首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
This paper mainly observed and analyzed the character of shear-wave splitting in rock specimens while they were in the critical state of rupture. The rock specimens for study are made of Laizhou marble from Shandong, China. A series of records were obtained from two rock specimens when they were in the critical state of rupture. The result shows that, in the critical state just before rock rupture, there may be the phenomenon of rise and fall in the time delay of shear-wave splitting, even though the load was kept constant. That is to say, the time delay of shear-wave splitting may have a falling process before rock rupture.  相似文献   

2.
The deep information of the Turfan sag was extracted and analyzed through the re-processing of the magneto-gravitational data of the Turfan sag in the Turfan-Hami basin. It is considered that the basement faults have played an important role in the controlling of the framework, lithology and the distribution of volcanic rocks in the basement of the Turfan sag. The deep crystalline basement and the upper Hercynian folded basement were studied part by part in the sag through the combined data of aeromagnetic and electric methods. It is revealed that the Huoyanshan fault is steep in the upper and lower parts but gentle in the middle, displaying a “S” type texture, and discovered that there are at least a row of local structures in the down-thrown block of the Huoyanshan fault, through the CEMP prospecting in Huoyanshan. The result is very important for the studying of the Turfan sag as a whole.  相似文献   

3.
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   

4.
The variation of Load/Unload Response Ratio (LURR) against time for earthquakes in Kerman Province, Iran, on February 22, 2005, M6.4 and in Lorestan Province, Iran, on March 31, 2006, M6.1, has been calculated and analysed in this paper. The tempo-spatial scanning of LURR in the region of Iran during January 1, 2003 to March 31, 2006 has been conducted, with 1 year as a time-window, 1 month as a time-step, and the comparison of the LURR anomalous regions in 2004 with the actual earthquakes with M≥5.0 in the next year (2005) is also given, which shows that 11 earthquakes with M≥5.0 occurred in LURR anomalous regions while 12 earthquakes with M≥5.0 in LURR regions in 2005. Furthermore, the seismicity in this region is studied by investigating the evolvement of the anomalous LURR regions.  相似文献   

5.
The depth of Moho in the mainland of China   总被引:1,自引:0,他引:1  
ThedepthofMohointhemainlandofChinaRong-ShengZENG;(曾融生)Wei-GuoSUN;(孙为国)Tong-EnMAO(毛桐恩)ZhongYangLIN;(林中洋)Hong-XiangHU;(胡鸿翔)andG...  相似文献   

6.
The modeling results are presented on the annual dynamics of seismicity in the northeastern segment of the Amur plate, which are obtained from statistical studies of the number of earthquakes with magnitudes 2 ≤ М ≤ 6 in different phases of variations in the Earth’s rotation rate. We have calculated a degree of relationship between the observed seismicity variations and phases of decrease and increase in the Earth’s rotation rate for the magnitude ranges between 2 ≤ М < 4 and 4 ≤ М < 5 using rank correlation methods. It has been established that epicenters of earthquakes with magnitudes 5 ≤ М ≤ 6 are spatially grouped into a sequence of homogeneous equally spaced, 3.5°–4°, on average, east-westerly oriented clusters.  相似文献   

7.
A total of 48 earthquakes with M_s ≥5.0 occurred in China in 1994 (29 on the Chinese mainland and offshore, 19 in Taiwan). Among them 9 earthquakes were of M_s ≥6.0 (4 on the mainland and offshore, 5 in Taiwan). The M_s 7.3 earthquake that occurred in Taiwan Straits on September 16 was the greatest one offshore, which was generally included in the mainland area according to the previous statistics. The most powerful earthquakes in Taiwan were the 2 with M_s =7.0 that occurred on May  相似文献   

8.
AttenuationofstresswaveinsandstoneDao-YingXI;Yong-LaiZHENGandTaoZHANG(席道瑛,郑永来,张涛)(DepartmentofEarthandSpaceSciences,Universit...  相似文献   

9.
I. SURVEY OF GLOBAL SEISMICITY IN 1998 A total of 17 earthquakes with M_s≥7.0 occurred in the world in 1998 according to the determination by the Chinese Seismic Station Network. The strongest earthquake occurred in Sulawesi, Indonesia (M_s7.8, November 5, 1998). The next strongest earthquake was the South Pacific Ocean earthquake (M_s7.7, March 25, 1998) and the Ryukyu earthquake (M_s7.7, May 4) (Fig. 1).  相似文献   

10.
Application of WebGIS in seismological study   总被引:1,自引:0,他引:1  
Introduction Earthquake is a destructive natural disaster. Earthquake studies are very complex, which not only involves space and time of large size, but also requires vast amount of spatially referenced data, such as historical records, modern instrument data, scientific experiment data and a lot of other data coming from related subjects. GIS, as an integrating tool processing multi-source data, has become a key technology in earthquake studies. In recent years, many GIS application system…  相似文献   

11.
1 SURVEYOFGLOBESEISMICITYIN 2 0 0 4Atotalof 1 9strongearthquakeswithMS≥ 7 0occurredintheworldaccordingtotheChineseSeismicStationNetworkin 2 0 0 4 (Table 1 ) .ThestrongestearthquakewastheSumatraearthquakewithMS8 7nearthenorthwestcoastofSumatraonDecember 2…  相似文献   

