ZHANG Li-qin , YU Wen-hui , WANG Jia-ying
2004, 26(2):97-107.
Abstract:With numerical evaluation, the effects of different parts of medium, such as elastic, viscous and porous filled with or without fluid, on the wave propagation especially in the range of low frequency band are discussed. Characteristics of seismic wave with Biot coupling are analyzed in the homogeneous and isotropic medium. The results show:(1) the phenomenon of critical porosity exists about the phase-velocity of slow P-wave in and the critical porosity is the blind spot of the phase-velocity of slow P-wave. (2) It is easy to observe slow P-wave in the condition of large porosity and low frequency band. (3) In the range of low frequency band, the phase-velocity of P-and S-wave is independent of penetrability, while the loss factor of P-and S-wave strongly depends on penetrability.
2004, 26(2):108-112.
Abstract:The relations between SIP real parameters of underground anomalous body and apparent complex resistivity spectra can be expressed by the combination of Cole-Cole models and dilute coefficient. In this paper, we use the modeling expression to compare several SIP inversion schemes with Cole-Cole model, and bring forward a new inversion scheme, it is fixing the polarizability of polarizable object body and adjacent rock, then simultaneity inverse other SIP parameters. Through a great deal theoretic checking computations, we find when polarizability is fixed, this inversion scheme has good stability, veracity and velocity.
ZHANG Yuan-sheng , GUO Xia , ZHANG Xiao-mei , LI Ming-yong
2004, 26(2):113-117.
Abstract:The inversion method of two-pass,diversified temporal phases can calculate the land surface temperature and the land surface emissivity individually when attaining the land surface temperature,is a good way for researching the variation of land surface temperature field by applying IR data of still satellite.The method is easy to realize processing mass data with simple computation,and is able to fulfil request on applying IR data to earthguake prediction.
LIU Xi-qiang , SHEN Ping , SHAN Chang-lun , JI Ai-dong , LI Hong , CAI Ming-jun
2004, 26(2):118-125.
Abstract:The time-frequency distribution of signal is more suitable for depicting unsteady signal than time-scale distribution. The development tendency of time-frequency analyses is improving the time-frequency conglomeration characteristics of signal and decreasing across disturbance energy item further. Based on the theory of time-frequency analyses on high order moment,this paper applies time-frequency technology to digital seismic wave data processing first. Compared Choi-Willams time-frequency distribution results of imitation signal with Wigner time-frequency distribution with different order moment, We think that high order moment Choi-Willams time-frequency distribution has higher time-frequency conglomeration characteristics and weaker across disturbance energy item, which has application foreground to improving earthquake source and medium parameters precision and intelligentized degree of earthquake emergency.
2004, 26(2):126-130.
Abstract:By using seismic risk analysis theory and artificial ground shaking acceleration techniques, the ground shaking acceleration history, used in Newmark method for slope stability evaluation, is created. Via a loess slope case computation, the relation between the peak acceleration in landslide and depth is deduced. In addition, a terminology, equivalent peak acceleration is put forward, and computing results by using equivalent shaking acceleration in the slope and shaking acceleration on the slope surface in Newmark method are compared.
ZHU Xin-yun , ZHONG Yu-yun , ZHANG Zhe-feng
2004, 26(2):131-136.
Abstract:Using waveform data of Jiaokou, Douhe, Hunyuan and Haicheng earthquake sequences, the characteristics of corner frequency changing with the earthquake process is studied. In order to remove the magnitude affects which imposed on the corner frequency change trend, we obtain the ratio curves of corner frequency values in every event to corner frequency mean values with equal magnitudes in the same earthquake sequence.The curve shows the ratio changing process clearly:in the foreshock-aftershock pattern sequence, the corner frequency of foreshock is higher than that of aftershock if their magnitudes, are equal, but in swarm sequence this trend is not show.Using the mean value of corner frequency from small events in a larger area as the background value,we obtain the ratio curve which reflect the changing process of earthquake sequence also clearly. The method which gives the changing trend in a earthquake sequence could be a new way for earthquake prediction.
QIAN Xiao-dong , HE Hong-wei , LIU Zheng-rong
2004, 26(2):137-143.
Abstract:According to limit time method,the h' values of 11 groups of MS6.5 strong earthquakes since 1970 in Yunnan province are calculated. The results show:h' anomalies appeared before 11 groups of MS6.5 strong earthquakes with sudden decrease of 28%(the average amplitude), meaning quiet anomaly of seismicity. It is the key index for make prediction. In 11 groups of strong event, 8 of the seismic process show the seismogenic mode of activation-quiet-main earthquake, which posses 73% of all; 3 are activation-quiet-activation(short-term)-main shock mode, which posses 23%; It was displayed clearly for quiet or activation of seismicity before strong earthquakes. Making forecasting to 11 groups of strong earthquakes suggests that forecast time is about 5 months.
BO Wan-ju , GUO Wei-xing , GUO Liang-qian , DU Xue-song , ZHOU Wei
2004, 26(2):144-148.
