HOKUSATSU BEND AND CLOCKWISE ROTATION OF THE SOUTHWEST JAPAN ARC

The Hokusatsu Bend, one of the major bends in South Kyushu, is mapped in detail. The Bend affects the Shimanto Supergroup and the Sambosan Group, and is accompanied by N-S right-lateral and NW-SE left-lateral strike-slip faults. Geometrical analysis has revealed that folds developed within the Hokusatsu Bend are conical style, like those of the Hitoyoshi Bend. They were formed by the flexural-slip folding of formerly inclined strata with vertical fold axes. The vertical cone axes of the conical folds later tilted about 30° toward west-northwest. Thus, the Shimanto Supergroup around the Hokusatsu Bend has a steeper dip than that of the other areas in Kyushu. The conical folds of the Bend were formed associated with the clockwise rotation of the Southwest Japan Arc in Miocene time. The Shimanto and Sambosan Terrains of Kyushu, to the northeast of the Hokusatsu Bend, rotated clockwise about 30°, and those to the south rotated counterclockwise about 30°-40°

LARGE DECKE STRUCTURES IN THE KUROSEGAWA AND SAMBOSAN TERRAINS, IN KYUSHU, SOUTHWEST JAPAN

Many large overthrusts have moved Paleozoic and Mesozoic strata toward south or southeast, producing decke structures in the Chichibu, Kurosegawa and Sambosan terrains in Southwest Japan. The decke structures of the Kurosegawa and Sambosan terrains in Kyushu have been clarified by the detailed analyses of geologic structures and conodont biostratigraphy. Two large deckes, the Shiraiwayama decke and the Gomayama decke which moved along the Shiraiwayama thrust and the Butsuzo Tectonic Line (thrust) respectively, occupy the most part of the terrains in Kyushu. The Shiraiwayama decke thrusts itself southeastward over the Gomayama decke which also thrusts itself southeastward over the Shimanto supergroup. The Gomayama decke is a single decke, in which strata are continuously distributed in general, whereas the Shiraiwayama decke consists of four subdeckes, S1, S2, S3 and. S4 deckes from northeast to southwest. These four subdeckes have a common character that they have the Permian limestone layers at their southeastern frontal edges. Overlapping of subdeckes takes place in the area where two subdeckes adjoin. The western subdecke always overlie the eastern one there. Those four subdeckes moved southeastward with a slight clockwise rotation, and are arranged in a left-handed en echelon pattern as a whole. The Kashimine decke moved along the Kashimine thrust in eastern Kyushu. The Kashimine decke covers both the Shiraiwayama decke and the Gomayama decke. Many minor thrusts are associated with the large overthrusts and produce an imbricate structure. Originally, therefore, these terrains must have been much wider. The upper Paleozoic and lower Mesozoic strata change their lithofacies remarkably from the Kurosegawa islands-area to the Sambosan geosyncline. The sedimentary facies show that there were land masses and shallow submarine hills in the Kurosegawa islands-area and in the southern marginal Sambosan geosyncline, whereas there was a relatively "deep" sea-area between them. The geosyncline was a narrow sedimentary basin which lay probably on the continental side of a trench

LARGE DECKE STRUCTURES AND THEIR FORMATIVE PROCESS IN THE SAMBAGAWA-CHICHIBU, KUROSEGAWA AND SAMBOSAN TERRAINS, SOUTHWEST JAPAN

Many large overthrusts have moved Paleozoic and Mesozoic strata toward south or southeast, producing decke structures in the Sambagawa-Chichibu, Kurosegawa and Sambosan terrains in Southwest Japan. The decke structures and their thrusting process in Kyushu, through Shikoku, to Kii Peninsula have been clarified by the detailed analyses of geologic structures. Four large deckes, all trending in the ENE-WSW to NE-SW direction, are arranged from north to south in Kyushu to Shikoku; the Kashimine-Kitatada-Ikegawa, Nanokawa-Onoyama, Shiraiwayama-Uonashi-Kambaradani, and Gomayama-Unomachi deckes, which moved along the Kashimine-Kitatada-lkegawa, Nanokawa-Onoyama, Shiraiwayama-Uonashi-Kambaradani, and Butsuzo thrusts respectively. The four large overthrusts have south- or southeastward vergence and are accompanied with smaller thrusts. The overthrusts observed in the earth surface probably join to form a master decollement in a deeper level of the crust. A northern thrust was always formed after the formation of a southern thrust. The master decollement or the Butsuzo thrust formed probably at first, and then the northern thrusts formed successively, branching off the master decollement. Along the master decollement, strata of the Sambagawa-Chichibu, Kurosegawa and Sambosan terrains moved southward over the Shimanto supergroup at certain ages between Late Cretaceous and Paleogene

