2001年施甸地震地质背景与发震构造分析

在讨论地震地质背景基础上，综合分析了震区的深部构造、地表活动断裂、地面形变、极震区展布方向、震害、余震分布、震源机制解等发震构造标志，并且进一步探讨了发震机制。初步认为北北西向罗明坝－太平断裂和北东向飞陵－丙麻断裂是2001年施甸地震的主要发震构造，二者具有共回轭构造活动的特征。     

云南2001年施甸地震的剪切波分裂参数变化特征

云南地区2001年4月10日至6月8日相继发生了4月10日MＳ5.2、4月12日MＳ5.9和6月8日MＳ5.3的施甸地震. 本文利用云南遥测数字地震台网的保山地震台记录的地震波形资料，使用SAM分析方法（即剪切波分裂系统分析方法），采用地震应力预测的分析手段，对这个强震系列进行剪切波分裂参数变化特征的研究. 初步结果表明，随着地震活动的增强，剪切波分裂时间延迟值t基本呈现增加的特征，但在强震即将发生之前的短时间内，发生t减小的现象，符合我们早先研究发现的震前应力释放现象. 研究认为，在地震活动强烈的构造地区和有强震发生危险的经济发达地区或重要城市，开展强烈地震的应力预测应用实践，可以减轻地震的危害程度.      

Onset of seafloor spreading in the Iapetus Ocean at 608 Ma: precise age of the Sarek Dyke Swarm, northern Swedish Caledonides

The Sarek Dyke Swarm (SDS) crops out in the Sarektjåkkå Nappe (SN) of the Seve-Kalak Superterrane in the northern Swedish Caledonides. The SN has two main components: (1) a 4–5 km thick succession of rift-related sedimentary rocks, which is intruded by (2) a suite of tholeiitic dykes (the SDS) constituting 70–80% of the nappe. The nappe was deformed during Caledonian thrusting, but dykes and sedimentary rocks in the interior of the eastern parts of the SN are preserved in a pristine state. The tholeiitic dykes of the SDS commonly occur in sheeted dyke complexes, and up to 11 successive generations can be identified from crosscutting relations. The SN represents the fossil continent–ocean transition between the Baltic craton and the Iapetus Ocean, marking the initiation of seafloor spreading. Bubble-shaped pods and veinlets of diorite are present in the SDS sheeted dyke complexes. The pods are absent in the oldest dykes, but the younger a dyke, the more frequent the pods. The diorite pods are the equivalent of gabbro pegmatites, and both cogenetic and coeval with the dykes. The rapid successive emplacement of tholeiitic magma raised the ambient temperature in the dyke complex, so that crystallization in the youngest dykes mimicked similar processes in gabbro plutons. Six zircon fractions, from the diorite pods including two single grains, were analysed geochronologically by the U–Pb thermal ionization mass spectrometry method. The data yield a linear array of points that are 0.4–0.8% normally discordant, indicating a crystallization age of 608±1 Ma (²⁰⁷Pb/²⁰⁶Pb=607.9±0.7 Ma, MSWD=0.33). This age is inferred to date the onset of seafloor spreading in the Iapetus Ocean along the Baltoscandian margin.     

我国几次大震及震群活动的时间分维特征

本文根据Mandellrot提出的分维理论,对我国三次大震及四次震群活动的时间分维进行了研究,得到如下结论:1.时间分维的总体特征:大震前分维较低,震后分维升高。2.时间分维的动态变化特征:火震前的分维呈现一总趋势的降维过程,且幅度较大;而震群的时间分维变化较平稳。3.对同一地震序列,起始震级愈低,计算出的分维值愈高;起始震级愈高,计算出的分维值愈低。笔者认为,地震序列起止时间的选取对计算时间分维会产生较大影响。     