Abstract:Most of the crass-fault deformation data measured at fixed stations and mobile sites in China are collected, the obvious anomaly variations of it such as stepping, pulse, tendency change and anniversary rule change are searched, and the comparison analysis between the anomalies and earthquakes with MS≥6.0 in the same area is made to find their distribution regulation both in time and space. The results show:(1)Both of the anomalies and strong earthquakes migrate to and fro from Southwest to North China in the last active cycle of strong seismicity.(2)There is a corresponding relation between the peak of abnormal deformation at stations and the active period of strong earthquakes.(3)Since 1987, both the deformation anomalies and activities of strong earthquake not migrate obviously from Southwest to North China yet, but the migrate feature is also existent in North-South seismic belt of China.(4)In the next period, the probability of occurring earthquake with MS≥6.0 in North China is low, but we are not sure about it for North-South seismic belt of China.
SHI Shao-xian , WANG Yong-an , LIU Qiang
2004, 26(2):149-153.
Abstract:The basic features,extracting method of anomaly information and prediction significance for the group anomaly from the measurement data of 8 cross-fault short baseline at Lijiang,Yongsheng,Xiaguan and Jianchuan survey points in northwest Yannan Province,from 1984 to 2002,are studied. The results show that the group anomalys is a short-term prediction index for grouped strong earthquakes in the region with clear physical sense and high corresponding probability.
LI Ying , ZHAO Wei-ming , SHENG Ju-qin
2004, 26(2):154-161.
Abstract:Using the analytic method of correlation function, study is done on the interrelations among strong earthquakes with M>7.0 occurred in Burma convert construct area, Southwest Yunnan revolve construct area, Xingdukushi moderate-deep source earthquake area and those occurred in West Chinese mainland and its neighbouring region since 1900. The results show that seismicities in Burma convert construct area, Southwest Yunnan revolve construct area and Xindukushi moderate-deep source earthquake area have certain corresponding relation with that of other seismic active areas in time and space. This result has significance on the strong earthquake prediction in West Chinese mainland and its neighbouring region.
MA Er-man , CHEN Yong-ming , ZHAO Guang-kong , GAO Xiao-ming , HE Wen-gui
2004, 26(2):162-167.
Abstract:On December 14,2002, A destructive MS5.9 earthquake occurred at Yumen city, Gansu province, and it caused damage to building structures and other engineerings. After the earthquake, the investigation of seismic field and the assessment of seismic disaster are done. On the base of general situation, natural environment, social economy, main industry, population and building situation in seismic area, the seismic area is divided into 7 parts, and the 66 investigating samples points are finished. According to the loss assessment system of seismic disaster(EDLES), a databank is set up, and a relatively practical assessment of economic loss is done.
AN Hai-jing , ZHAO Jia-liu , ZHAO He-yun , LIU Bao-qin
2004, 26(2):168-173.
Abstract:Based on all geoelectric and geomagnetic data observed in 6 years at Sino-France cooperate station,in contrasting of annual variation for years, the observation data in measuring lines are selected reasonably and the time series curves are plotted by these data. It is discovered that normal background fluctuation is added the variation of distortion for a month and more before western Kun Lun Mountain earthquake MS=8.1. According to the distortional shape, there are 2 kinds of forms:the step abrupt change and the sudden change with single needle shape. A possible mechanism of 2 kinds anomaly is discussed in this paper.
2004, 26(2):174-177.
Abstract:The source of risk to invest on the influence areas of strong earthquake is introduced, and the basic contents of investment policy on the influence area are discussed. The forbidding into mechanism, insurance mechanism, venture capital mechanism, as well as enhancing the management mechanism for earthquake resistance pretection should be considered in establishing the investment policy on the influence area. In the paper, the author shows three principles about the investment policy on the influence area of strong earthquake in China.
2004, 26(2):178-182.
Abstract:The theory of Load and Unload Response Ratio (LURR) has applicated in earthquake prediction extensivelly,but it meet challenge also.In this paper,the theory of LURR and its application are analyzed and some aspects for study in near futuer are proposed:(1) Weight of Benioff strain of every small earthquake would be added in LURR calculation according to Coulomb failure stress generated by earth tide; (2) The region shape in where small earthquakes are selected would be determined by the range of LURR would-be-high according to stress distribution before impending large earthquake; (3) By comparing the results of LURR from the assumed same mechanism of small earthquakes and that from measured mechanism of small earthquakes, study the improvement of LURR from using measured data; (4) The applicability of LURR to different seismic fault types of large earthquake would be studied.
2004, 26(2):183-185.
Abstract:The field judgment and its evidences for the post-seismic tendency of Yumen earthquake with MS5.9 Gansu Province, on Dec.14, 2002 is introduced. The Particularity of the field judgment for post-seismic tendency and how to combining science with sociality in the judgment are also discussed.
XIA Zhong , FENG Zhi-sheng , JI Cai-jian , CHEN Xing-dong
2004, 26(2):186-189.
Abstract:Using the vector compensate measuring theory and the declination compensate measuring theory for vector proton precession magnetometer, a mathematical method for selecting vector compensate current and bias current is worked out. The selecting method have been applied in a new style of vector proton precession magnetometer,and shows it is accurate and simple in practice.
2004, 26(2):190-192.
Abstract:Two kinds of advantage antiseismic structure shapes are proposed on the basis of the structure system's entirety action. In the two structure shapes the bearing condition and property of structure are improved, whole guality of structure system is increased, and the antiseismic capacity is strengthened. Also the new shapes can save reinforcement and concrete,has great economic benefit.
Sopyright:China Earthquake Engineering Journal