Acta seismologica sinica

ＡＣＴＡＳＥＩＳＭＯＬＯＧＩＣＡＳＩＮＩＣＡＨｏｎｏｒａｒｙＥｄｉｔｏｒＳ－ｉｎ－ＣｈｉｅｆＰｒｏｆｅｓｓｏｒＧｏｎｇ－ＸｕＧＵ（顾功叙）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＳＳＢ，Ｂｅｉｊｉｎｇ，ＣｈｉｎａＰｒｏｆｅｓｓｏｒＸｉｎ－Ｌｉｎｇ...     

Effects of magnitude accuracy and complete－ness data on seismic hazard parameters

Ｅｆｆｅｃｔｓｏｆｍａｇｎｉｔｕｄｅａｃｃｕｒａｃｙａｎｄｃｏｍｐｌｅｔｅ┐ｎｅｓｄａｔａｏｎｓｅｉｓｍｉｃｈａｚａｒｄｐａｒａｍｅｔｅｒｓＨＵＩ－ＣＨＥＮＧＳＨＡＯ（邵辉成），ＪＩＡ－ＳＨＵＸＩＥ（谢家树），ＰＩＮＧＷＡＮＧ（王平）ａｎｄＹＡ－Ｘ...     

The Sixth Symposium of the Seismological Society of China held at Zhangjiajie，Hunan Province，China

ＴｈｅＳｉｘｔｈＳｙｍｐｏｓｉｕｍｏｆｔｈｅＳｅｉｓｍｏｌｏｇｉｃａｌＳｏ┐ｃｉｅｔｙｏｆＣｈｉｎａｈｅｌｄａｔＺｈａｎｇｊｉａｊｉｅ，ＨｕｎａｎＰｒｏｖｉｎｃｅ，ＣｈｉｎａＪＩ－ＣＨＵＡＮＨＡＯ（郝纪川）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，...     

Geneticprogrammingforpredictionofearth┐quakesequencetype

Ｇｅｎｅｔｉｃｐｒｏｇｒａｍｍｉｎｇｆｏｒｐｒｅｄｉｃｔｉｏｎｏｆｅａｒｔｈ┐ｑｕａｋｅｓｅｑｕｅｎｃｅｔｙｐｅＹＵ－ＤＯＮＧＣＡＩ（蔡煜东）ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｕｒｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ...     

The regional characteristics of seismic activity in China

ＴｈｅｒｅｇｉｏｎａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｓｅｉｓｍｉｃａｃｔｉｖｉｔｙｉｎＣｈｉｎａＺｈｅｎ－ＬｉａｎｇＳＨＩ，ＪｉａｎＷＡＮＧａｎｄＸｉａｏ－ＤｏｎｇＺＨＡＮＧ（时振梁，王健，张晓东）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，Ｓ...     

Characteristic of crustal structure in the Shulu fault basin and its vicinity

（王椿镛，张先康，林中洋，李学清）ＣｈａｒａｃｔｅｒｉｓｔｉｃｏｆｃｒｕｓｔａｌｓｔｒｕｃｔｕｒｅｉｎｔｈｅＳｈｕｌｕｆａｕｌｔｂａｓｉｎａｎｄｉｔｓｖｉｃｉｎｉｔｙ￥Ｃｈｕｎ－ＹｏｎｇＷＡＮＧＩ；Ｘｉａｎ－ＫａｎｇＺＨＡＮＧ；Ｚｈｏｎｇ－ＹａｎｇＬ...     

Deformation datum in source mechanism inversion

ＤｅｆｏｒｍａｔｉｏｎｄａｔｕｍｉｎｓｏｕｒｃｅｍｅｃｈａｎｉｓｍｉｎｖｅｒｓｉｏｎＳＨＯＵ－ＷＥＮＧＯＮＧ（巩守文，ＱＩＮＧ－ＬＩＡＮＧＷＡＮＧ（王庆良），ＹＩ－ＱＩＮＧＺＨＵ（祝意青）ａｎｄＢＩＮＧＣＨＥＮ（陈兵）（ＳｅｃｏｎｄＣｒｕｓｔａｌＤｅ...     

Measurement of radon gas on major faults in California,USA

ＭｅａｓｕｒｅｍｅｎｔｏｆｒａｄｏｎｇａｓｏｎｍａｊｏｒｆａｕｌｔｓｉｎＣａｌｉｆｏｒｎｉａ，ＵＳＡＷｅｉＺＨＡＮＧ（张炜）ａｎｄＣｈｉ－ＹｕＫＩＮＧ（金继宇）（ＣｅｎｔｅｒｆｏｒＡｎａｌｙｓｉｓａｎｄＰｒｅｄｉｃｔｉｏｎ，ＳｔａｔｅＳｅｓｉｍｏｌｏ...     