基于Swarm卫星GPS/TEC观测的顶部电离层三维电子密度分布的层析法研究

利用两颗伴飞的Swarm A/C卫星搭载的双频GPS接收机获取的TEC数据,在两个卫星轨道平面同时对顶部电离层电子密度进行层析成像,实现对顶部电离层电子密度的三维观测.为了能够重现扰动期间电离层电子密度的空间变化特征,在正则化求解过程中,我们引入了水平矩阵H和垂直矩阵V刻画电子密度的空间变化特征,引入整体约束矩阵C以调节不同空间对电子密度相对变化的权重.数值验证结果表明我们的算法对常见的观测误差具有较强的包容性,反演计算出的电子密度平均偏差优于10%.在不同地磁活动条件下,与第三方观测数据的对比,验证了本文反演算法的可靠性.实测数据反演结果表明我们的算法不仅能够较好地重现顶部电离层子午向百公里级别的不规则结构,还能有效分辨纬向相隔~150 km的两个卫星轨道平面的电子密度差异.     

广西寒露风开始期短期气候预测方法研究

利用1951-2013年广西90个气象观测站气温资料、国家气候中心74项指数和美国National Oceanic and Atmospheric Administration（NOAA）的Climate Prediction Center（CPC）60项指数以及海温和陆地雪盖资料、美国国家冰雪研究中心（NSIDC）的两极海冰资料,使用相关分析方法得到广西寒露风开始期气候影响因子,利用逐步回归和神经网络方法进行寒露风开始期的预测。结果表明：寒露风开始期与前一年9-10月北极海冰面积、当年3月南极海冰面积、前一年6月欧亚雪盖、当年5月北美雪盖、北半球雪盖的相关显著。与前一年9月北半球极涡面积指数、前一年10月亚洲区极涡面积指数、前一年3月热带印度洋海温偶极子等指数相关显著。粒子群-神经网络方法预测误差低于逐步回归方法,预报能力有明显提高。     

云南省施甸县东山铅锌矿成因分析

云南省施甸县东山铅锌矿为一中型铅锌矿床.矿体赋存于二叠系沙子坡组,主要受近SN向的区域断裂F2和F18及次级断裂构造控制,岩石（性）控矿也十分明显,成矿与构造、深部断裂、岩浆热液活动密切相关.成矿地质背景及成矿地质条件有利,通过对矿床成因分析,展示了矿区较好的找矿前景和资源潜力.     

K–Ar and Ar/Ar ages of dikes emplaced in the onshore basement of the Santos Basin, Resende area, SE Brazil: implications for the south Atlantic opening and Tertiary reactivation

New K–Ar and ⁴⁰Ar/³⁹Ar data of tholeiitic and alkaline dike swarms from the onshore basement of the Santos Basin (SE Brazil) reveal Mesozoic and Tertiary magmatic pulses. The tholeiitic rocks (basalt, dolerite, and microgabbro) display high TiO₂ contents (average 3.65 wt%) and comprise two magmatic groups. The NW-oriented samples of Group A have (La/Yb)_N ratios between 15 and 32.3 and range in age from 192.9±2.2 to 160.9±1.9 Ma. The NNW-NNE Group B samples, with (La/Yb)_N ratios between 7 and 16, range from 148.3±3 to 133.9±0.5 Ma. The alkaline rocks (syenite, trachyte, phonolite, alkaline basalts, and lamprophyre) display intermediate–K contents and comprise dikes, plugs, and stocks. Ages of approximately 82 Ma were obtained for the lamprophyre dikes, 70 Ma for the syenite plutons, and 64–59 Ma for felsic dikes. Because Jurassic–Early Cretaceous basic dikes have not been reported in SE Brazil, we might speculate that, during the emplacement of Group A dikes, extensional stresses were active in the region before the opening of the south Atlantic Ocean and coeval with the Karoo magmatism described in South Africa. Group B dikes yield ages compatible with those obtained for Serra Geral and Ponta Grossa magmatism in the Paraná Basin and are directly related to the breakup of western Gondwana. Alkaline magmatism is associated with several tectonic episodes that postdate the opening of the Atlantic Ocean and related to the upwelling of the Trindade plume and the generation of Tertiary basins southeast of Brazil. In the studied region, alkaline magmatism can be subdivided in two episodes: the first one represented by lamprophyre dykes of approximately 82 Ma and the second comprised of felsic alkaline stocks of approximately 70 Ma and associated dikes ranging from 64 to 59 Ma.

