Genetic mechanism and failure process of the Mogangling seismic landslide

This paper presents a case study on the Mogangling landslide and its characteristics and geological mechanism. The Mogangling landslide is a giant rock landslide located at the intersection of Dadu river and Moxi river. It is a landslide triggered by an earthquake with large magnitude that occurred in 18th century. Based on detailed site investigation, it shows the Mogangling landslide developed in the Kangding complex strata, composed of completely decomposed aggregates of massive-block stone, debris and soil with some gravels, pebbles and sand layer found distributed in front of the landslide. The control factor of the deformation of this landslide is the combined effect of Detuo fault which is located under the slope, and the regional stress formed along structural planes as well as the free surfaces formed by river cutting. Therefore, when the Kangding-Moxi earthquake (Ms =7.7) occurred on 1st June, 1786, due to seismic shaking, topographic amplification effects and back slope effects, the Mogangling landslide occurred. The Dadu River is the most important river for hydropower development in China; large-scale seismic landslides along the Dadu River are the most important geological issue during the construction of hydropower stations. Therefore, this research is important from the point of view of economic and social benefits.     

琼东南盆地华光凹陷天然气水合物稳定带厚度的影响因素

为了探讨琼东南盆地华光凹陷海底天然气水合物稳定带的分布规律,定量研究了静水压力、底水温度、地温梯度和气源组分对水合物稳定带的影响程度。在此基础上,分析了华光凹陷现今甲烷水合物稳定带的厚度分布。最后,综合各因素的历史演化过程,初步探讨了华光凹陷1.05 Ma BP以来天然气水合物稳定带的演化。结果表明:(1)气源组分和海底温度的变化对研究区内水合物稳定带的影响较大;水合物稳定带厚度与海底温度呈良好的线性负相关性。(2)水深超过600 m的海域具备形成天然气水合物的温压条件;超过600 m水深的海域水合物稳定带厚度大部分超过 100 m,其中西北部稳定带的最大厚度超过300 m,是有利的水合物勘探区。(3)华光凹陷1.05 Ma BP以来天然气水合物稳定带厚度经历了快速增厚–窄幅变化–快速减薄和恢复的过程。麻坑群与水合物稳定变化敏感区在空间上具有较好的叠合关系。结合前人的研究成果,推测其形成与天然气水合物的分解释放有关。     

适用于数值预告及客观分析的平滑算子的研究

通常的过滤二格距波长波动的平滑算子具有以下几个缺点,(1)进行一次平滑运算则能使除二格距波动以外的波动强度有不同程度的削弱,对于中短波而言,影响更大.(2)如果要减低波动强度削弱的程度,可以利用多点平滑算子,但这将引入边界如何处理的麻烦,而且边界误差将传入域内.(3)利用平滑后的物理量来计算差分,则有较未经平滑的差分为大的截断误差.本文就是为了克服上述缺点而设计了一个简便的平滑算子,并给出了数值例子,证明它是有一定成效的。     

黎平双江电站水库暴雨洪水设计

该文选用参证站资料的方法,对黎平县双江电站水库1954—2021年近68 a来逐年最大日降水量采用PearsonⅢ型研究方法和贵州省暴雨洪水计算公式进行研究。结果表明：黎平双江电站水库年最大日降水量年变化呈上升趋势,2010年以后上升趋势较显著。暴雨洪水设计以H_1d=119.29 mm、C_v=0.47、C_s/C_v=3.5作为研究成果,防洪标准按50 a一遇的暴雨洪水设计成果为P=2.0%,日最大降水量=277 mm、洪峰流量=2509 m³·s^-1;洪水校核按500 a一遇的暴雨洪水设计成果为P=0.2%,日最大降水量=391 mm、洪峰流量=3905 m³·s^-1;消能防冲设计标准按30 a一遇的设计成果为P=3.3%,日最大降水量=252 mm、洪峰流量=2209 m³·s^-1。研究成果对黎平双江电站水库预防灾害性强降水、安全渡汛和水库优化调度、提高产能具有十分重要...     

