天山东段尾亚地区麻粒岩相变质岩存在的矿物化学证据

本文根据天山东段尾亚地区麻粒岩的主要造岩矿物斜方辉石、单斜辉石、黑云母、石榴子石和斜长石的电子探针分析结果,重点研究了尾亚麻粒岩各主要造岩矿物的化学成分特点,并且讨论其对变质作用温度压力条件的指示意义。矿物化学的研究结果表明,变质作用峰期达到了中压麻粒岩亚相。     

油井动态观测井映震能力的评价

本文利用胜利、大港、华北和辽河油田油井动态观测井的地震前兆异常资料,对1975年以来华北北部地区发生的9次中强地震进行了油井动态观测井映震能力的分析和研究,获得如下主要认识:油井映震能力较强,是一项重要的前兆观测项目;前兆异常在时间上以短临为主,空间上距震中100—300km为映震灵敏区。     

利用近震及远震转换波测定永清M4.3级地震的震源深度

根据近震沉积层基底界面转换波Sp震相和远震深度震相sP、pP的特征,对2018-02-12永清M4.3地震的震源深度进行分析,运用F-K波数与频率方法拟合近震理论波形、Teleseis方法拟合远震理论波形,并与实际波形对比,对震源深度进行测试。结果表明,永清地震的震源深度为16~17 km,从发震位置和震源深度分析来看,此次地震发生在中上地壳,与区域内其他地震事件类似。     

Phase equilibrium modeling of zircon stability in mantle peridotite: Implication for crust-mantle interaction

Zircon is a common accessory mineral in various rocks,especially in the crustal ones.It is the best mineral for U-Pb dating.Meanwhile,trace elements and isotopes of the mineral can also provide much information concerning the formation and evolution of rocks.There are a growing number of reports of zircon existing in mantle peridotite.However,it is generally considered that zircon is unlikely crystallized in ultrabasic rocks due to SiO₂-unsaturation.In this paper,the SiO₂ activity and zircon/baddeleyite transition curve at different conditions were calculated through thermodynamic phase equilibrium modeling,to reveal the main factors affecting the SiO₂ activity and the stability of zircon/baddeleyite in ultrabasic and basic rocks,especially in mantle peridotite.These results provide a thermodynamic basis for interpreting the genesis and significance of zircon in mantle rocks.That is,the SiO₂ activity is mainly controlled by stable mineral assemblages and temperature-pressure conditions.The orthopyroxene+olivine assemblage in peridotite as an effective buffer restricts the SiO₂ activity in a relatively high range with a small variation.The upper temperature limit of zircon can reach more than 1500℃ with this mineral assemblage.During the low-temperature serpentinization of peridotite,the replacement of olivine and pyroxene by serpentine can result in a significant decrease of SiO₂ activity,and baddeleyite can be stabilized at<530℃ and<2.7 GPa.When peridotite is strongly metasomatized by the SiO₂-bearing fluid,the addition of SiO₂ can increase its activity and make zircon stable at low temperatures.The SiO₂ activity in ultrabasic-basic rocks is not only positively correlated with the SiO₂ content but also negatively correlated with the Ca and Na contents of rocks.This is because Ca and Na preferentially combine with Si and Al to form Si-rich minerals,such as clinopyroxene and feldspar.This process will consume excessive SiO₂,decreasing the SiO₂ activity.This may be the reason why zircon can be found in ultrabasic rocks,while baddeleyite can exist in some basic and alkaline rocks.The thermodynamic modeling can also reasonably explain the mutual transformation between zircon and baddeleyite in ultrabasic-basic rocks.Our results indicate that zircon can exist stably in mantle peridotite in a wide range of temperature-pressure conditions and its formation is related to melt/fluid metasomatism.That is,the presence of zircon in mantle peridotite is an important information carrier of crust-mantle interaction for deep material cycling.     

