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. 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

  6. 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

  7. 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. δ13C and δ18O values of UCS have narrow ranges of 0.51 to 1.70‰ and -1.87 to -1.46‰, respectively. On the other hand, δ13C and δ18O 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 δ13C and δ18O values change gradually at the same rates with the increase in LMC content within UCS, both values change quickly and the change rate of δ13C value is larger than that of δ18O 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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 70-80°dipping 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.

  18. 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 ∘, α95 = 9.6 ∘, and κ = 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 ∘, α95 = 7.1 ∘, and κ = 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.

  19. 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

  20. 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

  1. 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

  2. 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 56±5% 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.

  3. 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

  4. Dental variation of Ryukyu islanders: a comparative study among Ryukyu, Ainu, and other Asian populations.

    PubMed

    Higa, Takako; Hanihara, Tsunehiko; Sunakawa, Hajime; Ishida, Hajime

    2003-01-01

    The presence or absence of 24 nonmetric dental traits was examined to investigate the inter- and intraregional variation of Ryukyu Islanders. We compared the dentition of the Kadena sample from the central district of Okinawa Island in the Ryukyu Island chain to those of samples from Nakijin from the northern district of the same Okinawa Island, Tokunoshima, another island of the Ryukyu Island chain, main-island Japanese in Kagoshima and Tokyo, Hokkaido Ainu, Atayal in Taiwan, and Pashtuns and Tajiks in Afghanistan. Many traits of the Ryukyu Islanders were found to be close to those of the main-island Japanese; however, several were intermediate between those of the main-island Japanese and the Ainu or Atayal. The intraregional variation in the Ryukyu Islanders was comparable to that in the main-island Japanese. This result supports the influence of a complex gene flow to the Ryukyu Islanders, as suggested by some genetic studies. Among the populations compared here, that closest to the Ainu was the population of Tokunoshima. PMID:12621601

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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 µm, n=8) from April to August. Numerous spermatozoa were observed from September through February, and seminiferous diameter was significantly large (216 ± 27 µm, 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

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

    PubMed

    Okano, Tsukasa; Nakata, Katsuhi; Nakaya, Yumiko; Nagamine, Takashi; Onuma, Manabu

    2015-06-01

    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 µm, n=8) from April to August. Numerous spermatozoa were observed from September through February, and seminiferous diameter was significantly large (216 ± 27 µm, 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

  15. 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.

  16. 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…

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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…

  4. 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

  5. [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 Lü 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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…

  13. Biology of Anopheles saperoi, an Endemic Species in Okinawajima, the Ryukyu Archipelago, Japan.

    PubMed

    Mannen, Kosuke; Toma, Takako; Minakawa, Noboru; Higa, Yukiko; Miyagi, Ichiro

    2016-03-01

    Biological studies of Anopheles saperoi were conducted using larval and adult mosquito collections in the northern part of Okinawajima of the Ryukyu Archipelago from June 2009 to July 2010. Anopheles saperoi was the most collected species in the northern Okinawajima, except Motobu Peninsula, where it was not collected. The southern distribution of An. saperoi was Sugita Stream, Nago City. Anopheles saperoi was collected throughout the year with reproduction (gonotrophic cycle) observed year-round. Immature densities varied for Hinna and Yona streams, and were negatively affected by precipitation patterns. Human attraction activity of females varied for by study area and collection time and was positively affected by temperature, but negatively by heavy rainfall. The greatest female human attraction activity was observed during 3:00-5:00 p.m., with peak at twilight. Parity rates varied from 23.1% to 83.3% throughout the year. PMID:27105212

  14. 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

  15. Succession and growth rates of encrusting crustose coralline algae (Rhodophyta, Cryptonemiales) in the upper fore-reef environment off Ishigaki Island, Ryukyu Islands

    NASA Astrophysics Data System (ADS)

    Matsuda, Shinya

    1989-01-01

    Observations were made on the succession and growth rates of crustose coralline algae growing in situ on artificial substrata in a shallow fore-reef environment on Ishigaki Island, Ryukyu Islands. Succession in well-illuminated environments manifests itself as a gradual replacement of species having very thin thalli by those having larger and thicker thalli. The species Porolithon onkodes, Paragoniolithon conicum and Lithophyllum insipidum achieved dominance by competitive interactions of overgrowing margins. The thicker species recruit quickly (within the first few months), but because of their slow growth rate do not displace the pioneer species that have very thin thalli until after the latter begin to die. Regardless of seasonal temperature fluctuations, which exceed 10 °C, the coralline algal succession is the same for each season. The maximum lateral growth rates of the major species range between 2.9 and 3.9 mm/month. Vertical growth rates of Porolithon onkodes, the thickest species, are the most rapid (more than 2 mm/year at maximum) relative to those of other species. Accretion rates of entire coralline algal cover on ungrazed substrata range from 1.0 to 1.2 mm/year (not allowing any lag time for recruitment), whereas those of grazed substrata are lower. These results are consistent with species which are ecological equivalents and live in similar environments on Caribbean reefs.

  16. 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.

  17. 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 Števčić, 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. Estimation of coupling factor in the northern part of Ryukyu trench by using 2D FEM

    NASA Astrophysics Data System (ADS)

    Nakao, S.; Maeno, S.; Goto, K.

    2009-12-01

    Philippine Sea plate (PH) subducts beneath Ryukyu Arc, where Nansei Islands are located, at the Ryukyu trench. Coupling factor has been studied in the subduction zones around the Japan Island since GEONET GPS network of GSI, Japan were deployed. The coupling factors of zero and 13 % in this subduction zone were estimated. The northern part of Okinawa trough spreads in the direction of East-West. It is difficult to make a model of subduction zone that spreading of Okinawa trough is taken into account. We make 2-dimensional Finite Element (FEM) model to calculate the displacement pattern on the plate. The 2-D model is taken into account for the subduction of PH plate and spreading of Okinawa trough. GeoFEST FEM program (Parker et al, 2008) is used in this calculation. We also try to estimate coupling factor by trial and error mothod. We make two cross sections which are perpendicular to the trench axis of Ryukyu trench. One is located on Tanegashima Island and the other is Amami-Oshima Island. The boundary of subducted PH plate is determined based on the hypocenter distribution by Goto et al. (2008). The thickness of Ryukyu Arc is 25km based on the structure of seismic velocity by Iwasaki et al. (1990). Elastic constants of crust and mantle are adopted by Suito et al. (2002). The direction of movement of PH plate with respect to the Ryukuy Arc is derived from Euler vectors: one is Amur plate with respect to PH plate (Miyazaki and Heki, 2001) and the other is the direction of Ryukyu Arc with respect to Amur plate (Nishimura et al., 2004). The direction of subduction of PH plate with respect to Ryukyu Arc is calculated by using Euler vectors which estimated by Nishimura et al. (2004). Spreading rate of Okinawa trough is given at upper part of the western edge of the 2-D model. Amount of spreading of Okinawa trough is calculate at the western potion of Ryukyu Arc by the Euler vector of Nishimura et al. (2004). The depth of coupling region of plates is from 20 to 30km and 10 to 35 km in Tanegashima and Amami-Oshima cross section, respectively. Horizontal displacement rate observed at eight GEONET sites are estimated by the least squares method using the coordinate solution of F2 analysis of GSI at Tanegashima cross section. In Amami-Oshima cross section horizontal displacement rates at six GEONET sites are estimated. Annual and semi-annual components are also estimated when horizontal displacement rates are estimated. The coordinate system of these displacement rates is transformed to that with respect to the Ryukyu Arc by using absolute Euler vector of Amur plate and relative Euler vector of Ryukyu Arc with respect to Amur plate (Nishimura et al., 2004). Horizontal displacement rates become smaller when the coupling factor is smaller at both cross sections. Horizontal displacements begin to be smaller at about 10km from the eastern edge of coupling region. Horizontal displacement rates are smallest at the Okinawa trough side. When the coupling factor is large, horizontal displacement becomes large. Coupling factors, 30% are estimated at both cross sections by using trial and error method. At Tanegashima cross section, the depth of coupling region is also changed at estimation of coupling factor, which is from 10 to 35 km.

  6. 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.

  7. 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.

  8. 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.

  9. Bathymetric patterns of α and β 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 α 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 (β) 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 (δ 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.

  10. 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).

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. A persistent localized microseismic source near the Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Zeng, Xiangfang; Ni, Sidao

    2010-12-01

    Very strong signals with apparent velocity higher than Rayleigh wave velocity are observed on noise correlation functions (NCFs) between seismic stations in East Asia. These signals are present on one-month NCFs in ten years period with stable arrival times, indicating their persistent and localized nature. The signals are strong in the frequency band of 0.07-0.12Hz, and their amplitudes show inter-annual but not seasonal variation. Location obtained from two algorithms with GSN and FNET data indicates that the source is situated in Kyushu Island, Japan. After an earthquake is used to account for heterogeneity effects, the location is closer to the Ariake bay but still in the island. The non-seasonal amplitude variation and the peak frequency of 0.1Hz suggest the signals are probably not generated by oceanic sources. This persistent localized microseismic source needs to be taken into consideration in ambient noise tomography studies in East Asia.

  18. 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.

  19. 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. 5°E 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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 125.5°E 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 125.5°E 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 125.5°E 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.

  6. 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

  7. 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.

  8. 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

  9. 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 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

  10. 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...

  11. 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.

  12. 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

  13. Geographical origin of Leucobryum boninense Sull. & Lesq. (Leucobryaceae, Musci) endemic to the Bonin Islands, Japan

    PubMed Central

    Oguri, Emiko; Yamaguchi, Tomio; Tsubota, Hiromi; Deguchi, Hironori; Murakami, Noriaki

    2013-01-01

    Leucobryum boninense is endemic to the Bonin Islands, Japan, and its related species are widely distributed in Asia and the Pacific. We aimed to clarify the phylogenetic relationships among Leucobryum species and infer the origin of L. boninense. We also describe the utility of the chloroplast trnK intron including matK for resolving the phylogenetic relationships among Leucobryum species, as phylogenetic analyses using trnK intron and/or matK have not been performed well in bryophytes to date. Fifty samples containing 15 species of Leucobryum from Asia and the Pacific were examined for six chloroplast DNA regions including rbcL, rps4, partial 5′ trnK intron, matK, partial 3′ trnK intron, and trnL-F intergenic spacer plus one nuclear DNA region including ITS. A molecular phylogenetic tree showed that L. boninense made a clade with L. scabrum from Japan, Taiwan and, Hong Kong; L. javense which is widely distributed in East and Southeast Asia, and L. pachyphyllum and L. seemannii restricted to the Hawaii Islands, as well as with L. scaberulum from the Ryukyus, Japan, Taiwan, and southeastern China. Leucobryum boninense from various islands of the Bonin Islands made a monophylic group that was closely related to L. scabrum and L. javense from Japan. Therefore, L. boninense may have evolved from L. scabrum from Japan, Taiwan, or Hong Kong, or L. javense from Japan. We also described the utility of trnK intron including matK. A percentage of the parsimony-informative characters in trnK intron sequence data (5.8%) was significantly higher than that from other chloroplast regions, rbcL (2.4%) and rps4 (3.2%) sequence data. Nucleotide sequence data of the trnK intron including matK are more informative than other chloroplast DNA regions for identifying the phylogenetic relationships among Leucobryum species. PMID:23610621

  14. 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.

  15. 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 Γ 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.

  16. Detailed Analysis of Japanese Population Substructure with a Focus on the Southwest Islands of Japan

    PubMed Central

    Nishiyama, Takeshi; Kishino, Hirohisa; Suzuki, Sadao; Ando, Ryosuke; Niimura, Hideshi; Uemura, Hirokazu; Horita, Mikako; Ohnaka, Keizo; Kuriyama, Nagato; Mikami, Haruo; Takashima, Naoyuki; Mastuo, Keitaro; Guang, Yin; Wakai, Kenji; Hamajima, Nobuyuki; Tanaka, Hideo

    2012-01-01

    Uncovering population structure is important for properly conducting association studies and for examining the demographic history of a population. Here, we examined the Japanese population substructure using data from the Japan Multi-Institutional Collaborative Cohort (J-MICC), which covers all but the northern region of Japan. Using 222 autosomal loci from 4502 subjects, we investigated population substructure by estimating FST among populations, testing population differentiation, and performing principal component analysis (PCA) and correspondence analysis (CA). All analyses revealed a low but significant differentiation between the Amami Islanders and the mainland Japanese population. Furthermore, we examined the genetic differentiation between the mainland population, Amami Islanders and Okinawa Islanders using six loci included in both the Pan-Asian SNP (PASNP) consortium data and the J-MICC data. This analysis revealed that the Amami and Okinawa Islanders were differentiated from the mainland population. In conclusion, we revealed a low but significant level of genetic differentiation between the mainland population and populations in or to the south of the Amami Islands, although genetic variation between both populations might be clinal. Therefore, the possibility of population stratification must be considered when enrolling the islander population of this area, such as in the J-MICC study. PMID:22509376

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. Imaging the subducting slabs and mantle upwelling under the Japan Islands

    NASA Astrophysics Data System (ADS)

    Zhao, Dapeng; Yanada, T.; Hasegawa, A.; Umino, N.; Wei, Wei

    2012-08-01

    A high-resolution P-wave tomography of the crust and mantle down to 700 km depth beneath the Japan Islands is determined using a large number of high-quality arrival-time data from local earthquakes and teleseismic events simultaneously. The tomography shows that the Philippine Sea slab is subducting aseismically down to 430 km depth under southwest Japan, though the seismicity within the slab ends at 180 km depth. A low-velocity (low-V) zone in the mantle wedge under Tohoku and Kyushu is found to extend westward from the volcanic front to the backarc under the Japan Sea and East China Sea. Significant low-V anomalies are revealed in the deep portion of the mantle wedge (400-500 km depth) above the Pacific slab under southwest Japan, which may reflect hot mantle upwelling associated with fluids from the deep dehydration of the Pacific slab. Low-V anomalies appear at 420-700 km depths beneath the Pacific slab under eastern Japan, which may reflect hot mantle upwelling associated with the deep subduction of the Pacific slab and its collapsing down to the lower mantle.

  4. 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.

  5. Paleomagnetic evidence for post-Late Miocene intra-arc rotation of South Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Kodama, Kazuto; Nakayama, Ken-Ichi

    1993-02-01

    Paleomagnetism of sedimentary rocks of the late Miocene Uchiumigawa Group exposed in southeast Kyushu yielded 17 tilt-corrected paleomagnetic directions with significant westward declinations. Fourteen of these were of reversed polarity, and three at the intervening horizons were of antipodal normal polarity. The overall formation mean direction is D = 322.0°, I = 48.6° with α95 = 6.0°. This is statistically indistinguishable from the mean direction of D = 331.2°, I = 41.3° with α95 = 9.9° for the middle Miocene deposits in Tanegashima Island of the northern Ryukyu arc. The common mean direction is D = 333.2°, I = 45.1° with α95 = 4.9°. This indicates that both south Kyushu and the northernmost Ryukyu arc have experienced 27° ± 6° of counterclockwise rotation with respect to the Eurasian continent after the latest Miocene, or during the last 6 m.y. This counterclockwise rotation cannot be fully explained by either a conventional model which links an arc rotation with the formation of back-arc oceanic crust, or the collision of the Kyushu-Palau ridge with southwest Japan arc. We propose that this intra-arc rotation took place during the period of extension of the continental crust behind the north Ryukyu arc. This study demonstrates that arc rotation may generally occur when the back-arc spreading is of a much less advanced phase.

  6. 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.

  7. Cobitis takenoi sp. n. (Cypriniformes, Cobitidae): a new spined loach from Honshu Island, Japan

    PubMed Central

    Nakajima, Jun

    2016-01-01

    Abstract A new species of spined loach, Cobitis takenoi sp. n., is described based on the holotype and ten paratypes collected from Tango District, Honshu Island, Japan. The new species is distinguished by a combination of the following character states: 1) the lamina circularis at the base of the pectoral fin in adult male having a simple roundish plate form; 2) a narrowing of the upper segments of the first branched ray of the pectoral fin; 3) a short maxillary barbel whose length equals diameter of the eye; 4) 14 prepelvic myotomes, and 5) L3 and L5 well developed, forming longitudinal obvious stripes in males during the spawning season. PMID:27103876

  8. Distribution characteristics of polychlorinated biphenyls (PCBs) in coastal areas of Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Sheikh, M. A.; Nakama, F.; Oomori, T.

    2007-07-01

    Surface sediment and seawater samples were collected from coastal areas around Okinawa Island from September 2001 to May 2002. The samples were analyzed for total polychlorinated biphenyl (PCB) levels and homolog composition. The results show that total PCB levels ranged from 0.32 to 128.7 ng/g (dry wt.) in sediment and 1.59 to 2.48 ng/L in seawater. The levels exceed the Environmental Quality Standard (EQS) for water pollution of Japan. The distribution of PCB homolog showed different patterns in the sediments and seawaters. Penta-chlorobiphenyls (CBs) comprised the main congener group in seawater, while hexa-CBs were more abundant homologs in the sediments. The heavily contaminated sites featured higher CBs, including penta-CBs, hexa-CBs, and hepta-CBs, than those in less contaminated sites where tri-CBs dominated. This study provides current distribution and geochemical behavior of PCBs in the coastal areas around Okinawa Island.

  9. 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…

  10. 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.

  11. Heterogeneous stress state of island arc crust in northeastern Japan affected by hot mantle fingers

    NASA Astrophysics Data System (ADS)

    Shibazaki, Bunichiro; Okada, Tomomi; Muto, Jun; Matsumoto, Takumi; Yoshida, Takeyoshi; Yoshida, Keisuke

    2016-04-01

    By considering a thermal structure based on dense geothermal observations, we model the stress state of the crust beneath the northeastern Japan island arc under a compressional tectonic regime using a finite element method with viscoelasticity and elastoplasticity. We consider a three-layer structure (upper crust, lower crust, and uppermost mantle) to define flow properties. Numerical results show that the brittle-viscous transition becomes shallower beneath the Ou Backbone Range compared with areas near the margins of the Pacific Ocean and the Japan Sea. Moreover, several elongate regions with a shallow brittle-viscous transition are oriented transverse to the arc, and these regions correspond to hot fingers (i.e., high-temperature regions in the mantle wedge). The stress level is low in these regions due to viscous deformation. Areas of seismicity roughly correspond to zones of stress accumulation where many intraplate earthquakes occur. Our model produces regions with high uplift rates that largely coincide with regions of high elevation (e.g., the Ou Backbone Range). The stress state, fault development, and uplift around the Ou Backbone Range can all be explained by our model. The results also suggest the existence of low-viscosity regions corresponding to hot fingers in the island arc crust. These low-viscosity regions have possibly affected viscous relaxation processes following the 2011 Tohoku-oki earthquake.

