华东地区态矢量的研究

态矢量来源于统计物理学,是对连续场进行粗粒化描述的方法。尹祥础等把该方法移植到地震学中用以定量刻画地震活动性的演化,取得较好的结果。作者对华东地区1970年以来发生5级以上12次地震进行了分析,总结震前态矢量的变化情况,发现震前态矢量均有显著变化,为本地区地震趋势预测提供一定的参考价值。     

大庆油田勘探50年：陆相生油理论的伟大实践

文章系统分析了陆相生油理论和大庆油田的勘探实践,总结了大庆油田的勘探历程并划分为三大阶段：构造油藏勘探阶段,岩性油藏勘探的探索阶段,岩性油藏勘探大发展阶段。详细阐述了“十五”以来,大庆油田依靠创新理论与技术,丰富完善了大型陆相坳陷盆地岩性油藏勘探理论与配套技术,深层火山岩气藏勘探理论与配套技术,复杂断陷盆地油气勘探理论与配套技术,从而带来了松辽盆地北部中一浅层、深层和海拉尔盆地油气勘探的大发展,大庆油田再次进入油气储量增长高峰期。在详细分析大庆探区的勘探实际和资源潜力的基础上,提出了“百年油田”勘探的工作思路,通过扎实推进科学勘探,努力为油田可持续发展提供有力资源保障的勘探战略。     

2013年广西平果震群尾波衰减特征研究

2013年6~7月在广西平果县中铝广西分公司3号排泥库附近出现密集小震群活动。本文搜集本次震群中146次可用于计算尾波的ML1.0地震的近距离台站数字地震波形,利用波形高信噪比的尾波时间域信号,采用计算尾波品质因子Q_C(f)值的Sato模型,通过滤波及去除环境噪声,计算了地震波传播路径上的尾波Q_C(f)值;拟合Q_C(f)值与频率f之间的关系,分析了排泥库区域地震波衰减的时空特征。根据信噪比及计算要求,从近场7个台站的记录中挑选出273条三分向记录,计算尾波衰减参数,得到尾波Q_C(f)与频率f的关系为:Q(f)=(69.07±40.09)f~(0.90±0.23)。结果表明,本区域为低衰减区域,库区Q值相对较高,地震波衰减较慢,且Q值对频率的依赖性不强,研究区介质非均匀性程度低,介质较为稳定。     

Simultaneous estimation of surface soil moisture and soil properties with a dual ensemble Kalman smoother

In this paper, a new state-parameter estimation approach is presented based on the dual ensemble Kalman smoother(DEn KS) and simple biosphere model(Si B2) to sequentially estimate both the soil properties and soil moisture profile by assimilating surface soil moisture observations. The Arou observation station, located in the upper reaches of the Heihe River in northwestern China, was selected to test the proposed method. Three numeric experiments were designed and performed to analyze the influence of uncertainties in model parameters, atmospheric forcing, and the model's physical mechanics on soil moisture estimates. Several assimilation schemes based on the ensemble Kalman filter(En KF), ensemble Kalman smoother(En KS), and dual En KF(DEn KF) were also compared in this study. The results demonstrate that soil moisture and soil properties can be simultaneously estimated by state-parameter estimation methods, which can provide more accurate estimation of soil moisture than traditional filter methods such as En KF and En KS. The estimation accuracy of the model parameters decreased with increasing error sources. DEn KS outperformed DEn KF in estimating soil moisture in most cases, especially where few observations were available. This study demonstrates that the DEn KS approach is a useful and practical way to improve soil moisture estimation.     

绝对重力仪研制中一种新的自由落体轨迹重建算法

真空系统中落体做自由下落运动的轨迹重建算法,是进行拟合求解绝对重力测量结果的关键步骤之一.在自主研制小型高精度激光干涉绝对重力仪的过程中,基于目前高速发展的数字测量技术,提出一种自由落体轨迹重建的算法.其基本原理是:首先通过高速采样,得到落体自由下落过程中产生的一系列数字化的激光干涉信号;其次通过数字处理算法提取干涉信...     