Resumo

Novos dados K–Ar e ⁴⁰Ar/³⁹Ar de enxames de diques toleíticos e alcalinos localizados no embasamento onshore da Bacia de Santos (SE Brasil) apontam para diferentes pulsos magmáticos ocorridos entre o Jurássico e o Terciário. Os diques de rochas toleíticas (basalto, diabásio e microgabro), são mais velhos, exibem altos teores de TiO₂ (3,65% peso na média) e podem ser subdivididos em dois grupos magmáticos. O Grupo A aflora a norte da Bacia de Resende, compreende diques orientados na direção NW, com razões (La/Yb)_N entre 15 e 32,3, e idades entre 192.9±2.2 e 160.9±1.9 Ma. O Grupo B aflora a sul e a leste da Bacia de Resende, engloba diques orientados na direção NNW e NNE, com razões (La/Yb)_N entre 7 e 16, e idades obtidas entre 148.3±3 e 133.9±0.5 Ma. As rochas alcalinas (sienito, traquito, fonolito, basalto alcalino e lamprófiro) possuem teores médios de K, e afloram como diques, plugs e stocks.. As idades obtidas são de ca. 82 Ma para os diques lamprofíricos, de ca. 70 Ma para os plugs sieníticos, e entre 64 e 59 Ma para os diques félsicos. Como estas idades Jurássicas para diques toleíticos ainda não foram descritas para a região sudeste do Brasil, pode-se especular que durante o emplacement dos diques do GrupoA o cenário tectônico indicaria esforços extensionais anteriores à abertura do Oceano atlântico Sul, e contemporânea ao derrame basáltico do Karoo na África do Sul. Já os diques do Grupo B são contemporâneos ao magmatismo Serra Geral e ao enxame de diques de Ponta Grossa, e portanto este episódio está diretamente relacionado à separação entre o Brasil e África no Cretáceo. O magmatismo alcalino está associado a diversos episódios tectônicos que sucedem à abertura do Oceano Atlântico Sul e que resultaram no desenvolvimento das Bacias terciárias do sudeste brasileiro. Está provavelmente relacionado à chegada da Pluma de Trindade e as idades obtidas para a região em estudo indicam que o magmatismo lamprofírico é mais antigo (ca. 82 Ma), seguido pelos plútons sieníticos (ca. 70 Ma) e diques associados (64 a 59 Ma.)     

粒子群算法与支持向量机相结合的热带气旋强度预报试验

支持向量机(SVM)的惩罚参数及核参数的选择直接影响到模型效果,通过粒子群算法(PSO)解决支持向量机的参数选择问题,实现了参数选择的自动化。将该方法应用于热带气旋强度预报,利用气候持续性因子,挑选了1990年的100个左右样本进行预报检验,预报时效为12 h、24 h、36 h、48 h的强度平均绝对误差分别为3.00、4.35、4.93和6.68 m/s。另外,还与国外预报结果及采用最小二乘回归法的预报结果进行了效果的比较,SVM方法显示了更好的预报能力。     

地表下沉系数选取的LWPSO-BP方法研究

针对BP神经网络自身收敛速度慢、容易陷入局部极小点的缺点,本文以线性下降惯性权重粒子群优化算法(LLWPSO)为前处理器,优化BP网络的权值和阈值,利用实测资料数据,建立LWPSO-BP的地表下沉系数预计模型,并同普通BP模型预计结果对比结果表明:LWPSO-BP神经网络不仅训练速度快,而且预测精度明显提高,该模型对地...