2006, 28(4):289-297.
Abstract:Probabilistic seismic hazard analysis (PSHA), the most widely used method for assessing seismic hazard and risk, contains an error in its hazard calculation; incorrectly equating the conditional exceedance probability of the ground-motion attenuation relationship (a function) to the exceedance probability of the ground-motion uncertainty (a variable). This error results in using the ground-motlon uncertainty (spatial characteristic) to extrapolate occurrence of ground motion (temporal characteristic) or the ergodic assumption. This error also results in difficulty in understanding and applying PSHA. An alternative approach, called KY-PSHA, is developed to correct the error in this paper.
DONG?Di , LIU?Rui , SANG?Xiang-guo
2006, 28(4):298-302.
Abstract:The practical application of simulation of ground motion using the stochastic method is studied. It can offer reliable seismic input for seismic design and sufficient data for fitting design response spectrum. Through the practical simulation testing ,the result shows that the stochastic method is effectual, simple, and practicability. However, it exists some shortages also.
WANG?Wei , LIN?Ming-zhou , ZHAO?Li-fei , MA?Qin-zhong
2006, 28(4):303-308.
Abstract:There are many parameters in analysis of are different in different period of seismic process, seismicity. The variations of those parameters and the earthquake forecast results of the parameters are not well. For existing some correlations among those parameters, 8 parameter, such as N(ML≥3.0), b-value, η-value, A(b)-value, M〈value,Ac-value, C-value and D-value are selected for factor analysis method, and an synthetic parameter Wf., that reflects the temporal, spatial and intensity characteristics of seismicity, is made. The result shows that Wf, had obvious anomalous change before Jiujiang MsS. 7 earthquake in 2005, Jiangxi Province, and 14 Ms≥5.7 earthquake events in North China, can reflect the anomalous variation in temporal, spatial and intensity characteristics of seismicity well. Some problems in the factor analysis method are discussed also.
SHI?Shuang-hu , HE?Qiao-deng , TENG?Ji-wen , GAO?Jian-rong , ZHAN?Shao-bin , SU?Mao-xin
2006, 28(4):309-313.
Abstract:Through forming a relationship between log and seismic data, and appling the relationship into area far from the logging well, for where there are only geological data without logging, the log property in the area can be predicted by the data from the logged well. There are two methods for this target: single-attribute analysis and multi-attribute analysis. In this paper, by an example, the characteristics of multi-attribute analysis and result of the method are described. The predictive power improves more and more when we use single-attribute regression, linear multi-attribute prediction and neural network prediction in order. Meanwhile how to choose the seismic attributs and determine their validities are discussed also. Applying this result into 2-D seismic profile could determine the log properties in the area outside the logged well.
2006, 28(4):314-318.
Abstract:More than 1 700 seismic events(which occurred from 1982 to 2005, distributed in the range of 40°W~180°E,40°S~80°N,with magnitudes in 5.0~7.0 and focal depths shallower than 100 kin) are selected from nearly 10 000 events recorded by 113 digital seismic stations in Asia, Europe and west Pacific networks. Total 9 980 accurate Rayleigh surface dispersion curves are employed for dispersion inversion, and the distribution map of Reyleigh wave group velocity in 28 periods from 8 s to 400 s for Eurasia continent and marginal seas of west Pacific are obtained. The result shows that horizontal and vertical anisotropy exist in this region.
LIU?Yu , YANG?Bin , LI?Ming-yong , WANG?Ai-guo , LIU?Hong-chun
2006, 28(4):319-326.
Abstract:Based on the seismo-geological field investigation, a co-seismic surface rupture zone in Changlingshan area, Gansu province, was discoved recently. The rupture phenomena include: rock collapse, landslip, downthrown-pit, earthquake slot, uplift, scarplet, earthquake fissure and so on. The distribution of the rupture zone is controled strictly by Changlingshan Northern Piedmont Fault. Through the comprehensive research on the characters of the rupture zone, TL age testing, data of the regional active tectonics and the relationship between rupture zone lengths and earthquake magnitudes, it is considered that this rupture zone was caused by Gulang Ms 8.0 earthquake in 1927.