  12. Spatial variation of attenuation factor in subduction zone of Philippine Sea slab around Kyushu Island Japan

    NASA Astrophysics Data System (ADS)

    Parithusta, Rizkita; Matsumoto, Satoshi; Shimizu, Hiroshi

    2010-05-01

    Kyushu Island, in south-western part of Japan is characterized by subduction from Philippine Sea Slab and Eurasian Plate (Amurian); volcanic front seen in islands arcs runs through the central part of Kyushu Island. In Kyushu, shallow and intermediate-depth earthquakes occur robustly through a depth of about 200 km. We estimated attenuation structure beneath Southern Part of Japan, at subduction zone of Philippine Sea Slab by applying modified coda normalization method (Eq.1) proposed by Parithusta, et.al. (2008*). The method estimates relative source spectra by taking spectral ratio in coda waves between two events at first. From a lot of the spectral data, those can be estimated with higher stability through singular value decomposition. After that, the relative source effect between event pair can be eliminated by the solution from ratios between direct wave spectra for many event pairs. We confirmed the estimation of source factor by assessment with empirical method, the result show that estimates of source factor almost satisfy empirical relation between magnitude and energy relation. The attenuation factor can be obtained from a relation below; ( ) Edij(tij,?-)- -1 dn = ln Edi'j(ti'j,?) = - ?Q(?) (tij - ti'j)+ const.... (1) Where: Ed denotes Direct S-wave power spectrum and Q is attenuation factor at target area; t is lapse time from origin time. Subscript i,jdenote identification number for event and station, respectively. Q-1 factor can be estimated from decay with ?tii'j(= tij - ti'j). By using this method, we obtained frequency dependent Q-1 value with smaller estimation error than previous study carried by Matsumoto et.al (2007). We used waveform data from earthquakes occurred in Philippine Sea Slab, recorded by Hi-net and Kyushu University seismic networks. Window length adopted here is 2.5 seconds for taking spectrum. The results shows the Q-1 values around Bungo-Suido area, northern part of Kyushu. Q-1 values are plotted in seven depth ranges as a function of frequency. The Q-1 values are obtained in a range from 10-4 to 10-1. This range is similar to that estimated in other studies. These results suggest that attenuation at depths 30-60 km is high but decreases markedly within 75 km depth, high attenuation is also observed at depth greater than 90 km. We found that Q-1 value in this study has frequency dependency, which decrease gradually with frequency. Keywords: Attenuation, Coda, Philippine Sea Slab, Subduction, Kyushu Island. *Presented on Japan Geosciences Union Makuhari -May 2008

  13. Theoretical epidemiology on bovine ephemeral fever outbreaks in Tanegashima Island, Kagoshima Prefecture of Japan in 1988.

    PubMed

    Ogawa, T; Fujisono, S

    1992-10-01

    From the end of September to November 1988, a compact scale of bovine ephemeral fever (BEF) outbreaks occurred suddenly in Tanegashima island of Kagoshima Prefecture, southern part of Kyusyu island of Japan. The BEF outbreak pattern showed epidemical characteristics as follows; (1) outbreak spread from few foci to zone during one month, and (2) the disease might be transmitted in farms with a fixed probability of adequate contact. By using the above aspects, we attempted to analyze the disease theoretically with the application of Poisson distribution and Reed-Frost model. The BEF incidence in farms was in well accord with the Poisson distribution. As the very rare event occurred in unit time or in unit area in this epidemic, the cattle population at risk were equivalently susceptible to BEF virus in this island, due to the influence of no vaccination to BEF control before the first outbreak. Similarly, the epidemic curve of the Reed-Frost model was proved to fit well the incidence observed in a farm, and the probability of adequate contact was induced as p = 0.226. If the cattle population is less than 5 in this farm, the outbreak would not occur in the first instance. PMID:1420574

  14. 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.

  15. 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.

  16. 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.

  17. LEPTOSPIROSIS AFTER RECREATIONAL EXPOSURE TO WATER IN THE YAEYAMA ISLANDS, JAPAN

    PubMed Central

    NARITA, MASASHI; FUJITANI, SHIGEKI; HAAKE, DAVID A.; PATERSON, DAVID L.

    2009-01-01

    Leptospirosis is a global zoonotic disease with a variety of clinical manifestations. We report an outbreak of leptospirosis in the Yaeyama Islands, Japan, in the summer of 1999 associated with heavy rainfall. Fourteen people were diagnosed with leptospirosis and required hospitalization. All cases were found to have exposure to contaminated soil or water. A history of recreational activities involving water sports was more frequent (71%) than occupational risk factors related to agriculture or construction (29%). Fever was the primary symptom in all cases, followed by chills (93%), headache (86%), myalgias (57%) and conjunctival suffusion (57%). All cases were successfully treated with antimicrobial therapy except one patient who improved spontaneously. Jarisch-Herxheimer reactions were seen in six cases (43%). The increasing incidence of leptospirosis related to recreational sports is an important public health problem in resort areas. A high-index of suspicion, early treatment, and prevention are crucial in this latently endemic area. PMID:16222003

  18. 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

  19. Japan

    ERIC Educational Resources Information Center

    Hawkins, John N.

    1986-01-01

    Analyzes the intergroup relations in Japanese society and Japan's educational system. Challenges the view that Japan is a homogeneous society by presenting the various forms of discrimination against Koreans, Ainu, and the burakumin. Suggests that despite ostracism and isolation, groups can affect public policy and achieve social advancement. (SA)

  20. 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…

  1. 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.

  2. 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.

  3. 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)

  4. Repeating tectonic tremors on a middle-aged oceanic plate: Kyushu, Japan & North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Yabe, S.; Ide, S.

    2011-12-01

    Tectonic tremors and low-frequency earthquakes (LFEs) are observed in many subduction zones, where typically young and warm oceanic plate is subducting. Here we report the discovery of tectonic tremor in Kyushu, Japan and the North Island of New Zealand, where a middle-aged oceanic plate (>50Ma) is subducting. Generally, old oceanic plate is considered incapable of supplying water near the Moho discontinuity of the overriding plate, where tectonic tremor occurs in warm subduction zones, This is probably because dehydration reaction is delayed by the low temperature of old subducting plate, but the limit of the age or temperature for tremor generation has not been clear yet. Thus the discovery of tremor in middle-aged subduction zones helps to constrain the condition for tremor generation. We apply the envelope correlation method of Ide et al. (2010) to continuous records of Hi-net NIED for Kyushu and Geo-Net for the North Island. In both data sets, we find characteristic waveforms of tectonic tremors, which are dominant in frequency range at 2-8 Hz, with detectable S-wave arrivals and obscure P-waves, and successive for a long time. However, waveforms have very small amplitude, which makes low signal to noise ratio and has prevented detection. In Kyushu, we identify eight tremor episodes repeated almost every eight month, from April 2004 to September 2009. S-P times measured by cross-correlating envelopes between vertical and horizontal components indicate that these tremors occurred at 35-45 km depth, which might be a little shallower than the plate interface, since a receiver function study estimated the local depth of the plate interface as about 50 km (Abe et al., 2011). The distribution of tectonic tremors is limited in a small area, unlike wide and dense tremor activities in the Nankai subduction zone next to Kyushu. Beneath the North Island, Kim et al., (2011) discovered tectonic tremor near the northern end of the island and Fry et al. (2011) detected tectonic tremors triggered by surface wave from 2010 Chile Mw8.8 Earthquake near the center of the island. Tectonic tremors discovered in the present study are close to that reported by Fry et al. (2011), but they are not accompanied with triggering events. These tectonic tremors are located near the bottom edge of slow slip events (Wallace and Beavan, 2006), suggesting close relations.

  5. Molecular phylogeny and geographic distribution of wood-feeding cockroaches in East Asian Islands.

    PubMed

    Maekawa, K; Lo, N; Kitade, O; Miura, T; Matsumoto, T

    1999-11-01

    Molecular phylogenetic relationships of the wood-feeding cockroach genera Salganea and Panesthia (Blaberidae; Panesthiinae) in East Asian Islands (Ryukyu archipelago and Taiwan Island) were analyzed based on the DNA sequence of the complete mitochondrial cytochrome oxidase II gene. Unweighted parsimony analysis resulted in high bootstrap support for relationships within Panesthia taxa; however, some nodes were unresolved between members of Salganea. Comparison of the number of transitions and transversions with genetic distance at each codon position suggested that saturation of third-codon substitutions has occurred between certain pairs of taxa. Consequently, differential weighting of substitutions at these sites was performed, which resulted in a substantial increase in resolution of Salganea relationships. The inferred phylogenies for both genera displayed good correspondence to the geographical locations of populations but however did not agree with previous subspecies designations based on morphological characters. It appears that both cockroach genera invaded the Ryukyu archipelago from the Taiwan region via a land-bridge present in the Miocene period. Invasion of the main islands of Japan by these cockroaches most likely occurred before the formation of the Tokara Tectonic Strait. Our study suggests that several barriers to gene flow have arisen and persisted over the past approximately 10 million years, which have caused segregation and vicariant speciation of the cockroach taxa of this region. PMID:10603264

  6. 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

  7. 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

  8. Caldera deformation in Kyushu island (SW Japan) through InSAR data

    NASA Astrophysics Data System (ADS)

    Nobile, Adriano; Pepe, Susi; Ruch, Joel; Trippanera, Daniele; Casu, Francesco; Castaldo, Raffaele; Tizzani, Pietro; Aoki, Yosuke; Geshi, Nobuo; Acocella, Valerio; Sansosti, Eugenio; Siniscalchi, Valeria; Borgstrom, Sven; Zoffoli, Simona

    2014-05-01

    Calderas are the surface expression of a long-lived and complex magmatic system, often hosting a shallower hydrothermal system. Most monitored calderas have experienced some forms of unrest, even though only a part of these unrest episodes has culminated in an eruption. This study focuses on surface deformation analysis using InSAR from 1993 to 2013 at two large active calderas, Aso and Aira, located on Kyushu Island (Japan). Despite being closely monitored, our knowledge on the deformation history of both calderas with regard to their activity is poor. ERS, ENVISAT, ALOS and COSMO-SkyMed SAR images have been processed to obtain mean velocity deformation maps and time series through the SBAS technique. Results are then inverted using the simulated annealing technique to evaluate the deformation source parameters. Aso caldera hosts several vents in its central portion. One of these, the Naka Dake crater is the only currently active and erupted 7 times since 1993. From January 1996 to November 1998, after the important 1994 - 1995 eruption, we observed a subsidence of ~1.2 cm/yr at the center of the caldera. Analytical models suggest a deflating source (with various possible shapes) at 5-7 km of depth, implying a magmatic nature for the deformation. Inversion results are consistent with available seismic and GPS data. Aira Caldera hosts the Sakurajima volcano along its southern rim, with a persistent eruptive activity since 1950s. From June 2006 to March 2011, we observed a broad uplift of ~1.5 cm along most of the caldera rim. Analytical inversion of both the entire dataset and a cross-correlated dataset suggests a deformation source at the caldera center, at a depth of 5-9 km (depending on the source shape), implying a magmatic nature of the deformation. Inversion results are in agreement with GPS and InSAR data inversions for other periods of activity. This research has been partially performed within the frame of Italian Space Agency (ASI) and Japan Aerospace Exploration Agency (JAXA) bilateral cooperation. COSMOSkyMed and ALOS SAR data have been provided by ASI and JAXA within the SAR4Volcanoes project (ASI agreement n. I/034/11/0). ERS and ENVISAT SAR data have been provided through the GEO Geohazards Supersite initiative and ESA Category 1 proposal 7486.

  9. 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

  10. 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

  11. A new species of Psammogammarus (Amphipoda: Melitidae) from Kuchinoerabu Island, Japan, with a note on its feeding habits.

    PubMed

    Tomikawa, Ko; Kakui, Keiichi; Yamasaki, Hiroshi

    2010-07-01

    A new melitoid Amphipoda, Psammogammarus mawatarii, is described from Kuchinoerabu Island, Kagoshima Prefecture, Japan. This is the first record of the genus from Asia. The new species is morphologically similar to P. garthi, but differs from the latter in the following features: 1) lateral cephalic lobe of head not strongly produced; 2) head lacking antennal sinus; and 3) posteroventral corner of epimeral plate 3 rounded. Morphology of maxillae 1 and 2, and mandible, and gut contents (harpacticoid Copepoda) of P. mawatarii indicate that the feeding type of the species seems to be, at least facultatively, carnivorous. PMID:20608852

  12. Contamination status and accumulation characteristics of metals and a metalloid in birds on Teuri Island, Hokkaido, Japan.

    PubMed

    Ishii, Chihiro; Ikenaka, Yoshinori; Nakayama, Shouta M M; Suzuki, Yuya; Watanuki, Yutaka; Watanabe, Yuji; Yohannes, Yared Beyene; Mizukawa, Hazuki; Ishizuka, Mayumi

    2014-08-01

    Teuri Island, Hokkaido in Japan is an important place for seabirds breeding. We measured the concentrations of heavy metals (Hg, Cd, Cr, Co, Ni, Cu, Zn, and Pb) and a metalloid (As) in rhinoceros auklet (Cerorhinca monocerata) (n = 7), thick-billed murre (Uria lomvia) (n = 2), spectacled guillemot (Cepphus carbo) (n = 6), slaty-backed gull (Larus schistisagus) (n = 15), jungle crow (Corvus macrorhynchos) (n = 3), Japanese anchovy (Engraulis japonica) (n = 6) and Atka mackerel (Pleurogrammus azonus) (n = 2). Spectacled guillemot had high As concentrations, with its source being their feeding habitat. Concentration of Hg in kidney of jungle crow was higher than other seabird species at Teuri. PMID:25282956

  13. P-wave anisotropic velocity tomography beneath the Japan islands: Large-scale images and details in the Kanto district

    NASA Astrophysics Data System (ADS)

    Ishise, M.; Koketsu, K.; Miyake, H.; Oda, H.

    2006-12-01

    The Japan islands arc is located in the convergence zone of the North American (NA), Amurian (AM), Pacific (PAC) and Philippine Sea (PHS) plates, and its parts are exposed to various tectonic settings. For example, at the Kanto district in its central part, these four plates directly interact with each, so that disastrous future earthquakes are expected along the plate boundaries and within the inland areas. In order to understand this sort of complex tectonic setting, it is necessary to know the seismological structure in various perspectives. We investigate the seismic velocity structure beneath the Japan islands in view of P-wave anisotropy. We improved a hitherto-known P-wave tomography technique so that the 3-D structure of isotropic and anisotropic velocities and earthquake hypocenter locations are determined from P-wave arrival times of local earthquakes [Ishise and Oda, 2005]. In the tomography technique, P-wave anisotropy is assumed to hold hexagonal symmetry with horizontal symmetry axis. The P-wave arrival times used in this study are complied in the Japan University Network Earthquake Catalog. The results obtained are summarized as follows; (1) the upper crust anisotropy is governed by the present-day stress field arising from the interaction between the plates surrounding the Japan islands arc, (2) the mantle anisotropy is caused by the present-day mantle flow induced by slab subduction and continental plate motion, (3) the old PAC slab keeps its original slab anisotropy which was captured when the plate was formed, while the youngest part of the PHS slab has lost the original anisotropy during its subduction and has gained new anisotropy which is controlled by the present-day stress field. We also carried out a further study on high-resolution seismic tomography for understanding the specific characteristics of the Kanto district. We mostly focused on the elucidation of the dual subduction formed by the PHS and PAC slabs using seismological data compiled by the Natural Research Institute for Earth Science and Japan Meteorological Agency. This will lead to more accurate source modeling of future plate- boundary earthquakes.

  14. 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.

  15. 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

  16. 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.

  17. Influence of land development on Holocene Porites coral calcification at Nagura Bay, Ishigaki Island, Japan.

    PubMed

    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

  18. 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

  19. 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.

  20. Sedimentary characteristics of possible paleo-tsunami deposits in Shimanoura Island, Eastern Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Goto, K.; Shinozaki, T.; Fujino, S.

    2013-12-01

    According to the ancient documents and geological records, the Pacific coast of western Japan has been repeatedly affected by large tsunamis. Among the historical tsunamis, the AD 1707 Hoei earthquake tsunami was one of the well-documented events, and it is known that the 3.0-4.5 m high tsunami arrived at northeastern Kyushu, where our study site is located [Hatori, 1985]. One of the purposes of this study is to determine whether the AD 1707 Hoei earthquake tsunami deposits exist in our study site, because the distribution of its deposits in eastern Kyushu is barely known outside of Ryujin-lake [Matsuoka and Okamura, 2009]. In addition, the oldest tsunami record is the AD 1596 Keicho-Bungo earthquake tsunami, and little is known about prehistorical tsunamis in eastern Kyushu. Another purpose of this study is to unravel the history of tsunamis in our study site before AD 1596. Shimanoura Island, our study site, has a swampy flat behind a barrier spit. We conducted hand coring at 16 study points along a 200 m shore-perpendicular transect in the swamp and at four additional study points out of the transect. Samples were collected for grain-size analysis and radiocarbon dating. The 0-2.5 m sedimentary successions were composed mainly of organic-rich mud, but fine-medium sand with grading structure was observed just below the ground surface at all study points along the transect. These graded sand layers sometimes contain rip-up clasts, and their upper and lower boundaries were sharp. In addition, these sand layers showed both landward fining (0.89 φ at 72 m from the shoreline, 1.32 φ at 186 m from the shoreline) and landward thinning trend (20 cm at 72 m from the shoreline, 2 cm at 170 m from the shoreline). These trends imply that this sand sheet was probably formed by some event associated with a seawater inundation. Adding to the landward thinning and fining sand layer, there were 11 sand layers at a depth of 1-2 m at one of the four study points out of the transect. These are probably older than the sand layer observed at the transect. From now on, the radiocarbon ages and additional field survey will be needed to clarify the history of tsunamis in this study site.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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 (< 26.5σθ), 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 (> 26.5σθ), the change in nitrate concentration is small and the Kuroshio recirculation dominates the downstream increase of nitrate transport.

  8. Conservation of biodiversity: a critical time for the hermatypic corals of Japan

    NASA Astrophysics Data System (ADS)

    Veron, J. E. N.

    1992-04-01

    Results of a long-term study of the taxonomy, distribution and abundance of the hermatypic corals of the Ryukyu Is. and mainland Japan indicate that the present high diversity is threatened by a quantitative and qualitative decrease in available habitat caused by Acanthaster planci predation and human-induced environmental deterioration. Ninety-eight sites were studied, allowing detailed comparison between the three main groups of the Ryukyu Is. (Yaeyama, Okinawa and Amami Groups) and seven principal coral regions of mainland Japan (Tanegashima, Amakusa Is., the Tosashimizu and Kushimoto regions, and the Shirahama, Izu and Tateyama Peninsulas). Within this area, 400 species have been recorded and 9 additional species are recorded from the literature, from additional localities, or with doubt, from the Ryukyu Is. In non-mutually exclusive distribution and abundance categories for the Ryukyu Is. and mainland Japan: 129 species are common in at least some Japanese localities; 24 are widely dispersed within the Indo-Pacific, but occur in small, perhaps disjunct populations in Japan; 149 are uncommon throughout their Indo-west Pacific distribution ranges including Japan; 38 are restricted to the Yaeyama Group where all but three are uncommon or rare; 69 purely reefal (Ryukyu Is.) species are rare; 17 are rare in the Ryukyu Is. but are relatively common in mainaland locations; and 8 species appear to be endemic to mainland Japan and adjacent Asian countries. Some 37% of all Japanese hermatypic corals are uncommon throughout their range in Japan and are at some risk of regional extinction, 29% of others are rare and at substantial risk as they occur only in very limited areas of high diversity or in species-specific refuges. These sites are dientified. Of the 8 endemic species, 5 are primarily restricted to species-specific refuges. These data indicate an unstable situation. At least one third of all Japanese hermatypic species will eventually be at risk if the present causes of diversity decrease are not remedied.