StudyofCurieisothermalsurfaceinSichuanBasinandtheseismicareaonitswesternmar┐gin

ＳｔｕｄｙｏｆＣｕｒｉｅｉｓｏｔｈｅｒｍａｌｓｕｒｆａｃｅｉｎＳｉｃｈｕａｎＢａｓｉｎａｎｄｔｈｅｓｅｉｓｍｉｃａｒｅａｏｎｉｔｓｗｅｓｔｅｒｎｍａｒ┐ｇｉｎＸＩＡＮＺＨＡＮＧ（张先），ＸＩ－ＦＥＮＧＨＵ（虎喜凤），ＪＩＮＧ－ＸＩＵＳＨＥＮ（沈京秀...     

The crustal fluid evolution and the causes of earthquakes(Ⅲ)

Ｔｈｅｃｒｕｓｔａｌｆｌｕｉｄｅｖｏｌｕｔｉｏｎａｎｄｔｈｅｃａｕｓｅｓｏｆｅａｒｔｈｑｕａｋｅｓ（Ⅲ）ＣＨＡＮＧ－ＦＡＮＧＸＵ（徐常芳）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ，ＳｔａｔｅＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ，Ｂｅｉｊｉｎｇ１０００...     

基于背向散射脉冲传播时间统计特性的随机界面参数反演研究

研究了利用背向散射脉冲传播时间统计特性反演随机界面参数的问题.首先扩展了Fuks & Godin关于随机界面背向散射脉冲传播时间统计特性理论,给出了当随机界面高度-斜率统计相关情形下,最早返回的两个脉冲传播时间及其时延的概率密度函数（PDF）表达式.进而提出了一种基于背向散射脉冲传播时间统计特性的随机界面参数反演算法：采用遗传算法匹配前两个背向散射脉冲传播时间及其时延的PDF实现随机界面高度—斜率相关系数的绝对值|ρ|和无量纲参数T的反演.最后利用参数的后验概率分析反演结果的不确定性.数值模拟结果表明：该算法可有效反演随机界面的参数,参数|ρ|相对于T反演精度较高;|ρ|和T之间存在较强的参数耦合.与前人认为可忽略高度—斜率相关性（|ρ|）的观点不同：此类反演问题中应同时考虑|ρ|和T.     

On the problems concerned in “The subter-ranean electrical conductivity structure at the Chinese Great Wall Station on Antarctic (CG-WSA)” by Xiaoping Zeng,Yunfang Lin and Yuechen Zhao

By means of the Capon spectral analysis technique Zenget al. (1995) calculated the frequency response of the geomagnetic transfer functions for the Chinese Great Wall Station on Antarctic, and made a preliminary inference for the underground electrical conductivity structure. In the present note, the writer considers that there are some problems concerned in their paper. Maybe it is worthwhile discussing these problems as below.     

Estimation of site amplifications from shear-wave velocity profiles in Yeşilyurt and Avcılar,Istanbul, by frequency–wavenumber analysis of microtremors

During the M_w = 7.4 Izmit earthquake of 17 August 1999, the Yeilyurt district of Istanbul underwent damage despite the epicentral distance of 90 km. At Avclar (20 km west of Yeilyurt), the ground motion was even stronger and has caused heavy damage and fatalities. We investigate whether the observed ground motions can be explained by theoretical site amplifications calculated from one-dimensional (1-D) shear-wave velocity models. For this purpose, microtremors recorded with sensor-arrays set up at two sites were analyzed to obtain phase velocity dispersion curves using both the conventional and the Capon frequency–wavenumber (f–k) methods. At the Yeilyurt site, the conventional f–k method offered reliable phase velocity estimations whereas the Capon method showed scatter in the estimations. At the Avclar site, on the other hand, the Capon method provided a higher resolution than the conventional method and hence, allowed estimation of wavelengths up to seven times the array size. At the Yeilyurt site, the shallow shear-wave velocity profile that is correlated with the lithology obtained from boreholes yields a ground motion amplification factor of about 3 at the frequency of 1 Hz. At the Avclar site, the phase velocity dispersion curve is comparable with the one previously obtained using the spatial autocorrelation method. The site amplification factors calculated from the 1-D shear-wave velocity model are around 2–3 at the frequencies of 0.4, 1.2 and 2.3 Hz, which are about 2–3 times smaller than the amplifications obtained from reference-site techniques using weak/strong motion records of earthquakes. We suggest that the discrepancy may be caused by a 2- or 3-D effect introduced by surface and/or bedrock topography not accounted for by the horizontally stratified model considered here.     

On the problems concerned in“The subter－ranean electrical conductivity structure at the ChineseGreatWalStationonAntarctic（CG┐WSA）”byXiaopingZeng，YunfangLinandYuechenZhao

Ｏｎｔｈｅｐｒｏｂｌｅｍｓｃｏｎｃｅｒｎｅｄｉｎ“Ｔｈｅｓｕｂｔｅｒ┐ｒａｎｅａｎｅｌｅｃｔｒｉｃａｌｃｏｎｄｕｃｔｉｖｉｔｙｓｔｒｕｃｔｕｒｅａｔｔｈｅＣｈｉｎｅｓｅＧｒｅａｔＷａｌＳｔａｔｉｏｎｏｎＡｎｔａｒｃｔｉｃ（ＣＧ┐ＷＳＡ）”ｂｙＸｉａｏ...     

