Zheng Wenheng , Guo Daqing , Shi Telin
1994, 16(2):1-11.
Abstract:Earthquakes withdiverse sizes show the form or extension of diverse size fractures in the crust which is in a self-organized state. Let P0,P1,…,Pn be the probability of the form or ex-tension of fracture in diverse size rock bodies with certain scales. According to renormalization group theory,sequence {P0,P1,…,Pn} has a limit that may be 0 or 1,and if P0=P1=…=Pn, the limit will get the constant(P*)。The P* is a critical value,and if P0>P* then Pn approaches to 1;if P0
*, Pn approaches to 0.
P0 can be determined by statistics of earthquake catalogue. There should be P0
* during the earthquake quiet period,and P0>P* during the active,therefore,P* can be determined as the value between the quiet period P0 and the active P0.Based on the conclution,a lot of renor-malization medels may be calculated and a model that its P* is within the range is choosen to gain a exact P* value. To predict earthquake,the P0 is worked out using recent data and judged if P0>P* not.
The data were calculated in northern district of Qinghai-Xizang plateau and the P0 is about 0.3-0.8 before strong earthquakes,while it is about 0.1-0.2 during quiet. Therefore,the P* is about 0.2-0.3 and the medel that was choosen gives a exact P* as 0.2324.
By this train of thought,a new way to predict strong earthquake is established.
Dong Jiping , zhang Shaoquan , Zhang Cheng , Qin Baoyan
1994, 16(2):12-22.
Abstract:In this paper,the combined mechanism of mining tremors is discussed and a reasonable combined point-source mechanism with its solution is proposed in consderation of decomposi-tion of interior source's moment tensor,that means inversion of relative moment tensor by theuse of first motion amplitudes which is valuable for us to distinguish double-couple events and non-double-couple events.
Fifteen tremors observed in Mentougou Mine in 1987 are studied in simplified way,as a result most of them are double-couple events.
1994, 16(2):23-28.
Abstract:It is very complex to determine the direction of Corioli force generating from slippage of an earthquake fault. For the sake of convenience,a method of the Corioli force direction solution by means of Wulff's net had been proposed.Besides,an example of the 1976 Tangshan strong earthquake had been presented.
Zhao Ming , Huang Jigang , Zheng zhizhen
1994, 16(2):29-35,49.
Abstract:The theory of minimum cross entropy spctrum was briefly introduced. One experimental data was used to examine the program of minimum cross entropy spectrum,and we used the method of minimum cross entropy spectrum to analvse water level data of rock blast.Besides the day change of 0.98Hz,the results show that there would appear high frequency of 1.2Hz several davs before some rock blasts. This result can not be obtained by ordinary methods. The new method provides a new path of rock blast forecast.
Chen Lide , Bao Dexiu , Zou Yongju , Zhang Xiong , He Hongwei
1994, 16(2):36-44.
Abstract:Through the observation and research of deep-well short-term and imminent electromag-netic information (E1) using whip-liked antenna,it is stated that: in time period 10 days to 4 months before an earthquake,three types of seismo-precursory signals such as short-immi-nent,short-term and imminent can be detected on l.9kHz and 2 7kHz underground signalchannel.The fact that the increasing and decreasing period of E1 is correspond to that of smallearthquake frequency in seismogenic zone stated that there may exist some relations betweenthe excitation of E1 and the mini fracture development in seismogenic zone, The dipolecharged body model (DCBM) proposed by us points out:the changing electromagnetic field iscomposed by three types of field such as qusi-static field,inductive field,and radiative field. Some quantitative results of these three type fields changing with observation distance and di-rection are given in this paper.
1994, 16(2):46-49.
Abstract:By using the data of outgoing long-wave radiation (OLR),received by the satellite,this paper calculated the anomalous variation of OLR before several earthquakes.The results show that the effect of cloud layer on the monthly mean value of OLR is only a little;the OLR value can reflect the heat state of the ground; before the earthquakes,the OLR value rises obvious-ly.Therefore, the anomalous variation of OLR is of applied prospect for short-impending earthquake prediction.
1994, 16(2):50-56,61.
Abstract:Firstly,this paper analyzed the data of bulk strain observed from various stations.By the mathematic method,it extracted the mid-short term strain trend variations, which probably relate to the preparedness and occurrence of earthquakes,and calculated the tide factor, Then, the anomalous variations are identified by selecting a certain discrimination criterion. By verify-ing some earthquake cases,it showed that the data processing method proposed by this paper is quite efficient in extracting anomaly information which is of some correlation with earthquake in time sequence.
Yao Tongfu , Fu Yinfa , Hou Kangming , Wang Xian
1994, 16(2):57-61.
Abstract:This paper deals with the morphological features of waveform anomaly recorded at several stations before the M7.2 Songpan earthquake of 1976, and the space-time distribution fea-tures. The anomalous waveforms can be divided into four types: the anomalous waveforms were recorded in verying degrees at all stations (epicenter distance within 80 km); the numbers of the waveforms were increased during the approaching of the earthquake; the amplitude was en-larged; the waveforms were densified ten days before the earthquake with obvious skipping changes. Finally, according to the features of the waveform anomaly, the physical mechanism of the anomalous waveforms was studied preliminarily. It shows that the appearance of the wave-form anomaly results from the rock microfracturing in seismogenic area before the earthquake.
