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1.
This paper aims to analyse the geoelectrical resistivityρ
s
data on the dipole electrode sounding, which were firstly accumulated from the earthquake prone region in China. The analyses
on the one order difference value of the geoelectrical resistivity indicated that, firstly, more than 4 percent of theρ
s
data reveals the precursors by 3 to 76 days ahead the earthquakes occurring, with the magnitude range of 4 ≤M ≤ 6. 4, in a region of 100 km around the station, and secondly, the results revealed that the seasonal variation ofρ
s
data were slight.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 211–219, 1992. 相似文献
2.
Based on the observation data, it is found that the Lancang-Gengma earthquake sequence is resulting from the propagation of
a nonuniform fracture system in which the lengths and strikes of fractures are different from each other, the stress field
and medium condition around fractures are also heterogeneous. Therefore, a mechanical model simulating suitably the fracture
processes of the Lancang-Gengma earthquake sequence is suggested in this paper. The fracture criterions and computation method
for elastic fracture and elasto-plastic fracture are studied. The stress intensity factor, strain energy release rate and
J-integral are evaluated respectively. The forward and inverse method jointing a variety of observation data to determine
the earthquake fracture processes is also developed in this paper.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 463–471, 1992.
This project was sponsored by the Chinese Jonit Seismological Science Foundation. 相似文献
3.
By the experiment, it is confirmed that water-marble rock system shows obviously chemical anomalous behaviors: the relevant
minerals which formed marble rock are resolved fast, water becomes alkaline, meanwhile H2 emission appears under action of ultrasound; based on rock identification by microscope and chemical analysis of water and
rock, the mechanism of above chemical reaction is analyzed and discussed.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15 498–507, 1993.
This study was supported by the Chinese Joint Seismological Science Foundation. 相似文献
4.
Shun-Liang Chi 《地震学报(英文版)》1993,6(3):731-737
The analysis results of observations data indicate that this shallow-borehole (21 m – 52 m) strainmeter can record accurate
crustal movements. Its records of earthquake and solid tide can be analysed. To use long period frequency data, null drift
must be considered. To extend its application, the technique of installation and anti-lightning stroke should be improved.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 224–231, 1993.
This project is supported by the Earth-quake Monitoring Department of the State Seismological Bureau. 相似文献
5.
In this paper, the coefficients of Parkinson vectora, b and the in-phase partA
r, Br and quadrature-phase partA
i, Bi of transter functions are calculated by using two kinds of data processing methods, respectively. The results of both methods
are close to each other. All these six parameters above are low in value, showing that the electric structure in Heze area
is rather uniform. It seems that the anomalous changes appeared in both results, and the values of parameters decrease before
and after Heze earthquake.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 113–120, 1991. 相似文献
6.
Since 1979 the repeated observations and experiments of geomagnetic total intensity and vertical component have been carried
out for ten years in the geomagetic network which is located in Jiangsu Province, China. Three earthquakes aboveM
s 5.0 occurred during the decade, and some seismomagnetic effects were observed. The observation results show that the anomalies
of the vertical geomagnetic component can’t be observed untill some months before the earthquake (M
s>5.0) in this area.
In this paper it is suggested that a densely distributed network for continuous observation of geomagnetic vertical component
may catch seismomagnetic anomalies and thus improve earthquake prediction in the light of the geomagnetic measurements of
the mid — or — low latitude locations.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 80–87, 1991.
This study is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
7.
Vertical differential movement rates of the fault on north margin of the Weihe downfaulted basin in recent 2000 years are
analyzed by using the data of shifts of the head of Zhengguo canal, dug in Qin dynasty and the data of burial depths of historical
relics and the data of levelling. The results show that in Ming dynasty this fault experienced the highest differential up-and-down
movement, about 6.6 mm/a, while the rate became lower since Qing dynasty, about 2.6 mm/a. The high rate activity coincided
with the period of high seismic activity in the Weihe downfaulted basin in the 15 – 16th centuries.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 195–200, 1992.
