排序方式： 共有8条查询结果，搜索用时 15 毫秒
1
1.
Formation and shortening deformation of a back-arc rift basin revealed by deep seismic profiling, central Japan 总被引：1，自引：0，他引：1
Hiroshi Sato Takaya Iwasaki Shinji Kawasaki Yasutaka Ikeda Nobuhisa Matsuta Tetsuya Takeda Naoshi Hirata Taku Kawanaka 《Tectonophysics》2004,388(1-4):47
The northern Fossa Magna (NFM) basin is a Miocene rift system produced in the final stages of the opening of the Sea of Japan. It divides the major structure of Japan into two regions, with north-trending geological structures to the NE of the basin and EW trending structures to the west of the basin. The Itoigawa-Shizuoka Tectonic Line (ISTL) bounds the western part of the northern Fossa Magna and forms an active fault system that displays one of the largest slip rates (4–9 mm/year) in the Japanese islands. Deep seismic reflection and refraction/wide-angle reflection profiling were undertaken in 2002 across the northern part of ISTL in order to delineate structures in the crust, and the deep geometry of the active fault systems. The seismic images are interpreted based on the pattern of reflectors, the surface geology and velocities derived from refraction analysis. The 68-km-long seismic section suggests that the Miocene NFM basin was formed by an east dipping normal fault with a shallow flat segment to 6 km depth and a deeper ramp penetrating to 15 km depth. This low-angle normal fault originated as a comparatively shallow brittle/ductile detachment in a high thermal regime present in the Miocene. The NFM basin was filled by a thick (>6 km) accumulation of sediments. Shortening since the late Neogene is accommodated along NS to NE–SE trending thrust faults that previously accommodated extension and produce fault-related folds on their hanging wall. Based on our balanced geologic cross-section, the total amount of Miocene extension is ca. 42 km and the total amount of late Neogene to Quaternary shortening is ca. 23 km. 相似文献
2.
The characteristics of a Lyman-alpha humidiometer have been carefully examined in an air-conditioned test chamber. The results confirm that when carefully used, this humidiometer is suitable for measurements of turbulent humidity fluctuations. Measurements with a Lyman-alpha humidiometer were carried out in the surface boundary layer over the ocean. The relation between turbulent intensity (
a
= a
ov2) and the friction humidity (a
*) can be expressed as
a
= l.6a
*. The spectrum of turbulent humidity for wind speeds larger than 3 m s –1 conforms to the similarity law in the surface boundary layer. The spectrum has two characteristic normalized frequencies, namely, a higher peak and a secondary peak (or a shoulder). 相似文献
3.
Yoko Ota Yu-Nung Nina Lin Yue-Gau Chen Nobuhisa Matsuta Takuya Watanuki Ya-Wen Chen 《Tectonophysics》2009,474(3-4):559-570
This study aims at the recent activity and development of an active wrench fault, the Touhuanping Fault in northwestern Taiwan. Northwestern Taiwan has been proposed in a current situation between the mature to waning collision in terms of tectonic evolution. The main drainage in this area, the Chungkang River, flows close to the trace of the fault mentioned above. We examined various types of deformation of fluvial terraces along the Chungkang River as a key to understanding the nature and rate of the late Quaternary tectonics. The E–W trending Touhuanping Fault has long been mapped as a geological boundary fault, but its recent activity was suspected. Field survey revealed that its late Quaternary activity is recorded in the offset fluvial terraces. Our result shows dextral slip and vertical offset with upthrown side on the south, and activated at least twice since the emergence of terrace 4 (older terrace 3 with OSL date of ca. 80 ka). Total amount of offset recorded in the Touhuanping terrace sequence is 15 m for dextral and 10 m for vertical offset. Estimated recurrence time of earthquake rupture may be a few tens of thousand years. Uplift on the upthrown side of the Touhuanping Fault also resulted in the formation of drowned valleys which were graded to terrace 4. Other deformation features, such as back-tilting, westward warping, and a range-facing straight scarp, were also identified. A second-order anticline roughly parallel to the Touhuanping Fault is suggested to be the origin of the northward tilting on terrace 3; it could have resulted from a flower structure on the Touhuanping Fault at shallow depth. This may demonstrate that the buried segment of the Touhuanping Fault has also been active since 80 ka. In the northern study area, the westward warping at terrace 2 probably represents late Quaternary activity of another NE–SW trending Hsincheng Fault. 相似文献
4.
