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Research study on the resolution process of the Kanchazu Island Incident and its impact - Focusing on the period after the sinking of the Soviet Gunboat
Get PDFIn this paper, the first topic describes the situation on the front line, from when the Soviet Unionʼs Peopleʼs Commissar for Foreign Affairs Maxim Litvinov promised to Ambassador Mamoru Shigemitsu that Soviet border guards and ships would be withdrawn, until the withdrawal was actually completed, as revealed from Japanese historical materials. The next topic will examine the Japan-Soviet negotiations regarding the salvaging of the Soviet gunboat sunk by the Japanese military. While the final topic will clarify the influence that the Kanchazu Island Incident had on the Japanese militaryʼs philosophy of war against the Soviet Union.departmental bulletin pape
Path and Manner of Motion, and Onomatopoeia and Sound Symbolism for Manner, in English and Japanese Picture Books
Get PDFdepartmental bulletin pape
Synoptic Climatological Analyses of Typhoons Based on El Niño/ La Niña Events
No full textEl Niño (EN) and La Niña (LN) events are part of atmosphere-ocean interaction, which is closely associated with the
genesis, development and tracks of typhoons. This study conducted a statistical analysis of typhoons from 1988 to 2021
and investigated the characteristics of typhoons based on El Niño and La Niña events, both in summer (June, July and
August; JJA) and in autumn (September, October and November; SON) to examine the effects of El Niño and La Niña on
typhoons. Seasonal differences of typhoons during El Niño and La Niña are summarized as follows; during El Niño, the
mean location of typhoon formation shifted about 1000 km east-southeastward in both summer and autumn, compared
with La Niña. In summer the mean location of typhoon formation was 18N-132E for La Niña (LN JJA) vs. 15N-142E for El
Niño (EN JJA), while in autumn 15N-136E for La Niña (LNSON) vs.13N-147E for El Niño (ENSON). The typhoons with the
central pressure of 960-989 hPa are 4.9 % more during La Niña than El Niño, whereas violent typhoons with 900-929 hPa
are 11.5 % more during El Niño than La Niña and tended to be intense and long-lasting. Typhoon No.19 in 1991 which is
famous for damage from fall apples in Aomori prefecture and Typhoon No.18 which caused severe damage to Kanto and
Tohoku regions in September 2015 both occurred during El Niño. When El Niño is happening, the distribution of surface
winds in the western Pacific indicated that moist currents tended to flow in from the Southern Hemisphere, so that in
autumn when El Niño is in place (ENSON), frequency of typhoon formation increased with a small vertical wind shear (≲
2m/s between 700 hPa and 925 hPa), east of the Philippines and in the vicinity of Mariana islands and typhoons tended to
turn in ca. 25N and head toward Japan.departmental bulletin pape
An Analysis of Extraction and Tracking of Drifting Pumice from the Fukutoku-Oka-no-Ba 2021 Eruption by Time Series Satellite Observation Data
No full textFukutoku-Oka-no-Ba of submarine volcano located in the southernmost end in the Ogasawara Islands caused the
large-scale eruption on August 13，2021．The eruption was very large-scale and the volcano spouted a lot of pumices．
The pumice raft was drifting toward the west，and the serious influence occurred in the Okinawa island by mass drifting
pumice washed ashore in early October．However，the detailed drifting movement situation of the pumice in the ocean
from Fukutoku-Oka-no-Ba to the Okinawa island has been not sufficiently investigated．In this study，development of a
method of extracting pumice raft from the satellite LANDSAT/OLI optical sensor data by an image data processing firstly
was performed．Next，through the applying of the developed method to 20 time-series satellite GCOM-C/SGLI data，the
extraction of the drifting pumice raft and detailed tracking of the drifting situation were analyzed in the sea from Fukutoku-Oka-no-Ba to the Okinawa island．Finally，based on analysis and measurement results，the consideration for the
characteristics of drift pumice movement was carried out．The result of this study is summarized as below.