This project is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
8.
In this paper a new method of the quantitative correction of influence of the rain on the water level in a well is given.
Using the faltung filtering and polynary regression, considering the effect of the rain on the well water level with the lag
“memory”, the correction of the influence of the rain on the well water level is made. The result of correction of the water
level in the well Lu-08 by the rain shows that the correction result of this method is better.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 202–207, 1993.
This study was supported by the Chinese Joint Seismological Science Foundation. Thank The Seismic Office of Victory Oil Field
for their help in gathering data of the well Lu-08. 相似文献
9.
The influence of the four different methods of measuring Lg amplitude, and the selection of different geometrical attenuation
coefficient ζ-values (=5/6 or 1) on the determination ofγ value of Lg wave are discussed.γ=0.0034±0.0001km−1 (when ζ=5/6) for six eastern provinces is redetermined. The revised magnitude calibration function ofm
Lg (mxh),q
E (Δ)=(5/6)logΔ+0.00147Δ+1.81 is deduced.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 171–178, 1991.
Projects sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
10.
In this paper we investigate the sources of two kinds of forces to form the stress field in the lithosphere. These are the
drag force caused by mantle flow and the force system along plate boundaries. The results show that both forces control the
basic stress pattern in China and compressive stresses can fit with the stress patterns constructed by focal mechanisms,in-situ stress measurements in boreholes and that deduced from other geophysical and geological observation.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 295–306, 1991.
This research is sponsored by the Chinese Joint Seismological Science Fundation. 相似文献
11.
We have made a data collection and analysis system for recording microcracks in rock to study the three dimensional pattern
of fracture and the dynamic properties of rock during pressurization. This system, with 8 channel data detection, records
in real-time, from the initial microcracks to the final vibration waveform excited by the master fracture. The detected data
are recorded digitally at the hard disk of an IBM computer (or 286, 386 personal computer) as well as transmitted to disk.
The sampling rate for each channel is 10 MHz.
Collecting every acoustic emission events in the loaded rock sample with 8 channels by this system, mathematically modelling
the AE event travel time, and taking the coordinates of the AE event hypocenter and the three components of P wave velocity
as unknown parameters, we set up a set of residual equations for joint inversion, so that the three dimensional localization
of AE event hypocenters can be completed under variable velocities, which will lay foundations for the research on rock fracture
clearly.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismological Sinica,13, 489–495, 1991.
The design and development of the system, and the experiments are sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
12.
Yun-Lin Zhang Hai-Jing An Xiao-Ling Liu Yu-Lan Si Mei Jiang Wu-Si Zhang 《地震学报(英文版)》1993,6(3):675-683
The high accuracy, automatic, digital MT measurement system with five electromagnetic components was firstly adopted by the
author to the section MT monitor and measurement in the middle Qilian mountain in the Northwestern China, the more real precursory
information of impending earthquake electromagnetic rediation of GongheM=7.0 earthquake (April, 1990) in Qinghai province was obtained by the system.
The new complete quantification frequency analysis was firstly used in this paper in both time and space domains for the analysis
of repeated measurement data at all sites.
This paper concludes the precursory spectral characteristics of electromagnetic radiation before strong earthquake as following:
1. The spectra appears as the synchronous electric field interference type mainly of conduction current; 2. Narrow band (0.5
– 20s) of spectral period; 3. The singularity of amplitude (the pulse amplitudes of interference electric field is 102 times the normal values); 4. They show the directionality of preparing focus to some extent; 5. The intermittent of radiation
(three peak periods appeared three days before the main shock). It is more significant that there existed a relative quiet
period of about 48 hours between the peak period and the occurrence, observators can response quickly at observational sites
and take it as one of the observational criterions for impending prediction.