  9. Differentials of Yayoi immigration to Japan as derived from dental metrics.

    PubMed

    Matsumura, H

    2001-01-01

    A major influx of new people, today termed Yayoi, migrated from the East Asian continent into the Japanese archipelago during the Aeneolithic and Protohistoric periods and interbred with the preexisting Jomon people. This study classifies ancient and more modern Japanese into natives or immigrants using discriminant analysis based on dental measurements in order to reconstruct the initial impact of the immigrants and the temporal and geographical differentials of mixture with the preexisting people. The results suggest that the earliest immigrants diffused into central Japan, including the Kanto region. The proportion of immigrant origin in the protohistoric Kofun was less in eastern Japan (72%) as compared to western Japan (81%-90%). The proportion of the immigrants in the Kanto District decreased during the medieval period (63%) and increased again in the early modern Edo and later modern times (75%), which might indicate that the gene flow still was occurring from west to east even in these times. Assuming the estimated proportions of either group reflect the intermixture ratio, the recent Japanese people may be regarded as hybrid of the native and immigrant groups with the following approximate ratios: 1:3 for the Kanto Japanese, 2:3 for the Ryukyu Islanders and 7:3 for the Hokkaido Ainu. These estimations support the "dual structure model" formed by Hanihara (1991) for explaining the population history of Japan. PMID:11802565

  10. 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.

  11. 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.

  12. 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

  13. 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 μM and 1400 μM, respectively, which represent strong enrichment of deep fluids in I and Br compared to seawater (I; 0.4 μM, Br; 840 μM). The ^{129}I/^{127}I ratios rapidly decrease with depth from the seawater value of 1500×10^{-15} to values between 400×10^{-15} and 600×10^{-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.

  14. 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.

  15. 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.

  16. A genetic analysis of the Sakishima islanders reveals no relationship with Taiwan aborigines but shared ancestry with Ainu and main-island Japanese.

    PubMed

    Matsukusa, Hirotaka; Oota, Hiroki; Haneji, Kuniaki; Toma, Takashi; Kawamura, Shoji; Ishida, Hajime

    2010-06-01

    The Sakishima islands are members of the Ryukyu island chain, stretching from the southwestern tip of the Japanese archipelago to Taiwan in the East China Sea. Archaeological data indicate cultural similarities between inhabitants of prehistoric Sakishima and Neolithic Taiwan. Recent studies based on tooth crown traits show remarkably high inter-island diversity among Ryukyu islanders, suggesting that the Sakishima islanders might have genetic backgrounds distinct from main-island Okinawa people. To investigate the genetic diversity of the Ryukyu islanders, we analyzed mtDNA, Y chromosome, and autosomal short tandem repeat loci in a sample of main-island Okinawa people and Sakishima (Miyako and Ishigaki) islanders whose participated in a previous study of tooth crown morphology. Our phylogenetic analysis of maternal (mtDNA) and paternal (Y chromosome) lineages shows that the Sakishima islanders are more closely related to people from the Japanese archipelago than to Taiwan aborigines. Miyako islanders and the Hokkaido Ainu have the first and second highest frequencies (respectively) of the Y-chromosomal Alu-insertion polymorphism, which is a presumable Jomon marker. Genetic diversity statistics show no evidence of demographic reduction or of extreme isolation in each island's population. Thus, we conclude that 1) Neolithic expansion from Taiwan did not contribute to the gene pool of modern Sakishima islanders, 2) male-lineage of the Ryukyu islanders likely shares a common ancestor with the Hokkaido Ainu who are presumably direct descendants of the Jomon people, and 3) frequent reciprocal gene flow among islands has masked the trace of common ancestry in the Ryukyu island chain. PMID:20091849

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. Current status of tropical fruit breeding and genetics for three tropical fruit species cultivated in Japan: pineapple, mango, and papaya.

    PubMed

    Ogata, Tatsushi; Yamanaka, Shinsuke; Shoda, Moriyuki; Urasaki, Naoya; Yamamoto, Toshiya

    2016-01-01

    Tropical fruit crops are predominantly produced in tropical and subtropical developing countries, but some are now grown in southern Japan. Pineapple (Ananas comosus), mango (Mangifera indica) and papaya (Carica papaya) are major tropical fruits cultivated in Japan. Modern, well-organized breeding systems have not yet been developed for most tropical fruit species. Most parts of Japan are in the temperate climate zone, but some southern areas such as the Ryukyu Islands, which stretch from Kyushu to Taiwan, are at the northern limits for tropical fruit production without artificial heating. In this review, we describe the current status of tropical fruit breeding, genetics, genomics, and biotechnology of three main tropical fruits (pineapple, mango, and papaya) that are cultivated and consumed in Japan. More than ten new elite cultivars of pineapple have been released with improved fruit quality and suitability for consumption as fresh fruit. New challenges and perspectives for obtaining high fruit quality are discussed in the context of breeding programs for pineapple. PMID:27069392

  3. Current status of tropical fruit breeding and genetics for three tropical fruit species cultivated in Japan: pineapple, mango, and papaya

    PubMed Central

    Ogata, Tatsushi; Yamanaka, Shinsuke; Shoda, Moriyuki; Urasaki, Naoya; Yamamoto, Toshiya

    2016-01-01

    Tropical fruit crops are predominantly produced in tropical and subtropical developing countries, but some are now grown in southern Japan. Pineapple (Ananas comosus), mango (Mangifera indica) and papaya (Carica papaya) are major tropical fruits cultivated in Japan. Modern, well-organized breeding systems have not yet been developed for most tropical fruit species. Most parts of Japan are in the temperate climate zone, but some southern areas such as the Ryukyu Islands, which stretch from Kyushu to Taiwan, are at the northern limits for tropical fruit production without artificial heating. In this review, we describe the current status of tropical fruit breeding, genetics, genomics, and biotechnology of three main tropical fruits (pineapple, mango, and papaya) that are cultivated and consumed in Japan. More than ten new elite cultivars of pineapple have been released with improved fruit quality and suitability for consumption as fresh fruit. New challenges and perspectives for obtaining high fruit quality are discussed in the context of breeding programs for pineapple. PMID:27069392

  4. 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).

  5. 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

  6. 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.

  7. 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.

  8. Relationship between Health-Seeking Behavior by Basic Health Examination and Subsequent Health Expenditure among Remote Island Inhabitants of Japan

    PubMed Central

    Kinjo, Aya; Myoga, Yoshinori; Osaki, Yoneatsu

    2014-01-01

    Background Convincing evidence has not been obtained as to whether having a basic health examination in the prime of life inhibits the surge of health expenditure in old age. Methods Data sources: Data on participants in the basic health examination from 1996 to 2000 among residents of a remote island in Japan, and individual health care expenditure data from March 2005 to February 2008. Study design: A community-based retrospective study. Data collection: Japanese residents who were subscribers to the National Health Insurance Scheme of Chibu Town from March 1996 to March 2007 and were aged 40 to 64 years in March 1996 (n = 179) were divided into 3 groups depending on the frequency of participating in the basic health examination over 5 years: 0 times (nontakers), 1 to 3 times (occasional takers), or 4 to 5 times (regular takers). The distribution of total health expenditure according to the frequency of having a basic health examination was determined, and the Cochrane-Armitage test was used for comparison. Results Nontakers formed the highest proportion of subjects with low expenditure (0–200,000 yen) (nontaker, occasional, regular: 38.5%, 24.1%, 23.5%; P = 0.002), and also accounted for the highest proportion of subjects with high expenditure (> 1,400,000 yen) (33.3%, 16.1%, 9.4%; P = 0.004). Conclusion Persons not participating in health examinations during middle age include a group with high future health care expenditure. PMID:25349465

  9. Geographical origin and sexual-system evolution of the androdioecious plant Gynochthodes boninensis (Rubiaceae), endemic to the Bonin Islands, Japan.

    PubMed

    Oguri, Emiko; Sugawara, Takashi; Peng, Ching-I; Yang, T Y Aleck; Murakami, Noriaki

    2013-09-01

    Gynochthodes boninensis is a woody climber endemic to the Bonin Islands, Japan. It is characterized by an androdioecious sexual system, which is rare in angiosperms. We conducted a molecular phylogenetic analysis of 29 taxa including 61 samples from the tribe Morindeae to elucidate the geographical origin of G. boninensis by determining its progenitor species. We also investigated evolutionary transitions among different sexual systems within this plant group. The combined ETS, ITS, and trnT-F sequence data showed that G. boninensis formed a monophyletic group, but it did not form a clade with G. umbellata, which was treated as the same species, whereas it formed a clade with G. parvifolia, which is distributed in southeastern Asia. This suggests that G. boninensis evolved independently from G. umbellata, and probably originated from a progenitor native to southeastern Asia. In the clade composed of the three species of G. boninensis, G. parvifolia, and G. umbellata, only G. boninensis is androdioecious, whereas the others are dioecious. Thus, the androdioecious sexual system of G. boninensis may have evolved from dioecy. PMID:23639296

  10. 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

  11. 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.

  12. 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

  13. Entamoeba marina n. sp.; a New Species of Entamoeba Isolated from Tidal Flat Sediment of Iriomote Island, Okinawa, Japan.

    PubMed

    Shiratori, Takashi; Ishida, Ken-Ichiro

    2016-05-01

    The genus Entamoeba includes anaerobic lobose amoebae, most of which are parasites of various vertebrates and invertebrates. We report a new Entamoeba species, E. marina n. sp. that was isolated from a sample of tidal flat sediment collected at Iriomote Island, Okinawa, Japan. Trophozoites of E. marina were 12.8-32.1 μm in length and 6.8-15.9 μm in width, whereas the cysts were 8.9-15.8 μm in diam. and contained four nuclei. The E. marina cells contained a rounded nucleus with a small centric karyosome and uniformly arranged peripheral chromatin. Although E. marina is morphologically indistinguishable from other tetranucleated cyst-forming Entamoeba species, E. marina can be distinguished from them based on the combination of molecular phylogenetic analyses using SSU rDNA gene and the difference of collection sites. Therefore, we propose E. marina as a new species of the genus Entamoeba. PMID:26452446

  14. 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.

  15. 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.

  16. Asymmetrically multi-collapsed structure of Kikai caldera in southern off Kyushu Island, Japan: A reconstruction from seismic reflection images

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Kikai caldera (Matsumoto, 1943) is a mostly submerged highly active caldera complex located in the southern Japan 40 km off Kyushu Island. The caldera has bathymetrically two rims partially that are previously considered as older-outer and newer-inner ones (Yokoyama et al., 1966). The caldera is believed to be the source of Akahoya tephra (Machida and Arai, 1978) which date was determined as 7300 cal. BP (Fukusawa, 1995) which is the most recent VEI-7 class eruption in the eastern margin of Asia. Intense earthquakes (Naruo and Kobayashi, 2002), low-aspect ratio Koya ignimbrite (Maeno and Taniguchi, 2007) and tsunami (Geshi, 2009) are presumed to have taken place at the climax of the eruption. There are at least two other series of giant eruption deposits that are considered to have originated from the Kikai caldera (Ono et al., 1986) and this indicates that it has been serving as an eruptive center for the past 150,000 years. We conducted seismic reflection observations 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). 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. First, the absence of large fault in northern and western caldera rim indicates Kikai likely had an asymmetric "trapdoor" style collapse (Lipman, 1995) rather than the ideal "piston" type one. Inner and outer topographic rims at the east to south do correspond with large faults, however the both of them may have worked in 7300 BP eruption because they reach to the seafloor. Such asymmetric multi-collapse would provide some characteristics to the climactic pyroclastic flow in 7300 BP. Second, the bathymetric rise at the center of the caldera consists of high-amplitude surface and chaotic thick facies outwardly collapsed by intense normal faulting. Topographically gully-shaped structures at the northeast flank correspond the faulting. Because they are never buried by other deposits, possibly the structure is brought by catastrophic landslide event just after the 7300 BP eruption. Third, at least three sequences of hundreds of meters height chaotic and stratified facies are seen on the slope at the southern outskirts of the Kikai. Those sequences should reflect cyclic giant eruptions in the past.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. [The causative agent from a patient with spotted fever group rickettsiosis in Japan on Awaji Island, Hyogo].

    PubMed

    Kobayashi, Y; Tange, Y; Okada, T; Kodama, K

    1990-04-01

    Misaka strain was isolated as the causative agent from a patient with spotted fever group rickettsiosis in Japan by using nude mice on Awaji Island, Hyogo in September 1988. The nude mice infected with the isolate showed weakness and splenomegaly and died in two or three weeks after the infection. The cyclophosphamide-treated mice infected with the isolate died between four and seven days after the infection. The infected normal mice recovered and acquired immunity. The infected adult male guinea pigs were feverish and showed swelling and redness of the scrotum between two and eight days after the infection, and recovered. The Misaka strain was propagated well in Vero cells in tissue culture. The rickettsial particles were seen as diplobacillary and diplococcal forms growing predominantly in the cytoplasm and occasionally in the nucleus of infected cells. The serological characteristics of the Misaka strain were analyzed by the cross-immunofluorescent antibody method. The Misaka strain, the Katayama strain first isolated in Tokushima in 1987, and the representative strains of spotted fever group rickettsiae in the world; R. rickettsii Smith, R. sibirica 246, R. conorii Moroccan, R. akari MK (Kaplan), R. australis Phillips, R. montana Tick and Thai TT-118 strains were used as antigens. And immune mouse serum samples against the Misaka, Katayama, 246, Phillips and TT-118 strains were used as antisera. The result revealed that these strains showed cross-reaction and share a common antigen of spotted fever group rickettsiae. Furthermore, it became obvious that the Misaka strain and the Katayama strain have the same serotype-specific antigen different from the strains of other spotted fever group rickettsiae using Anti-Katayama monoclonal antibodies. PMID:2205668

  3. 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

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

    PubMed

    Novković, Biljana; Kimura, Masahito T

    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

  5. A tale of two seas: Reservoir age correction values ( R, Δ R) for the Sakhalin Island (Sea of Japan and Okhotsk Sea)

    NASA Astrophysics Data System (ADS)

    Kuzmin, Y. V.; Burr, G. S.; Gorbunov, S. V.; Rakov, V. A.; Razjigaeva, N. G.

    2007-06-01

    This paper presents reservoir age determinations of pre-bomb marine mollusc shells from Sakhalin Island, Sea of Japan and Okhotsk Sea. The samples were collected from Japanese waste disposal sites created between 1905 and 1945. Radiocarbon analyses of the shells are used to establish marine reservoir age corrections for each site. The ΔR value for the Sea of Japan, +95 ± 60 years, is consistent with previous data. The ΔR value for the Okhotsk Sea is found to be +578 ± 50 years. The large difference in reservoir age between the two locations results from significantly different sources of surface water. The water source for the Sea of Japan is the Tsushima Current, a branch of the Kuroshio Current that originates in the equatorial Pacific and has a ΔR value close to the mean ocean value. The primary water source for the Okhotsk Sea is the Oyashio Current, which transports water from the Bering Sea in the open Northern Pacific. This source is depleted with 14C, as compared with waters of the equatorial Pacific. The southern Kuriles (Zeleny and Yuri islands) reflect a mixture of Oyashio and Kuroshio waters, with a ΔR value of +354 ± 23 years.

  6. Nagoya, Ise Bay, Japan

    NASA Technical Reports Server (NTRS)

    1982-01-01

    This view of Nagoya, Ise Bay and nearby Kyoto, on the main island of Honshu, Japan (35.0N, 137.0E) combines in a single photo both the political, cultural and educational centers of early Japan as well as one of the main educational and business centers of modern Japan. Besides being a business, cultural and educational center, Nagoya is near the geographic center of the Japanese home islands.

  7. A new species of the genus Ocadia (Testudines: Geoemydidae) from the middle Miocene of Tanegashima Island, southwestern Japan and its paleogeographic implications.

    PubMed

    Takahashi, Akio; Ōki, Kimihiko; Ishido, Takahiro; Hirayama, Ren

    2013-01-01

    A new geoemydid turtle, Ocadia tanegashimensis (Testudines: Geoemydidae) is described on the basis of a relatively well-preserved shell from the lower middle Miocene of Tanegashima Island, Kagoshima Prefecture, southwestern Japan. This species is clearly distinguished from two congeneric species (extant O. sinensis and O. nipponica from the middle Pleistocene of eastern Japan) due to the presence of the following character states: length of the entoplastron as long as the interhyoplastral suture, the costals dovetailed with one another in outline, the third pleural overlapping only the sixth and seventh peripherals. The present study suggests that the initial intrageneric diversification of Ocadia began not later than the early Miocene in eastern Asia. PMID:26295126

  8. 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.

  9. 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

  10. 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.

  11. 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 Tribeč 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

  12. 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.

  13. Japan: Shikoku Island

    Atmospheric Science Data Center

    2013-04-16

    ... apply new spacecraft measurements to global climate change research, they must carefully test their understanding of the data under ... left part of the images. At the same time, the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter ...

  14. 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.

  15. Analysis of Genetic Variation and Phylogeny of the Predatory Bug, Pilophorus typicus, in Japan using Mitochondrial Gene Sequences

    PubMed Central

    Ito, Katsura; Nishikawa, Hiroshi; Shimada, Takuji; Ogawa, Kohei; Minamiya, Yukio; Tomoda, Masafumi; Nakahira, Kengo; Kodama, Rika; Fukuda, Tatsuya; Arakawa, Ryo

    2011-01-01

    Pilophorus typicus (Distant) (Heteroptera: Miridae) is a predatory bug occurring in East, Southeast, and South Asia. Because the active stages of P. typicus prey on various agricultural pest insects and mites, this species is a candidate insect as an indigenous natural enemy for use in biological control programs. However, the mass releasing of introduced natural enemies into agricultural fields may incur the risk of affecting the genetic integrity of species through hybridization with a local population. To clarify the genetic characteristics of the Japanese populations of P. typicus two portions of the mitochondrial DNA, the cytochrome oxidase subunit I (COI) (534 bp) and the cytochrome B (cytB) (217 bp) genes, were sequenced for 64 individuals collected from 55 localities in a wide range of Japan. Totals of 18 and 10 haplotypes were identified for the COI and cytB sequences, respectively (25 haplotypes over regions). Phylogenetic analysis using the maximum likelihood method revealed the existence of two genetically distinct groups in P. typicus in Japan. These groups were distributed in different geographic ranges: one occurred mainly from the Pacific coastal areas of the Kii Peninsula, the Shikoku Island, and the Ryukyu Islands; whereas the other occurred from the northern Kyushu district to the Kanto and Hokuriku districts of mainland Japan. However, both haplotypes were found in a single locality of the southern coast of the Shikoku Island. COI phylogeny incorporating other Pilophorus species revealed that these groups were only recently differentiated. Therefore, use of a certain population of P. typicus across its distribution range should be done with caution because genetic hybridization may occur. PMID:21526929

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Anatahan Island

    Atmospheric Science Data Center

    2013-04-19

    ... the Philippine Sea plate creates a series of island arc volcanoes and the Earth's deepest ocean trench. Anatahan had no known ... Mariana of Austria, the widow of Spanish King Philip IV. Japan took control of the Mariana Islands in 1914 (the first year of World War ...

  3. 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.

  4. 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.

