Kane Fracture Zone

The Kane Fracture Zone probably is better covered by geophysical survey data, acquired both by design and incidentally, than any other fracture zone in the North Atlantic Ocean. We have used this data to map the basement morphology of the fracture zone and the adjacent crust for nearly 5700 km, from near Cape Hatteras to the middle of the Mesozoic magnetic anomalies west of Cap Blanc, northwest Africa. We use the trends of the Kane transform valley and its inactive fracture valley to determine the record of plate-motion changes, and we interpret the basement structural data to examine how the Kane transform evolved in response to changes in plate motion. Prior to about 133 Ma the Kane was a small-offset transform and its fracture valley is structurally expressed only as a shallow ( < 0.5 km) trough. In younger crust, the offset may have increased to as much as 190 km (present offset 150 km) and the fracture valley typically is up to 1.2 km deep. This part of the fracture valley records significant changes in direction of relative plate motion (5°–30°) near 102 Ma, 92 Ma, 59 Ma, 22 Ma, and 17 Ma. Each change corresponds to a major reorganization of plate boundaries in areas around the Atlantic, and the fracture-zone orientation appears to be a sensitive recorder of these events. The Kane transform has exhibited characteristic responses to changes in relative plate motion. Counterclockwise plate-motion changes put the left-lateral transform offset into extension, and the response was for ridge tips at the ridge-transform intersections to propagate across the transform valley and against the truncating lithosphere. Heating of this lithosphere appears to have produced uplift and formation of a well developed transverse ridge that bounds the inactive fracture valley on its older side. The propagating ridge tips also rotated toward the transform fault in response to the local stress field, forming prominent hooked ridges that now extend into or across the inactive fracture valley. Clockwise (compressional) changes in relative plate motion produced none of these features, and the resulting fracture valleys typically have a wide-V shape. The Kane transform experienced severe adaptions to the changes in relative plate motion at about 102 Ma (compressional shift) and 92 Ma (extensional shift), and new transform faults were formed in crust outside the contemporary transform valley. Subsequently, the transform offset has been smaller and the rates of change in plate motion have been more gradual, so transform-fault adjustment has been contained within the transform valley. The fracture-valley structure formed during extensional and compressional changes in relative plate motion can be decidedly asymmetrical in conjugate limbs of the fracture zone. This asymmetry appears to be related to the ‘absolute’ motion of the plate boundary with respect to the asthenosphere.     

不等时距的灰色模型预测

本文就实际观测中的不等时距情况进行了讨论，经过变换，将等时距的GM（1，1）模型，转为不等时距的GM（1,1）模型，进行预测．并经过残差修正，提高预测精度．     

Estimation of characteristic parameters m region-time-length algorithm and its application

On the basis of gap＇s temporal-spatial characteristics in and around source area before an earthquake, we propose a method to estimate characteristic parameters （characteristic distance and time） in the region-time-length （RTL） algorithm and introduce the method of correlation coefficient developed by some authors in 2006 to determine the characteristic parameters. The anomalous seismic activities before four moderately strong earthquakes occurred in the northwestern and southwestern China in recent years are studied by the two methods. The results show that the method to estimate characteristic parameters advanced in this paper is a simple one, which possesses a physical meaning and is well applicable to the four moderately strong earthquakes studied.     

基于精密测距方法监测基坑平面位移的探讨

在简述基坑水平位移监测的作用和主要技术手段的基础上,重点介绍了一种采用精密距离测量方式对基坑平面位移进行监测的方法,并将该方法应用于工程中,说明此方法的实用性。     

京沪高铁站点对周边地区的经济带动效应研究——来自DMSP/OLS和NPP/VIIRS卫星灯光数据的证据

随着中国高铁建设的全面铺开,高铁新城正在成为许多城市发展的“新引擎”。本研究以京沪高铁站点为例,分析沿线高铁站点对周边地区的经济带动效应。由于相关社会经济数据的匮乏,文章应用DMSP/OLS和NPP/VIIRS卫星灯光数据结合距离圈层法对京沪高铁站点的经济效应进行评估。研究结果表明,高铁开通后,中等规模城市所在的高铁站点周边地区受益最大,其次是大城市高铁站点的周边地区,而居于小城市的高铁站点对周边地区的带动效果不明显。     

