龙门山断裂带科学钻探3号井孔附近微震近震震级与矩震级的关系及意义

通过震源谱拟合得到龙门山断裂带科学钻探3号井孔附近218个微震的矩震级,并分别基于《地震台站监测规范》的量规函数(量规函数GF)和李学政等(2003)的量规函数(量规函数LXZ)计算了这些微震的两种近震震级。基于回归分析得到了两种近震震级与矩震级的关系,并讨论了此关系可能隐含的意义。近震震级与矩震级拟合关系M_W=a+bM_L中系数b的取值与应力降Δσ和地震矩M_0的关系相关,b=1/(1+γ)等价于Δσ∝M_0~γ,本文对应于γ=1的情形。由于动态应力降在数值上与静态应力降差别不大,这种关系同样适用于折合能量和视应力,因此仅根据拟合关系M_W=a+bM_L中b的大小就可以判断地震矩与应力降、折合能量及视应力的关系。基于量规函数LXZ得到的近震震级与能量震级更为接近,且两者在与矩震级的拟合关系M_W=a+bM_L中有相同的b,接近于0.5,这既印证了从b的大小来判断应力降与地震矩关系的论断,也说明从能量的角度来看量规函数LXZ优于量规函数GF。     

新源、和静交界ML6.8级地震序列应力降和震源机制研究

Based on the digital waveform data recorded by Xinjiang Digital Seismic Network for the Xinyuan-Hejing M_L6.8 earthquake sequences of June 30,2012,this paper analyzes the stress drops of earthquake sequences and the correlation coefficients of focal mechanisms significant for strong aftershocks.Firstly,the source parameters of the Xinyuan-Hejing M_L6.8 earthquake sequences are obtained by applying the spectrum analysis and the Brunes source model.Then,the correlation coefficients of spectral amplitudes are calculated using the low-frequency spectral amplitude recorded by the same station for the different events.Finally,based on the results of the correlation coefficients of spectral amplitudes,the events with similar focal mechanisms are grouped using the clustering method.The results show that:(1)The stress drop values show a steady trend in the aftershock sequence calm period and the stress drop values show a rise-fall in strong aftershocks.(2)The moving average correlation coefficient of amplitude spectrum begins to spread after the main shock.It shows that the correlation decreases between the main shock and the aftershocks in mechanisms.(3)The results of focal mechanism groups show that the earthquake sequences are mainly strike slips.The stress distribution of the main pressure axis is nearly NS,which is the same as the structural stress field.(4)The magnitude and mechanism show that there is an agreement before the strong aftershock,which shows that the regional stress field is enhanced.     

移动式三维激光扫描技术在隧道扫描中的应用研究

移动式三维激光扫描技术通过发射激光并以螺旋线形式对隧道进行全断面高密度扫描,初步获取隧道表面特征信息,再通过内业分析发射和接收激光信号的强度,可以获得隧道衬砌内表面的影像信息.使用这些数据信息,可以对隧道状态、病害、限界、变形、收敛情况等进行分析和评价.本文采用移动式三维激光扫描技术选取杭州地铁5号线一个车站和区间进行...     

On standardizing the ‘Water Drop Penetration Time’ and the ‘Molarity of an Ethanol Droplet’ techniques to classify soil hydrophobicity: A case study using medium textured soils

Two common methods to assess soil hydrophobicity are the ‘Water Drop Penetration Time’ and ‘Molarity of an Ethanol Droplet’ techniques. For these, uncertainty exists regarding the representativeness of laboratory tests reflecting field conditions, their replicability, and the comparability of results between the two techniques. Using air-dried soils with a broad particle size and hydrophobicity range, this study shows that a high representativeness and replicability of results can be achieved. A close relationship between the two tests was found for highly, but not for moderately hydrophobic soils. Guidelines are suggested to increase representativeness, replicability and comparability of results in future studies. © 1998 John Wiley & Sons, Ltd.     

验证法处理密立根油滴实验探讨

为了更好、更快地进行密立根油滴实验,减小实验中的误差,对常规处理密立根油滴实验数据的验证法进行分析研究,用分析后的结果反过来指导实验。通过适当选取密立根油滴实验中的平衡电压和下落时间,可以在一定范围内减小实验误差,有利于尽快锁定平衡电压,快速准确的完成实验的测量,节约实验时间。     

Uptake of the NO <Subscript>3</Subscript> Radical on Aqueous Surfaces

Using a single drop experiment, the uptake of NO₃ radicals on aqueous solutions of the dye Alizarin Red S and NaCl was measured at 293 K. Uptake coefficients in the range (1.7–3.1) ⋅ 10^{− 3} were measured on Alizarin Red S solutions. The uptake coefficients measured on NaCl solutions were in the range of (1.1–2.0) ⋅ 10⁻³ depending on the salt concentration. Both experiments lead to a consistent result for the mass accommodation coefficient of α_NO3 = (4.2_{− 1.7}^+2.2)⋅ 10⁻³. The product H(D_l k_Cl−^II)^0.5 for the NO₃ radical was determined to be (1.9 ± 0.2) M atm^{− 1} cm s^−0.5 M^−0.5 s^−0.5 by fitting the uptake data for the NaCl solutions to the so-called resistance model. The yield of the chemical NO₃ radical source was characterized using UV-VIS and FT-IR spectroscopy. The amount of gas-phase NO₃ radicals measured at elevated humidities was less than expected. Instead, a rise of the gas-phase HNO₃ concentration was found indicating a conversion of gas-phase NO₃ radicals to gas-phase HNO₃ on the moist reactor walls.     