YAN?Feng , JIN?Ping , FAN?Guang-chao
2006, 28(4):327-330.
Abstract:Frequency wave-number analysis (f-k analysis) is often taken to estimate the slowness and azimuth of sismic signal in seismic array. There are different algorithms of f-k analysis and in Some special cases they lead to quite different results. For example, as being applied to the WRA array of Australia which is different from many other short period arrays by employing broadband seismic recordings at its substations, the standard f-k algorithm usually yields incorrect estimations of azimuth and slowness. It is found in this paper that the error is caused by the spectral leakage effect of FFT and may be avoided by applying a highpass filter to raw data before f-k. After comparing the time domain approach of estimating azimuth and slowness in the f-k method with the frequency domain, it is shown that the time domain approach actually is not less accurate or efficient than the improved frequency domain approach, and in the case of signal-to-noise ratio is very low, the results obtained from the time domain approach are more reliable.
WU?Zi-quan , WANG?Zhi-cai , CAO?Wen-hai , WANG?Ji-qiang , TAO?Jiu-qing , JIANG?Zao-feng
2006, 28(4):331-334.
Abstract:According to the sedimental condition and the thickness of overburden on sea bottom of Weihai bay, Shandong province, sonic prospeding method is selected to survey the direction and location of Shendaokou Fault. The result shows that the profiles are well and the method is suitable for prospecting structure in shallow strata on sac bottom. Conbining with the submarine topographical data, the result is tested, and the precise crientation of the fault on sea bottom has been done successfully.
WANG?Hai-tao , WANG?Qiong , ZHAO?Cui-ping
2006, 28(4):335-340.
Abstract:Since the last Ms6 earthquake event in 1997 to 1998 Jiashi strong earthquake swarm, the seismicity in this region tended to quiet. Then occurred Jiashi MsS. 4 earthquake on Jan. 4,2003, and Bachu--Jiashi Ms6.8 earthquake about 20 km far from the MsS. 4 earthquake 50 days later. After that 7 strong aftershocks(Ms≥5.0) followed it, and the aftershocks of the sequence are richer and strong. By calculating static Coulomb rupture stress changes of the mainshock acting on the rupture surfaces of strong aftershocks, combining spatial and temporal characters of aftershock evolution, the quantitatively possible mechanism of the strong aftershock activity is discussed. The result shows that Bachu--Jiash Ms6.8 earthquake not only encouraged saftershock occurring, whose direction of epicenter distribution is consistent with main rupture surface, but also triggered seismicity in the conjugated direction of the main rupture surface.
WANG?Xiao-ping , ZHU?Yuan-qing , LI?Hui-min , WANG?Yan-wen
2006, 28(4):341-347.
Abstract:Using the local seismic events which were recorded by seismic networks of Shanghai and it's adjacent areas and some artificial blasting events, adopting seismic tomography method, the 3 D P, S wave crust velocity structure of this region is inversed. The tomographic images in different depths show that the P, S wave velocity perturbation orientates NW direction. Most of local earthquakes occurred in low velocity zones, it indicates that earthquake activity is not only related to active faults and maybe linked to crustal structure and its material property. There is a close relationship among velocity structure, active faults and upper crustal materials in Shanghai and its adjacent areas.
FENG?Yong , LI?Yong-hong , DU?Wen-zhe
2006, 28(4):348-351.
Abstract:The geological disasters often occur in the construction of tunnel, it is necessary to adopt geology prediction before the construction. In this paper, technique characteristic and principle of TSP system are introduced and some techniques in using TSP are discussed based on an application example. It is found that the geotechnical investigation can help us decide reasonable probing program and heighten the prediction precision.