Ando Haruo Maki Hideaki Kashiwagi Nobuhisa Ishii Yuuichi 《Journal of Oceanography》2021,77(6):843-858
Journal of Oceanography - Long-term trends of bottom-water concentrations of dissolved oxygen (DO), total nitrogen, and total phosphorus at 42 sites in Tokyo Bay were analyzed using monthly data... 相似文献
5.
An analytical method for the determination of the roughness parameters over complex regions 总被引：1，自引：0，他引：1
The values of roughness length for momentum z
0and zero-plane displacement d
0over a hilly rough complex region with vegetation were evaluated without any assumption concerning z
0and d
0.It was found that for widely scattered profile data, the method of least squares will not give a reasonable result in determining the roughness parameters. For this purpose, the method of maximum correlation was introduced instead. This method gave a fair result for captive balloon observations conducted in hilly terrain mainly covered with forest in the northwestern part of the Kanto Plain, Japan. 相似文献
6.
In order to determine the values of the Dalton and the Stanton numbers, an observational study was made over a saturated barley field in the Hachirogata. flat reclaimed land located in the northern part of Japan. The mean height of the barley was about 11 cm; the roughness height for momentum was determined from the mean wind profiles as 4.24 ± 0.18 cm and the zero-plane displacement height as 0 cm. Under neutral stratification and a saturated surface, the reciprocals of the Dalton and Stanton numbers, Da-1 and St-1, were estimated. The results show that the mean value of St-1 is 12.1, and the ratio of the bulk transfer coefficient for heat to that for momentum. C
H/CM, is 0.53, which are not entirely incompatible with the few results available from past observations. The mean value of Da- is 38.2. This value is larger than St-1, and fits reasonably well with the semi-empirical equation proposed by Brutsaert (1975a,b). 相似文献
7.
Nobuhisa Yasuda 《Boundary-Layer Meteorology》1988,43(3):209-221
Diurnal variations of the vertical profiles of wind and temperature have been surveyed, and the diffusivity and the dimensionless gradient function in the atmospheric boundary layer have been estimated. Even in the middle of the atmospheric boundary layer (e.g., below a height of 442 m), the vertical wind profile normalized by the surface friction velocity has approximately a universal profile function different from that in the surface boundary layer. Under strong stability conditions, the dimensionless gradient function has a value of about 9. 相似文献
8.
The fluxes of planktonic foraminifera (calcareous shell producing zooplankton) were examined in order to clarify temporal and regional variations in production in the upper ocean in relation to hydrographic conditions. Three time-series sediment traps were deployed in the central North Pacific along 175°E for about one year, beginning in June 1993. Trap sites were located in the subarctic, the transition, and the subtropical water masses, from north to south. The southernmost site was under the influence of the transition zone in January to May. Both temporal and regional fluxes of planktonic foraminifera showed large variations during the experiment. In the subarctic water mass, high total foraminiferal fluxes (TFFs) and high organic matter fluxes (OMFs) were observed during summer to fall, suggesting that food availability is the most important factor for the production of planktonic foraminifera. Furthermore, low TFFs during winter were ascribed to low food availability and low temperatures. The OMFs and TFFs correlated well and increased rapidly after the disruption of the seasonal thermocline during winter, peaking in late February to early March in the transition zone. In the subtropical water mass, both OMFs and TFFs remained low due to lower productivity under oligotrophic conditions. In general, TFFs show a positive correlation with OMFs during the trap experiment, suggesting that food availability is one of the factors controlling the production of planktonic foraminifera in the central North Pacific. Relatively low TFFs during summer to fall in the subtropical water mass may be caused by the thermal structure of the upper ocean. Low SST possibly reduces the production of foraminifera during winter in the subarctic region. 相似文献
1