山东蒙阴三个金伯利岩带金刚石的矿物学特征与对比

山东蒙阴常马庄、西峪和坡里三个金伯利岩带的金刚石含矿性存在显著差异,而三个矿带金刚石的矿物学特征是否亦存在差异还不清楚.本文整理和统计前人研究的山东蒙阴10万余粒金刚石数据,发现三个金伯利岩带金刚石的晶体颜色、粒度、晶体形态及表面形貌和包裹体等具有明显不同的特征:①51484粒常马庄金刚石以淡黄色为主,其次为无色和浅黄...     

用时频峰值滤波方法消减地震勘探资料中随机噪声的初步研究

时频峰值滤波算法是一种新颖的基于时频分析的信号增强算法,能够有效地消除随机噪声,恢复有效波信息.本文将这种时频分析算法用于消除地震勘探资料中的随机噪声,对淹没于随机噪声下的40道共炮点记录进行时频峰值滤波,恢复出来的共炮点记录可以清楚地表现原始记录同相轴的位置.经过对40道中任选两道（即第21道和第7道）滤波前后的子波形态Wigner\|Ville分布、傅立叶振幅谱等的比较,可知仅在谷值和峰值点误差较大,子波带宽相对误差小于25％.仿真试验表明信噪比可达－7dB,说明该方法可以有效地消减地震资料中的随机噪声.     

Deciphering the pulsations of G 29-38 with optical time series spectroscopy

We present optical time series spectroscopy of the pulsating white dwarf star G 29-38 taken at the Very Large Telescope (VLT). By measuring the variations in brightness, Doppler shift and line shape of each spectrum, we explore the physics of pulsation and measure the spherical degree (ℓ) of each stellar pulsation mode. We measure the physical motion of the g modes correlated with the brightness variations for three of the eight pulsation modes in this data set. The varying line shape reveals the spherical degree of the pulsations, an important quantity for properly modelling the interior of the star with asteroseismology. Performing fits to the Hβ, Hγ and Hδ lines, we quantify the changing shape of the line and compare them to models and previous time series spectroscopy of G 29-38. These VLT data confirm several ℓ identifications and add four new values, including an additional ℓ= 2 and a possible ℓ= 4. In total, from both sets of spectroscopy of G 29-38, eleven modes now have known spherical degrees.     

半滑舌鳎苗种体外挂牌标志技术研究

研制了4种不同规格的T型标志牌(T-A,T-B,TC,T-D),对不同规格的半滑舌鳎苗种进行了标记试验,记录了标记后的脱牌率、成活率、行为特征和生长情况,筛选了适宜于半滑舌鳎苗种标志放流的T型标志牌.结果表明:T-A标志牌适宜于标记全长8 cm以上的苗种,标记后的实验鱼生长与对照组无显著差异,标志后暂养成活率92％～100％;T-B标志牌适宜标记全长16 cm的苗种,标记后实验鱼成活率达到100％,脱牌率为0.T-C和T-D标志牌不适宜于标记全长16 cm以下的半滑舌鳎苗种.2011年,利用本研究开发的T-A标志牌标记半滑舌鳎苗种,并在莱州开展大规模标志放流试验,标记效果良好.     

Crustal seismic anisotropy in Yunnan, Southwestern China

Using seismic data recorded by Yunnan Telemetry Seismic Network from January 1, 2000, to May 31, 2005, the polarization directions of fast shear waves are obtained at 15 seismic stations by SAM technique, which is a systematic analysis method on shear-wave splitting. The results show that predominant directions of polarizations of fast shear waves at most stations are mainly nearly in the N–S or NNW directions in Yunnan. The predominant polarization directions of fast shear waves at stations located on the active faults are consistent with the strike of active faults, directions of regional principal compressive strains from GPS measurement, and directions of regional principal compressive stress. A few of the stations show that polarization patterns of fast shear waves are more complicated or inconsistent with the strike of active faults and the directions of principal GPS compressive strains; these stations are always located at the junction of several faults. We conclude that the predominant polarization direction of fast shear waves indicates that the direction of the in situ maximum principal compressive stress is controlled by multiple tectonic aspects, such as the regional stress field and faults.     

A reappraisal of shear wave splitting parameters from Italian active volcanic areas through a semiautomatic algorithm

Shear wave splitting parameters represent a useful tool to detail the stress changes occurring in volcanic environments before impending eruptions. In the present paper, we display the parameter estimates obtained through implementation of a semiautomatic algorithm applied to all useful datasets of the following Italian active volcanic areas: Mt. Vesuvius, Campi Flegrei, and Mt. Etna. Most of these datasets have been the object of several studies (Bianco et al., Annali di Geofisica, XXXXIX 2:429–443, 1996, J Volcanol Geotherm Res 82:199–218, 1998a, Geophys Res Lett 25(10):1545–1548, 1998b, Phys Chem Earth 24:977–983, 1999, J Volcanol Geotherm Res 133:229–246, 2004, Geophys J Int 167(2):959–967, 2006; Del Pezzo et al., Bull Seismol Soc Am 94(2):439–452, 2004). Applying the semiautomatic algorithm, we confirmed the results obtained in previous studies, so we do not discuss in much detail each of our findings but give a general overview of the anisotropic features of the investigated Italian volcanoes. In order to make a comparison among the different volcanic areas, we present our results in terms of the main direction of the fast polarization (φ) and percentage of shear wave anisotropy (ξ).     