LIU?Yu-lan , WANG?Shu-ming , DU?Xue-bing , WU?Yan
2006, 28(4):352-354,385.
Abstract:Using ANSYS as analysis tool, and the influence of river water fluctuating on geoelectric observation data in different distance from riverway to geoelectric monitoring observe station is numerically simulated, and the relationship between error of observation data and distance from riverway to the stations is summarized. The result has the reference significance for choosing geoelectric observation location and observation data error correction.
2006, 28(4):354-354.
Abstract:
LI?Ya-rong , RONG?Dai-lu , HE?Xin-she
2006, 28(4):355-359.
Abstract:Locating and source mechanism inverting of Lanzhou Ms2.5 earthquake on April 19, 2006 are done using the records of Lanzhou temporary digital microquake network. The source mechanism solutions obtained by using two methods (the initial motion of P wave and moment tensor inverting) show identically. Combining with the earthquake distribution in Lanzhou area, the possible seismogenic fault is primary discussed.
2006, 28(4):360-363.
Abstract:Based on the field investigation in loess area, the loess landslides are divided into three types, according to their characteristics of structure, cause of formation, and rock type, etc. The main features of each type loess landslide are stated and main influential factor for loess slope destabilizing are preliminarly analyzed.
FAN?Xiao-ping , YANG?Cong-jie , LI?Qing-he , ?TIAN?Tao , TIAN?Tao
2006, 28(4):364-368,376.
Abstract:Seismo-electric effect is a main factor for causing the anomalies of seismic electro-magmetic phenomena. In this paper the seismo-electric effect is introduced firstly. Then the observation, experimentation and theory study for seismo-electric effect phenomena are summarized respectively. At last the research and application foreground of seismo-eiectric effect in earthquake observation and prediction are disscussed.
HUANG?Yun , LI?Qing-he , SUN?Ye-jun , JIN?Shu-mei
2006, 28(4):369-376.
Abstract:The research works on the crust and upper mantle structure in Jiangsu province and its adjacent areas, that is divided into the southeastern Yangzi block, the southern segment of Tancheng-Lujiang fault zone, the eastern segment of Dabie orogen and the Sulu UHPM block according to geotectonics and research level, are introduced based on the results of different research methods such as deep seismic sounding, earthquake travel time tomography and other geophysical survey. The main characteristics are summarized as following points. The depths of Moho is various from 28 km to 33 km beneath the southeastern Yangzi block with decreasing from weat to east. It exists a high velocity layer in the top of crust of Dabie-Sulu UHPM zone with thickness less than 10 kin. The thickness of crust in Sulu block is in 32-33 km, and is thicker than those in the surrounding area. For Dabie orogen, the depth of crust is about 33 km and changes gently along the direction of the orogen belt, but changes greatly across the belt with the greatest 41 km depth of Moho in some areas. The results of earthquake tomography commonly have low-resolution because of large size of research area. Many works of deep seismic sounding in Dabie-Sulu zone have been done but the work range is too small and survey layer is shallow, so more works on larger area are needed to the deep structure of crust.
2006, 28(4):377-378.
Abstract:Data warehouse is a new technology in information field which develops rapidly in recent years. In this paper the method and application of Data Warehouse are discussed, and a resolve program for appling this technology to seismic information system is put forward.
YANG?Xing-yue , WANG?Yan , YAN?Wan-sheng
2006, 28(4):379-380.
Abstract:Using the subordinate function method, the observation date of radon in No. 22 well at Wushan station from 1984 to 2003 are analyzed. Five Middle-term anomalies on the curves of subordinate function are found, and 4 of the anomalies corresponded with earthquake (Ms≥5.8) in Gansu province and adjacent regions. With this the relationship between the anomaly and earthquake, the feature of anomaly are discussed. The method and criterion of time prediction for strong and moderate-strong earthquake are obtained from the amonaly of radon.
Sopyright:China Earthquake Engineering Journal