七. 地震预测与地震学研究

(负责人：王培德 陈顒)

Earthquake Forecast and Seismology Research

(Conveners: WANG Peide CHEN Yong)

1. THE PRIMARY STUDY OF LG CODA Q FOR THE AFTERSHOCKS

OF THE ZHANGBEI EARTHQUAKE

Yan Xiaowei Liu Jianhua

(Institute of Geophysics, Chinese Academy of Science )

Abstract

In this paper, from several Lg coda time series of aftershocks of Zhangbei principal earthquake (Ml=6.2) on January 10, 1998, which were recorded by two test digital ocean bottom seismograghs, we choose high signal-to-noise ratio records to obtain the Lg coda Q and frequency dependence h with stacked spectral ratio method. Because the two seismograghs were laid on the same seismic station (in Baijiatuan, Beijing),all the aftershocks have almost the same ray trace to get to them. The results show that all the Lg coda Q of the aftershocks are similar, furthermore, the Lg coda Q obtained by the same earthquake respectively recorded by the two seismograghs are insistent with each other. And then, the results are summarized as following : 1. SSR method is one of the good choice methods for crustal Q measurement. 2. The two seimograghs are stable and reliable.

2. The Correlation And the Implied Meaning of Seismic Activity

in Both East And West Sections of South Tianshan

Su Naiqing

(Seismological Bureau of Xinjiang Uygur Autonomous Region Urumqi 830011)

Abstract

In this paper, we use seismically active degree that can quantificationally describe seismic active strong-weak frequency to study seismic active characteristic of both east and west sections of south Tianshan in Xinjiang. We find that seismicities are close correlation between these two adjacent sections. And they move on the decline from west to east. Comparing the seismicity of west section, one of east section drops behind a year or so. By further studying them, we think, the characteristic above mentioned is agree on section stress field. Because the Indian Ocean plate presses on north, it makes that Pamirs and adjacent southwest sections become dynamical source of seismicity in south Tianshan. Meantime, basing on the correlation of seismicity, it is possible that we use seismicity of seismic active in upriver section to predict one in downriver one.

3．广义前震特征震级结构的实验研究, 李世愚, 和雪松, 王健, 滕春凯

The experimental investigation of the characteristic magnitude structure of general foreshock, Li Shiyu, He Xuesong, Wang Jian, Teng Chunkai

Abstract

The method based on the characteristic magnitude structure of direct and general foreshock is tested experimentally. This method is one of the tens of methods that were used to distinguish the foreshock with the others from the groups of concentrated moderate and weak earthquakes. According to Wang Jian(1999), this method is to analyze the contour line of V_j,m,t, (r_m≤D_i≤R_m), where V is the density value of earthquake events, j is the serial number of node points, m is magnitude, t is time interval，D_i is the distance between the source of i^th earthquake event to the j^th node point. Wang Jian (1999) analyzed the seismicity of Huabei area in recent 30 years by using the image of contour line of V_j,m,t. We processed the AE data of large scale rock sample rupture in 1993 in Moscow by using the similar method suggested by Wang Jian(1999). The results show the concentration of foreshock and general foreshock of AE events before local or main rupture of the rock sample. The images of evolution of different magnitude of AE are different. The events of 1.0<M<2.0 (here the level M is the same as earthquake) relatively disperse, and departure from the source of the future main rupture. While the events of 2.0<M<3.0 is relatively concentrated, and near to the source of the future main rupture. The series of AE shows disperse-quiet before local and main rupture, but the frequency of 2.0<M<3.0 events increasing abruptly in the stage of critical of rupture. This level of magnitude of AE event is called characteristic magnitude. One can see that the behavior of characteristic magnitude events is similar to that in natural earthquakes in Huabei area(Wang Jian，1999).

4．Y形雁列式块体交界处多点大破裂的模拟实验研究

许昭永¹⁾ 熊秉衡²⁾ 杨润海¹⁾ 赵晋明¹⁾ 王正荣²⁾ 张永安²⁾

补英摘

5. 强地震震源动力学过程研究

郑文卿(甘肃省地震局，兰州，730000),陈　瑶

Study On The Earthquake Source Dynamics Of Strong Events

Zheng wenqing Chen yao

Study On The Earthquake Source Dynamics Of Strong Events

Zheng wenqing Chen yao

(Seismological Bureau Of Gansu Provime, Lanzhou 730000)

The study on the earthquake source dynamics, which largely influence themethods and results of earthquake prediction, is atlached to much importance. In this article, with the basis of multiple stress concentration theory, underthe necessary and enough ynamical and thermodynamical conditions ofonearthquake occurrence as well as observations, the earthquake source dynamicalprocess and stage propenty are systematically invastigated. And throughearthquake predition practice, the reliability and fensibicity of our methodsare fested. The aim of this study is trying to explone new path for earthquakeprediction.