Rhyoke granitic basement (Sampling No.15), (b) rock fragments from intruded biotite andesites (Nos. 2,15), (c) impact-induced fragments of shocked Quartz grains (Nos. 2,3,6,15), diaplectic feldspars (Nos. 2,3,6,15), silica glasses (Nos. 2,15) and small Fe-Ni metallic grains (No.15), and (d) small sedimentary fragments of halite and mordenite, as listed in Table 1. Table I, showing the characterization of surface samples around small intrusions of the Takamatsu crater, appears here in the hard copy. The following anomalous mixed materials are considered to be impact-induced origin: 1) Fe-Ni grains: Black glassy rocks at Jissojiyama (No. 15) contain irregularly Fe-Ni grains of 10 to 100 micrometers in diameter. Chemical composition of the small Fe+Ni grains varies from ca. 18~90 atom. % mixed with the major granitic components. Atomic ratios of Fe/Ni are the same of kamacite as 3.4 to 68.7, but differ from those of awaruite (Fe/Ni<0.5) from the deep seated rock of the interior of the Earth [4]. The similar tiny Fe grains are found on the Wolf Creek and Ries impact craters. 2) Shocked quartz with high-density and shock lamellae: Anomalous quartz grains with undulatory anomalous extinction and shock lamellae are found at the Hiyama (Nos. 2,3,6 in whitish fine rocks) and Jissoiiyama (No. 15 in black glass) as brecciated xenolith from the interior of crater sediments. Typical shocked quartz grain shows with two sets of shock lamellae along pi (102) crystallographic planes [5]. The main X-ray diffraction peaks of each Miller plane show high Bragg angle and X-ray density (Delta rho=+0.9+/-0.3%) and lower values (ca.- 0.4%) of each plane-distance of all shock-generated Plane deformation features (PDFs). The structural data of high density are the same of shocked quartz grains in terrestrial impact craters [6,7]. 3) Diaplectic feldspars: Shock-generated diaplectic feldspars with compositions of albite plagioclases with undulatory extinction are observed with dark or partly dark (i.e. diaplectic) glassy materials under cross-polarized microscope (Nos. 2,3,6,15). Crushed plagioclases with circular or ellipsoidal shape are also found at Hiyama (No. 6) and Hiraike (No. ll). Diffuse and irregular textures of feldspar fragments are different with other localities outside the crater [2,3]. 4) G1asses of potassium feldspar compositions: Many glassy fragments with flow texture are observed from fine-grained sediments around Hiyama (Nos. 2,3,6), which have potassium feldspars compositions by the AEM of high-silica (SiO2=78~85wt.%) without MgO [2]. K-Ar dating of the glassy breccias is 14.2 +/-0.7(Ma). This suggests that fine-grained breccias are mixed with Hiyama andesitic intrusion, suggesting that formation of the Takamatsu crater is older than small and many volcanic intrusions [2,3]. Therefore, the Takamatsu crater is considered to be the similar type of crater as buried impact crater followed by small volcanic intrusions [2,3]. The Takamatsu crater seems to be the first impact crater in Japan. Referenocs: [1] Y. Kono et al. (1994): ISAS Lunar and Planetary Symp.(Japan), 27, 67-70. [2] Y. Miura et al. (1995): Lunar. Planet. Sci.(USA), XXVI, 987-988. [3] Y. Miura et al.(1995): Antarctic Metcorites (NIPR), 2?, 163-165. [4] Y. Miura et al. (1981): Contrib. Mineral. Petr?l., 76, 17-23. ?5] R.A.F.Grieve et al.(l988): LPI Technical RePorl (USA), No.88-03, 89 pp. [6] Y. Miura (1991): Shock ?aves (Springer-Verlag), 1, 35-41. [7] Y. Miura et al. (1992): Celestial ?echanic? ?4 ?4 ?

  12. Seafloor Crustal Deformation Close to the Nankai Trough, Japan

    NASA Astrophysics Data System (ADS)

    Tadokoro, K.; Sugimoto, S.; Watanabe, T.; Okuda, T.; Muto, D.; Kimoto, A.; Ando, M.; Sayanagi, K.; Kuno, M.

    2007-12-01

    \\ \\ \\ The Nankai Trough is one of the active plate boundaries in the world. Major subduction earthquakes, Nankai and Tonankai earthquakes, repeatedly occur with intervals of 100-150 years at the Nankai Trough. The last large earthquakes occurred in 1944 and 1946. Therefore, the 50-years probabilities of next major earthquakes are 80- 90 %. It is necessary to monitor crustal deformation above the source regions for the sake of earthquake prediction and disaster prevention. The source regions of the earthquakes are located beneath the sea bottom, to the south of the Japan Islands. \\ \\ \\ One of the useful tools to monitor seafloor crustal deformation is the observation system composed of the acoustic ranging and kinematic GPS positioning techniques. We have installed seafloor benchmarks for acoustic ranging at the Nankai Trough region. We repeatedly observed at the two sites from 2004. The result of the repeated observation shows that the repeatability of the measurement is +/- 2-3 cm for the horizontal components. Also we detect crustal deformation related to plate convergence using our system. The velocity vectors derived from our repeated observation are (7.0 cm/yr, N78W) and (5.2 cm/yr, N87W), which is consistent to the on-land continuous observations. \\ \\ \\ This study is promoted by Ministry of Education, Culture, Sports, Science and Technology, Japan. We are grateful to the captains and crews of Research Vessels, "Asama"and "Hokuto."

  13. Impacts of Long-Range Transport of Metals from East Asia in Bulk Aerosols Collected at the Okinawa Archipelago, Japan

    NASA Astrophysics Data System (ADS)

    A, Sotaro; S, Yuka; I, Moriaki; N, Fumiya; H, Daishi; A, Takemitsu; T, Akira

    2010-05-01

    Economy of East Asia has been growing rapidly, and atmospheric aerosols discharged from this region have been transported to Japan. Okinawa island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km of south Korea. Its location in Asian is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air mass which has been affected by anthropogenic activities. Therefore, Okinawa region is suitable area for studying impacts of air pollutants from East Asia. We simultaneously collected bulk aerosol samples by using the same type of high volume air samplers at Cape Hedo Atmospheric Aerosol Monitoring Station (CHAAMS, Okinawa island), Kume island (ca. 160 km south-west of CHAAMS), and Minami-Daitou island (ca. 320 km south-east of CHAAMS). We determined the concentrations of acid-digested metals using atomic absorption spectrometer and inductively-coupled plasma mass spectrometry (ICP-MS). We report and discuss spatial and temporal distribution of metals in the bulk atmospheric ae