1） According to the analysis of the comparatively high spatial resolution LANDSAT/OLI･TIRS data，the result of
applying a multi level slice classifier to the visible to short wavelength infrared data showed that the extraction of detailed
pumice distribution on the ocean was possible.
2） By the applying of a multi level slice classifier to time-series GCOM-C/SGLI data of high observation frequency，
the extraction of the drift pumice distribution and the investigation of its movement situation in the object sea area were
sufficiently carried out.
3） Although it became clear that drift pumices mainly moved in an average of about 1.15 km/h toward the west，and
reached the Okinawa island in mid-October，it turned out that the complicated drift movement toward the north or the
east was also shown temporarily.
4） It was shown that the drift pumice movement was strongly affected by the influence of ocean current or sea wind
direction based on the comparative analysis with such related data，and also the influence by a typhoon passing through
the neighboring sea area was presumed．departmental bulletin pape
Study on Determination of Hypocenter of Earthquakes Occurring in the Extremely Shallow Area of the Boso Peninsula
No full textCompared to other crustal earthquakes, earthquakes at very shallow depths of the earth’s surface can cause even
small earthquakes to become surface earthquake faults. Even if the damage caused by shaking is small, earthquakes may
have a strong impact on the safety of underground space utilization, such as geological disposal and underground storage
of carbon dioxide. We focused on the earthquake in Chiba Prefecture, Japan, on June 29, 2012. This earthquake hypocenter was determined to be M4.5 with a depth of 0 km by the Japan Meteorological Agency. By redetermining the hypocenter, we examined whether the earthquake occurred near the ground surface. Also, experiments were conducted on rock
samples to estimate the stress field during the earthquakes.
We redetermined the hypocenter of the earthquake, it found that the depth of the hypocenter is likely to be shallower
than 2 km, and the seismic mechanism solution for the initial motion of the earthquake was a normal fault solution. Also,
by conducting Direct shear tests, Coulombʼ s failure criterion line was determined for the area where the earthquake
occurred, and the stress polygon used to estimate the stress field at that time. It found that earthquakes in shallow areas
may be caused by tensile failure.departmental bulletin pape
An upper bound of geometric genus of normal two-dimensional star-shaped singularities
No full textFor normal two-dimensional star-shaped singularity, we show an upper bound
of the geometric genus. The bound is given by pa(Z0) times some numerical bound defined related to a-invariant of the normalized of associated graded ring of the centeral
filtration of star-shaped singularity (Theorem 1). Further we give a sufficient condition for a numerical Gorenstein star-shaped singularity to be Gorenstein by attaining
sufficiently large value with respect to our bound (Theorem 3). We also study a criterion for a normal graded ring R = R(E,D) to be numerical Q-Gorenstein in terms of
Pinkham-Demazure’s data E,D (Theorem 2).departmental bulletin pape
A Critical Review of the “Balance of Payments Stages” Hypothesis
Get PDFThis paper provides an overview of the “Balance of Payments Stages” hypothesis (hereinafter, the Hypothesis) and evaluates its applicability based on previous researches and data from Japan and the United States over several decades. When the Hypothesis is not applicable, the paper discusses what perspective should be adopted to properly understand a country’s balance of payments situation and changes in its external competitiveness. The paper finds that the Hypothesis cannot explain the balance of payments situation of Japan, the United States, or indeed most countries. Even if a country’s balance of payments appears to move in accordance with the Hypothesis, the underlying reasons differ from those stated in the Hypothesis. To properly understand a country’s economic situation in light of its relationships with other countries, one should analyze gross data, i.e., exports and imports rather than, as in the Hypothesis, balance (net) data. Furthermore, one should analyze the economic situation not only on the basis of the balance of payments, which only records cross-border transactions, but also using various complementary data, such as those on the activities of multinational companies. The new Balance of Payments Manual (the international standard for balance of payments statistics), scheduled for publication in 2025, will give greater consideration to such complementary data. In other words, in preparing the new manual, a more appropriate framework for understanding a country’s economic situation in the context of its relationships with other countries will be incorporated.departmental bulletin pape
