Persistent organochlorine residues in sediments from the Chukchi Sea, Bering Sea and Gulf of Alaska   总被引：14，自引：0，他引：14  

Hisato Iwata  Shinsuke Tanabe  Mari Aramoto  Norio Sakai  Ryo Tatsukawa 《Marine pollution bulletin》1994,28(12):746-753

Three surface sediments and two sediment cores were collected from the Gulf of Alaska, Bering Sea and Chukchi Sea, and analysed for persistent organochlorines (OCs). The geographical distributions of OCs showed different patterns according to their physicochemical properties. The concentrations of HCHs and HCB revealed rather uniform distribution, suggesting their more transportable nature in long-range atmospheric transport. On the other hand, DDTs and PCBs were predicted to be less transportable via the atmosphere due to the decreasing trends of residue levels in sediments from south to north. The OC profiles in the sediment core from the Gulf of Alaska which seemed to be preserved without turbation revealed the elevated residue levels from bottom to surface layers. This implies that the aerial inputs of OCs in the cold ocean are still continuing significantly. The accumulation rates of OCs into sediments were rather smaller than the atmospheric inputs, indicating that the residue levels in water bodies are unlikely to decrease rapidly in the near future.  相似文献   

Re-evaluation of the large deep earthquake of January 21, 1906     

Katsuyuki Abe 《Physics of the Earth and Planetary Interiors》1985,39(3):157-166

The large deep earthquake of January 21, 1906 is re-evaluated using old seismogram data and updated analysis techniques. From the P and pP-P time data the hypocentre parameters are determined as follows: origin time, 13h 49min 35s; latitude, 33.8°N; longitude, 137.5°E; depth, 340 km. The body-wave magnitude m_B is re-evaluated from the amplitude and periods of P, PP and S waves. The average value of 7.4 is obtained. This value is the smallest among any values assigned previously to this shock, and it is denied that the earthquake is the world's largest deep shock in this century. The focal mechanism is estimated from the P-wave first motions and amplitude distribution of P and S waves. Synthetic body waves are used to constrain the mechanism and to determine the seismic moment. The mechanism solution suggests the down-dip compression typical of this region. A seismic moment of 1.5 × 10²⁷ dyn · cm is obtained. This value and the re-evaluated value of m_B are consistent with the moment-_B relation obtained for other deep earthquakes.  相似文献   

Modeling of the runup heights of the Hokkaido-Nansei-Oki tsunami of 12 July 1993     

Katsuyuki Abe 《Pure and Applied Geophysics》1995,144(3-4):735-745

The Hokkaido-Nansei-Oki earthquake (M _w 7.7) of July 12, 1993, is one of the largest tsunamigenic events in the Sea of Japan. The tsunami magnitudeM _t is determined to be 8.1 from the maximum amplitudes of the tsunami recorded on tide gauges. This value is larger thanM _w by 0.4 units. It is suggested that the tsunami potential of the Nansei-Oki earthquake is large forM _w . A number of tsunami runup data are accumulated for a total range of about 1000 km along the coast, and the data are averaged to obtain the local mean heightsH _n for 23 segments in intervals of about 40 km each. The geographic variation ofH _n is approximately explained in terms of the empirical relationship proposed byAbe (1989, 1993). The height prediction from the available earthquake magnitudes ranges from 5.0–8.4 m, which brackets the observed maximum ofH _n , 7.7 m, at Okushiri Island.  相似文献   

Revision of magnitudes of large shallow earthquakes, 1897–1912     

Katsuyuki Abe  Shin&#x;ichi Noguchi 《Physics of the Earth and Planetary Interiors》1983,33(1):1-11

