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。     

Carbon isotopic composition and flux of particulateorganic matter in the Changjing River

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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.     

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.     

Zircons LA-ICP-MS U-Pb Dating on the Baluntai Deformed Granitoids,Central Tianshan Block, Northwest China,and Its Tectonic Implications

本文对巴仑台地区中天山南北边缘的变形花岗岩体进行了详细的锆石LA-ICP-MS U-Pb年代学研究.中天山北缘花岗质麻岩中岩浆锆石结晶年龄为630.0±5.0Ma,代表了中天山微陆基底的新元古代岩浆事件年龄;其变质增生锆石边的年龄为440.9±3.3Ma,精确限定了中天山北缘洋盆闭合与碰撞造山作用的时代为早志留世.中天山南缘糜棱岩化花岗闪长岩中岩浆锆石结晶年龄为389.5±3.2Ma,指示出中天山南缘洋壳在中泥盆世向北俯冲形成陆缘岩浆弧;其变质增生锆石边的年龄为362.1±4.3Ma,精确限定了中天山南缘洋盆闭合与碰撞造山作用的时代为晚泥盆世末期.研究结果还表明中天山微陆块具有年龄为2.5Ga和1.8Ga的古老结晶基底.     

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。     

北秦岭-祁连结合区大草滩群碎屑锆石U-Pb年代学研究

应用LA-ICP-MS法对北秦岭-祁连结合区的晚泥盆世大草滩群进行了系统的碎屑锆石U-Pb年代学研究。地层剖面从下至上,大草滩群三个岩组的碎屑锆石U-Pb年龄谱具有以下特征:①古生代年龄组分(550Ma)所占的比例依次变小(分别为36%,32%,25%),且最年轻的锆石年龄值也是逐渐变小(分别为403±5Ma,385±5Ma,375±6Ma),这一特征反映的是大陆边缘岩浆弧前缘同岩浆活动的隆升-剥蚀和沉积。②750～2600Ma年龄组分所占的比例逐渐增大(分别为54%,65%,72%),且主要的峰值年龄向老的方向变化,这一特征反映的是往造山带深部基底和大陆内部逐渐延伸的隆升和剥蚀。本研究工作阐明大草滩群的碎屑沉积物来自多种构造环境中的岩石地层单元,主要来自北秦岭-祁连微陆块基底,其次是来自古生代洋壳持续俯冲形成的大陆边缘岩浆弧和加里东期碰撞造山带再旋回物质,还有少量来源于华北克拉通西部地块的物质成分。晚泥盆世大草滩群陆相粗碎屑沉积组合在构造位置上是处于弧(微陆)-大陆碰撞造山带的南缘与安第斯型大陆边缘岩浆弧的弧前盆地这一构造叠加复合地区,是弧(微陆)-大陆碰撞造山作用以后,洋壳持续俯冲造山作用阶段同火山-岩浆活动的沉积响应。     

天津前兆台网映震能力评价

收集了自１９８９年至１９９３年１０月天津及其附近地区发生的ＭＬ≥４．０地震和大同地区发生的中强地震共２１次，经统计计算认为：天津台网对唐山地区发生的地震反映能力较强，北京地区次之，对大同地区发生的中强地震的一定的反映能力，其综合映震能力为６１．９％，可预报能力为２３．８％，异常对应能力不超过５５．７％，观测项目综合灵敏度为２４％，对天津及其附近地区发生的中等地震仅可能有３．１７％观测项目产生异常。     

皱唇鲨食性与繁殖状况

皱唇鲨为黄勃海常见的底栖中小型鲨鱼,它是以游泳生物为主的杂食性鱼类,捕食蓝点马鲛、青鳞鱼、黄鲫、绵、长蛸、日本枪乌贼、对虾、鹰爪虾、虾姑、鲽科鱼、底栖多毛类和蟹类。皱唇鲨为卵胎生,7～8月性成熟后体内受精,雄性性腺成熟明显表现出:鳍脚增大呈飞跃式的增大,产仔期为5～6月,胚胎在母体内发育时间为9～10月,雌鲨怀胎最多为42尾,仔鱼的雌雄比例为1:1。