This paper also points out that the impending earthquake electromagnetic radiation obtained by the MT measurement system is
mainly the conduction current, and the high-conductive layer existed commonly in the crust may serve as the better paths for
the conduction current circuit and enables the far away MT measurement sites to receive it.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 186–193, 1993. 相似文献
13.
The parameters of rocks in ultrahigh-presure state are very important to understanding the geodynamics and explosion engineering
of rocks. In these experiments the plane wave dynamite lenses were used to drive the flying plates. The flying plate hits
the target and produces the ultrahigh-pressure shock wave. The propagation velocity and the particle velocity of shock wave
in rock samples were measured by probes, and the relation between density of rocks and pressure was obtained by Rankine-Hugoniot
formulas. The maximum pressure in experiments was higher than 70 GPa. The ultrahigh-pressure state formulas obtained are:
Limestoneρ=3.22+0.016p; Graniteρ=3.20+0.024p. In which the unit for ρ is g/cm3, the unit forp is GPa.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 96–103, 1991. 相似文献
14.
Based on wave equation a fundamental formula for plane wave propagaton is derived, the theoretical method of inverting wave
volocity structure of earth interior through the observational wave field is discussed in this paper. The observational wave
field can be decomposed into the surface plane wave field by using τ −p transform. The maximum amplitude curve in the plane wave field can show stably the change tendency of wave velocity with
depth in the Earth. This property can be used to restrict the solution space. By using the wave field continuation method
more useful information from the observational wave field can be extracted and the inverion solution not only can be obtained
simply and quickly, but also is stable and less influenced by the subjective factor. The wave field continuation is a fine
inversion method.
Theoretical analysis and numerical modelling are carried out in the study of wave field continuation. By applying homomorphic
decovolution the signal — to — noese ratio is improved.
Finaly a sonar refraction profile in the northern part of the South China Sea is interpreted and computed. It is found as
a result that there is a velocity interface from 1.76 km/s to 2.21 km/s at the depth of 1.4 km. The velocity gradients in
the upper and lower layers are 0.54 km · s−1/km and 0.63 km · s−1/km respectively. A discussion of the characteristics of shallow sea structure in the view of tectonic movements is geven.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13. 41–52, 1991. 相似文献
15.
Using observational data of geomagnetic total intensity from 13 stations in the Beijing-Tianjin region, 3 stations in the
western Yunnan region of China, and 6 stations in California of U. S. A., the daily variations and their spectra of geomagnetic
total intensity were analyzed and compared. The results show that the morphology, the range and spectrum of daily variations
in geomagnetic total intensity are basically the same within the local extent of 100–200 km and are different in the large
extent of 500 km. The latitude factor of the daily variation range of geomagnetic total intensity is about 1–2 nT/degree within
the latitude extent of 25°–40°.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 83–89, 1992.
This work is supported by the State Seismological Bureau and the Chinese Joint Seismological Science Foundation, and U.S.
Geological Survey. 相似文献
16.
Under normal temperature, the creep experiments with complete samples of Gabbro and Marble rocks are made under uniaxial compression.
It is found that at the instantaneous creeping stage, AE activities increase with loading; at the steady creeping stage, large
AE signals may appear at lower background of AE action, andm—value which shows the relationship between AE amplitude and frequency keeps stable on the low value or decreases; at the
accelerate creeping stage, AE activities increase andm—value decreases quickly or decreases again after recovery. These experimental results are related to the quality of the samples.
In this paper, AE activities during three stages of creeping process are connected with the seismic patterns (for exampleb—value, foreshocks). Finally, it is pointed out the possibility that the foreshock—mainshock—aftershock earthquake sequence
has been formed by the mechanism of creep fracture of crustal rocks.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 104–112, 1991.
This subject is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
17.
