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1.
Li Gang 《中国地震研究》2007,21(1):110-120
1 SURVEY OF GLOBAL SEISMICITY IN 2006 A total of 15 strong earthquakes with Ms ≥ 7.0 occurred in the world according to the Chinese Seismic Station Network in 2006 (Table 1 ). The strongest earthquakes were the Kamchatka earthquake with Ms8.0 on March 29 and the Kuril Islands earthquake with Ms8.0 on November 15 (Fig. 1). The frequency was slightly lower, and the energy release of earthquakes reduced in 2006 compared with the seismicity in 2005. The seismicity last year had the following characteristics:  相似文献   

2.
A total of 16 strong earthquakes with Ms≥7.0 occurred in the world in 2002 according to the determination of the Chinese Seismic Station Network (Table 1 ). The two strongest earthquakes were Sumatra earthquake (Ms7.8, November 2) and Alaska earthquake ( Ms 7.8 November 4) . Fig. 1 is the distribution of strong earthquakes that occurred in 2002. The global seismicity pattern in 2002 was similar to the ones since 1999. The frequency and strength apparently decreased in 2002 compared with the seismicity in 2001.  相似文献   

3.
In 2003, a total of 20 strong earthquakes with Ms7.0 occurred in the world as determined by the Chinese Seismic Station Network (Table 1). The strongest one was the Hokkaido earthquake with Ms=8.0 on September 26 (Fig. 1). When compared with 2002, the frequency and energy release of earthquakes in 2003 increased obviously. The characteristics of activity of global earthquakes with Ms7.0 will be discussed here.  相似文献   

4.
1 SURVEY OF GLOBE SEISMICITY IN 2007
A total of 22 strong earthquakes with Ms ≥ 7.0 occurred in the world according to the Chinese Seismic Station Network in 2007 (Table 1 ).  相似文献   

5.
In 1997 - 2003, 27 earthquakes with M≥ 5.0 occurred in the Jiashi-Bachu area of Xinjiang. It was a rare strong earthquake swarm activity. The earthquake swarm has three time segments of activity with different magnitudes in the years 1997, 1998 and 2003. In different time segments, the seismic activity showed strengthenin-qguiet changes in various degrees before earthquakes with M ≥ 5.0. In order to delimitate effectively the precursory meaning of the clustering (strengthening) quiet change in sequence and to seek the time criterion for impending prediction, the nonlinear characteristics of seismic activity have been used to analyze the time structure characteristics of the earthquake swarm sequence, and further to forecast the development tendency of earthquake sequences in the future. Using the sequence catalogue recorded by the Kashi Station, and taking the earthquakes with Ms≥ 5.0 in the sequence as the starting point and the next earthquake with Ms = 5.0 as the end, statistical analysis has been performed on the time structure relations of the earthquake sequence in different stages. The main results are as follows: (1) Before the major earthquakes with M ≥ 5.0 in the swarm sequence, the time variation coefficient (δ-value) has abnormal demonstrations to different degrees. (2) Within 10 days after δ= 1, occurrence of earthquakes with M ≥ 5.0 in the swarm is very possible. (3) The time variation coefficient has three types of change. (4) The change process before earthquakes with M5.0 is similar to that before earthquakes with M6.0, with little difference in the threshold value. In the earthquake swarm sequence, it is difficult to delimitate accurately the attribute of the current sequences (foreshock or aftershock sequence) and to judge the magnitude of the follow-up earthquake by δ-value. We can only make the judgment that earthquakes with M5.0 are likely to occur in the sequence. (5) The critical clustering characteristics of the sequence are hierarchical. Onl  相似文献   

6.
The active and quiet phenomenon of moderate strong earthquakes one year before the earthquakes with Ms ≥ 7.0, the spatial distribution characteristics of the solid tide modulating and triggering earthquakes and the strong earthquake mechanisms on the Chinese continent have been studied. The secondary arcuate tectonic zone composed of the west Kunlun-A‘nye^maqe^n faults is believed to be a very important boundary to characterize strong earthquake activity of Ms ≥ 7.0 on the Chinese continent, that is, a boundary between the seismically active region and the quiet region of moderately strong earthquakes one year before earthquakes with Ms ≥ 7.0, and a boundary of the spatial distributions between the solid tidemodulating strong earthquakes ( Ms ≥ 7.0) and the non-modulating ones. It might be related with the characteristics of spatial distribution of focal mechanism solutions of strong earthquakes on the Chinese Continent.  相似文献   

7.
1. A SURVEY OF THE GLOBAL SEISMICITYAccording to the recording of the seismic network of China, 20 large earthquakes with Ms ≥7.0 occurred in 2000 (Table 1 ), the maximum magnitude of which is 7.8, they are: three Ms = 7.8 earthquakes on June 5 in the south of the Sumatra Island, Indonesia, on June 18 in India Ocean and on November 16 in Solomon Islands (Fig. 1).   ……  相似文献   

8.
Group Strong Earthquakes and Triggering by Tidal Stress   总被引:4,自引:1,他引:4  
The results obtained using the group model of earthquakes generated in tectonic blocks are fur ther used in this paper to analyze the relationship between the Ms ≥ 7.0 events in Chinese ma inland and the modulation and triggering from the earth tides. The research shows that the Ms 7.0 events in Chinese mainland have been significantly triggered by the tidal stress, especially within the active period with group strong earthquakes. In the quiescence period of strong earthquakes, no Ms7.0 events were triggered, while within the active period, over 82.4% of strong earthquakes took place within a special moon phase, which is 36.4 % higher than the average. Therefore, the modulation and triggering of tidal stress can be used to distinguish the active periods and to forecast the time of the strong earthquakes within the active period. The relationship between the tidal triggering and the tectonic dynamic condition is investigated and the mechanism of the modulation is simulated with the group model of earthquakes generated in tectonic blocks.  相似文献   

9.
1. A SURVEY OF THE GLOBAL SEISMICITYAccording to the recording of the seismic network of China, 20 large earthquakes with Ms ≥7.0 occurred in 2000 (Table 1 ), the maximum magnitude of which is 7.8, they are: three Ms = 7.8 earthquakes on June 5 in the south of the Sumatra Island, Indonesia, on June 18 in India Ocean and on November 16 in Solomon Islands (Fig. 1).   ……  相似文献   

10.
In this paper,the time-space features of Ms≥6.0 strong earthquakes that have occurred on the Chinese mainland since the beginning of this century were analyzed; the effect of Ms≥7.0 large shocks in mitigating Ms≥6.0 strong earthquakes subsequent to them vas studied both temporally and spatially; and the accumulative probabilities for the occurrence of Ms≥6.0 strong earthquakes subsequent to Ms≥7.0 large shocks were calculated.The results seem to imply that the effect of Ms≥7.0 large shocks in mitigating subsequent strong events is relatively obvious within certain time-space ranges.This is because the strain energy accumulated over a long time in the region around the source has been mostly released through the fracture produced by the large shock,the possibility for another large fracture to occur again in the same region within a certain period of time has been greatly reduced and therefore the probability for subsequent strong earthquakes to occur in that region is very low.These results can be  相似文献   

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