青藏高原及邻近区域的S波三维速度结构

本文收集了WWSSN台网和我国台网中13个地震台站的长周期地震记录,用140条10-90s瑞利波频散曲线和作者提出的Tarantola-Backus面波频散层析成象方法,作了青藏高原及邻区的速度反演,得出该地区岩石层速度结构的三维图象.结果表明,1.在10-110km深度范围内,速度结构出现与大地构造特征相关的分区性,显示出四个构造单元:青藏块体、柴达木-巴颜喀拉-三江块体、塔里木块体和印度块体.2.高原内部,深度为10-70km内速度较低,莫霍界面呈不对称盆形分布,藏北那曲附近地壳厚度超过70km,高原边缘壳厚为45-50km,90-110km为高速异常,表明高原内部存在上地幔盖层.3.高原北部的班公湖断裂和东部的三江断裂系是该区重要的分界线,是岩石层结构存在明显差异的重要接触部位,可能是冈瓦纳古陆与欧亚古陆的缝合带.4.柴达木-巴颜喀拉-三江块体内部速度分布不均匀,地壳厚度由北向南从45km加深到60km;在深度90-110km存在一低速层.5.塔里木地块内速度随深度均匀增加,从地壳到上地幔110km内没有发现低速层.地壳厚度约50km.     

Focal mechanism inversion in the Giudicarie–Lessini seismotectonic region (Southern Alps, Italy): Insights on tectonic stress and strain

A set of 41 focal mechanisms (1989–2006) from P-wave first polarities is computed from relocated seismic events in the Giudicarie–Lessini region (Southern Alps). Estimated hypocentral depths vary from 3.1 to 20.8 km, for duration magnitudes (M_D) in the range 2.7–5.1. Stress and strain inversions are performed for two seismotectonic zones, namely G (Giudicarie) and L (Lessini). This subdivision is supported by geological evidence, seismicity distribution, and focal mechanism types. The available number of data (16 in G, 22 in L) does not make possible any further subdivisions. Seismotectonic zones G and L are undergoing different kinematic regimes: thrust with strike-slip component in G, and strike-slip in L. Principal stress and strain axes in each sub-region show similar orientations. The direction of maximum horizontal compressive stress is roughly perpendicular to the thrust fronts along the Giudicarie Belt in zone G, and compatible with right-lateral strike-slip reactivation of the faults belonging to the Schio-Vicenza system in zone L. On the whole, kinematic regimes and horizontal stress orientations show a good fit with other stress data from focal mechanisms and breakouts and with geodetic strain rate axes.     

Comments on ‘A comparative study of ANN and neuro-fuzzy for the prediction of dynamic constant of rockmass’

Singh et al (2005) examined the potential of the ANN and neuro-fuzzy systems application for the prediction of dynamic constant of rockmass. However, the model proposed by them has some drawbacks according to fuzzy logic principles. This discussion will focus on the main fuzzy logic principles which authors and potential readers should take into consideration.     

The role of heterogeneous strain in the development and preservation of a polymetamorphic record in high-P granulites, western Canadian Shield

Mafic rocks in the Chipman domain of the Athabasca granulite terrane, western Canadian Shield, provide the first well‐documented record of two distinct high‐P granulite facies events in the same domain in this region. Textural relations and the results of petrological modelling (NCFMASHT system) of mafic granulites are interpreted in terms of a three‐stage tectonometamorphic history. Stage 1 involved development of the assemblage Grt + Cpx + Qtz ± Pl (M₁) from a primary Opx‐bearing igneous precursor at conditions of 1.3 GPa, 850–900 °C. Field and microstructural observations suggest that M₁ developed synchronously with an early S₁ gneissic fabric. Stage 2 is characterized by heterogeneous deformation (D₂) and synkinematic partial retrogression of the peak assemblage to an amphibole‐bearing assemblage (M₂). Stage 3 involved a third phase of deformation and a return to granulite facies conditions marked by the prograde breakdown of amphibole (Amph₂) to produce matrix garnet (Grt_3a) and the coronitic assemblage Cpx_3b + Opx_3b + Ilm_3b + Pl_3b (M_3b) at 1.0 GPa, 800–900 °C. M₁ and M_3b are correlated with 2.55 and 1.9 Ga metamorphic generations of zircon, respectively, which were dated in a separate study. Heterogeneous strain played a crucial role in both the development and preservation of these rare examples of multiple granulite facies events within single samples. Without this fortuitous set of circumstances, the apparent reaction history could have incorrectly led to an interpretation involving a single‐cycle high‐grade event. The detailed P–T–t–D history constructed for these rocks provides the best evidence to date that much of the east Lake Athabasca region experienced long‐term lower crustal residence from 2.55 to 1.9 Ga, and thus the region represents a rare window into the reactivation and ultimate stabilization processes of cratonic lithosphere.     