In previous research, trace amplitudes of surface wave maxima recorded by undamped Milne seismographs were used to determine the surface-wave magnitudes M_s of large shallow earthquakes which occurred prior to 1912. For this purpose, the effective gain of these instruments was calibrated by using the surface-wave magnitudes M_s(GR) which were calculated from the unpublished worksheets for Seismicity of the Earth of Gutenberg and Richter. In this paper, the real quality of M_s(GR) is critically re-evaluated by using independent sets of data. It is found that M_s(GR) for the period 1904–1909 is considerably overestimated. The average excess from the real M_s is 0.5 units for 1904–1906, 0.4 for 1907, 0.3 for 1908–1909 and 0.0 for 1910–1912. This overestimation is so systematic and large that the previous results are all redetermined. The average effective gain of Milne instruments is revised to be 21.9; previously, the gain depended on M_s. This revision results in systematic reduction in the previously assigned magnitudes. The revised values of M_s for 264 shallow earthquakes, with M_s=6.8 and over in the period 1897–1912 inclusive, are listed. The present revision is large enough to preclude the possibility of the high activity of large shallow earthquakes around the turn of the century. The present results have a direct effect on all the magnitude catalogues of shallow earthquakes which occurred prior to 1909.  相似文献   

Phases Representing Source Lengths of Tsunami in Tide Gauge Records     

Kuniaki Abe 《Pure and Applied Geophysics》2007,164(2-3):453-463

We identified a phase representing the source length of tsunami's in the tide gauge records around Japan. This phase was observed at tide stations, located in the direction of the long axis of the sources, for four large tsunamis: 1964 Niigata, 1968 Tokachi-oki, 1983 Nihonkaichubu, and 1993 Hokkaido-nanseioki. The phase consists of two continuous crests starting as the initial arrival and has a time length of 15–47 minutes. This is the time required to propagate across the source area along the long axis. Strong evidence that the phase is generated at the source is the good correlation between waveform observed at one side and time-inversed waveform at another side. The correlation results from the instantaneous generation of the source. The source lengths of 74–254 km were obtained under an assumption of sea depths at the sources and verified to coincide with ones within a relative error of 15% that were previously obtained by other methods.  相似文献   

Subcellular distribution of trace elements in the liver of sea turtles     

Anan Y  Kunito T  Sakai H  Tanabe S 《Marine pollution bulletin》2002,45(1-12):224-229

Subcellular distribution of Cu, Zn, Se, Rb, Mo, Ag, Cd and Pb was determined in the liver of green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) from Yaeyama Islands, Japan. Also, hepatic cytosol from sea turtles was applied on a Sephadex G-75 column and elution profiles of trace elements were examined. Copper, Zn, Se, Rb, Ag and Cd were largely present in cytosol in the liver of both species, indicating that cytosol was the significant site for the accumulation of these elements in sea turtles. In contrast, Mo and Pb were accumulated specifically in nuclear and mitochondrial fraction and microsomal fraction, respectively. Gel filtration analysis showed that Cu, Zn, Ag and Cd were bound to metallothionein (MT) in the cytosol of sea turtles. To our knowledge, this is the first report on the association of trace elements with MT in sea turtles.  相似文献   

Trace elements in skin of Dall's porpoises (Phocoenoides dalli) from the northern waters of Japan: an evaluation for utilization as non-lethal tracers     

Yan J  Kunito T  Tanabe S  Amano M  Miyazaki N 《Marine pollution bulletin》2002,45(1-12):230-236

Concentrations of Fe, Zn, Cu, Se, Mn, Mo, Hg, Cd, Cr, Ag, Pb, Sr and V were determined in skins of Dall's porpoises (Phocoenoides dalli) of the Pacific coast truei-type population (PT population) (N=45), and the Sea of Japan-Okhotsk dalli-type population (JD population) (N=31) from the northern waters of Japan. Cutaneous Hg concentrations in both PT and JD populations were significantly correlated with age, indicating a possible alternative method of age estimation. A significant correlation was also noted between Hg concentrations in skin and liver, suggesting that biopsy samples of skin can provide a non-lethal surrogate for monitoring Hg contamination in this species. Trace element accumulation patterns differed strongly between PT and JD populations, when analyzed by principal component analysis, suggesting these patterns could be utilized as non-lethal tracers of population identification.  相似文献   