  5. Fabric characterization associated with asthenospheric upwelling in the uppermost mantle, back-arc region of the southwest Japan arc: Evidence from peridotite xenoliths, Oki-Dogo Island

    NASA Astrophysics Data System (ADS)

    Satsukawa, Takako; Michibayashi, Katsuyoshi

    2010-05-01

    Oki-Dogo Island is an important site in terms of xenoliths because it makes the most continent ward occurrence of mantle peridotite xenoliths in the back-arc region of the southwest Japan arc. We describe the microstructure of peridotite xenoliths obtained from Oki-Dogo Island with aim of understanding the evolution of the uppermost mantle beneath the back-arc side of the Japan arc. Basement on the island consists of gneissic metamorphic complex. The alkaline basalts that contain the xenoliths were erupted during the Pliocene-Pleistocene after the opening of the Japan Sea which is thought to have occurred during the Oligocene-Miocene as a consequence of back-arc spreading. Peridotite xenoliths found on Oki-Dogo Island are up to 10 cm in size, show granular texture, and are mainly spinel lherzolites, with some harzburgites. Large xenoliths (> 3 cm) contain a foliation defined by compositional banding and aligned spinel grains, and a lineation defined by the long axes of spinel grains. All spinel lherzolites contain spinel with a low Cr# (=Cr/Fr+Al) (< 0.45); this feature, combined with their mineral assemblages and high NiO content in olivine, suggests that they are of residual origin. The Mg# (=Mg/Mg+Fe) of silicate minerals in some spinel lherzolites is lower (e.g. down to Fo86) than that in typical residual peridotites of the upper mantle, indicating that the observed Fe enrichment occurred in mantle rocks during metasomatism. We have measured crystallographic preferred orientations (CPOs) of olivine grains from highly polished thin sections using a scanning electron microscope equipped with an electron backscatter diffraction system. The dominant slip system in olivine, as determined from kink bands and CPO data, was {0kl}[100] slip. Moreover, peridotites with low olivine Mg# tend to show a AG-type ([010]-fiber) CPO pattern. This finding suggests that the peridotites were deformed in the presence of melt and represent various degrees of rock-melt interaction as supported by petrologic and geochemical studies. In particular, the decreasing of olivine Mg# is correlated with not only a decrease in crystallographic fabric strength (J-index) but also the change in olivine CPO. Thus, heat transfer from a neighboring large-scale partial melting domain (or ‘asthenospherized' mantle) results in an extremely high thermal gradient in this domain, which controls both deformation distribution and the melt migration ahead of the partial melting zone. The variation of in olivine CPO intensities implies that the presence of melt result in a higher contribution of diffusion to deformation, leading to a slower CPO evolution. Thus, peridotites in SW Japan derived from the uppermost mantle were deformed in the melting field due to asthenospheric upwelling associated with back-arc spreading. Consequently, the uppermost mantle peridotites in the back-arc region of the SW Japan were deformed on a condition that melts distributed no homogeneous field due to the asthenosphere upwelling of back-arc spreading. And now, they erupt with keeping structures formed by the back-arc spreading.

  6. Spatial variation of the crustal stress field along the Ryukyu-Taiwan-Luzon convergent boundary

    NASA Astrophysics Data System (ADS)

    Wu, Wen-Nan; Kao, Honn; Hsu, Shu-Kun; Lo, Chung-Liang; Chen, How-Wei

    2010-11-01

    We applied an improved stress inversion method to a comprehensive data set of earthquake focal mechanisms to depict the pattern of crustal stress along the western convergent boundary of the Philippine Sea plate. Our results indicate that the crustal stress along the Ryukyu fore arc is segmented with boundaries at or near the places of seamount subduction, including the Tokara channel. An extensional stress regime is observed along the entire Ryukyu back arc, implying that back-arc rifting may have extended northward to Kyushu. A triangular area near the southernmost terminus of the Ryukyu arc is characterized by a unique stress signature. The eastern boundary of this Ryukyu-Taiwan Stress Transition coincides with the 123°E meridian where the Gagua ridge intercepts the Ryukyu trench; whereas its western boundary agrees remarkably well with the border between the postcollision and waning-collision domains in northern Taiwan. The Taiwan collision zone is dominated by compression that rotates locally according to the structural configuration of the Lukang Magnetization High (LMH), suggesting that the LMH may be critical in controlling the local stress distribution. The stress signature of the Luzon arc-Taiwan collision reaches as far south as 19.5°N. The tectonic stress along the Manila trench-Luzon fore arc is dominated by a complex regime of extension that cannot be explained by simple plate bending or in-slab membrane stress. Since this extensional regime is observed only south of ˜22°N, it probably marks the northern limit of the contemporary boundary between the subduction along the Manila trench and the collision in Taiwan.

  7. 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.

  8. Molecular characterization of Cryptosporidium parvum detected in Japanese black and Holstein calves in Iwate Prefecture and Tanegashima Island, Kagoshima Prefecture, Japan.

    PubMed

    Aita, Junya; Ichikawa-Seki, Madoka; Kinami, Aiko; Yaita, Seiko; Kumagai, Yoshihiro; Nishikawa, Yoshifumi; Itagaki, Tadashi

    2015-08-01

    Cryptosporidium oocysts were found in 43 out of 77 calves from two farms in Iwate Prefecture and nine farms on Tanegashima Island, Kagoshima Prefecture, Japan. The DNA fragments of 18S ribosomal RNA (18S rRNA) gene were amplified by a nested PCR from 43 oocyst-positive as well as one oocyst-negative samples. All of them were precisely identified as C. parvum by analyzing the nucleotide sequences of the 18S rRNA gene. C. parvum oocyst-positive calves ranged in age from 6 to 13 days old and significantly have watery diarrhea (P<0.05). Sequences of the gene encoding the 60-kDa glycoprotein (GP60) in 43 Cryptosporidium oocyst-positive samples were identical to that of the zoonotic IIaA15G2R1 subtype. We therefore suggest that calves could be potential sources of C. parvum infections in humans. PMID:25819544

  9. Molecular characterization of Cryptosporidium parvum detected in Japanese black and Holstein calves in Iwate Prefecture and Tanegashima Island, Kagoshima Prefecture, Japan

    PubMed Central

    AITA, Junya; ICHIKAWA-SEKI, Madoka; KINAMI, Aiko; YAITA, Seiko; KUMAGAI, Yoshihiro; NISHIKAWA, Yoshifumi; ITAGAKI, Tadashi

    2015-01-01

    Cryptosporidium oocysts were found in 43 out of 77 calves from two farms in Iwate Prefecture and nine farms on Tanegashima Island, Kagoshima Prefecture, Japan. The DNA fragments of 18S ribosomal RNA (18S rRNA) gene were amplified by a nested PCR from 43 oocyst-positive as well as one oocyst-negative samples. All of them were precisely identified as C. parvum by analyzing the nucleotide sequences of the 18S rRNA gene. C. parvum oocyst-positive calves ranged in age from 6 to 13 days old and significantly have watery diarrhea (P<0.05). Sequences of the gene encoding the 60-kDa glycoprotein (GP60) in 43 Cryptosporidium oocyst-positive samples were identical to that of the zoonotic IIaA15G2R1 subtype. We therefore suggest that calves could be potential sources of C. parvum infections in humans. PMID:25819544

  10. 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

  11. Trial of multidisciplinary observation at an expandable sub-marine cabled station "off-hatsushima island observatory" in sagami bay, Japan.

    PubMed

    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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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).

  20. 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)

  1. 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 128°E 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.

  2. Nested Architecture of Pyroclastic Bedforms Generated by a Single Flow Event: Outcrop Examples from the Izu Volcanic Islands, Japan

    NASA Astrophysics Data System (ADS)

    Nemoto, Y.; Yoshida, S.

    2009-12-01

    We claim that compound bedforms, where small bedforms (e.g., dunes and antidunes) occur within and around the larger bedforms, are common in pyroclastic-flow deposits, using Quaternary-Holocene outcrop examples from the modern Izu volcanic island chain some 100-150 km SSW of Tokyo. The nested occurrence of bedforms have been well documented for siliciclastic deposits, as exemplified by compound dunes where small dunes (c. cm- dm thick) occur between the avalanche surfaces within larger dunes, indicating that these dunes of different sizes were produced simultaneously. However, compound dunes have rarely been reported from pyroclastic deposits. In contrast, we have discovered that compound dunes are common in pyroclastic flow deposits in the late Pleistocene & Holocene outcrops in Niijima and Oshima of the Izu volcanic island chain. Moreover, these outcrops contain abundant compound antidunes, which have been reported from neither siliciclastic or pyroclastic deposits. This is probably because flume studies, where most of published antidune studies are based, focus on small (c. cm-dm high) antidunes. In Niijima Island, we examined pyroclastic-flow deposits shed from Mt. Miyatsuka (14 ka) and Mt. Mukai (886 A.D.). Both groups of deposits contain abundant antidune stratifications, which commonly form nested structures in a two- or three-fold hierarchy, with subordinate crossbeddings originated from dune migrations. Each class of antidunes is characterized by multiple scour surfaces and vertical aggradations around mounds of lag deposits above erosion surfaces, and typically has both upstream and downstream accretion components with different proportions. The late Pleistocene pyroclastic outcrops of the nearby Oshima Island exhibit similar patterns. The geometry of the accretion surfaces vary significantly in the outcrops of both Niijima and Oshima. Whereas the antidunes dominated by upstream accretion are characterized by (1) gently inclined accretion surface and (2) round crest shape, the antidunes dominated by downstream accretion are characterized by (i) steep accretion surface that commonly exceed the angle of repose and (ii) angular to cuspate crest shape. The mechanism in charge of generating the compound antidunes is unclear; however, observations of standing waves in the modern siliciclastic depositional environments (e.g., shallow running water on the beach) suggest that compound antidunes are produced by a gravitational collapse of the crest of large and exceedingly steepened standing waves. When the crest collapes, it commonly breaks into two smaller standing waves that are positioned on the flanks of the large (but now slightly deflated) standing wave, and stay there until the angle of the flanks increases again to form a new large standing wave. The collapse-rebuilding cycle persists as long as the flow condition is sustained.

  3. Contents of various elements in the organs of seabirds killed by an oil spill around Tsushima Island, Japan.

    PubMed

    Mochizuki, Mariko; Yamamoto, Hanae; Yamamura, Risa; Suzuki, Tomoko; Ochiai, Yoshitsugu; Kobayashi, Jun; Kawasumi, Koh; Arai, Toshiro; Kajigaya, Hiroshi; Ueda, Fukiko

    2013-01-01

    Twenty nine oil-soaked birds were collected from around the Coast of Tsushima Island. The contents of eight elements in the livers and kidneys of the birds were investigated. Statistically higher concentrations of vanadium and thallium in the liver and of titanium in the kidney were found in the birds that were found dead compared with those that died after rescued. A significant correlation (r=0.695, P<0.01) was observed only for the molybdenum content between the kidneys and livers from the birds found dead. Although the controls of the eight elements of birds investigated in the present study remain unexplained, some of lower concentration in rescued birds can be blamed on a decrease in food intake of birds. The relation between oil contamination and concentration of elements need to be further explored. PMID:23292103

  4. Stable Isotope Anomalies and Low Chloride Concentrations in Pore Water of CH4-Rich Sediments at the Tanegashima Mud Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Nakayama, N.; Tsunogai, U.; Ashi, J.; Gamo, T.

    2004-12-01

    Pore water from sediments collected at a Tanegashima mud volcano was analyzed for δ 13C (PDB) of dissolved CH4 together with other chemical components, Cl- and SO42-, and the δ 18O and δ D (SMOW). The Tanegashima mud volcanoes are located at the water depths from 1400 m to 1800 m, off Tanegashima island between Ryukyu trench and Ryukyu arc of Japan. It is situated at the end of south-western convergent plate boundary on Nankai-trough, which forms a part of Philippine Sea plate subducting under Eurasian plate. This cruise was conducted as a part of the JNOC (Japan National Oil Corporation) geochemical survey by R/V Hakurei-maru II. The concentrations of CH4 were generally higher than 100 micro-mol/kg. Its highest concentration (715 micro-mol/kg) was found in the crest core of a mud volcano. The δ 13C values ranged from -32 to -50 ‰ . C2H6 was detected only in the pore waters collected from the vicinity of the crest of the mud volcano. The highest δ 13C (around -22 ‰ ) and low C1/C2 concentration ratios (less than 100) were measured at the crest site, supporting the thermogenical production of methane. Other geochemical anomalies were also observed in the crest pore water. The concentrations of Cl- in the pore water at this site were extremely depleted to a minimum of 350 mmol/kg. The Cl- anomaly has not been previously reported for pore water from mud volcanoes around Japan. An endmember of isotopic composition of the fluid is estimated to be +12 ‰ for δ 18O and -40 ‰ for δ D. From these results we conclude that the most likely process to reduce pore water salinity is primarily the mixing of clay mineral dehydration water with seawater. The thermogenic methane found in the crest pore waters of the Tanegashima mud volcano may be brought from the depths of sediments due to the migration of fluid evolved by mineral the dehydration process.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. Overwintering strategies of mosquitoes (Diptera:Culicidae) on warmer islands may predict impact of global warming on Kyushu, Japan.

    PubMed

    Mogi, M

    1996-05-01

    Mosquito overwintering was studied on Tanegashima and Yakushima, islands south of Kyushu, to predict the impact of global warming on northern Kyushu where mosquitoes overwinter in diapause. On Tanegashima and Yakushima, the following 5 types of overwintering strategies were recognized: (1) continued reproduction without diapause (2 Anopheles spp., 2 Culex spp., 2 Aedes spp.); (2) diapausing female adults but a few adults from late-developing larvae may emerge in midwinter (2 Anopheles spp. and 9 culex spp.); (3) diapausing eggs but a few adults may emerge in midwinter (5 Aedes spp.); (4) diapausing larvae (1 Orthopodomyia sp., 1 Aedes sp., 1 Armigeres sp., 1 Uranotaenia sp., 1 Toxorhynchites sp.); and (5) diapausing eggs and larvae (1 Tripteroides sp.). Few females of 4 aedine species were collected while seeking hosts in midwinter, but neither larvae nor adults of Culex tritaeniorhynchus Giles or southern house mosquito, Culex quinquefasciatus Say, were found during this survey. The 5 degrees C increase in the midwinter mean temperature in northern Kyushu probably will not produce serious mosquito problems directly, but the proximity of the subtropical regions may have significant effects through dispersal of adult mosquitoes. PMID:8667392

  11. 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.

  12. In situ stress magnitudes at the toe of the Nankai Trough Accretionary Prism, offshore Shikoku Island, Japan

    NASA Astrophysics Data System (ADS)

    Huffman, K. A.; Saffer, D. M.

    2016-02-01

    Quantifying the orientation and magnitude of tectonic stresses is essential toward understanding deformation and faulting in subduction zones. However, constraints on in situ horizontal stress magnitudes (Shmin and SHmax) are rare. We estimate Shmin and SHmax at Ocean Drilling Program Site 808 at the toe of the Nankai accretionary prism offshore Japan, using coupled constraints from (1) the width of wellbore breakouts together with estimates of rock strength and a model describing stress redistribution at the borehole wall and (2) limits on regional differential stress defined by failure on preexisting faults. Our analysis extends from 175 to 915 m below seafloor (mbsf) and spans the active frontal thrust. For an upper bound on rock unconfined compressive strength (UCS) and assuming hydrostatic formation pore pressure, Shmin and SHmax (referenced to the seafloor) increase from 6.5 MPa at 175 mbsf to 17.4 MPa at 915 mbsf, with the stress state gradually transitioning from a thrust or strike-slip faulting regime above 800 mbsf to a normal faulting regime below. For cases with higher formation pore pressure, horizontal stresses are slightly lower but follow a similar pattern. We show that estimated Shmin and SHmax are strongly dependent on UCS, breakout width, and friction coefficient, all of which are characterized by uncertainty. Our results suggest that the prism is near thrust failure in the upper ~300 mbsf, but far from failure below. This may be reconciled with active thrusting if thrust faults are locally weaker than the surrounding rock or if SHmax fluctuates during the seismic cycle.

  13. 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.

  14. Genetic differentiation and connectivity of morphological types of the broadcast-spawning coral Galaxea fascicularis in the Nansei Islands, Japan.

    PubMed

    Nakajima, Yuichi; Zayasu, Yuna; Shinzato, Chuya; Satoh, Noriyuki; Mitarai, Satoshi

    2016-03-01

    Population connectivity resulting from larval dispersal is essential for the maintenance or recovery of populations in marine ecosystems, including coral reefs. Studies of species diversity and genetic connectivity within species are essential for the conservation of corals and coral reef ecosystems. We analyzed mitochondrial DNA sequence types and microsatellite genotypes of the broadcast-spawning coral, Galaxea fascicularis, from four regions in the subtropical Nansei Islands in the northwestern Pacific Ocean. Two types (soft and hard types) of nematocyst morphology are known in G. fascicularis and are significantly correlated with the length of a mitochondrial DNA noncoding sequence (soft type: mt-L; hard type: mt-S type). Using microsatellites, significant genetic differentiation was detected between the mitochondrial DNA sequence types in all regions. We also found a third genetic cluster (mt-L+), and this unexpected type may be a cryptic species of Galaxea. High clonal diversity was detected in both mt-L and mt-S types. Significant genetic differentiation, which was found among regions within a given type (F ST = 0.009-0.024, all Ps ≤ 0.005 in mt-L; 0.009-0.032, all Ps ≤ 0.01 in mt-S), may result from the shorter larval development than in other broadcast-spawning corals, such as the genus Acropora. Nevertheless, intraspecific genetic diversity and connectivity have been maintained, and with both sexual and asexual reproduction, this species appears to have a potential for the recovery of populations after disturbance. PMID:27087925

  15. Photochemical age of air pollutants, ozone, and secondary organic aerosol in transboundary air observed on Fukue Island, Nagasaki, Japan

    NASA Astrophysics Data System (ADS)

    Irei, Satoshi; Takami, Akinori; Sadanaga, Yasuhiro; Nozoe, Susumu; Yonemura, Seiichiro; Bandow, Hiroshi; Yokouchi, Yoko

    2016-04-01

    To better understand the secondary air pollution in transboundary air over westernmost Japan, ground-based field measurements of the chemical composition of fine particulate matter ( ≤ 1 µm), mixing ratios of trace gas species (CO, O3, NOx, NOy, i-pentane, toluene, and ethyne), and meteorological elements were conducted with a suite of instrumentation. The CO mixing ratio dependence on wind direction showed that there was no significant influence from primary emission sources near the monitoring site, indicating long- and/or mid-range transport of the measured chemical species. Despite the considerably different atmospheric lifetimes of NOy and CO, these mixing ratios were correlated (r2 = 0.67). The photochemical age of the pollutants, t[OH] (the reaction time × the mean concentration of OH radical during the atmospheric transport), was calculated from both the NOx / NOy concentration ratio (NOx / NOy clock) and the toluene / ethyne concentration ratio (hydrocarbon clock). It was found that the toluene / ethyne concentration ratio was significantly influenced by dilution with background air containing 0.16 ppbv of ethyne, causing significant bias in the estimation of t[OH]. In contrast, the influence of the reaction of NOx with O3, a potentially biasing reaction channel on [NOx] / [NOy], was small. The t[OH] values obtained with the NOx / NOy clock ranged from 2.9 × 105 to 1.3 × 108 h molecule cm-3 and were compared with the fractional contribution of the m/z 44 signal to the total signal in the organic aerosol mass spectra (f44, a quantitative oxidation indicator of carboxylic acids) and O3 mixing ratio. The comparison of t[OH] with f44 showed evidence for a systematic increase of f44 as t[OH] increased, an indication of secondary organic aerosol (SOA) formation. To a first approximation, the f44 increase rate was (1.05 ± 0.03) × 10-9 × [OH] h-1, which is comparable to the background-corrected increase rate observed during the New England Air Quality Study in summer 2002. The similarity may imply the production of similar SOA component, possibly humic-like substances. Meanwhile, the comparison of t[OH] with O3 mixing ratio showed that there was a strong proportional relationship between O3 mixing ratio and t[OH]. A first approximation gave the increasing rate and background mixing ratio of ozone as (3.48 ± 0.06) × 10-7 × [OH] ppbv h-1 and 30.7 ppbv, respectively. The information given here can be used for prediction of secondary pollution magnitude in the outflow from the Asian continent.

  16. 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.

  17. 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.

  18. 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.

