用Lg波资料反演场地效应与地震波衰减参数

基于谱比法,以台站记录地震波频谱为观测数据,通过扣除仪器响应及几何扩散后同一地震不同台站记录谱比,扣除震源方向性、 震源因子的影响,在此基础上,建立数学模型通过联合反演求解场地效应及地震波衰减参数. 以浙江省地震台网台站记录的台湾地震数字化地震波资料为基础,使用地震波记录中的Lg波, 评估浙江省台网丘陵地带基岩台站场地效应, 计算穿越台湾海峡较单一路径Lg波衰减参数. 研究使用20次发生于2002——2005年、 震级在MS5.0~6.7之间的台湾东北部较小区域地震, 参与评估台站16个, 地震波记录960条. 地震波处理频段为0.5～10.0 Hz, 每间隔0.2 Hz计算一次,对应于垂直、 东西及南北分量获得的衰减参数, 数据结果分别为:gamma;(f )=0.001 75f 0.43485, gamma;(f )=0.001 45f 0.48467, gamma;(f )=0.0021f 0.41241. 庆元台(QIY)在1.5 Hz以上放大效应非常明显,宁波台(NIB)在大部分频率点场地效应最小,参与评估台站场地效应各分向基本相当,未表现出方向性特征.      

三种■属(Seriola)鱼类表型特征比较分析

为全面了解■属鱼类表型性状的种间差异,描述了我国养殖的黄条■(Seriola lalandi)、高体■(Seriola dumerili)和五条■(Seriola quinqueradiata)的形态学特征,测量了群体的表型数据,通过单因素方差分析、通径分析、主成分分析、判别分析和聚类分析等多元统计方法,对3种■鱼共计190尾样品的形态种质特征和可量可数性状进行了比较研究。单因素方差分析显示,除叉长/体长(FL/SL)、体长/尾柄长SL/PL)、头长/眼间距(HL/ID)和下颌长/上颌长(LJL/UJL)外,其余9个指标均存在显著性差异(P<0.05)。通径分析显示,黄条■的体长(SL)、体高(BH)、尾柄长(PL)和尾柄高(PD)是主要影响其体质量的4个表型性状;高体■的体长(SL)、体高(BH)、眼间距(ID)、下颌长(LJL)和眼后头长(POL)是主要影响其体质量的5个表型性状;五条■的体高(BH)、下颌长(LJL)和全长(TL)是主要影响其体质量的3个表型性状。主成分分析构建了4个主成分,其中第一项主成分贡献率为34.974%,其他3个主成分的贡献率依次为23.897%、...     

大连湾赤潮异弯藻赤潮的多元分析

赤潮的发生是海水化学与物理因子、海水动力、地理环境、气象条件、历史因素以及浮游生物生态适应性等综合作用的结果,因此,诱发赤潮的因素有很多,其规律也十分复杂·多年来人们从统计学的角度尝试赤潮的预测预报,并做了大量的工作[1~10].赤潮异弯藻(Heterosigma akashiwo)是大连湾海域常见的赤潮生物,郭玉洁[1]曾对大连湾赤潮异弯藻分类地位及生物学作过研究.     

Probabilities of Perception and Population Index in Visual Observations of Meteor Showers

Earth, Moon, and Planets -     

LOCATIONAL CHARACTERISTICS OF FOREIGN EQUITY JOINT VENTURE INVESTMENT IN CHINA, 1979–1985

An examination of the locational characteristics of intended foreign equity joint venture (EJV) investment in China during the period 1979 to 1985 indicates that foreign EJV investment was highly concentrated in the coastal region, in the more developed areas of the provinces, and in large cities. The locational characteristics, however, differed between economic sectors and between countries of origin of investment. Although foreign EJV investment became spatially more dispersed through time, the impacts on the development of inland regions and backward areas in China remained limited.     