12.
1. SURVEY OF SEISMICITY IN CHINA IN 1995 A total of 48 earthquakes with M_s≥5.0 occurred in China in 1995 (30 on the Chinese mainland and offshore, 1 in the South China Sea, and 17 in Taiwan) (Fig. 1). Among these, 8 earthquakes were  相似文献   

13.
Ⅰ. SURVEY OF THE GLOBAL SEISMICITY A total of 28 earthquakes of M_s ≥7.0 occurred over the entire world in 1996 according to the determination by the Chinese Seismic Station Network. The strongest one is the Irian earthquake (M_s 7.9, February 17, 1996, Indonesia) (Fig. 1). It is considered that the global seismicity in 1996 is still situated in the active period based on the comprehensive analysis of its frequency, magnitude, and range.  相似文献   

14.
For showing the epicentral distribution in and near China as well as all over the world, twoepicentral maps for the earthquakes occurred last year are published annually in the 6-th issue eachyear. Figures 1 and 2 represent the epicentral distributions in and near China and all over the worldin 2003, respectively.Maps of epicentral distribution in 2003@陈培善$Institute of Geophysics, China Earthquake Administration, Beijing 100081, China…  相似文献   

15.
Summary A review is given of the present (1959) seismological stations in Sweden, i.e. Uppsala, Kiruna, Skalstugan, and Göteborg, as well as of older stations, which are no longer in operation, i.e. Vassijaure, Abisko, and Lund, including all pertinent information. The disturbing effect of the loose ground at Lund in distinction from the four first-mentioned stations is clearly demonstrated. The very good ground at Uppsala, Kiruna, Skalstugan, and Göteborg, together with the use of modern equipment of high magnification has made these stations, especially Uppsala and Kiruna, very sensitive. This is obvious from the number of recorded earthquakes. The method of time measurements, including direct recording of time signals, is described, and means to reach a high time accuracy are outlined, including the recommendation to use quartz clocks. Long-period (0.5–2 min) disturbances on the long-period Benioff combinations were mainly due to air currents in the seismometer room and were eliminated by providing the seismometers with special covers. The method of ground amplitude determinations is outlined, especially for the Benioff instruments, and typical magnification curves are given. Comparisons of ground amplitudes from simultaneous records of BenioffE, N and WiechertE, N and of BenioffZ and GrenetZ have been made. The amplitude comparison between Benioff and Wiechert has given a new estimate of the effect of friction (especially of the recording pen against the paper) in the Wiechert apparatus.
Zusammenfassung Eine Übersicht sowohl von den gegenwärtigen (1959) seismologischen Stationen in Schweden, d.h. Uppsala, Kiruna, Skalstugan und Göteborg, als auch von früheren Stationen, die nicht mehr im Betrieb sind, d.h. Vassijaure, Abisko und Lund, wird gegeben. Die störende Wirkung des lockeren Bodens in Lund zum Unterschied gegen die vier erstgenannten Stationen wird deutlich hervorgehoben. Der sehr gute Untergrund in Uppsala, Kiruna, Skalstugan und Göteborg und die Verwendung moderner Apparate hoher Vergrösserung haben diese Stationen, besonders Uppsala und Kiruna, sehr empfindlich gemacht. Dieser Umstand geht aus der Anzahl registrierter Beben hervor. Die Methode der Zeitmessungen (direkte Registrierung der Zeitsignale einbegriffen) wird beschrieben, und Massnahmen eine hohe Zeitgenauigkeit zu erreichen werden erwähnt, die auch die Verwendung von Quarz-Uhren umfassen. Langperiodische Störungen (Perioden 0.5–2 Min) auf den langperiodischen Benioff-Registrierungen waren hauptsächlich durch Luftströmungen im Seismometerraum verursacht und wurden durch spezielle Kappen über den Seismometern eliminiert. Die Methode der Bestimmung von Boden-Amplituden wird beschrieben, hauptsächlich für die Benioff-Instrumente, und typische Vergrösserungskurven sind gegeben. Vergleichungen der Bodenamplituden von parallelen Registrierungen von BenioffE, N und WiechertE, N und von BenioffZ und GrenetZ sind ausgeführt worden. Die Amplitudenvergleichung zwischen Benioff und Wiechert hat eine neue Schätzung des Einflusses der Reibung (speziell vom Schreibfeder gegen das Papier) im Wiechert-Seismographen gegeben.
  相似文献   

16.
Ⅰ. SURVEY OF GLOBAL SEISMICITY A total of 23 earthquakes with M_s ≥ 7.0 occurred over the world in 1997 according to the determination of the Chinese Seismic Station Network. The strongest one was the Kamchatka peninsula earthquake (M_s 7.9, December 5, 1997) (Fig. 1). Although the frequency and strength of global seismicity was lower compared with the higher activity state in 1995 and 1996, the frequency of seismicity was still obviously higher than the average level during this century.  相似文献   

17.
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   

18.
Mapsofepicentredistributionin1993¥//FortheconvenienceofknowingthedistributionofepicentersinandnearChinaaswellasallovertheworl...  相似文献   

19.
1 SURVEY OF GLOBAL SEISMICITY IN 2006A total of 15 strong earthquakes with M_S≥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 M_S8.0 on March 29 and the Kuril Islands earthquake with M_S8.0 on November 15 (Fig.1).  相似文献   

20.
We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy covariance technique was lower than chamber estimates by 19.8%.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号