  19. Japan launches mission to Venus

    NASA Astrophysics Data System (ADS)

    Banks, Michael

    2010-06-01

    The Japanese space agency JAXA has launched its first mission to Venus. The Akatsuki craft, which means "dawn" in Japanese, took off last month from the Tanegashima Space Center on the island of Kagoshima, south-west of mainland Japan.

  20. 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

  1. 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.

  2. 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.

  3. Deep structure of the Beppu hydrothermal system, Kyushu, Japan

    SciTech Connect

    Yusa, Y.; Ohsawa, S.; Kitaoka, K.; Fukuda, Y.

    1995-12-31

    The central part of Kyushu Island, southwest Japan, is located at the junction of the Southwest Japan Arc and the Ryukyu Arc, where a graben (Beppu-Shimabara Graben) has been formed by the rifting tectonic movement. There are many Quaternary volcanoes and active geo- and hydro-thermal fields within the Graben. The Beppu hydrothermal system extends around the Tsurumi-Garandake volcanoes at the eastern end of the Graben. This report will deal with the hydrothermal system beneath the volcanoes specially focusing on Garandake. Modest or violent fumarolic activities are visible near the summit of Garandake (1045 m in height). The total water(steam) output is 1.4 kg/s and its heat output 3.8 MW, while the heat output from the ground surface of 5.5 x 10{sup 4} m{sup 2} is 19.5 MW estimated by a heat balance analysis based on infrared radiation measurements (Yuhara et al., 1987). Thus the main process of heat discharge from Garandake, totally 23.3 MW, is the radiation from the ground surface. The geothermal gradient observed in a well drilled near the summit indicates that the large heat output is caused by some special process different from conduction because the heat flow by conduction is estimated to be 0.03 MW, which is very small compared with the observed output. Allis and Yusa (1989) suggested that a two-phase flow system is developed in Garandake. The two-phase flow, steam rising and water failing, acts as a heat pipe, by which a large quantity of (latent) heat can be transported upwards. Applying the theory of two-phase flow (Yusa and Oishi, 1989) to the Garandake system, the upflow rate of steam is estimated to be 10.3 kg/s at 100{degrees}C; the temperature near the ground surface, A part of rising steam (1.4 kg/s) flows out through fumaroles, and the remnant condenses to flow downwards. If the system is vapor-dominated, the intrinsic permeability at the shallow part should be about 1 darcy.

  4. 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

  5. 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 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

  6. 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

  7. Crustal Deformation at the Southernmost Part of the Ryukyu Subduction (East Taiwan) as Revealed by New Marine Seismic Experiments

    NASA Astrophysics Data System (ADS)

    Theunissen, T.; Lallemand, S.; Font, Y.; Gautier, S.; Lee, C.; Liang, W.; Wu, F. T.; Berthet, T.

    2011-12-01

    The southernmost part of the Ryukyu subduction, where the Philippine Sea Plate (PSP) is subducting under the South China Block (SCB) (~Eurasian Plate), is known to be a very seismically active region of transition from a north-dipping subduction along the Ryukyu subduction to a ~SE-NW collision along the Taiwanese orogenic wedge. In this paper, we will focus on the Ryukyu forearc area close to Taiwan where the deformation is paroxysmal. Previous studies were non-conclusive regarding the geometry and mechanism of offshore active faults. In order to decipher the nature of the seismic deformation in this region, 15 short-period Ocean Bottom Seismometers (OBS) have been deployed during three months in 2008. This experiment has been called RATS for Ryukyu Arc Tectonics and Seismology. The seismic network has been combined with 7 OBSs from the TAIGER experiment (TAiwan Integrated Geodynamics Research) and 51 inland seismic stations. By using an a-priori 3D P-wave model, we have obtained 1300 earthquake hypocenters, a new P-wave velocity structure and 14 focal mechanisms. Results show that the use of the new 3D tomography together with the OBS data has greatly improved the hypocenter determination, especially at depth. The seismicity along the Ryukyu forearc is mainly located in the vicinity of the Interplate Seismogenic Zone (ISZ) but also within both the subducting PSP and the overriding plate. Seismicity within the upper-plate is essentially localized east of Nanao basin where NW-SE extension occurs, and northwest of the Hoping basin where strike-slip dominates. As revealed by both the P-wave velocity structure and the newly derived seismicity, we argue that a sub-vertical step offsetting the subducting PSP around 10 km may support the presence of a trench-parallel tear. The PSP also undergoes extension in its upper part that is probably caused by buckling and slab pull.

  8. Concentration variations of total reactive nitrogen and total nitrate during transport to Fukue Island and to Cape Hedo, Japan in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Yuba, Akie; Sadanaga, Yasuhiro; Takami, Akinori; Hatakeyama, Shiro; Masui, Yoshihiko; Ohara, Toshimasa; Yonemura, Seiichiro; Kato, Shungo; Kajii, Yoshizumi; Bandow, Hiroshi

    2014-11-01

    We conducted continuous measurements of NOy and total nitrate (T.NO3 = HNO3 + NO(p)) at Fukue Island, Nagasaki, and Cape Hedo, Okinawa, Japan. We compared variations of NOy or T.NO3 concentrations measured at two remote sites when the air masses were originated from the same regions of the Asian Continent. Long-range transport events from the Asian Continent were extracted by CO concentration peaks at Fukue and Hedo and backward trajectory analyses. We compared the transport time difference at two sites from the Asian continent with the ratios of NOy at Hedo to that at Fukue (=R(NOy)) to find the predominant factor in NOy removal. R(NOy) were less than unity and decreased with the transport time difference. The ratios of NOy/CO at Hedo to those at Fukue (R(NOy/CO)) was assumed to be affected by the deposition process. R(NOy/CO) showed negative correlation with transport time difference as the same the case of R(NOy). This indicates that NOy was mainly removed by deposition rather than dilution. Air mass ages were classified by the ratio of T.NO3 to NOy at Fukue: T.NO3/NOy < 0.2 was fresh air, 0.2-0.4 was middle-aged, and greater than 0.4 was aged. The ratios of T.NO3/NOy at Hedo to those at Fukue (R(T.NO3/NOy)) in the fresh air mass were greater than unity. In contrast, R(T.NO3/NOy) values in the aged air mass were unity and were less correlated with transport time difference. This indicates that T.NO3 generation proceeded in fresh air mass. On the other hand, T.NO3 generation rate was comparable to removal rate in the aged air mass. According to the relationship between R(NOy/CO) and transport time difference, the removal rate constant and NOy lifetime were (1.24 ± 0.33) × 10-5 s-1 and 18-31 h, respectively.

  9. 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

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

    NASA Astrophysics Data System (ADS)

    Brenna, Marco; Cronin, Shane J.; Kereszturi, Gábor; 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.

  11. 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.

  12. Numerical Simulation Study of Potential Megathrust Event Along the Southernmost Ryukyu Trench

    NASA Astrophysics Data System (ADS)

    Lin, T. C.; Lee, S. J.; Hung, S. H.

    2014-12-01

    Over the past one hundred years, several big earthquakes with magnitude larger than 9 had occurred along the subduction zones. For example, the 1960 Chile earthquake (M 9.5), the 2004 Sumatra-Andaman earthquake (M 9.3), and the 2011 Tohoku earthquake (M 9.0). In this study, we focus on the southernmost Ryukyu Trench offshore northeastern Taiwan where the Philippine Sea Plate subducts beneath the Eurasian Plate at a rate of 80-85 mm/yr. Once a megathrust event hit this area, the ground shaking and tsunami would cause extreme disaster in northern Taiwan, especially the Taipei metropolitan area. Interseismic GPS data in northeast Taiwan shows a pattern of strain accumulation suggests that the maximum likely magnitude of a potential future large earthquake along the southernmost Ryukyu subduction zone is probably about Mw 8.7. In order to evaluate the influence of this potential megathrust event, we analyze the ShakeMap and ShakeMovie from different rupture scenarios based upon spectral-element method. Tsunami simulations based on coseismic deformations of seabed are carried out to evaluate the amplitudes of tsunami along the coastal areas of Taiwan. In addition, we apply the interseismic GPS data to invert the source slip pattern on a 3D subduction zone. We also discuss the influence of dynamic rupture process on the seabed coseismic deformation and tsunami generation. These numerical simulation results can provide physics-based information of megathrust earthquake scenario for the government and emergency response agency to take the appropriate action before the really big one occurs.

  13. 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.

  14. 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

  15. Origin of Japanese White-Eyes and Brown-Eared Bulbuls on the Volcano Islands.

    PubMed

    Sugita, Norimasa; Kawakami, Kazuto; Nishiumi, Isao

    2016-04-01

    The Ogasawara Archipelago comprises two groups of oceanic islands: the Bonin Islands, formed in the Paleogene, and the Volcano Islands, formed in the Quaternary. These groups are located within a moderate distance (ca. 160-270 km) of one another; thus, most land bird species are not distinguished as different subspecies. Two land birds, however, show unusual distribution. The Japanese white-eyes Zosterops japonicus originally inhabited only the Volcano Islands, but has been introduced to the Bonin Islands. The brown-eared bulbuls Hypsipetes amaurotis are distributed as a different subspecies. We investigated their genetic differences and divergences in the Ogasawara Archipelago using mitochondria DNA. The Volcano population of white-eyes had four endemic haplotypes that were divergent from one another, except for the Bonin population, which shared three haplotypes with the Volcano, Izu, and Ryukyu Islands and did not have any endemic haplotype. This is the first genetic suggestion that the Bonin population is a hybrid of introduced populations. With respect to bulbuls, the Volcano and Bonin Islands each had a single endemic haplotype. The Volcano haplotype is closest to a haplotype shared with Izu, the Japanese mainland, Daito and Ryukyu, whereas the Bonin haplotype is closest to one endemic to the south Ryukyu Islands. This indicates that the sources of the two bulbul populations can be geologically and temporally distinguished. The populations of the two species in the Ogasawara Archipelago are irreplaceable, owing to their genetic differences and should be regarded as evolutionarily significant units. In order to prevent introgression between the two populations, we must restrict interisland transfers. PMID:27032679

  16. The influence of the Kuril Islands on the penetration of tsunamis into the Sea of Okhotsk (on the example of the Japan tsunami on March 11, 2011)

    NASA Astrophysics Data System (ADS)

    Kostenko, I. S.; Kurkin, A. A.; Pelinovsky, E. N.; Yalciner, A.

    2016-01-01

    The features of the propagation of the tsunami of March 11, 2011 in the northeastern Pacific have been studied with the aim of revealing the degree of influence of the Kuril Islands on the penetration of the tsunami in the Sea of Okhotsk. For this, a series of computational experiments have been performed within the shallow water theory using bathymetry (1) with and (2) without the Kuril Islands. The wave heights calculated have been analyzed, and the tsunami's magnitude and intensity in the Sea of Okhotsk have been estimated. The computational experiments performed allow assessment of a decrease in the tsunami intensity while passing the Kuril Islands.

  17. 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.

  18. 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.

  19. 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

  20. 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, ...

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Diatoms from Lake Kushu: A pilot study to test the potential of a Late Quaternary palaeoenvironmental archive from Rebun Island (Hokkaido Region, Japan)

    NASA Astrophysics Data System (ADS)

    Schmidt, Mareike; Tarasov, Pavel E.; Hoelzmann, Philipp; Meyer, Hanno; Leipe, Christian

    2016-05-01

    Rebun Island is a key research area for the Baikal-Hokkaido Archaeology Project to better understand the dynamics of the Neolithic hunter-gatherers in the NW Pacific region. Hence, the ca. 19.5 m sediment core RK12 spanning the last ca. 16.6 cal. kyr BP was obtained from Lake Kushu. Our aim is to test its potential as a high-resolution multi-proxy archive. Here, we used diatoms to investigate the modern ecosystem of Lake Kushu and its surrounding area on Rebun Island and of Hime-numa Pond on Rishiri Island and selected core samples for comparison. Modern diatom and stable isotope analyses show well-mixed freshwater bodies with eutrophic, alkaline conditions. The fossil diatom and geochemical sediment analyses display three phases that represent major changes in the lake development: (i) a marshy phase (ca. 16.6-10 cal. kyr BP); (ii) a brackish water lagoon phase (ca. 10-6.6 cal. kyr BP); and (iii) a freshwater lake phase (since ca. 6.6 cal. kyr BP). This shows the major role of the post-glacial climate amelioration, global sea-level rise and marine transgression in the development of this landscape. Further analyses will provide a palaeolimnological record at (sub-)decadal resolution that will facilitate the interpretation of the hunter-gatherer dynamics.

  6. 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.

  7. Nd-isotopic composition of Phanerozoic sediments in the Inner Zone of Southwest Japan Arc : implications on provenance characteristics and contribution to formation of mature island arc system

    NASA Astrophysics Data System (ADS)

    Kagami, H.; Kawano, Y.; Ikawa, T.; Nishi, N.; Toyoshima, T.; Hamamoto, T.; Hayasaka, Y.; Ikeda, Y.; Yuhara, M.; Tainosho, Y.

    The Nd-isotopic data on sedimentary and metamorphic rocks of SW Japan Arc allow their discrimination into five different depleted mantle (TDM) model age clusters, 2.6-2.45 Ga, 2.3-2.05 Ga, 1.9-1.55 Ga, 1.45-1.25 Ga, 1.2-0.85 Ga. The 2.6-2.45 Ga and 1.9-1.55 Ga model ages are also coincident with U-Pb inherited zircon ages of the above two epochs as well as the major magmatic activity in the Sino-Korean Craton (SKC). The 2.3-2.05 Ga model ages can be considered as the initial formation ages for the precursors of sedimentary rocks. The Nd-isotopic data suggest that the Hida Belt was most likely formed as a part of the SKC. The mantle underlying the Ryoke Belt had continental lithospheric signature during Triassic-Jurassic period. The 1.9-1.55 Ga model ages, especially 1.8 Ga~, can be associated with the formation of this belt. The source material for the sedimentary rocks occurring in the accretionary terrane of northeastern areas in the SW Japan Arc was probably in and around the SKC of the Ryoke Belt itself. The sedimentary rocks occurring in southwestern areas of the Arc were mainly composed of materials derived from a relatively younger source (1.45-0.85 Ga).

  8. 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.

  9. Residence time of submarine fresh groundwater discharge in Hachijo Island, Japan: Application of dating tracers of Tritium, CFCs and SF6

    NASA Astrophysics Data System (ADS)

    MOGI, K.; Asai, K.

    2013-12-01

    Hachijo is a volcanic Island in the Western Pacific Ring of Fire. Submarine fresh groundwater discharge (SGD) distribute around the coastal area of Hachijo Island. In this study, we estimate the residence time of the SGD using the multi age tracer method, to understand the mechanism of SGD. Water samples were collected from 1 SGD, 5 mountain springs and 6 costal wells, and were measured in Tritium, CFCs and SF6 concentrations. All water samples contain detectable tritium, indicating that these waters are mainly recharged at post-bomb period. CFC-12 and SF6 concentration of water samples show wide variations from 163 to 247 pg/kg and from 1.06 to 2.61 fmol/kg, respectively. The SF6-based apparent ages for the mountain springs and shallow well were estimated at less than 6 years, and ranged from 12 to 20 years in the deep wells. Estimated SF6 age of the SGD (13 years) coincide with the age of the deep wells, suggesting that the SGD play a role of outlet of deep groundwater.

  10. 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.

  11. Update Japan.

    ERIC Educational Resources Information Center

    Hoopes, Aaron

    This book is a guide intended for persons planning on relocating to Japan. Following a chapter on background information, 13 additional chapters lead the reader step-by-step through the relocation process. These chapters include: before leaving, on arrival, language, culture, doing business in Japan, household pointers and everyday life, schools…

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Detection of microwave emission due to rock fracture as a new tool for geophysics: A field test at a volcano in Miyake Island, Japan

    NASA Astrophysics Data System (ADS)

    Takano, Tadashi; Maeda, Takashi; Miki, Yoji; Akatsuka, Sayo; Hattori, Katsumi; Nishihashi, Masahide; Kaida, Daishi; Hirano, Takuya

    2013-07-01

    This paper describes a field test to verify a newly discovered phenomenon of microwave emission due to rock fracture in a volcano. The field test was carried out on Miyake Island, 150 km south of Tokyo. The main objective of the test was to investigate the applicability of the phenomenon to the study of geophysics, volcanology, and seismology by extending observations of this phenomenological occurrence from the laboratory to the natural field. We installed measuring systems for 300 MHz, 2 GHz, and 18 GHz-bands on the mountain top and mountain foot in order to discriminate local events from regional and global events. The systems include deliberate data subsystems that store slowly sampled data in the long term, and fast sampled data when triggered. We successfully obtained data from January to February 2008. During this period, characteristic microwave pulses were intermittently detected at 300 MHz. Two photographs taken before and after this period revealed that a considerably large-scale collapse occurred on the crater cliff. Moreover, seismograms obtained by nearby observatories strongly suggest that the crater subsidence occurred simultaneously with microwave signals on the same day during the observation period. For confirmation of the microwave emission caused by rock fracture, these microwave signals must be clearly discriminated from noise, interferences, and other disturbances. We carefully discriminated the microwave data taken at the mountaintop and foot, checked the lightning strike data around the island, and consequently concluded that these microwave signals could not be attributed to lightning. Artificial interferences were discriminated by the nature of their waveforms. Thus, we inferred that the signals detected at 300 MHz were due to rock fractures during cliff collapses. This result may provide a useful new tool for geoscientists and for the mitigation of natural hazards.

  17. 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

  18. 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.

  19. Sumisu volcano, Izu-Bonin arc, Japan: site of a silicic caldera-forming eruption from a small open-ocean island

    NASA Astrophysics Data System (ADS)

    Tani, Kenichiro; Fiske, Richard S.; Tamura, Yoshihiko; Kido, Yukari; Naka, Jiro; Shukuno, Hiroshi; Takeuchi, Rika

    2008-03-01

    Sumisu volcano was the site of an eruption during 30 60 ka that introduced ˜48 50 km3 of rhyolite tephra into the open-ocean environment at the front of the Izu-Bonin arc. The resulting caldera is 8 × 10 km in diameter, has steep inner walls 550 780 m high, and a floor averaging 900 m below sea level. In the course of five research cruises to the Sumisu area, a manned submersible, two ROVs, a Deep-Tow camera sled, and dredge samples were used to study the caldera and surrounding areas. These studies were augmented by newly acquired single-channel seismic profiles and multi-beam seafloor swath-mapping. Caldera-wall traverses show that pre-caldera eruptions built a complex of overlapping dacitic and basaltic edifices, that eventually grew above sea level to form an island about 200 m high. The caldera-forming eruption began on the island and probably produced a large eruption column. We interpret that prodigious rates of tephra fallback overwhelmed the Sumisu area, forming huge rafts of floating pumice, choking the nearby water column with hyperconcentrations of slowly settling tephra, and generating pyroclastic gravity currents of water-saturated pumice that traveled downslope along the sea floor. Thick, compositionally similar pumice deposits encountered in ODP Leg 126 cores 70 km to the south could have been deposited by these gravity currents. The caldera-rim, presently at ocean depths of 100 400 m, is mantled by an extensive layer of coarse dense lithic clasts, but syn-caldera pumice deposits are only thin and locally preserved. The paucity of syn-caldera pumice could be due to the combined effects of proximal non-deposition and later erosion by strong ocean currents. Post-caldera edifice instability resulted in the collapse of a 15° sector of the eastern caldera rim and the formation of bathymetrically conspicuous wavy slump structures that disturb much of the volcano’s surface.

  20. 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.

  1. 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.

  2. 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.

  3. 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 ...

  4. 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…

  5. 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.

  6. 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.

  7. 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.

  8. 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;…

  9. 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.