Based on Generalized Seismic Ray Theory (Helmberger, 1968), a new quickly linear inversion method from the data of seismic
waveform to seismic moment tensor and source mechanism for domestic earthquake is studied in this paper. Six moderately strong
earthquakes which occurred in Chinese mainland in the past few years are studied. The seismic source parameters of these earthquakes,
seismic moment tensors, scalar seismic moments, fault plane solutions and source time functionsetc, are obtained.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 261–268, 1993. 相似文献
18.
The Earth＇s free core nutation （FCN） is a retrograde eigenrnode which is attributed to the interaction between the solid mantle and the liquid core of the rotational elliptical Earth. This mode appears as an eigenmode of nearly diurnal free wobble （NDFW） in a terrestrial reference frame with a period of about one day （XU et al, 2001）. Therefore, the NDFW will lead to an obvious resonance enhancement in the diurnal tidal gravity observations, especially those of the tidal waves with frequencies closed to its eigenfrequency such as P1, K1, ψ1 and Ф1. The FCN resonance parameters can be retrieved accurately by high-precision tidal gravity observations, especially those recorded with the superconducting gravimeters （SG）. The Global Geodynamics Project （GGP） organized by IUGG took it as an important content for determining the FCN resonance parameters by using gravity data. However, the results are affected by many factors such as station location, background noise, the selection of the tide-generating potential tables, ocean tide models, data processing techniques and so on. In our study, the FCN parameters will be retrieved by using the SG observations at Wuhan, and the effects of the choices of various tide-generating potential tables, oceanic models and weight functions on the estimation of the FCN parameters will be discussed in detail, 相似文献
19.
In this paper, we attempt to use satellite gravity data and a new inversion method to study the lateral density anomaly distribution
in the mantle.
First, density difference Δρ(τ,θ,φ) is expanded in terms of a three—dimensional orthogonal function system, the coefficients of the expansion are to be determined.
Then, a set of observation equations is established from the relationship between density anomaly and disturbing geopotential.
In the equations the unknown vector contains the coefficients of density anomaly expansion, the observational vector is obtained
by computing geopotential perturbations using the potential coefficients of GEM10B, and a filtering process is done for the
observational values by properly selecting the harmonic degrees of geopotentical. Finally, the lateral density variations
in the lower mantle (670 km toCM boundary) are investigated. In this case, the degrees of disturbing geopotential are selected as 2–11, the truncated degrees
of density anomaly expansion are taken asL=6 andK=4, and the damping least squares method is used to solve the observation equations.
The resulting model shows the high level of density perturbations at 670 km discontinuity and core — mantle boundary, a high
— density zone circumscribing the Pacific and a lower—density region under the center of Pacific. These features are in agreement
with the three—dimensional seismic velocity variation features by Dziewonski (1984). In the Antarctic region and some parts
of Atlantic and Indian Ocean, however, the resulting density anomalies are negatively correlated with the seismic velocity
anomalies, the cause resulting in these phenomena is preliminarily analysed in this paper.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 53–65, 1991.
The principle and method represented in this paper can also be suitable to study the lateral density anomaly distribution
in the earth’s crust and the upper mantle. 相似文献
20.
Time changes in transfer functions of short period geomagnetic variations in 28 years from 1960 through 1987 are studied,
systemically and in detail in this paper. The results indicate that: (1) It is evident that seasonal and secular changes in
the transfer functionsA at exist the Guangzhou Geomagnetic observatory. The characteristics for seasonal changes are large in summer and smaller
in winter with main cycles of 12 and 6 months. The characteristic for secular change is a descend with a rate of 0.0025 per
year. The seasonal and secular changes in transfer functionsB are not evident. (2) The direction of Parkinson vector at Guangzhou geomagnetic observatory is clearly affected by the ocean,
and is associated with coastal effect. (3) The values of the transfer function A and B are related to geomagnetic activity
ata=0.05. Secular change is not related to geomagnetic activity, maybe it is affected in a great measure by earth conductivity
change.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica sinica,13, 480–488, 1991.
This study is part supported by Chinese Joint Seismological Science Fundation. 相似文献