Xie Yuanding , Shao Shunmei , Zhou jianguo
1994, 16(2):62-70.
Abstract:In this paper,we discussed mainlythe variation of the rock density, S & P wave speed and calculated wave resistance with the pressure up to 1 000MPa. These deep-seated rocks were collected in Tianshui earthquake region. It was found that the state parameters of different kinds of deep-seated rocks, which didn't form at the same time, changed very little under high pressure. After the pressure up to 400 MPa,the variation of the rock density and S & P wave speed almost can't be found.We simply discussed the reasons of the phenomenon,and made practical error analysis on the parameters under 400 MPa pressure, The result shows that, without considering tempreture, the state parameters which were gained under 400 MPa pressure can completely replace the parameters under higher pressure (400 MPa-2000MPa) in practical application. so the rock state parameters (under 400 MPa characteristic pressure) are still significant for the artificial deep seismic sounding explanation and gravitation explana-tion.
Lin Changyou , Yang Zhinong , Ye Jianxiang
1994, 16(2):71-78,95.
Abstract:In this paper,the behavious and character of time partial derivative of vertical magnetic field and its apparent resistivity for the TEM late time field excited by vertical magnetic dipole and horizontal electric dipole are discussed. Some problems about one dimensional inversion for them are studied,a practically applied inverse program is designed. It is shown that this in-verse program has better applied effect.
1994, 16(2):79-84.
Abstract:In this paper,by themethod of grep catastrophic prediction,the seismic grey prediction models of Yangzhou-Tongling seismotectonic belt Ms≥5.0 and Ms≥4.0 are built respec-tively, according to the time intervals between two moderately strong earthquakes or the origin times of all previous moderately strong earthquakes. It shows that the prediction accuracy and result are pleasing,by the prediction practice in recent years;and the method of grey predic-tion can be one of comprehensive earthquake prediction.
Teng Ruizeng , Jin Yaoquan , Li Xihou , Su Xiangzhou
1994, 16(2):85-90.
Abstract:In this paper, based on the filling active faults in geologic map with large scale in recent years,the authors present the basic activity characteristics of the fault zone at northern edge of western Qinling Mt. since late Quaternary period, and study the spatial distribution, geometry and kinematics characteristics, slip rate of fault,paleoearthquake and seismic recurrence period. The results show that the active way of the fault zone changes from compression to left-later-al slip since Quaternary period, with a horizontal slip rate 2.1-2.8mm/ year and a vertical slip rate of 0.4-0.7mm/year. The recurrence period of earthquake is about 5000 years in the fault zone.
Guo Jiankang , Guo Daqing , Wang Zhenya
1994, 16(2):91-95.
Abstract:This paper presents the earthquake prediction practice system (EPPS ) in Gansu province. EPPS makes full use of existing software and hardware configuration. The seismological data base,the computer software for the key task of the earthquake analysis and prediction practice, the expert system for earthquake prediction and the consulation conference on earthquake sys-tem were on-line used. Experience and practical use show that EPPS is more suitable and practical,and improves the work for earthquake analysis and prediction in Gansu province。
1994, 16(2):96-96.
Abstract:柯氏力与强余震讨论用柯里奥利力(简称柯氏力)预报强余震是一种震源物理方法。其中有以下几点值得说明。
1994, 16(2):97-99.
Abstract:疏松土体对弹性波能吸收比致密岩体大得多。疏松的土体在我国覆盖面广阔,人口聚集区和大多数工程建筑物都位于地表土体上。
Zhang Wenmian , Tian Shaobai , Chen Wenbin
1994, 16(2):100-104,99.
Abstract:In the paper,we statistically analyze the sudden impending earthquake anomalies and obvious trend anomalies of all kinds of precursors of 11 great earthquakes (Bohai Ms7.4, Luhuo Ms7.9,Yongshan Ms7.1 ,Haicheng Ms7.3,Longling Ms7.4,Tangshan Ms7.8,Songpan Ms7.2,Daofu Ms6.9 Wuqia Ms7.4,Lancang Ms7.6,Gonghe Ms7.0)in Chinese continent from 1969 to l990 by synthesizing many stages and phenomena. Then we study the whole characters and physical explaination of sudden anomalies before the megaseisoms,summarize the evolutionary law of time, space and intensity(or frequence)of each precursory anomaly.the distributing law of the item-and-frequency of the sudden impending earthquake anomalies with titne(the intenrval from sudden changes to eartbqllake occurrence)and the constitutional and synchronous laws of these anomalies,and discussthe com-prehensive methods distinguishing imminent anomalies of megaseisms,the synthetic indices of imminent predic-tion and the effectively temporal predIction.
Sopyright:China Earthquake Engineering Journal