电渗固结中的界面电阻问题

结合试验对电渗固结中的界面电阻问题进行了详细的分析和探讨,提出了界面电压降假定,在该假定的基础上,经过一系列理论推导,给出了一个简洁的界面电阻表达式,这将有助于我们对电渗固结的电流以及能耗做出更为准确的估计。     

工业开采诱发地震的应力降研究现状和主要科学议题

诱发地震及其灾害风险已成为非常规油气资源开发和废水回注等新型工业活动顺利实施的重要威胁。应力降是反映地震破裂前后断层上平均应力差的物理量,对诱发地震中应力降的系统研究有助于揭示诱发地震的震源特征、高频地震动特征、构造背景和地震危险性。本文系统地总结了近20年来工业开采诱发地震中应力降的相关研究进展,分别从计算所用理论方法、获得的平均应力降数值、影响应力降数值的主客观因素、围绕应力降的重要科学讨论等方面做了归纳分析。介绍了直接进行谱拟合、经验格林函数(EGF)、谱叠加和广义反演3种适用性的计算方法,通过案例考察了工业开采诱发地震的应力降平均值,分析影响应力降测定数值的主客观因素,并总结应力降空间分布依赖性、与震源机制类型相依性、自相似性、深度依赖性等4个主要科学问题。同时,阐述了诱发地震应力降的测定可靠性仍未突破、主要科学问题存在广泛争议、在新型工业开采活动中具有重要应用潜力等现状。本文的总结分析可为从事新型能源开发、地震安全监管和科学研究领域的企业、管理人员和科学研究人员提供参考。     

Remotely sensed estimation of water discharge into the rapidly dwindling Dead Sea

Abstract

The Dead Sea is shrinking as its water level drops at the alarming rate of about 1 m year^-1. The Dead Sea is important to the economies of Israel and Jordan due to the extracted minerals (primarily potassium, also magnesium and bromide). It is also central to regional tourism. It is the lowest place on Earth and its endorheic, saline basin attracts international research in various disciplines. Additional to the Lower Jordan River, the discharge of which has been decreased to a small fraction of its original value, fresh to brackish springs are the main source of water to the rapidly dwindling Dead Sea. Although the existence of these springs has been known for decades, until recently estimates of spring water discharge into the Dead Sea were scarce. In this study, we developed a methodology of water discharge estimation for channels incising into a lacustrine bed using remotely sensed data and a single hydraulic geometry variable, water-surface width. Based on calibration of over 400 in situ measurements and simultaneous hydrometric data from aerial images, width–discharge rating curves were established, tested, and found suitable (r² = 0.92, p = 0.001) for the estimation of water discharge, with ±5% uncertainty. Furthermore, we used these relationships to estimate retrospectively the temporal changes in water discharge of seven main channels traceable in historical aerial images. The reconstructed trend reveals a major (63%) reduction in average freshwater inflow between 1990 and 2006. Our results maximize the use of water-surface width information from aerial imagery, and suggest applicability to areas experiencing rapid exposure of sea/lake bed and consequent access difficulties in in situ discharge monitoring.

Editor Z.W. Kundzewicz     

A model of a homogeneous isotropic turbulent flow and its application for the simulation of cloud drop tracks

Abstract

A model of a homogeneous isotropic turbulent flow is presented. The model provides different realizations of the random velocity field component with given correlation latitudinal and lateral functions and a spatial structure which obeys the Kolmogorov theory of homogeneous and isotropic turbulence. For the generation of the turbulent flow the structural function of the flow in the form suggested by Batchelor (Monin and Yaglom, 1975) was used. This function describes the spectrum of turbulence both in the viscous and inertial ranges. The isotropy and homogeneity of the velocity field of the model are demonstrated.

The model is aimed at simulating the ‘‘fine'’ features of drop's (aerosol particles') motion, such as the deviations of drops’ velocity from the velocity of the flow, detailed structures of drops’ tracks, related to drops’ (particles') inertia. The model is intended also for the purpose of studying cloud drops’ and aerosol particles’ motion and their diffusional spreading utilizing the Monte Carlo methods.

Some examples of drop tracks for drops of different size are presented. Drops’ tracks are very sophisticated, so that the relative position of drops falling initially from the same point can vary drastically. In some cases drops’ tracks diverge very quickly, in other cases all drops move within a turbulent eddy along nearly the same closed tracks, but with different speed. The concentration of drop tracks along isolated paths is found in spite of the existence of a large number of velocity harmonics. It is shown that drops (aerosol particles) tend to leave some areas of the turbulent flow apparently due to their inertia. These effects can possibly contribute to inhomogeneity of drops’ concentration in clouds at different spatial scales.