  10. 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…

  11. 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,…

  12. 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

  13. 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 (δ13C) and oxygen-isotope (δ18O) compositions of nine specimens of a subtropical brachiopod, Basiliola lucida, collected west of Okinawa-jima, Ryukyu Islands, southwestern Japan. The δ13C 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 δ13C values that fall within the range of calcite precipitated in isotopic equilibrium with ambient seawater (equilibrium calcite) (δ13CEC values), and their mean δ13C values are ˜1.1-1.6‰ less than those from the older shells. This decrease in δ13C 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 δ18O 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 (δ18OEC values). A statistically significant negative linear relationship is established between seawater temperature and mean δ18O 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 δ13C and δ18O values suggest that the degree of the vital effect varies among individuals in this species. The δ13C and δ18O values of B. lucida are potentially useful for reconstructing the δ13C and δ18O evolution of ancient oceans, because both values show small intraspecific variations, the former is identical to the δ13CEC values, and the latter shows small within-shell variations and small, nearly constant offsets from the δ18OEC values.

  14. First detection of the 2009 slow slip event under northeast Taiwan at the Ryukyu subduction system from continuous GPS data

    NASA Astrophysics Data System (ADS)

    Ching, Kuo-En; Chen, Ying-Cheng; Rau, Ruey-Juin

    2014-05-01

    Transient fault slip episodes have been documented with continuously-recording GPS instruments located at several subduction margins on the Pacific Rim due to the fluid released from the dehydration of the subducted oceanic crust. A slow-slip event is detected from June 2009 to October 2009 based on the analysis of coordinate time series from 22 continuous GPS stations in northeastern Taiwan, belonging to the backarc extension region of the Ryukyu subduction zone. The GPS data from 2006 to 2011 were processed using GAMIT software and the common-mode errors were removed from the coordinate time series by the spatial filtering. The accumulative displacement pattern shows the displacement direction towards SSE with the maximum value of ~9 mm. The accumulative slip distribution and fault geometry parameters are inverted by surface accumulative displacements using the uniform stress drop inversion. The optimized model indicates a reverse fault plane with a shallow dip angle of ~10° and a depth of ~10 km. A maximum of 4.4 cm of slip is inferred near the southeastern part of the study area. However, the tomography study results indicate that the depth of subduction interface in northeastern Taiwan is ~30-40 km and the dip angle is ~30°-40°, much deeper and steeper than our inferred fault plane. In addition, the northeastern Taiwan has been thought as a westward extension of the Okinawa through with an ultra-rapid collision-induced clockwise rotation of ~ 29.5° ± 3.1°/Myr in the present. In the same time, several nearly east-west-striking seismogenic zones develop and mainly act as left-lateral strike-slip faulting and normal faulting accompanying the opening of the backarc basin. The bottom depth of these seismogenic zones is ~10 km, corresponding to the depth of our inferred fault plane. This may suggest a new shallow north-dipping thrust between the interface and the shallow seismogenic zones in northeast Taiwan. The relationship between this slow slip event and other regular large earthquakes in this region will be studied soon.

  15. 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 .

  16. 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

  17. 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

  18. 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

  19. 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…

  20. Radar Image, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The southeast part of the island of Hokkaido, Japan, is an area dominated by volcanoes and volcanic caldera. The active Usu Volcano is at the lower right edge of the circular Lake Toya-Ko and near the center of the image. The prominent cone above and to the left of the lake is Yotei Volcano with its summit crater. The city of Sapporo lies at the base of the mountains at the top of the image and the town of Yoichi -- the hometown of SRTM astronaut Mamoru Mohri -- is at the upper left edge. The bay of Uchiura-Wan takes up the lower center of the image. In this image, color represents elevation, from blue at the lowest elevations to white at the highest. The radar image has been overlaid to provide more details of the terrain. Due to a processing problem, an island in the center of this crater lake is missing and will be properly placed when further SRTM swaths are processed. The horizontal banding in this image is a processing artifact that will be removed when the navigation information collected by SRTM is fully calibrated. 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: 100 by 150 kilometers (62 by 93 miles) Location: 42.5 deg. North lat., 140.3 deg. East lon. Orientation: North towards upper left Image Data: SRTM Original Data Resolution: SRTM 30 meters (99 feet) Date Acquired: February 17, 2000

  1. 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

  2. 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.

  3. 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…

  4. 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 = ...

  5. 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 (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

  6. 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

  7. 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…

  8. Distribution of Two Subgroups of Human T-Lymphotropic Virus Type 1 (HTLV-1) in Endemic Japan

    PubMed Central

    Otani, Masashi; Honda, Noritaka; Xia, Pin-Cang; Eguchi, Katsuyuki; Ichikawa, Tatsuki; Watanabe, Toshiki; Yamaguchi, Kazunari; Nakao, Kazuhiko; Yamamoto, Taro

    2012-01-01

    Endemic areas of human T-lymphotropic virus type 1 (HTLV-1) have been reported in Japan as well as tropical Africa, Central and South America and Melanesia. The existence of two subgroups, i.e., the transcontinental and Japanese subgroups, was reported in Japan. In the present study, we provide data on the ratio of the two subgroups in each endemic area and infection foci and examine the distribution of HTLV-1 in Japan and neighboring areas. A 657 bp fragment of env region of HTLV-1 proviral genome was successfully amplified for 183 HTLV-1 positive DNA samples. The subgroup determination was done by RFLP reactions using endonucleases HpaI and HinfI. The northern part of mainland Kyushu, represented by Hirado and Kumamoto, was monopolized by the Japanese subgroup, while the transcontinental subgroup ranged from 20 to 35% in the Pacific coast areas of Shikoku (Kochi), the Ryukyu Archipelago (Kakeroma and Okinawa) and Taiwan. An interesting finding in the present study is the presence of the transcontinental subgroup in Kochi, suggesting the endemicity of the transcontinental subgroup along the Kuroshio Current. PMID:23097620

  9. Degregulation in Japan

    SciTech Connect

    Zimmer, M.J.; Miller, D.B.

    1995-09-01

    In recent years Japan has emerged as a major economic force in the world economy which, in spite of its strength, has produced another, less positive side. Driven by continual trade disputes and the unexpectedly high value of the yen, Japan`s Ministry of International Trade and Industry (MITI), the architect of Japan`s industrial policy, has undertaken to increase efficiency in the domestic economy. MITI`s process lies beneath the surface of the current effort to deregulate the electricity sector in Japan. Cited for inefficiency resulting in high energy costs, this key industrial sector is central to MITI`s plan to improve domestic industrial efficiency. Major points include allowing independent power production, developing a bidding system for wholesale power, permitting non-utilities to engage in the retail sale of electricity within certain specified areas, and permitting non-utilities to use the grids of the country`s 10 major utilities. A strong currency and stable economy together with an absence of a significant country risk will be comforting factors to both developers and foreign lending institutions seeking to finance projects in Japan. Japan`s future, therefore, holds some promise for future independent power project development.

  10. 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.

  11. 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 ...

  12. TWELVE DOORS TO JAPAN.

    ERIC Educational Resources Information Center

    BEARDSLEY, RICHARD K.; HALL, JOHN WHITNEY

    THE TWELVE DOORS OF THIS COLLEGE-LEVEL TEXT ARE TWELVE CHAPTERS ON ASPECTS OF JAPAN AND JAPANESE CULTURE AS TREATED BY VARIOUS ACADEMIC DISCIPLINES. THE AUTHORS' PURPOSE IN CHOOSING THIS FORMAT WAS TO PRESENT INTRODUCTORY INFORMATION ABOUT JAPAN AND TO ACQUAINT STUDENTS WITH THE AIMS, MATERIALS, AND METHODS OF DISCIPLINES OTHER THAN THE ONE THEY…

  13. 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)

  14. Shaded Relief Mosaic of Umnak Island, Aleutian Islands, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image is a shaded relief mosaic of Umnak Island in Alaska's Aleutian Islands.

    It was created with Airsar data that was geocoded and combined into this mosaic as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  15. Microelectronics in Japan

    NASA Technical Reports Server (NTRS)

    Boulton, William R.

    1995-01-01

    The purpose of this JTEC study is to evaluate Japan's electronic manufacturing and packaging capabilities within the context of global economic competition. To carry out this study, the JTEC panel evaluated the framework of the Japanese consumer electronics industry and various technological and organizational factors that are likely to determine who will win and lose in the marketplace. This study begins with a brief overview of the electronics industry, especially as it operates in Japan today. Succeeding chapters examine the electronics infrastructure in Japan and take an in-depth look at the central issues of product development in order to identify those parameters that will determine future directions for electronic packaging technologies.

  16. 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.

  17. The Japan Prize

    ERIC Educational Resources Information Center

    Yoshida, Tadashi

    1970-01-01

    The Deputy Director-General of NHK (Japan Broadcasting Company) describes the procedures involved in awarding the prize (for outstanding radio and television programs) and offers some comments on educational broadcasting. (LS)

  18. 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.

  19. VSATs in Japan

    NASA Astrophysics Data System (ADS)

    Fujii, Akira

    1993-08-01

    In Japan, VSAT private domestic communications satellites, JCSAT and SuperBird, carrying Ku-band transponders, were launched in 1989. To expedite a wider use of these VSAT systems, regulations were amended in June 1989 to permit simplified licensing procedures for the VSATs which conformed to technical standards. This contribution describes the usage of VSAT systems in Japan along with the licensing procedures and the technical standards.

  20. 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...

  1. Island Panoramic

    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. ...

  2. 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.

  3. 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.

  4. 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

  5. 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).

  6. Japanese Population Structure, Based on SNP Genotypes from 7003 Individuals Compared to Other Ethnic Groups: Effects on Population-Based Association Studies

    PubMed Central

    Yamaguchi-Kabata, Yumi; Nakazono, Kazuyuki; Takahashi, Atsushi; Saito, Susumu; Hosono, Naoya; Kubo, Michiaki; Nakamura, Yusuke; Kamatani, Naoyuki

    2008-01-01

    Because population stratification can cause spurious associations in case-control studies, understanding the population structure is important. Here, we examined Japanese population structure by “Eigenanalysis,” using the genotypes for 140,387 SNPs in 7003 Japanese individuals, along with 60 European, 60 African, and 90 East-Asian individuals, in the HapMap project. Most Japanese individuals fell into two main clusters, Hondo and Ryukyu; the Hondo cluster includes most of the individuals from the main islands in Japan, and the Ryukyu cluster includes most of the individuals from Okinawa. The SNPs with the greatest frequency differences between the Hondo and Ryukyu clusters were found in the HLA region in chromosome 6. The nonsynonymous SNPs with the greatest frequency differences between the Hondo and Ryukyu clusters were the Val/Ala polymorphism (rs3827760) in the EDAR gene, associated with hair thickness, and the Gly/Ala polymorphism (rs17822931) in the ABCC11 gene, associated with ear-wax type. Genetic differentiation was observed, even among different regions in Honshu Island, the largest island of Japan. Simulation studies showed that the inclusion of different proportions of individuals from different regions of Japan in case and control groups can lead to an inflated rate of false-positive results when the sample sizes are large. PMID:18817904

  7. 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.

  8. 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.

  9. Space robotics in Japan

    NASA Astrophysics Data System (ADS)

    Whittaker, William; Lowrie, James W.; McCain, Harry; Bejczy, Antal; Sheridan, Tom; Kanade, Takeo; Allen, Peter

    1994-03-01

    Japan has been one of the most successful countries in the world in the realm of terrestrial robot applications. The panel found that Japan has in place a broad base of robotics research and development, ranging from components to working systems for manufacturing, construction, and human service industries. From this base, Japan looks to the use of robotics in space applications and has funded work in space robotics since the mid-1980's. The Japanese are focusing on a clear image of what they hope to achieve through three objectives for the 1990's: developing long-reach manipulation for tending experiments on Space Station Freedom, capturing satellites using a free-flying manipulator, and surveying part of the moon with a mobile robot. This focus and a sound robotics infrastructure is enabling the young Japanese space program to develop relevant systems for extraterrestrial robotics applications.

  10. Space robotics in Japan

    NASA Technical Reports Server (NTRS)

    Whittaker, William; Lowrie, James W.; Mccain, Harry; Bejczy, Antal; Sheridan, Tom; Kanade, Takeo; Allen, Peter

    1994-01-01

    Japan has been one of the most successful countries in the world in the realm of terrestrial robot applications. The panel found that Japan has in place a broad base of robotics research and development, ranging from components to working systems for manufacturing, construction, and human service industries. From this base, Japan looks to the use of robotics in space applications and has funded work in space robotics since the mid-1980's. The Japanese are focusing on a clear image of what they hope to achieve through three objectives for the 1990's: developing long-reach manipulation for tending experiments on Space Station Freedom, capturing satellites using a free-flying manipulator, and surveying part of the moon with a mobile robot. This focus and a sound robotics infrastructure is enabling the young Japanese space program to develop relevant systems for extraterrestrial robotics applications.

  11. 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.

  12. 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

    2015-10-01

    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.

  13. 2009 Slow Slip Event under the Northeast Taiwan at the Backarc Extension of the Ryukyu Subduction Zone from Continuous GPS Data

    NASA Astrophysics Data System (ADS)

    Ching, K. E.; Rau, R. J.; Wang, K.; Peng, Z.; Wang, Y. J.

    2014-12-01

    A slow-slip event is detected from June 2009 to October 2009 based on the analysis of coordinate time series from 22 continuous GPS stations in northeastern Taiwan, belonging to the backarc extension region of the Ryukyu subduction zone. The GPS data from 2006 to 2011 were processed using GAMIT software. The seasonal signals and common-mode errors were removed from the coordinate time series. Accumulative displacement pattern shows horizontal displacement direction towards SSE with the maximum value of ~9 mm. However, no significant vertical displacements are detected. The accumulative slip distribution and fault geometry parameters are inverted by surface accumulative displacements using the uniform stress drop inversion. The optimized model indicates a normal fault with a shallow dip angle of ~5° and a depth of ~8 km. A maximum of ~40 mm of slip is inferred near the eastern part of the study area. Comparison with rainfall data indicates that this slow slip event is not the seasonal response. Seismicity distribution and focal mechanism solutions imply that several nearly east-west-striking seismogenic zones develop and mainly act as left-lateral strike-slip faulting and normal faulting accompanying the opening of the backarc basin. The bottom depth of these seismogenic zones is ~10 km, corresponding to the depth of our inferred fault plane. A low Qp/Qs layer is also discovered at the same region, which suggests a high fluid within this layer. Therefore we suggest a shallow south-dipping décollement under the backarc basin in northeastern Taiwan. The relationship between this slow slip event and other regular large earthquakes in this region will be studied soon.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. English Language Education in Japan.

    ERIC Educational Resources Information Center

    Ogose, Hideko

    2001-01-01

    Focuses on recent changes in English language education in Japan, examines the reasons for these changes, discusses attitudes towards them, and predicts what the future of English language education in Japan will look like. (Author/VWL)

  20. 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.

  1. 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)

  2. Teaching Unit: Japan.

    ERIC Educational Resources Information Center

    Evans, Dina

    The cultural diversity of Japan can provide a rewarding learning experience for children of all grade levels. This teaching unit includes resources and ideas for the study of Japanese society, art, folklore, and poetry. Included among the instructional objectives are: (1) children will compare U.S. lifestyles with Japanese lifestyles by reading…

  3. Language Testing in Japan.

    ERIC Educational Resources Information Center

    Brown, James Dean, Ed.; Yamashita, Sayoko Okada, Ed.

    Papers on second language testing in Japan include: "Differences Between Norm-Referenced and Criterion-Referenced Tests" (James Dean Brown); "Criterion-Referenced Test Construction and Evaluation" (Dale T. Griffe); "Behavioral Learning Objectives as an Evaluation Tool" (Judith A. Johnson); "Developing Norm- Referenced Tests for Program-Level…

  4. The Japan Papers.

    ERIC Educational Resources Information Center

    Bailey, Jackson H.; And Others

    This publication contains three papers on college student exchange between Japan and the United States. The first paper, entitled "The University of Massachusetts and Hokkaido University: A Case Study in Educational Cooperation," by Barbara B. Burn, describes the long-standing relationship between these two institutions in order to identify some…

  5. 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…

  6. 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)

  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. Folly Island Tidal Lines

    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....

  11. Folly Island Panorama

    A panorama 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....

  12. Folly Island Tidal Lines

    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....

  13. 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.…

  14. Lifelong Learning Facilities in Japan.

    ERIC Educational Resources Information Center

    Hirai, Akishige

    1997-01-01

    Examines Japan's educational system and the role of national policy and local government in fostering lifelong learning. Reasons why Japan is building a lifelong learning society are examined, as are the opportunities available in Japan for learning beyond traditional education, the national and local government's role, access to facilities,…

  15. 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,...

  16. 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.

  17. 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…

  18. 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 μm thickness.

  19. [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

  20. 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.

  1. 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.

  2. Psychology in Japan.

    PubMed

    Imada, Hiroshi; Tanaka-Matsumi, Junko

    2016-06-01

    The purpose of this article is to provide information about Japan and its psychology in advance of the 31st International Congress of Psychology (ICP), to be held in Yokohama, Japan, in 2016. The article begins with the introduction of the Japanese Psychological Association (JPA), the hosting organization of the ICP 2016, and the Japanese Union of Psychological Associations consisting of 51 associations/societies, of which the JPA is a member. This is followed by a brief description of a history of psychology of Japan, with emphasis on the variation in our approach to psychology in three different periods, that is, the pre- and post-Pacific War periods, and the post-1960 period. Next, the international contributions of Japanese psychology/psychologists are discussed from the point of view of their visibility. Education and training in psychology in Japanese universities is discussed with a final positive remark about the long-awaited enactment of the Accredited Psychologist Law in September, 2015. PMID:26892102

  3. 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

  4. Native fruit tree genetic resources in Japan.

    PubMed

    Iketani, Hiroyuki

    2016-01-01

    The diversity of climate, from subarctic to subtropical, and the complex geological history of Japan have produced a rich biodiversity. The flora includes several hundred species of native woody plants with edible fleshy fruits or nuts. People have eaten them from prehistoric times until about a half century ago. In Hokkaidō and the Ryūkyū Islands nut species had an important role in the diet, but fleshy fruits were also eaten until recently. Only Castanea crenata and a few minor species became domesticated as edible fruit trees in pre-modern times. Recently, Vitis coignetiae, Lonicera caerulea, Akebia quinata, Akebia trifoliata, Stauntonia hexaphylla, and Actinidia arguta have entered small-scale cultivation. The conservation of the germplasm of many of these native species, both in situ and ex situ, is precarious. PMID:27069393

  5. Native fruit tree genetic resources in Japan

    PubMed Central

    Iketani, Hiroyuki

    2016-01-01

    The diversity of climate, from subarctic to subtropical, and the complex geological history of Japan have produced a rich biodiversity. The flora includes several hundred species of native woody plants with edible fleshy fruits or nuts. People have eaten them from prehistoric times until about a half century ago. In Hokkaidō and the Ryūkyū Islands nut species had an important role in the diet, but fleshy fruits were also eaten until recently. Only Castanea crenata and a few minor species became domesticated as edible fruit trees in pre-modern times. Recently, Vitis coignetiae, Lonicera caerulea, Akebia quinata, Akebia trifoliata, Stauntonia hexaphylla, and Actinidia arguta have entered small-scale cultivation. The conservation of the germplasm of many of these native species, both in situ and ex situ, is precarious. PMID:27069393

  6. 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.

  7. 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.

  8. 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...

  9. 21 CFR 186.1555 - Japan wax.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 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...

  10. 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...