海洋激光雷达多次散射回波信号建模与分析

海洋激光雷达是实现上层海水3维探测的重要工具,激光在海水中的传输伴随着复杂的多次散射效应,建立准确的海洋激光雷达多次散射回波信号模型有助于实现海水光学特性的高精度反演。本文介绍了仿真海洋激光雷达多次散射信号的解析模型、半解析MC(Monte Carlo)仿真方法和传统MC仿真方法,定量对比分析了不同工作条件下3种模型的仿真结果,讨论了工作高度、接收视场角、水质和水体分层等因素对仿真结果的影响。研究表明:3种模型具有高度一致的仿真结果,但在计算效率方面,解析模型优于半解析MC法,半解析MC法优于传统MC法。解析模型优异的计算效率和可靠的计算精度使其在海洋激光雷达辐射传递机理及应用的研究中具有显著优势。     

A statistical damage constitutive model based on unified strength theory for embankment rocks

Abstract

Fluctuant marine and reservoir water levels are the main failure-inducing factors for embankment slopes. The soft embankment rocks, e.g., red-bed mudstone, eroded by the reservoir water level in the Three Gorges Reservoir area greatly influence the stability of the embankment slopes. In this study, unified strength theory was innovatively applied for damage evaluation and combined with the Weibull distribution to obtain the strength statistics of micro units. Additionally, one damage constitutive model and one damage evolution model considering the initial damage, strain softening and damage weakening were proposed. Then, a series of tests, e.g., modified cyclic wetting and drying test, triaxial compression test and modified numerical simulation test for reservoir embankment red-bed mudstone, were conducted to verify the feasibility of the proposed models. In addition, grey system theory was originally used to evaluate the effects of the Weibull distribution parameters (m and w) and the confining stress on the peak stress. Finally, the proposed model was tentatively applied to the modification of the limit failure height model of the bedded rock slopes. The verification implies that the proposed model results are consistent with the testing results, especially in the simulation of compaction, elastic deformation and strain softening and in the prediction of peak strength. The results from grey system theory analysis indicate that the micro unit strength parameter (w) has the most obvious effect on the strength. Moreover, the modified method based on the damage evolution model for calculating the limit failure height of the bedded rock slopes is conservative.     

反卷积在人工震源数据处理中的应用

震源到接收台站之间的地层响应函数能够反映地下介质信息。对地震波传播过程中的卷积模型进行推导:记录信号是众多震源子波经过时移加权叠加的结果;通过反卷积方法可去除震源子波信息,提取震源到接收台站之间的地层响应函数;地层响应函数中第一个突跳值对应的时间即为P波走时。在河北赤城—张北地区进行人工震源实验,通过反卷积计算得到该地区地层响应函数剖面图,得出P波波速约6 km/s。利用人工震源系统还可以对地下介质波速变化进行长期动态监测,对地震预测具有一定意义。     

赵县地震台地表及深井地震计观测数据对比分析

由于城市化进程加快,人为干扰因素逐渐增多,地震观测数据质量受到严重的影响。通过对赵县地震台地表及深井地震计记录的数据进行幅频、功率谱分析,并对比二者的地震监测能力等,分析发现:与地面观测相比,深井地震计在避免噪声及提高地震监测能力范围方面具有更大优势,观测数据精度能提高1—2个数量级。通过总结分析地表及深井地震计记录的优缺点,为测震台网今后的发展方向提供依据。     

基于开源WebGIS的测震台站运维管理系统的设计与实现

本文介绍了一套测震台站运维管理系统的设计与实现。在研发过程中,使用开源的WebGIS服务器GeoServer和前端技术Openlayers,实现了测震台站WebGIS、在线式台站运维信息管理、台站仪器状态监视和台站故障统计功能,对测震台站运维管理工作提供软件支持。系统在河北测震台网的应用效果良好,具有一定的推广应用价值。     

一种测震仪器数据实时接入中间件设计与实现

分析了几种地震数据采集器的网络协议和数据格式,开发了一套独立的仪器数据访问中间件,为实现上位机应用程序与多种仪器的网络通信、各种数据流的统一接收、处理、发布和共享提供了方法和工具。将中间件应用于测震台站数据监控系统中,为运维人员对台站运行质量的跟踪和数据应用提供了方法和工具,为面向仪器的软件工程实施提供了典型示范。