Wide-Field Camera for Gravitational Microlensing Survey: MOA-cam2     

Toshifumi Yanagisawa  Yasushi Muraki  Yutaka Matsubara  Fumio Abe  Kimiaki Masuda  Sachiyo Noda  Takahiro Sumi  Yuji Kato  Mitsuaki Fujimoto  Shuji Sato  Ian Bond  Nicholas Rattenbury  Philip Yock  Pam Kilmartin  John Hearnshaw  Micheal Reid  Denis Sullivan  Brian Carter  Richard Dodd  Garry Nankivell  Noiman Rumsey  Morihiro Honda  Maki Sekiguchi  Masanori Yoshizawa  Takashi Nakamura  Humitaka Sato  Seiji Kabe  Makoto Kobayashi  Yoshiyuki Watase  Jun Jugaku  Toshiharu Saito  Barbel Koribalsky 《Experimental Astronomy》2000,10(4):519-535

We have constructed a large, mosaic CCD camera called MOA-cam2 which has 4096 × 6144-pixelsto search for gravitational microlensing events. MOA-cam2 has three4096 × 2048-pixel SITe CCD chips, which have a very high quantum efficiency (nearly 80% in the wave region 500 to 800 nm),and three buttable sides. We have placed the threechips side by side with 100 m dead space. MOA-cam2 has been installed on the 61 cm Boller and Chivens telescope of the MOA collaboration at the Mt. John University Observatory (MJUO) in NewZealand since July 1998. The field coverage is 0.92° × 1.38° per exposure. The technical details of MOA-cam2 and the first images obtained with the Boller and Chivens telescope are presented. MOA-cam2 introduces a second phase of research on gravitational microlensing by the MOA collaboration.  相似文献   

Mechanism and tectonic implications of the great Banda Sea earthquake of November 4, 1963     

Masaki Osada  Katsuyuki Abe 《Physics of the Earth and Planetary Interiors》1981,25(2):129-139

The Banda Sea earthquake of November 4, 1963 (h = 100 km, m_B = 7.8) is probably one of the largest intermediate-depth shocks to have occurred worldwide this century. The mechanism of this earthquake is studied in detail on the basis of P-wave first motion, surface wave and aftershock data. From the analysis of long-period multiple surface waves, a seismic moment of 3.1 × 10²⁸ dyn-cm is obtained, which is the largest reported so far for any intermediate or deep focus shock. This value, together with the estimated fault area of 90 × 70 km², gives an average dislocation of 7.0 m and a stress drop of 120 bar. This event represents an oblique thrust movement on a plane with dip direction N170°E, dip 48° and rake 52°. A geometrical consideration for the fault plane and the configuration of the inclined seismic zone beneath the Banda arc suggests, almost definitely, that the large-scale faulting took place within the subducted plate and offset it. Further repetition of such large-scale faulting might eventually break the subducted plate. The 1963 Banda Sea earthquake thus represents a seismological manifestation of the large-scale deformation of the subducted plate in the mantle.  相似文献   

Under‐ice salinity and stable isotope distribution of Saroma‐ko Lagoon,Hokkaido, northern Japan     

Maki Morimoto  Kyoko Kawanobe  Osamu Abe  Takayoshi Kawai  Toshiyuki Kawamura  Kunio Shirasawa 《水文研究》2010,24(7):904-916

In winter, lakes and lagoons at high altitudes or high latitudes have interesting hydrological cycles that differ from those in other seasons or in other regions, because water surfaces are covered with ice. Hydrological balances of lakes and lagoons are complex dynamic systems, and to elucidate them, isotopic tracers of water have been used as effective tools along with observations of precipitation, evaporation, inflows, and outflows. Here, to understand hydrological processes during freezing periods in the brackish Saroma‐ko Lagoon, Hokkaido, northern Japan, we examined horizontal and vertical distributions of salinity and isotope compositions of lagoon water and ice in 2005 and 2006. Horizontal and vertical gradients of salinity and isotope compositions were observed from the river mouth to the sea channel, and factors determining these distributions were considered. The mixing of freshwater and seawater and a freezing effect were presumed to be factors in relationships between salinity and isotopes and in relationships between surface waters and ice just above the water. A simple box model for water balance was constructed based on these putative factors to reproduce the distributions of salinity and isotope compositions of surface waters and ice. An evaluation of the model revealed that this hydrological system is controlled primarily by horizontal advection of the epilimnion, freshwater influx, and the ice growth rate. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献