  11. Comparison of Helmert and rigorous orthometric heights over Japan

    NASA Astrophysics Data System (ADS)

    Odera, Patroba Achola; Fukuda, Yoichi

    2015-02-01

    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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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,…

  17. 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";…

  18. China and Japan (Theme Issue).

    ERIC Educational Resources Information Center

    Kiernan, Henry, Ed.; Pyne, John, Ed.

    1993-01-01

    This serial issue is devoted to the theme "China and Japan" and contains six articles that focus on educational, political, and cultural issues in the two Asian countries. In the first article, "China and Japan: A New Era in Relations with the United States," Henry Kiernan and John Pyne provide a brief overview of the history of United States'…

  19. 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.

  20. [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

  1. 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.

  2. Aeromagnetic surveys in the seas around Japan in 1980

    NASA Astrophysics Data System (ADS)

    Utashiro, S.; Oshima, S.; Kaneko, T.

    1984-07-01

    Aeromagnetic surveys in the seas around Japan were carried out in 1979 to 1980 by a YS-11 aircraft of the Maritime Safety Agency of Japan using a new type of airborne magnetometer system. The new type of airborne magnetometer system consists of a ring-core type three-component fluxgate magnetometer, an inertial sensing system, a fish-eye camera to measure the true north, an 8-bit microcomputer and a proton magnetometer. The VLF/OMEGA system is used to fix the position of the aircraft. Tracks extended to about 600 nautical miles off the coast of the Japanese islands in the Sea of Japan and the North-West Pacific Ocean. Average spacing between tracks was about 80 miles. The flights were carried out at an altitude of 9500 feet. From the survey results, magnetic charts of the seven geomagnetic elements for 1980 over the sea around Japan were compiled by the method of least squares using a polynomial. Also, the contour charts of secular variation in 1980 were compiled.

  3. 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)

  4. Overwash on Assateague Island

    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....

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Overwash on Assateague Island

    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....

  12. Bouvet Island near Antarctica

    Atmospheric Science Data Center

    2013-04-16

    ... the island is visible within a relatively clear area of open ocean. In the lower right image, the island is partially obscured by ... Steep cliffs surrounding most sides of the island also made access difficult, and after various attempts, a landing was made in 1822 by an ...

  13. [Geobotanical studies on the island of Tanegashima (affinity of world property island Yakushima)].

    PubMed

    Satake, M; Kaburagi, K; Seki, T; Nozaki, T; Lee, I; Katsuki, S

    1999-01-01

    A list was drawn up of wild plants growing on Tanegashiama island that were identified in our field work, and the list was compared with the flora of the rest of Japan and the flora of Taiwan. There were 166 families and 1,218 species consisting of 23 families and 159 species of Pteridophyta, 4 families and 7 species of Gymnosperma, 113 families and 700 species of the dicotyledous Angiosperma, and 26 families and 353 species of monocotyledous Angiosperma. There are 229 families and 5,500 species of plants in Japan, 196 families and 3,019 species in Kyushu, and 228 families and 3,477 species in Taiwan. There are 11 species of endemic plants on Tanegashima and Yakushima, and the best known of them is Pinus armandii Francht. var. amamiana Hatsushima. There are 181 species of flora of flora limited to the northern element, including several important medicinal plants, such as Akebia quinata Decaisne and Zanthoxylum piperitum DC. The 69 species of flora limited to the southern element include several important tropical plants, such as Messerschmidia argentea Johnston and Clerodendrum inerme Gaertn. Most of these plants are distributed on both island, but some of are distributed only Tanegashima. We concluded that one of the temperate borderlines of Japanese flora in the temperate zone is the islands of Tokara. The flora of Tanegashima and Yakushima are having a closely affinity of plant species and having the rich plant species. PMID:10859935

  14. 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 Vaníček, 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.

  15. 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)

  16. 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

  17. 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.

  18. 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...

  19. [Increase of poisoning by tropical mushrooms in Japan in recent years].

    PubMed

    Yokoyama, Kazumasa; Gonmori, Kunio

    2009-09-01

    A tropical poisonous mushroom, Chlorophyllum molybdites, invaded into Japan in recent years, and distributed in south-eastern and central part of Japan including 27 Prefectures in 2009; Gunma, Tochigi, Saitama, Ibaraki, Tokyo (including Bonin Islands), Chiba, Shizuoka, Ishikawa, Aichi, Mie, Shiga, Kyoto, Nara, Osaka, Wakayama, Hyogo, Tottori, Okayama, Hiroshima, Yamaguchi, Kagawa, Tokushima, Kochi, Ohita, Kumamoto, Kagoshima and Okinawa. Poisoning by this fungus has increased recently (Table 2). Topics on distribution and poisoning by Russula subnigricans and Podostroma cornu-damae briefly discussed. PMID:19882971

  20. 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.

  1. 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.

  2. 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

  3. 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…

  4. 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

  5. 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.

  6. Y chromosomal DNA variation and the peopling of Japan.

    PubMed Central

    Hammer, M F; Horai, S

    1995-01-01

    Four loci mapping to the nonrecombining portion of the Y chromosome were genotyped in Japanese populations from Okinawa, the southernmost island of Japan; Shizuoka and Aomori on the main island of Honshu; and a small sample of Taiwanese. The Y Alu polymorphic (YAP) element is present in 42% of the Japanese and absent in the Taiwanese, confirming the irregular distribution of this polymorphism in Asia. Data from the four loci were used to determine genetic distances among populations, construct Y chromosome haplotypes, and estimate the degree of genetic diversity in each population and on different Y chromosome haplotypes. Evolutionary analysis of Y haplotypes suggests that polymorphisms at the YAP (DYS287) and DXYS5Y loci originated a single time, whereas restriction patterns at the DYS1 locus and microsatellite alleles at the DYS19 locus arose more than once. Genetic distance analysis indicated that the Okinawans are differentiated from Japanese living on Honshu. The data support the hypotheses that modern Japanese populations have resulted from distinctive genetic contributions involving the ancient Jomon people and Yayoi immigrants from Korea or mainland China, with Okinawans experiencing the least amount of admixture with the Yayoi. It is suggested that YAP+ chromosomes migrated to Japan with the Jomon people > 10,000 years ago and that a large infusion of YAP- chromosomes entered Japan with the Yayoi migration starting 2,300 years ago. Different degrees of genetic diversity carried by these two ancient chromosomal lineages may be explained by the different life-styles (hunter-gatherer versus agriculturalist). of the migrant groups, the size of the founding populations, and the antiquities of the founding events. Images Figure 1 PMID:7717406

  7. Stewart Head from Folly Island

    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. 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.

  9. 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

  10. 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.

  11. 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.

  12. Geology of Northeast Part of Fukue Island, Goto Islands, Nagasaki Prefecture

    NASA Astrophysics Data System (ADS)

    Hasegawa, T.; Kiyokawa, S.; Yamamoto, A.; Hasebe, N.

    2007-12-01

    The Goto islands situated in the western part of Japan expose after Lower to Middle Miocene sedimentary and igneous rocks. The geologic evidences in this area are very important to identify relation between the north west of Kyushu and the Asian continent. We examined stratigraphy and geological structure of the Fukue Island of the southwest part of the Goto islands. Stritigraphy: In The Fukue Island, three lithofacies, Goto Group, Goto granite intrusion and Fukue Rhyolite are observed. Lower Goto Group consists of green colored volcaniclastics and massive tuff, based on the petrographic observation, there are very rounded quartz, siltstone listhic fragments and volcanic rock fragments. Upper Goto Group consists of alternation of sandstone and mudstone with upward grading structure, which is considered fluvial-lacustrine. And these were intruded by granitic dike. The Fukue Rhyolite is reported that the age is 12.4 ± 0.6Ma. Deformation: In center of the Fukue Island, there are about 10-20 degree plunges into north NE-SW trending fold, which is called "Goto central fold". In the northwest side of the fold hinge, high angle dipping beds and asymmetric fold are observed. On the other hand, in the southeast side of the fold hinge, dipping to east gentle bedding structure is observed. In the Fukue Island, the following three structures can be recognized. D1-a; NE-SW trending normal fault and fault related fold; The Goto center fold, which is one of the main structure in the deformation. D1-b; NE-SW trending west dipping normal fault and right lateral strike-slip fault. In the southwest region, the high angle bed formed by D1-a is bended from NE-SW trend to N-S by D1-b. D2; NW-SE trending normal fault and left lateral strike-slip fault. The trend of this structure is vertical to NE-SE trending of The Goto islands. Because of the cross cutting relationship, we consider that D1-a and D1-b were formed from 15 to 7 Ma, and D2 was formed in later 7Ma. Based on age data and lithology, we suggest that the Goto Group was deposited in the rifting area of the southwest end of the Japan sea. In the near northwest off the Goto islands, there is NE-SW trending tectonic line that is west end fault of the Japan sea opening, called the Tsushima-Goto TL. The early stage volcanic activity which formed the lower Goto Group and D1-a might be related to the TL movement. The trend of D2 is parallel to the Goto submarine canyon at the south of the Fukue Island, we consider that D2 possibly related to the opening of the north Okinawa trough.

  13. 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).

  14. 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…

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. Barnacles on Folly Island

    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 ...

  20. 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)

  1. Rhode Island Seafloor

    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....

  2. 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…

  3. 76 FR 18202 - Applications for New Awards; Asian American and Native American Pacific Islander-Serving...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... the Federal Register on December 15, 2010 (75 FR 78486) (Supplemental NFP). Competitive Preference... subcontinent (including, for example, Cambodia, China, India, Japan, Korea, Malaysia, Pakistan, the Philippine... October 30, 1997 (62 FR 58789)). Native American Pacific Islander means any descendant of the...

  4. 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.

  5. 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.

  6. Identity of Cypripedium calceolus (Orchidaceae) in Rebun Island: comparative DNA analysis of related species.

    PubMed

    Taniguchi, H; Nakamura, T; Mizukami, H; Kawano, S; Sano, H; Katsumi, M

    2001-06-01

    Cypripedium calceolus was found in 1980 in Rebun Island off the north coast of Hokkaido, Japan, but the origin of this plant has been a controversial issue. In this study, we have made a comparative study by chloroplast DNA sequencing analysis among C. calceolus which occurs in Rebun Island and populations of C. calceolus from western Europe, China and far eastern Russia (Nakhodka), and also as references, C. macranthos in Japan and other Cypripedium species in North America. A Cypripedium cf. "calceolus", found recently in eastern Hokkaido, was also included in this analysis. The C. calceolus samples analyzed were categorized into three groups, i.e., those from Western Europe, from China and far eastern Russia, and from Rebun Island. The C. calceolus in Rebun Island was clearly different from the others in terms of DNA sequence and morphological features. The C. cf. calceolus from eastern Hokkaido and one sample from Nadhodka, Russia, were also classified into the same group as those from Rebun Island, although some differences in their morphological features were observed. It is concluded that the C. calceolus found in Rebun Island is not identical with those growing in Europe and China. In addition, it was found that it may be possible to classify C. macranthos into two groups, namely groups which include or do not include var. rebunense. An unidentified Cypripedium species found in Rebun Island falls into the same group as var. rebunense. PMID:11569501

  7. Solar radiation monitoring network of Tokai University, Japan

    NASA Astrophysics Data System (ADS)

    Takeshita, Shu; Sasaki, Masako

    2003-11-01

    Seasonal variation of global solar radiation: ultraviolet-B (UV-B: 290 - 320 nm), ultraviolet-A (UV-A: 320 - 400 nm) and Total (Total: 300 - 3000 nm) has been measured at the Shonan Campus of Tokai University (35°21"N, 139°16"E, in central Japan) since October 1990. To clarify regional difference of solar radiation in East Asia, the same type of radiometers were installed at Wakkanai (October 2000: 141°48"N, 145°21"E, in Hokkaido, at the northern end of Japan), Mashiki (June 1996: 32°50'N, 130°52'E, in Kumamoto, at the mid-west Japan; Taketomi (July 1998: 24°20"N, 123°41'E, on Iriomote Island, in Okinawa, at the south western end of Japan). Observation data are transferred to the Shonan Campus every day via Internet, and the data were posted on our web site. Comparison of sensitivity among all radiometers used in this network was carried out from August 2002 to September 2002. Observed data were corrected based on the comparison results. Solar radiation showed clear regional differences depending on the season. Global solar radiation in summer was almost the same among stations, but in winter, global radiation showed very significantly among the stations. The ratio of UV-B in winter to summer was 14 times at Wakkanai, 6 times at Shonan and Mashiki, and 2 times at Taketomi. The ratio of Total in winter to summer was 2 times at Shonan, Mashiki and Taketomi, and 6 times at Wakkanai. The seasonal variation of the ozone level corresponded the latitude with Taketomi registering the least amplitude.

  8. Zoonotic filariasis caused by Onchocerca dewittei japonica in a resident of Hiroshima Prefecture, Honshu, Japan.

    PubMed

    Uni, Shigehiko; Boda, Tomoyuki; Daisaku, Koichi; Ikura, Yoshihiro; Maruyama, Haruhiko; Hasegawa, Hideo; Fukuda, Masako; Takaoka, Hiroyuki; Bain, Odile

    2010-09-01

    A female of Onchocerca sp. was found to be the probable causative agent of a subcutaneous nodule in the left knee of a 70-year-old man in a rural area of Hiroshima Prefecture, Honshu, the main island of Japan. We compared the characteristics of the agent with the features of the four previously suspected species found in cattle and horses in various parts of the world, as well as O. lupi and O. jakutensis that were suspected or proved, respectively, in zoonotic cases in Europe. In addition, the morphologic characteristics of this parasite were compared with those of the four Onchocerca species found in wild animals in Japan. Based on such characteristics as the large triangle ridges, the considerable distance between any two adjacent ridges, and the absence of inner cuticular striae in the longitudinal sections, we found the causative agent in the present case to be identical to the female of Onchocerca dewittei japonica. All five previous cases of zoonotic onchocerciasis in Japan had been found in Oita, Kyushu, the main southern island. This human case caused by O. dewittei japonica suggests that zoonotic onchocerciasis is liable to occur in rural areas in Japan where wild boar, Simulium vectors, and humans overlap. PMID:20561913

  9. Analyses and numerical modeling of a polar low over the Japan Sea on 19 December 2003

    NASA Astrophysics Data System (ADS)

    Guo, Jingtian; Fu, Gang; Li, Ziliang; Shao, Limin; Duan, Yihong; Wang, Jianguo

    2007-09-01

    A meso-α-scale polar low was observed over the Japan Sea on 19 December 2003. It initialed around 11 UTC over the northwestern part of the Japan Sea within a synoptic-scale parent low under the influence of baroclinic environment and disappeared over the eastern edge of Japan Islands with a lifetime of about 20 h. It is of interest that this polar low had "concentric eye-walls" and "warm core" structure at its mature stage. The evolutionary process and spatial structure of this polar low were investigated by using almost all available observational data, including the Geostationary Operational Environmental Satellite (GOES)-9, the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery, the Final Analyses (FNL) data issued by National Centers for Environmental Prediction (NCEP), the surface observational data and the 9-station sounding data of Japan Islands. In order to study its development mechanism, a 24-h numerical simulation using the version 4.4 of the Regional Atmospheric Modeling System (RAMS) starting from 12 UTC 19 December 2003 with an 8 km × 8 km resolution was performed. It is shown that the RAMS model reproduced the main features of the polar low reasonably well. The vorticity budget analyses indicate that the stretching term is the major contributor for the vorticity increase of the polar low. The baroclinic background seems to play significant role for the initial development of this polar low. However, the effect of the diabatic heating for its later development is also significant.

  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. 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…

  12. 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

  13. Modernization of Education in Japan.

    ERIC Educational Resources Information Center

    National Inst. for Educational Research, Tokyo (Japan).

    The document traces the development of education in Japan from the 17th century to the present. It is presented in four chapters. Chapter one discusses the Tokugawa Period (1603-1867). Principal forms of schooling were hanko for the Samurai class and terakoya for the commoners. The hanko were established for the benefit of the fiefs; objectives of…

  14. How Japan Supports Novice Teachers

    ERIC Educational Resources Information Center

    Ahn, Ruth

    2014-01-01

    When U.S. educators first hear that Japanese teacher preparation programs require only four weeks of formal student teaching at the end of the credential program, they're appalled: How can this be? More surprising still, few new teachers in Japan (1.35 percent) leave the profession during their first year. So where are these beginning…

  15. 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…

  16. 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…

  17. Projecting HIV Transmission in Japan

    PubMed Central

    Gilmour, Stuart; Li, Jinghua; Shibuya, Kenji

    2012-01-01

    Background Little is known about the epidemiology of HIV in Japan, though newly-identified cases amongst men who have sex with men (MSM) show an increasing trend. Predictions of future trends in the HIV epidemic are essential to identify suitable interventions. Methods A deterministic, compartmental model was developed that incorporated risk groups, disease stages, and treatment and testing parameters. This model was calibrated against current figures on new infections and run over 30 years to identify trends in prevalence amongst MSM, low-risk men and low-risk women. Multivariate sensitivity analysis was used to estimate sensitivity ranges for all outcomes. Results Without new interventions amongst MSM in Japan, HIV prevalence will climb from its current rate of 2.1% to 10.4% (sensitivity range 7.4% to 18.7%), while HIV prevalence among low-risk men and women will likely decline. With small changes in safer sex behavior and testing rates, HIV prevalence can remain stable or even decline amongst MSM. Conclusions Japan is at risk of an epidemic of HIV amongst MSM unless significant changes are made to its current public health intervention framework. More research is necessary to understand the key drivers of the epidemic in Japan. PMID:22916268

  18. Aerial Measuring System in Japan

    SciTech Connect

    Lyons, C., Colton, D. P.

    2012-05-01

    The U.S. Department of Energy National Nuclear Security Agency’s 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 System’s mission beyond the borders of the US.

  19. 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…

  20. 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…

  1. 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…

  2. 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

  3. Japan: Images of a People.

    ERIC Educational Resources Information Center

    Smigielski, Alan; Casey, Douglas, Ed.

    1997-01-01

    This issue of "Art to Zoo" focuses on Japanese art and is adapted from materials developed by the education department of the Smithsonian Institution's Freer Gallery of Art and the Arthur M. Sackler Gallery. After learning how to look at paintings, students make paper screens that resemble Japanese screens. Background essays about Japan place the…

  4. 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

  5. Recent meteor observing activities in Japan

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.

    2005-02-01

    The meteor train observation (METRO) campaign is described as an example of recent meteor observing activity in Japan. Other topics of meteor observing activities in Japan, including Ham-band radio meteor observation, the ``Japan Fireball Network'', the automatic video-capture software ``UFOCapture'', and the Astro-classroom programme are also briefly introduced.

  6. 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...

  7. 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,…

  8. The US Occupation and Japan's New Democracy

    ERIC Educational Resources Information Center

    Kumano, Ruriko

    2007-01-01

    During the US Occupation of Japan (1945-1952), a victorious America attempted to reform Japanese education by replacing Japan's tradition system of values with one that promoted American democratic values. The United States had considered the source of Japan's militarism to lie in the selfless loyalty and love of country that many older Japanese…

  9. 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…

  10. 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

  11. 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, 74·7 % are hermaphroditic, 13·0 % are dioecious and 7·1 % are monoecious. Classification by flower colour revealed that 36·0 % were white, 21·6 % green and 13·8 % yellow. Woody species (trees and shrubs) comprised 36·5 % of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 66·7 % 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 60·1 % 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

  12. 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.

  13. 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.

  14. 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.

  15. The Island Approach.

    ERIC Educational Resources Information Center

    Schroder, Peter C.