多窗谱分析在Q值估算中的应用

正弦窗谱分析和Slepian窗谱分析是两种常用的多窗谱分析方法.本文利用两种窗函数分别对含噪声的衰减模型进行谱分析对比,并根据谱比法估算了Q值.研究结果表明：正弦窗函数谱分析应用的效果优于Slepian窗谱分析应用的效果,而且多正弦窗谱估计更接近真实的谱.对于深部地层,噪声的影响更加严重,利用多正弦窗谱估计估算的Q值更接近理论的Q值.     

基于保角变换的双谱域相位谱估计方法及其在地震子波估计中的应用(英文)

地震子波估计是地震资料处理与解释中的重要环节,它的准确与否直接关系到反褶积及反演等结果的好坏。高阶谱(双谱和三谱)地震子波估计方法是一类重要的、新兴的子波估计方法,然而基于高阶谱的地震子波估计往往因为高阶相位谱卷绕的原因,导致子波相位谱求解产生偏差,进而影响了混合相位子波估计的效果。针对这一问题,本文在双谱域提出了一种基于保角变换的相位谱求解方法。通过缩小傅里叶相位谱的取值范围,有效避免了双谱相位发生卷绕的情况,从而消除了原相位谱估计中双谱相位卷绕的影响。该方法与最小二乘法相位谱估计相结合,构成了基于保角变换的最小二乘地震子波相位谱估计方法,并与最小二乘地震子波振幅谱估计方法一起,应用到了地震资料混合相位子波估计中。理论模型和实际资料验证了该方法的有效性。同时本文将双谱域地震子波相位谱估计中保角变换的思想推广到三谱域地震子波相位谱估计中。     

IMPROVED LOW-FREQUENCY DECAY ESTIMATION USING THE MULTITAPER SPECTRAL ANALYSIS METHOD1

Spectral analysis is one of the most ubiquitous signal processing tools used in exploration geophysics. Among many applications, it is used simply to look at the frequency content of seismic traces, to find notches, to estimate wavelets under the minimum-phase assumption, and to match broadband synthetic seismograms to seismic data. Seismic spectra exhibit very large dynamic ranges, particularly at low frequencies. Estimation of low-frequency decay is very important for accurate modelling. However, when using traditional spectral estimates incorporating smoothing windows, too much sidelobe energy leaks from high power into low power areas, spoiling our ability to estimate low-frequency spectral decay. The multitaper method of spectral analysis due to D. Thomson does not employ just a single window, but rather a set of orthogonal data tapers. It is possible to have much less sidelobe contamination, while maintaining a stable estimate. The trace is tapered by each of a subset of the orthogonal tapers, and a raw spectral estimate produced in each case. These are combined to produce a final spectral estimate. The technique can be made adaptive by applying different weights to the different raw spectra at different frequencies. A comparison of seismic spectral estimation using this multitaper technique with a traditional approach having the same analysis bandwidth and stability demonstrates the very different estimates of spectral decay in the areas of high dynamic range. The multitaper approach provides estimates with much reduced sidelobe leakage, and hence is a very appealing method for reflection seismology.     

A method for canopy water content estimation for highly vegetated surfaces-shortwave infrared perpendicular water stress index

In this paper, a new method for canopy water content (FMC) estimation for highly vegetated surfaces- shortwave infrared perpendicular water stress index (SPSI) is developed using NIR, SWIR wavelengths of Enhanced Thematic Mapper Plus (ETM ) on the basis of spectral features and distribution of surface targets with different water conditions in NIR-SWIR spectral space. The developed method is further explored with radiative transfer simulations using PROSPECT, Lillesaeter, SailH and 6S. It is evident from the results of validation derived from satellite synchronous field measurements that SPSI is highly correlated with FMC, coefficient of determination (R squared) and root mean square error are 0.79 and 26.41%. The paper concludes that SPSI has a potential in vegetation water content estimation in terms of FMC.     

Empirical site response evaluations: case studies in Israel

A closed-loop, time-efficient technique for site effect evaluation for seismic microzonation in urban areas is developed and implemented. It includes the following successive steps: microtremor measurements using a triangular array of three-component seismometers; estimation of the Nakamura horizontal-vertical spectral ratio, calculation of Rayleigh wave dispersion using the Aki spatial correlation method; inversion of the dispersion curve to determine a shear wave velocity model of the shallow subsurface; analytical computation of Rayleigh wave spectral ellipticity and 1-D SH transfer function for this model; and a comparison of empirical and analytical ratios and correction of the model if required. The technique has been tested at several locations in a number of towns near the active Jordan Rift valley. A reasonable agreement is obtained when comparing empirical spectral ratios and analytical transfer functions.