多种岩石的Qp,Qs,Qc

本采用脉冲传播谱振幅比法、能量法、尾波法分别测多种岩样的Ｐ波Ｑ值、Ｓ波Ｑ值及尾波Ｑ值。结果表明，能量法所得Ｑｐ、Ｑｓ较小。谱振幅比法所得Ｑｐ一般居中，Ｑｓ较大。尾波Ｑｃ有的偏大，有的偏小。     

新疆北天山地区中强震前单台地震波参数异常特征研究

强地震的孕育过程也是孕震介质的形成过程,在强震前震源附近小地震的地震波运动学,动力学特征的变化过程,则反映了孕震介质的变化过程,为研究地震的孕育,发展和发生的过程,采用单台地震波振幅比,尾波持续时间比,尾波衰减系数这３项地震波参数作为地震学短期前兆指标,分析其震兆特征,从而达到监测孕震介质变化的目的,研究结果表明,单台地震波参数能够有效地发现地震的前兆,但地震波参数的前兆图像复杂多变,不具有统一的     

Coda Q in the Kachchh Basin, Western India Using Aftershocks of the Bhuj Earthquake of January 26, 2001

Q_C-estimates of Kachchh Basin in western India have been obtained in a high frequency range from 1.5 to 24.0 Hz using the aftershock data of Bhuj earthquake of January 26, 2001 recorded within an epicentral distance of 80 km. The decay of coda waves of 30 sec window from 186 seismograms has been analysed in four lapse time windows, adopting the single backscattering model. The study shows that Q_c is a function of frequency and increases as frequency increases. The frequency dependent Q_c relations obtained for four lapse-time windows are: Q_c=82 f^1.17 (20–50 sec), Q_c=106 f^1.11 (30–60 sec), Q_c=126f^1.03 (40–70 sec) and Q_c=122f^1.02 (50–80 sec). These empirical relations represent the average attenuation properties of a zone covering the surface area of about 11,000, 20,000, 28,000 and 38,000 square km and a depth extent of about 60, 80, 95, 110 km, respectively. With increasing window length, the degree of frequency dependence, n, decreases marginally from 1.17 to 1.02, whereas Q₀ increases significantly from 82 to 122. At lower frequencies up to 6 Hz, Q_c⁻¹ of Kachchh Basin is in agreement with other regions of the world, whereas at higher frequencies from 12 to 24 Hz it is found to be low.     

浙江及邻区尾波Q值研究

基于单次散射(Aki)模型,利用2000年至今浙江及安徽台网记录的37次ML3.0以上地震的数字地震波资料,计算了浙江及邻近省区平均尾波Q值,并拟合了Q值对频率的依赖关系数据。结果为:Q(f)=212±33.5f0.62±0.11,与国内其它区域相比,本区域为Q值高值、对频率低依赖性区域。认为本研究区内构造活动弱,地震活动水平低。本文就Q值对频率、尾波窗长等的依赖性特征及影响Q值计算的噪声水平、滤波器、数据采样等因素进行了深入分析。     

青海玉树单台地震序列的尾波Q值研究

利用玉树单台记录到的2006年7月19日玉树Ms5．4级地震序列的数字地震波形资料，计算了不同频率下该序列尾波Q值的变化特征，为今后将数字地震资料应用到地震预报工作中提供了参考依据。     

阿拉斯加巴罗AB—67钻孔岩芯的沉积环境分析

巴罗ＡＢ－６７钻孔岩芯的４８个样品被进行了２５个项目的粒度分析和４４个项目的地球化学分析。本文对这些数据进行了Ｑ型因子分析,并得到了４个主因子。研究表明,这４个因子分别代表了沉积环境的四项指标,它们分别为沉积速率,降水,海平面和温度。从岩芯顶部５个样品与巴罗气象台观测记录研究了古温度和古降水的转换函数,从＾２１０Ｐｂ测年和几个环境事件确定了沉积速率的转换函数。     

Coda Q before and after the eruptions of 13 November 1985, and 1 September 1989, at Nevado del Ruiz Volcano, Colombia

 Coda Q^–1 was calculated at Nevado del Ruiz Volcano (NRV) before and after two phreatomagmatic eruptions (November 1985, September 1989) and for a period of stability (May 1987) using a functional form for coda derived from a single scattering model (Sato 1977). Substantial changes were found before and after the eruptions. The highest value of Q^–1 was found during the November 1985 eruption, an intermediate value for the September 1989 eruption, and the lowest value for May 1987. It seems that the changes in coda Q^–1 at NRV have a still-unknown relationship with the volume or magnitude of the eruption. A relatively strong frequency dependence was found for all periods. Also Q^–1 clearly changed with time, suggesting that the scattering was strong for the eruption of November 1985 and decreased for the eruption of September 1989, and that the intrinsic absorption probably increased. This suggests the possibility that crystallization is taking place in the NRV magma. The clear change of coda Q^–1 before and after the eruptions at NRV also suggests the possibility that coda Q^–1 is a premonitory tool of activity at this volcano. Received: 25 October 1996 / Accepted: 21 January 1998     

西昌地区地方震尾波衰减Q值

基于单次散射模型的尾波动功率谱分析法,利用西昌遥测台网地震波实时处理系统记录的２４个地震数字化波形资料,计算了西昌地区地球介质对应于１３个不同的ＱＣ值,在１．０－２０．０Ｈｚ频率范围内,以幂函数ＱＣ＝ＱＣｆ＾ｎ拟合ＱＣ值随的变化关系,其中Ｑ０值在４３．０－８２．４之间,ｎ值在０．２４－０．９４之间,平均值分别为６６．２和０．５３。     

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Short time-scale fluctuations in the difference light curves of QSO 0957+561A,B: microlensing or noise?

From optical R -band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (with an overlap of about 330 d between the time-shifted light curve for the A image and the magnitude-shifted light curve for the B image). We observed noisy behaviours around the zero line and no short time-scale events (with a duration of months), where the term 'event' refers to a prominent feature that may be a result of microlensing or another source of variability. Only one event lasting two weeks and rising −33 mmag was found . Measured constraints on the possible microlensing variability can be used to obtain information on the granularity of the dark matter in the main lensing galaxy and the size of the source. In addition, one can also test the ability of the observational noise to cause the rms averages and the local features of the difference signals. We focused on this last issue. The combined photometries were related to a process consisting of an intrinsic signal plus a Gaussian observational noise. The intrinsic signal has been assumed to be either a smooth function (polynomial), a smooth function plus a stationary noise process, or a correlated stationary process . Using these three pictures without microlensing, we derived some models totally consistent with the observations. We finally discussed the sensitivity of our telescope (at Teide Observatory) to several classes of microlensing variability.