“7·22”云南盐津地震房屋震害分析

本文根据地震现场的考查情况,介绍了2006年7月22日云南盐津5.1级地震的灾害概况,归纳和分析了灾区生土墙结构、石结构、钢筋混凝土框架结构和木构架结构房屋的震害特征及其破坏原因,并对我国村镇房屋的防震减灾研究提出了若干建议。     

Quasi-waveform seismic tomography of crustal structures in the capital circle region of China

Seismic tomography is one of the main tools to explore the interior of the earth.In this study,the quasi-waveform seismic tomographic method is used for the first time to reveal the crustal structures in the capital region of China.3-D highresolution V_P,V_S and the Poisson’s ratio models are generated by inverting 29839 direct P-and 29972 direct S-wave traveltimes selected from 3231 local earthquakes.The results reveal strong crustal heterogeneities.The velocity anomalies at shallow depths are well consistent with surface geologic structures.The relatively low-velocity anomaly layer in the middle crust may be the result of multiple phases of tectonic activity.Earthquakes generally occurred on the boundaries of high-and low-velocity and Poisson’s ratio anomalies.There are obvious low-velocity anomalies below the hypocenters of the Tangshan earthquake and the historical Sanhe-Pinggu earthquake,implying the existence of fluids.The similar velocity structures around the hypocenters of the two earthquakes indicate that the occurrences of the two earthquakes may be related to the same mechanism.The highresolution velocity models provide important observational constraints on the small-scale heterogeneities and dynamic mechanism of the crust in the capital region of China.     

Improved preconditioned conjugate gradient algorithm and application in 3D inversion of gravity-gradiometry data

With the continuous development of full tensor gradiometer (FTG) measurement techniques, three-dimensional (3D) inversion of FTG data is becoming increasingly used in oil and gas exploration. In the fast processing and interpretation of large-scale high-precision data, the use of the graphics processing unit process unit (GPU) and preconditioning methods are very important in the data inversion. In this paper, an improved preconditioned conjugate gradient algorithm is proposed by combining the symmetric successive over-relaxation (SSOR) technique and the incomplete Choleksy decomposition conjugate gradient algorithm (ICCG). Since preparing the preconditioner requires extra time, a parallel implement based on GPU is proposed. The improved method is then applied in the inversion of noisecontaminated synthetic data to prove its adaptability in the inversion of 3D FTG data. Results show that the parallel SSOR-ICCG algorithm based on NVIDIA Tesla C2050 GPU achieves a speedup of approximately 25 times that of a serial program using a 2.0 GHz Central Processing Unit (CPU). Real airborne gravity-gradiometry data from Vinton salt dome (southwest Louisiana, USA) are also considered. Good results are obtained, which verifies the efficiency and feasibility of the proposed parallel method in fast inversion of 3D FTG data.     

Mountain Glacier Flow Velocities Analyzed from Satellite Optical Images

Mountain glaciers are sensitive to environment. It is important to acquire ice flow velocities over time for glacier research and hazard forecast. For this paper, cross-correlating of optical images is used to monitor ice flow velocities, and an improvement, which is called ＂moving grid,＂ is made to this method. For this research, two remote-sensing images in a certain glacier area, dur-ing different times are selected. The first image is divided into grids, and we calculated the correlation coefficient of each window in the grid with the window on the second image. The window with the highest correlation coefficient is considered the counter-part one on the first image. The displacement of the two corresponding windows is the movement of the glacier, and it is used to calculate glacier surface velocity. Compared to the traditional way of dividing an image with ascertain grid, this method uses small steps to move the grid from one location to another adjacent location until the whole glacier area is covered in the image, thus in-creasing corresponding point density. We selected a glacier in the Tianshan Mountains for this experiment and used two re-mote-sensing images with a 10-year interval to determine this method.