Scaling of geological discontinuity normal load–deformation response using fractal geometry

The mechanical behaviour of discontinuities in rock, such as joints, is known to be size‐dependent. It is also suspected that the behaviour of larger size features, such as faults, is also size‐dependent. This size dependence has serious implications for performing numerical response simulations of geological media. In this paper, we develop a new mathematical theory for scaling of one particular discontinuity property, namely the interface normal stiffness. To accomplish this, we idealize an interface to have fractal geometry, and we develop analytical relations which show that the interface normal stiffness, which is commonly thought to be a size‐independent property, is in fact a size‐dependent property and has fractal characteristics that may be exploited to develop a fundamental theory for scaling. Copyright © 2001 John Wiley & Sons, Ltd.     

The Nu Expression for Probabilistic Data Integration

The general problem of data integration is expressed as that of combining probability distributions conditioned to each individual datum or data event into a posterior probability for the unknown conditioned jointly to all data. Any such combination of information requires taking into account data interaction for the specific event being assessed. The nu expression provides an exact analytical representation of such a combination. This representation allows a clear and useful separation of the two components of any data integration algorithm: individual data information content and data interaction, the latter being different from data dependence. Any estimation workflow that fails to address data interaction is not only suboptimal, but may result in severe bias. The nu expression reduces the possibly very complex joint data interaction to a single multiplicative correction parameter ν ₀, difficult to evaluate but whose exact analytical expression is given; availability of such an expression provides avenues for its determination or approximation. The case ν ₀=1 is more comprehensive than data conditional independence; it delivers a preliminary robust approximation in presence of actual data interaction. An experiment where the exact results are known allows the results of the ν ₀=1 approximation to be checked against the traditional estimators based on assumption of data independence.     

An inversion of site response and Lg attenuation using Lg waveform

Based on spectral ratio method, a joint inversion method was used to obtain parameters of Lg wave attenuation and site response. The inversion method allows simple and direct (two-parameter) determination of Lg wave attenua- tion and site response from sparse spectral data, which are not affected by radiation pattern factor and different response of same instrument after geometrical spreading. The method was used successfully for estimating site re- sponse of stations of Zhejiang Seismic Network and measuring Lg wave attenuation. The study is based on 20 earth- quakes occurred in northeast of Taiwan with magnitude MS5.0~6.7 and 960 seismic wave records from 16 stations in Zhejiang area from 2002 to 2005. The parameters of site response and Lg attenuation were calculated with a fre- quency interval of 0.2 Hz in the range of 0.5 Hz to 10 Hz. Lg wave attenuation coefficient corresponding to U-D, E-W and N-S components are γ ( f )=0.00175 f 0.43485, γ ( f )=0.00145f 0.48467 and γ ( f )=0.0021f 0.41241, respectively. It is found that the site response is component-independent. It is also found that the site response of QIY station is significant above the frequency of 1.5 Hz, and that the site response of NIB station is low for most frequency     

The use of multivariate statistics to elucidate patterns of floodplain sedimentation at different spatial scales

Floodplains are depositional features of riverine landscapes that display complex sedimentation patterns that are amenable to multi‐scale approaches. We examined sedimentation in the Lower Balonne floodplain, Queensland, Australia, at three different spatial scales: the channel (10³ km), floodplain process zone (10 km) and geomorphic unit (10² m) scales, and compared scale‐related patterns evident from stratigraphy with those evident from quantitative multivariate analysis. Three stratigraphic sequences were found in the Lower Balonne floodplain: generally fining upward, episodic fining upward, and mud‐dominated. Stratigraphical analysis revealed the detailed character of sedimentary sequences embedded within the scale patterns derived from multivariate analysis. Multivariate statistical analyses of a range of textural and geochemical data revealed different patterns of floodplain sedimentation at each scale. At the channel scale, sediment texture and geochemistry were more heterogeneous in the Culgoa River than in Briarie Creek. At the floodplain process zone scale clear patterns of sediment texture and geochemistry were observed along the upper, mid and lower floodplain process zones of Briarie Creek, but not along the Culgoa River. At the geomorphic unit scale, clear patterns of sediment texture and geochemistry were observed among the bank, buried channel and flat floodplain units of the Culgoa River, but were not as clear in Briarie Creek. Recognition of rivers as hierarchically organized systems is an emerging paradigm in river science. Our study supports this paradigm by demonstrating that different sedimentation patterns occur at different scales to reveal a hierarchically organized floodplain environment. Copyright © 2006 John Wiley & Sons, Ltd.