Shear-wave splitting in the southeast of Cathaysia block, South China

This study is focused on Fujing Province in China, southeast of Cathaysia block (SECB). The present work benefits from the data provided by the Fujian Seismic Network (FJSN) to study the seismic anisotropy in the crust. By means of a systematic analysis and adequate software package, we examine shear-wave splitting from data recorded at ten FJSN stations during the period January 1999 to December 2003. The results demonstrate that the average fast wave polarization is N109.4° E ± 42.6°, corresponding to the horizontal principal compressive stress in the test zone, and the average normalized slow wave time delay is 2.5 ± 1.5 ms/km. The predominant polarizations at stations in the eastern part of SECB are in the N–W direction, which suggests that they are related to the regional horizontal principal compressive stress and also to the strikes of faults. In contrast, the predominant polarizations at two stations in the western part of SECB are in the N–E direction. This polarization direction does not coincide with the direction of the horizontal principal compressive stress, but it follows the strikes of near faults, thus suggesting the influence of the local tectonics and a change in the stress field. The results prove that the predominant polarizations are parallel to the strikes of faults whenever the stations are on active faults. At a few stations near the coastal line, some polarizations show a certain amount of scatter which may be caused by crossing faults and irregular topography. Finally, the spatial distribution of time delays depicts strong lateral variations near the coast just where the seismic activity is comparatively bigger, so that the magnitude of anisotropy seems to be consistent with the most seismically active area.     

等离子体参量春夏季节背景变化特征研究

使用DEMETER卫星上Langmiur探针记录的电子密度（Ne）、离子密度（Ni）和电子温度（Te）资料,分析了2007年1～6月份地磁活动平静时段全球6个经度区（每60°一个区）,不同时间的电离层等离子体参量Ne、Ni和Te值在春夏季节的背景变化特征,发现Ne、Ni和Te随纬度空间变化比较大,且峰（谷）值纬度分布与地球的经度区也有一定的关系。对全球6个经区各个时段的Ne、Ni和Te值进行对比,发现不同时段,Ne、Ni和Te峰值的大小不等,可能与当地日变化有关。等离子体各参量与月份季节也存在一定的相关性。在一些相同的区域时段,1～3月的等离子参量数值明显高于4～6月的等离子参量数值。     

THE SHEAR-WAVE SPLITTING OF GAIZHOU EARTHQUAKE SWARM IN LIAONING

An M_L4.7 earthquake occurred on February 2,2012 in Liaoning Gaizhou (40.56°N,122.36°E),since then,small earthquakes are frequent in this area,and until now the seismic activity does not stop,several earthquakes with magnitude larger than 4.0 have occurred.As of October 30,2014,1223 earthquakes have happened in the Gaizhou area,including 934 earthquakes with the magnitude M_L1.0~1.9,247 with the magnitude M_L2.0~2.9 and 45 with the magnitude M_L3.0~3.9.Meanwhile,earthquakes are continuously active in Haicheng area where the M_S7.3 earthquake happened in 1975,and there are over 1100 earthquakes (M_L ≥ 1.0) having occurred since the Gaizhou earthquake swarm activity.Because the polarization direction of the fast shear wave is very sensitive to the variation of the principal stress environment,the shear wave splitting parameter can reflect the regional stress state and the local structural features,especially effective for the analysis of small-scale stress environment characteristics.So based on the seismic activities of the two earthquake clusters,this study analyzes the characteristics of shear-wave splitting in Gaizhou-Haicheng area.Preliminary results show that predominant polarization direction of fast shear-waves in the old earthquake region of Haicheng is stable,consistent with the direction of regional stress field.Due to presence of active fault below the Gaixian station (GAX),the predominant polarization direction of fast shear-waves is more complicated.There are two predominant polarizations,consistent respectively with Jinzhou Fault strike which is below the station and the maximum principal stress direction in this area.In addition,Gaizhou earthquake swarm activity increased after December 22,2013,and after the time node,the predominant polarization direction of fast shear-waves in Gaixian station is SEE,which is close to the predominant polarization direction of fast shear-waves in Yingkou station,at the same time consistent with the maximum principal stress direction of this region.Thus it can be inferred,the enhanced activity of Gaizhou earthquake swarm since December 22,2014 may be related to local enhancement of regional stress.In addition,the average time-delays of slow waves in station YKO and GAX show that there are no obvious changes before and after the time point of December 22,2013,which is different greatly with the previous related researches on the variation of slow wave time-delays,and there is no possibility that the Gaizhou earthquake swarm evolved into foreshock sequences from current preliminary results.We should do more work to study the details of the time delay variation of shear wave splitting parameter.     

土层结构对油气管线工程地震动峰值加速度区划图的影响研究

油气管线工程是生命线工程的重要组成部分,工程跨度通常超越几十甚至几千公里,从而导致横穿地区覆盖层中土层结构存在明显差异,对地震动峰值加速度(PGA)产生较大影响,进而影响区划结果。本文采用分区拟合放大系数的方法,对华北平原地区某大型管线进行研究,给出研究区不同土层结构条件下场地放大系数KS-基岩PGA拟合函数结果,得到沿线附近10km范围内的PGA区划图结果,并与第四代和第五代中国地震动参数区划图提出的场地系数公式的计算结果进行比较。三种计算方法的结果表明,研究区内50年超越概率10%条件下实际场地放大系数为1.30~1.45,50年超越概率5%条件下实际场地放大系数为1.15~1.30,均高于我国第四代和第五代区划图对场地系数的建议值。50年超越概率10%下的PGA区划图结果显示,局部区域在第四代和第五代地震动参数区划图场地系数的结果中位于0.15g或0.20g区,由于KS的提高,其实际计算结果会提升为0.20g或0.25g分区,这说明场地系数对峰值加速度区划图结果具有较大影响。