上韮生川断層

The NE-trending Kaminirogawa fault is one of the major left-lateral strike-slip faults in the Outer Zone of Southwest Japan. The Odochi-Kahoku Area in Kochi Prefecture was mapped and the trace of the fault was clarified. The Cretaceous Formation of the Chichibu Terrain is displaced southwestward, and is in contact with the Shimanto Supergroup. The limestone-dominated Formation of the Sambosan Group is separately distributed in four blocks, produced by the NW-trending Odochi fault and the crosscutting Kaminirogawa fault. Left-lateral strike-slip displacement of the Kaminirogawa fault is estimated by using three geological markers, taking vertical displacement of 0.5-1.0 km into consideration. The strike-slip displacement is 10.3-11.3 km, 10.4 km and 8.6-10.0 km, decreasing from NE to SW. The values are larger than those clarified in Tokushima Prefecture. The Kaminirogawa fault was fonned in Miocene-Pliocene times after the major strike swinging of the Chichibu-Sambosan and Shimanto Terrains

Distributed Cooperative Relaying Based on Space-Time Block Code: System Description and Measurement Campaign

In cooperative relaying, intermediate stations are required to enhance the end-to-end transmission performance. The performance of the cooperative relaying scheme has been investigated theoretically and via computer simulations. However, cooperative relaying using transmit diversity techniques in actual environments has not been investigated thus far. This paper presents an experimental system for distributed cooperative relaying using space-time block code and evaluations of its transmission performances in real propagation channels. To this end, four wireless stations-specifically, one source, two relays, and one destination-were developed using analog transceivers and field-programmable gate arrays for real-time digital signal processing. Sample timing and frequency synchronizations among the four wireless stations were established by using the received signals as a reference. The end-to-end error performance of distributed cooperative relaying was compared to those of noncooperative relaying schemes, and the performances of three relaying schemes were evaluated quasisimultaneously in terms of their cumulative distribution functions of the bit-error ratios (BERs). The experimental results indicated that the BER performance of the two-hop distributed cooperative relaying scheme was substantially superior to those of noncooperative two-hop relaying schemes, including a route diversity scheme

シコク チュウトウブ ミウネ ツルギサン チイキ ノ ミカブ リョクショク ガンルイ チチブ ホクタイ ノ チシツ コウゾウ

Geological structures of the Mikabu greenstones and Northern Chichibu Terrain were studied in the Miune-Tsurugisan area, Middle East Shikoku. The Mikabu greenstones and phyllite with schistose sandstone and chert of the Northern Chichibu Terrain are folded by the Tanimichi antiform, which occurs from north of Tanimichi, to north of Shiragayama with ENE-WSW trending. Thick basaltic volcanic rocks of the Northern Chichibu Terrain, occurring in the south wing of the antiform, occupy the same structural horizon as the Mikabu greenstones. Therefore, the volcanic rocks are possibly correlative with the Mikabu greenstones. The Tanimichi antiform is displaced by the left-lateral strike-slip Kaminirogawa fault, and probably extends eastward to the Kisawa area in East Shikoku

Geological structures of the Chichibu Terrain in the Onoyama Area, Ehime Prefecture

Geological structures of the Chichibu Terrain in the Onoyama Area, Ehime Prefecture, are reexamined. Yamakita (1998) and Matsuoka et al. (1998) considered that there is the Kurakawa syncline with horse-shoe shape distributions of cherts in the northern Chichibu Terrain, and that strata of the northern half of the northern Chichibu Terrain dip toward south. However, the syncline does not occur, because there are no horse-shoe shape distributions and because the strata of the northern Chichibu Terrain dip toward north fundamentally. Strata consisting of phyllites with cherts, greenstones and limestones near Mt. Onoyama do not occur as a window, but occur as the hanging wall of the Onoyama thrust. The Uonashi thrust occurs at the southwestern margin of the Permian limestone near Tojikano. The thrust does not extend toward north, and does not displace the Mikabu Greenstones, because it is cut by the Onoyama thrust