锆石中磷的分带趋势、成因及地质意义

本文用电子探针对岩浆和变质重结晶锆石进行了成份分带的研究，结果表明，变质重结晶锆石具有从晶体中心至边缘Ｐ２Ｏ５含量增大的特点，可作为它们的成因标型特征，岩浆锆石则Ｐ２Ｏ５含量变化不稳定，本文论述了它们的成因。     

The hydrothermal karstification and its effect on Ordovician carbonate reservoir in Tazhong uplift of Tarim Basin,Northwest China

With a detailed study on petrology, mineralogy and geochemistry of some important Ordovician carbonate well core samples in Tazhong uplift of Tarim Basin, the distinguishing symbols of hydrothermal karstification are first put forward as the phenomena of rock hot depigmentation, hot cataclasm and the appearance of typical hydrothermal minerals such as fluorite, barite, pyrite, quartz and sphalerite. The main homogenization temperatures of primary fluid inclusions in fluorite are from 260 to 310°C, indicating the temperature of hydrothermal fluid. The fluid affected the dissolved rocks and showed typical geochemistry features with low contents of Na and Mg, and high contents of Fe, Mn and Si. The ratio of ³He/⁴He is 0.02R _a, indicating the fluid from the typical continental crust. The hydrothermal fluid karstification pattern may be described as follows: the hot fluid is from the Permian magma, containing dissolving ingredients of CO₂ and H₂S, and shifts along fault, ruptures and unconformity, and dissolves the surrounding carbonates while it flows. The mechanism of hydrothermal karstification is that the mixture of two or more fluids, which have different ion intensity and pH values, becomes a new unsaturated fluid to carbonates. The hydrothermal karstification is an important process to form hypo-dissolved pinholes in Ordovician carbonates of Tazhong uplift of Tarim Basin, and the forming of hydrothermal minerals also has favorable influence on carbonate reservoirs.

     

Heavy-Rain expert-system realized by logical language prolog

This article, on the basis of the expert’s analyses and theories of the forecast of heavy-rain, summarizes a variety of the current instruments and methods of forecast and, according to the train of thought of the high-rank forecasters, distills their experiences in forecasting heavy-rain into an inference-tree of 106 junctures from which 101 rule-bases are derived. The logical calculation is automatically carried out with our introduced and developed PROLOG, one of the intelligent languagas by means of micro-computer. This process adopts the uncertain inferential method based on the theory of fuzzy sets, breaks through the limits of two-value logic and is characteristic of the thinking of human brain.     

Interannual and interdecadal variations of the South Asian and western Pacific subtropical highs and their relationships with Asian-Pacific summer climate

In this study, interdecadal and interannual variations of the South Asian high (SAH) and the western Pacific subtropical high (WPSH), as well as their relationships with the summer climate over Asian and Pacific regions, are addressed. The variations of SAH and WPSH are objectively measured by the first singular value decomposition (SVD) mode of geopotential heights at the 100- and 500-hPa levels. The first SVD mode of summertime 100- and 500-hPa geopotential heights represents well the relationship between the variations of SAH and WPSH. Both SAH and WPSH exhibit large interannual variability and experienced an apparent long-term change in 1987. The WPSH intensifies and extends westward when SAH intensifies and extends eastward, and vice versa. The India?CBurma trough weakens when WPSH intensifies. The changes in SAH and WPSH at various levels are linked to broad-scale increases in tropical tropospheric temperature and geopotential height. When SAH and WPSH strengthen, monsoon flow becomes weaker over eastern Asia. In the meantime, precipitation decreases over eastern South China Sea, Philippines, the Philippine Sea and northeastern Asia, but increases over China, Korea, Japan and the ocean domain east of Japan. Similar features are mostly found on both interdecadal and interannual timescales, but are more evident on interannual timescale.     

太湖14000年以来古环境演变的湖泊记录

本文根据东西太湖短柱岩芯的沉积物的物理、化学、生物指标的综合分析,讨论了该区距今14ka来的古气候变化过程,结果表明14.3-13.3kaBP,太湖水位低,环境指标甚至表现为暴露特征,反映了气候干旱:13.3-12.4kaBP,为偏暖湿的过渡阶段;该孔柱270-280cm (11.5kaBP左右)各类指标均明显反映冷干特征,可能是YoungerDrays事件的记录,与我国东部其它地区有可比性;约10.9-10kaBP,这一时期是整个研究时段内一个较显著的温暖期。表现为还原沉积环境和水位相对较深;约10-7.2kaBP为冷暖交替的过渡带;7.2-5.737kaBP为暖湿气候;5.05kaBP多项分析指标发生突变,反映物源发生显著变化,可能存在沉积间断;表层沉积物则呈现现代环境的特征,西太湖藻类生长茂盛,偏氧化的沉积环境。目前湖泊生产力较高,富营养化程度高,表现为藻型湖泊特征;东太湖有机质来源以东太湖中生长较为茂盛的维管水生植物为主,目前湖泊生产力较低,富营养化程度低,表现为典型的草型湖泊特征。