水库大容量气枪震源激发条件优化实验研究

Through manual pickup of seismic phases,the number of recording stations,the farthest observation distance of station and received energy are determined,then optimal operating condition processing software is developed to evaluate the excitation effect of operating conditions. The optimal operating conditions in the Mianhuatan Reservoir are determined using this software. They are: optimal water depth 25 m,airgun array sink depth 9m and airgun array size 7m × 7m. At the same time,accumulative stacking results for every 10 times are analyzed for 300 fixed-point excitations. It is concluded that the excitation effect shows a rapidly rising trend at 10 to 90 times stacking,a slowly rising trend at 100 to 150 times stacking,a rapidly rising trend at 160 to 240 times stacking,and a slowly rising trend at 250 to 300 times stacking. As the number of stacking increases,the propagation distance and the number of recording stations also increase gradually.     

希尔伯特-黄变换中拟合过冲和端点飞翼的原因及解决办法s

深入分析了现有的三次样条拟合方法,指出ldquo;拟合过冲rdquo;现象产生的原因,并提出新的三次样条拟合方法和正弦函数拟合方法. 这两种新拟合方法都具有消除ldquo;过冲rdquo;现象,拟合函数连续、一阶导数连续、计算简便、计算量小、易于操作等优点. 同时,指明了ldquo;端点飞翼rdquo;现象产生的原因,并提出一种处理资料曲线的端点问题的技巧. 该技巧能够在不改变资料曲线的条件下消除ldquo;端点飞翼rdquo;现象. 拟合新方法和新技巧能结合运用,得到完全没有ldquo;拟合过冲rdquo;和ldquo;端点飞翼rdquo;的拟合曲线,为时序曲线固有模态函数分解提供了可靠的技术基础.     

最小GDOP定位构型的一种嵌套圆锥结构

在圆锥构型的基础上,定义了一种嵌套圆锥构型,并导出了最小PDOP嵌套圆锥构型所应满足的条件。讨论了构造最小GDOP(几何精度衰减因子)构型的方法。在最小PDOP嵌套圆锥构型的基础上给出了最小GDOP嵌套圆锥构型。在此基础上,由最小GDOP嵌套圆锥构型导出了数学上仅有的J种正多面体构型,证明了J种正多面体均满足GD}}P极值条件。     

基于测井数据小波变换的四川孝泉地区须家河组层序划分

尽管测井数据具有良好的连续性和高分辨率特性,地质科研中对测井曲线和地层层序的研究仍以观察实践为主.沉积旋回的复杂性和相对一致性、测井曲线的连续性和非周期性以及小波变换的多分辨率和时频域兼顾的特性,这三者相互联系、相互对应,构成了小波变换用于测井数据层序划分的理论基础.以四川孝泉区须家河组某井为例,对该井地质数据进行了连续小波变换,并将该组段划分为3个层序和18个准层序.     

广义S变换时频域滤波在MT数据处理中的应用

短时傅里叶变换是建立在稳态信号基础之上,它仅能提供信号的频域信息,对信号的时间分辨能力差。这影响了它在大地电磁测深数据处理中的应用效果。S变换是一种优于短时傅立叶变换的时频分析方法,能够提供信号时-频域信息。利用S变换对大地电磁测深数据进行时频分析,有助于实现大地电磁测深数据噪声的时频-域滤波,从而提高大地电、磁分量数据的频谱分析精度。从广义S变换理论出发,分析了各类波形噪声的时-频域特征及其对大地电磁测深数据的影响。针对大地电磁测深数据处理特点,利用广义S变换得到时频谱,采用时频比值和门槛值方法,研究适合压制电磁噪声的时频滤波器和滤波方法。对实际大地电磁测深数据的处理结果表明这个方法提高了阻抗张量的估算质量,验证了该方法的有效性。