    1994-01-01

    Proposes the study of islands to develop a method of integrating sustainable development with sound resource management that can be extrapolated to more complex, highly populated continental coastal areas. (MDH)

  16. 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)

  17. 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.

  18. 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.

  19. 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.

  20. Volcanisme, activité anthropique et circulation des masses océaniques : leur influence respective sur la distribution des populations d'ostracodes dans la baie de Kagoshima (île de Kyushu, Japon)Impact of volcanism, human activities, and water mass circulation on the distribution of ostracod populations in Kagoshima Bay (Kyushu Island, southern Japan)

    NASA Astrophysics Data System (ADS)

    Bodergat, Anne-Marie; Oki, Kimihiko; Ishizaki, Kunihiro; Rio, Michel

    2002-11-01

    The distribution of ostracod populations in Kagoshima Bay (Japan) is analysed with reference to different environmental parameters. The bay is an area of volcanic activity of Sakurajima volcano under the influence of the Kuroshio Current. Most of the Head environment is occupied by an acidic water mass. Numbers of individual and species decrease from the Mouth of the bay towards the Basin and Head environments. In this latter, acidic water mass has a drastic effect on ostracod populations, whereas volcanic ashes and domestic inputs are not hostile. Ostracod distribution is influenced by the quality and structure of water masses. To cite this article: A.-M. Bodergat et al., C. R. Geoscience 334 (2002) 1053-1059.

  1. Development of Pabelokan Island

    SciTech Connect

    Powell, D.R.

    1982-01-01

    Pertamina and Iiapco has an expanding complex of offshore production platforms in the S.E. Sumatra contract area of the Java Sea. One of the requirements for this complex is a treatment facility for water to be used in secondary recovery operations. Because of the water quality required, the water treatment system is substantially larger than that normally used off shore. Instead of constructing one or more platforms for the treatment system, a small coral island named Pabelokan Island has been utilized for this purpose. Although the water treatment system is the primary reason for the base, other facilities were co-located to centralize electric power generation, living quarters and recreation facilities, and facilities for storage and maintenance of offshore equipment. Future plans for the island include a gas-liquids recovery system. This work describes the island facilities, and provides a case study in responsible planning and construction techniques in the development of a coral island for use as an offshore base. The experience gained should be useful in the planning of other coral islands for similar purpose.

  2. 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.

  3. 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.

  4. 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.

  5. Biomedical materials research in Japan

    SciTech Connect

    Anderson, J.M.

    1982-09-01

    The state of research in biomedical materials, particularly biomedical polymers, in Japan as of July 1981 is summerized. Based on visits to approximately 30 universities, research institutes, and medical schools, this report does not cover every relevant research group in Japan. References to provide further information to readers in selected areas are included, including recent articles by Japanese scientists that are written in English or have an English abstract. R and D in the areas of artificial heart blood pumps, artificial organs, bioenergetics, polymers for pharmaceutical use, the biocompatibility and structure of hydrogels, and the synthesis of photosensitive materials is discussed. The authors note that the Japanese Ministry of Education published a major report, approx. 600 pages long and containing 80 separate reports, which dealt with various aspects of basis research on biomedical polymers from 1977 to 1980.

  6. Endangered vascular plants in Japan

    PubMed Central

    Iwatsuki, Kunio

    2008-01-01

    The history of the Red List of Japanese vascular plants is briefly reviewed for editing and research. Especially on the results of recent monitoring, the present status of information and conservation activities on the endangered plants in Japan is discussed and the dynamics of the Japanese flora are taken up, in relation to basic research on plant biodiversity on the Japanese Archipelago. The figures of endangered plants are not very variable during the past quarter of a century, but we can surmise that the conservation of threatened species in Japan has been promoted to some extent. Based on the results of such a study, proposals are made to contribute to the sustainable use of plant biodiversity on the Japanese Archipelago under a global conspectus. PMID:18941303

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. Controls of barrier island morphology

    SciTech Connect

    Henderson, V.; Pilkey, O.H.; Keysworth, A.

    1988-08-01

    A study of 530 barrier islands from around the world has been made to determine broad physical and geologic controls on island occurrence and morphology. A total of 74 island chains, consisting of three or more islands each, was included in the investigation. Data for the study were derived from geologic and topographic maps and navigation charts. Environmental parameters considered include wind direction and velocity, mean significant wave height and storm-wave height, and tidal range. Island parameters include length, width, elevation, shape, volume, inlet width, tidal delta length, shoreface slope, coastal plain slope, and continental shelf slope. Most island chains (42%) occur along Amero-trailing edges of continents. Marginal seacoasts are second in importance (32%), and 22% of all island chains are found on collision coasts. Most islands (70%) are found in microtidal (< 2 m mean tide range) environments, with only 1% of individual islands occurring under macrotidal conditions (> 4 m mean tide range). According to the second-order coastal classification of Inman and Nordstrom, most barrier islands are found on either mountainous (32%) or wide shelf plains (32%). Next in importance are barrier islands on deltaic coasts (15%). Tidal range does not seem to play a strong role in determining island length (or inlet frequency). Islands are mostly less than 20 km in length, regardless of tidal range, although virtually all long islands (> 20 km) are found on microtidal coasts.

  15. 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.

  16. 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).

  17. 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.

  18. Heron Island, Australia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Heron Island is located at the sourthern end of Australia's 2,050 km-long Great Barrier Reef. Surrounded by coral reef and home to over 1000 species of fish, scuba divers and scientists alike are drawn to the island's resort and research station. The true-color image above was taken by Space Imaging's Ikonos satellite with a resolution of 4 meters per pixel-high enough to see individual boats tied up at the small marina. The narrow channel leading from the marina to the ocean was blasted and dredged decades ago, before the island became a national park. Since then the Australian government has implemented conservation measures, such as limiting the number of tourists and removing or recycling, instead of incinerating, all trash. One of the applications of remote sensing data from Ikonos is environmental monitoring, including studies of coral reef health. For more information about the island, read Heron Island. Image by Robert Simmon, based on data copyright Space Imaging

  19. 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 ?

  20. 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 aerosols collected at CHAAMS, Kume island and Minami-Daitou island during June, 2008 to June 2009. We also determined 'background' concentration of metals in Okinawa archipelago. We then compare each chemical component among CHAAMS, Kume island and Minami-Daitou island to elucidate the influence of the transport processes and distances from Asian continent on metal concentrations.

  1. 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."

  2. 11. VIEW NORTH, WOODLYNNE AVENUE ISLAND FROM 130 SOUTH ISLAND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW NORTH, WOODLYNNE AVENUE ISLAND FROM 130 SOUTH ISLAND - White Horse Pike Rond Point, Intersection of Crescent Boulevard (U.S. Route 130), White Horse Pike (U.S. Route 30), & Clay Avenue, Collingswood, Camden County, NJ

  3. Upwelling process of mantle helium in northeast Japan

    NASA Astrophysics Data System (ADS)

    Horiguchi, K.; Kazahaya, K.; Tsukamoto, H.; Morikawa, N.; Ohwada, M.; Nakama, A.

    2014-12-01

    Northeast Japan has an island arc structure where the Pacific plate subducts from the east. The helium isotope ratio is a good indicator to discriminate the origin of fluid carring helium, because the ratios in the mantle and crust are clearly different from each other. We performed a detailed study of helium isotope ratios in northeast Japan, and clarified the boundaries of the higher and lower helium isotope ratio distributions. The crustal components are dominant in the fore-arc region, whereas the mantle components dominate along the volcanic front and in the back-arc region. It is suggested that the clear contrast of the helium isotope ratio between the fore-arc and back-arc regions is due to the difference in whether helium isotope ratio of the wedge mantle or radiogenic helium-4 production rate in the crust. Specifically, we found the following characteristics; 1) comparison of the distribution between helium isotope ratios and faults revealed that the area along faults shows higher helium isotope ratios, 2) distribution of the helium isotope ratios is correlated with that of Li/Cl ratios which is the indicator of slab-derived water or magmatic water, suggesting that the mantle helium is transported by the slab-derived aqueous fluid. Important constraints on mantle helium upwelling are concluded as follows; a) the slab-derived water as the carrier of mantle helium, b) the faults, tectonic lines and volcanoes as the flow paths of slab-derived water, and c) crustal helium-4 contamination during upwelling process. *This research project has been conducted as the regulatory supporting research funded by the Secretariat of Nuclear Regulation Authority (Secretariat of NRA), Japan.

  4. Maintenance of biodiversity on islands.

    PubMed

    Chisholm, Ryan A; Fung, Tak; Chimalakonda, Deepthi; O'Dwyer, James P

    2016-04-27

    MacArthur and Wilson's theory of island biogeography predicts that island species richness should increase with island area. This prediction generally holds among large islands, but among small islands species richness often varies independently of island area, producing the so-called 'small-island effect' and an overall biphasic species-area relationship (SAR). Here, we develop a unified theory that explains the biphasic island SAR. Our theory's key postulate is that as island area increases, the total number of immigrants increases faster than niche diversity. A parsimonious mechanistic model approximating these processes reproduces a biphasic SAR and provides excellent fits to 100 archipelago datasets. In the light of our theory, the biphasic island SAR can be interpreted as arising from a transition from a niche-structured regime on small islands to a colonization-extinction balance regime on large islands. The first regime is characteristic of classic deterministic niche theories; the second regime is characteristic of stochastic theories including the theory of island biogeography and neutral theory. The data furthermore confirm our theory's key prediction that the transition between the two SAR regimes should occur at smaller areas, where immigration is stronger (i.e. for taxa that are better dispersers and for archipelagos that are less isolated). PMID:27122558

  5. 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

  6. Draft Genome Sequence of Flavobacterium psychrophilum Strain KTEN-1510 with Genotype A/G-C, Isolated from an Ayu (Plecoglossus altivelis altivelis) in the Kagami River, Kochi, Japan.

    PubMed

    Shimizu, Masato; Goda, Hikaru; Yamasaki, Kenichi; Oshima, Syun-Ichirou; Ohnishi, Kouhei; Osaki, Yasuo; Kataoka, Shigehiko; Imajoh, Masayuki

    2016-01-01

    In this paper, we describe the draft genome sequence of Flavobacterium psychrophilum strain KTEN-1510, with genotype A/G-C. This strain was isolated in October 2015 from the gills of an ayu (Plecoglossus altivelis altivelis) in the upper Kagami River in central Kochi Prefecture on Shikoku Island, Japan. PMID:26893435

  7. Draft Genome Sequence of Flavobacterium psychrophilum Strain KTEN-1510 with Genotype A/G-C, Isolated from an Ayu (Plecoglossus altivelis altivelis) in the Kagami River, Kochi, Japan

    PubMed Central

    Shimizu, Masato; Goda, Hikaru; Yamasaki, Kenichi; Oshima, Syun-ichirou; Ohnishi, Kouhei; Osaki, Yasuo; Kataoka, Shigehiko

    2016-01-01

    In this paper, we describe the draft genome sequence of Flavobacterium psychrophilum strain KTEN-1510, with genotype A/G-C. This strain was isolated in October 2015 from the gills of an ayu (Plecoglossus altivelis altivelis) in the upper Kagami River in central Kochi Prefecture on Shikoku Island, Japan. PMID:26893435

  8. Seismic constraints of the formation process on the back-arc basin in the southeastern Japan Sea

    NASA Astrophysics Data System (ADS)

    Sato, Takeshi; No, Tetsuo; Kodaira, Shuichi; Takahashi, Narumi; Kaneda, Yoshiyuki

    2014-03-01

    To clarify the formation process of the back-arc basin in the Japan Sea, which is located next to the northwestern Pacific, a seismic survey using ocean bottom seismographs and an air gun array was undertaken in areas from the northern Yamato Basin to the coast of the northeastern Japan Island Arc off Awa-shima Island. The crust beneath the northern Yamato Basin off Awa-shima Island is approximately 16 km thick. The upper and lower crusts are, respectively, about 5 km thick with a steep velocity gradient and about 10 km thick with a gentle velocity gradient. In the basin, there are very few units with P wave velocity of 5.4-6.0 km/s, corresponding to the continental upper crust. The crustal structure of the northern Yamato Basin has characteristics of thicker oceanic crust. The high-velocity lowermost crust in the northern Yamato Basin with 7.2-7.4 km/s might show melt formed by a slightly high mantle temperature during the opening of the basin. However, the crust beneath the areas from the Sado Ridge to the coast, which is approximately 25-26 km thick, is slightly thinner than that of the continental crust and island arc crust. The crustal structure beneath this area is inferred to be a rifted continental and/or a rifted island arc crust.

  9. Spatial heterogeneities of deviatoric stress and pore-pressure in Kyushu, Japan, and their implication for seismic activity

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Chikura, Hiromi; Ohkura, Takahiro; Miyazaki, Masahiro; Shimizu, Hiroshi; Abe, Yuki; Inoue, Hiroyuki; Yoshikawa, Shin; Yamashita, Yusuke

    2013-04-01

    We investigated the spatial variation in stress fields and pore fluid pressures on Kyushu Island, southwestern Japan. High seismic activity is found not only along active faults in Kyushu Island (southwestern Japan) but also in the central area of the island where there are active volcanoes. We consider the focal mechanisms of the shallow earthquakes on Kyushu Island to determine the relative deviatoric stress field and pore fluid factor. Generally, the stress field corresponds to a strike slip regime in this area. A decline in the maximum principal compressional stress is found in the western part of the high seismicity area, in the middle of Kyushu Island; this may be caused by a thickening of the seismogenic zone, as estimated from D90 analysis. At thin seismogenic layer, strike slip faulting dominates and strain rate from GPS study is high. In the active fault zone, seismic activity along the fault is high, and the pore pressure within the zone is higher than the values observed elsewhere, suggesting a mechanism explained by the fault valve model of Sibson [1992]. The pore pressure in the high seismic area with scattered hypocenter distribution in the middle part is lower than that in the active fault zones.

  10. Contextual view of Treasure Island from Yerba Buena Island, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of Treasure Island from Yerba Buena Island, showing Palace of Fine and Decorative Arts (Building 3), far right, Hall of Transportation (Building 2), middle, and The Administration Building (Building 1), far left, Port of Trade Winds is in foreground, camera facing northwest - Golden Gate International Exposition, Treasure Island, San Francisco, San Francisco County, CA

  11. Us-Japan cooperation on safeguards

    SciTech Connect

    Beddingfield, David H; Menlove, Howard O; Hori, Masato; Kawakubo, Yoko; Mcclelland - Kerr, J

    2009-01-01

    There is a long history of collaborative safeguards development between the United States and Japan. Japan has built, and continues to expand, the largest civil nuclear fuel cycle under full-scope IAEA safeguards in world. This development has posed unique challenges to the international safeguards system. Safeguards developments made through the US-Japan cooperation to address these unique challenges have significantly impacted the technologies deployed for international safeguards applications around the world.

  12. Archaeoastronomy of Easter Island

    NASA Astrophysics Data System (ADS)

    Edwards, Edmundo

    Astronomer priests or "skywatchers" on Easter Island lived in stone towers that were used as observatories and built stone markers in the periphery that indicated the heliacal rising of certain stars that served to indicate the arrival of marine birds, turtles, the offshore fishing season, and times for planting and harvest. Petroglyphs related to such sites depict outriggers, fishhooks, pelagic fish, and turtles and supposedly represented a star map. In this chapter, we analyze a set of such skywatchers dwellings, and stone markers located upon the North coast of Easter Island that have astronomic orientations, its related petroglyphs, and the relations between these directions with their yearly activities and their ritual calendar.

  13. Sakhalin Island terrain intelligence

    USGS Publications Warehouse

    U.S. Geological Survey Military Geology Branch

    1943-01-01

    This folio of maps and explanatory tables outlines the principal terrain features of Sakhalin Island. Each map and table is devoted to a specialized set of problems; together they cover the subjects of terrain appreciation, climate, rivers, water supply, construction materials, suitability for roads, suitability for airfields, fuels and other mineral resources, and geology. In most cases, the map of the island is divided into two parts: N. of latitude 50° N., Russian Sakhalin, and south of latitude 50° N., Japanese Sakhalin or Karafuto. These maps and data were compiled by the United States Geological Survey during the period from March to September, 1943.

  14. Long Island Solar Farm

    SciTech Connect

    Anders, R.

    2013-05-01

    The Long Island Solar Farm (LISF) is a remarkable success story, whereby very different interest groups found a way to capitalize on unusual circumstances to develop a mutually beneficial source of renewable energy. The uniqueness of the circumstances that were necessary to develop the Long Island Solar Farm make it very difficult to replicate. The project is, however, an unparalleled resource for solar energy research, which will greatly inform large-scale PV solar development in the East. Lastly, the LISF is a superb model for the process by which the project developed and the innovation and leadership shown by the different players.

  15. Salt Marshes at Chincoteague Island

    Salt marshes at Chincoteague Island. The salt marshes that make up Chincoteague Island are important habitat for migrating waterfowl. In addition, they serve an important role in protecting inland ecosystems and communities from oceanic storms....

  16. Mosquito Point at Chincoteague Island

    Salt marshes at Mosquito Point of Chincoteague Island. The salt marshes that make up Chincoteague Island are important habitat for migrating waterfowl. In addition, they serve an important role in protecting inland ecosystems and communities from oceanic storms....

  17. Clean coal activities in Japan

    SciTech Connect

    Komoto, Mitsuaki

    1994-12-31

    Asia-Pacific coal use is expected to rapidly increase in the future, and the global environmental problems associated with coal utilization are of increasing concern. Japan, in addition to its commitment to the domestic development of the technology necessary for the cleaner use of coal (clean coal technology), actively promotes clean coal technologies internationally including {open_quotes}Desulphurization Technology-Related Model Projects{close_quotes} and {open_quotes}Joint Demonstration Projects Relating to Coal Production and Utilization Technologies.{close_quotes}

  18. Solid waste management in Japan

    SciTech Connect

    Naito, S.

    1995-09-01

    On Friday 17 June 1994, as the invited speaker of the International Congress of IWM/ISWA at Torbay, UK the author presented a paper of {open_quotes}A framework for success: the role of legislation{close_quotes}. THis was to introduce the amendment of Waste Disposal Cleansing Law and the Basic Environment Law in 1991, but the combination of the two amended laws has enforced promoting and assisting the fulfillment of the responsibilities of corporations and citizens. In addition to such presentation, the author pointed out a new manner of solid waste management (SWM) in Japan.

  19. Japan Biotech Forum: London 2010.

    PubMed

    Al-Shamahi, Asma

    2010-11-01

    The Japan Biotech Forum, held in London, included topics covering new licensing developments in the Japanese pharma and biotech industries. This conference report highlights selected presentations on licensing opportunities from several Japanese companies, including CanBas, LivTech, REGiMMUNE, D Western Therapeutics Institute and Chiome Bioscience. Investigational drugs discussed include CBP-501 (CanBas), LIV-2008 (LivTech), RGI-2001 (REGiMMUNE), IVX-214 (D Western Therapeutics Institute/ Nippon Shinyaku) and anti-Sema 3A (Chiome Bioscience). PMID:21046519

  20. Japan's technology and manufacturing infrastructure

    NASA Technical Reports Server (NTRS)

    Boulton, William R.; Meieran, Eugene S.; Tummala, Rao R.

    1995-01-01

    The JTEC panel found that, after four decades of development in electronics and manufacturing technologies, Japanese electronics companies are leaders in the development, support, and management of complex, low-cost packaging and assembly technologies used in the production of a broad range of consumer electronics products. The electronics industry's suppliers provide basic materials and equipment required for electronic packaging applications. Panelists concluded that some Japanese firms could be leading U.S. competitors by as much as a decade in these areas. Japan's technology and manufacturing infrastructure is an integral part of its microelectronics industry's success.

</