舟山国家石油储备基地堆载预压加固效果分析

介绍了舟山国家石油储备基地试验区软基堆载预压大型现场试验结果,根据现场试验测得的数据,分析了软土地基堆载预压下沉降变化规律、分层沉降变化规律、深层土体位移变化规律、超静孔隙水压力变化规律,进一步探讨了根据应力和应变分析得到的地基固结性状,其中通过应变分析得到适用于储备基地的沉降经验系数m。结果表明,打设塑料排水板结合堆载预压处理软弱地基具有良好的效果。     

从厌氧反应器的发展谈UASB反应器的改良

对厌氧反应器的发展沿革、技术现状和研究进展进行了较为全面的总结。介绍了第 1代、第 2代和第 3代厌氧反应器的特点及应用状况。分析了厌氧反应器的发展趋势 ,对比了 EGSB、IC反应器与 UASB反应器的结构特征 ,提出并验证了改良 UASB反应器。结果显示 ,改良 UASB反应器有利于提高负荷和设备开发。     

Effect of Cyclic Loading Frequency on Undrained Behaviors of Undisturbed Marine Clay

Based on a series of cyclic triaxial tests, the effect of cyclic frequency on the undrained behaviors of undisturbed marine clay is investigated. For a given dynamic stress ratio, the accumulated pore water pressure and dynamic strain increase with the number of cycles. There exists a threshold value for beth the accumulated pore water pressure and dynamic strain, below which the effect of cyclic frequency is very small, but above which the accumulated pore water pressure and dynamic strain increase intensely with the decrease of cyclic frequency for a given number of cycles. The dynamic strength increases with the increase of cyclic frequency, whereas the effect of cyclic frequency on it gradually diminishes to zero when the number of cycles is large enough, and the dynamic strengths at different frequencies tend to the same limiting minimum dynamic strength. The test results demonstrate that the reasons for the frequency effect on the undrained soil behaviors are beth the creep effect induced by the loading rate and the decrease of sample effective confining pressure caused by the accumulated pore water pressure.     

一种计算台风风场的方法

揭示Ｒａｎｋｉｎｅ涡风场模式和Ｊｅｌｅｓｎｉａｎｓｋｉ风场模式之间的联系，并设计了一种台风风场分布模式，它的风速分布曲线落在Ｊｅｌｅｓｎｉａｎｓｋｉ和Ｒａｎｋｉｎｅ涡两个风场模式的风速分布曲线之间，具有一个既优于Ｊｅｌｅｓｎｉａｎｓｋｉ又优于Ｒａｎｋｉｎｅ涡的风速衰减速率，因此它同时克服了Ｒａｎｋｉｎｅ涡模式计算风速偏小和Ｊｅｌｅｓｎｉａｎｓｋｉ模式计算风速偏大的缺点，以一种比较合理的变化趋势向远方衰减，成为一个比较切合实际的台风风场分布模式。同时，文中提出的移行台风风场计算方法对宫崎正卫、上野武夫和Ｊｅｌｅｓｎｉａｎｓｋｉ模式都有一定的改进。     

在各类天气系统影响下石臼港沿岸波浪场的分布

本文查阅了从１９７３－１９８５，１３年的历史资料，对石臼港沿岸波浪场进行了详细的分类、统计分析和计算，提出了各类较强天气系统影响石（即指石臼港）的极端区域，同时获得了石港沿岸各类天气系统影响下的波浪分布特点以及波高计算式，为保障石港的生产及港口建设为石港的波了提供了有益的分析数据和预报手段。     

渤海中南部悬浮物海洋调查资料分析

对于悬浮物 (SPM)的研究目前已引起诸多学者关注。作者利用 1998和 1999年的中德合作海洋调查所获得的资料进行分析。主要进行三个方面的工作 :研究悬浮物与透明度的关系 ;研究悬浮物与浊度的关系 ;估计海底剪切速度。并为研究悬浮物输运提供资料和作前期研究