全球大震和中国及邻区中强震地震活动(2008年7—8月)

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

2008年地震震中分布图

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动（2008年11月-2009年2月）

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动 （2008年9-10月）

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动（2002年4-5月）a

本目录中的地震参数来自"中国地震台临时报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震局地球物理研究所九室按月做出.     

全球大震和中国及邻区中强震地震活动(2010年3—4月)

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报"). 其中, 国内及邻区给出M≥4.7的事件, 全球给出M≥6的事件. "月报"由中国地震台网中心按月做出. 本目录中的发震时刻采用协调世界时(UTC); 为了方便中国读者, 也给出北京时(BTC). 震中位置除给出经纬度外, 还给出参考地区名, 它仅用作查阅参考, 不包含任何政治意义; 还给出测定震源位置的台数(n)和标准偏差(SD).     

全球大震和中国及邻区中强震地震活动(2005年10-11月)

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动（2006年12-2007年1月）.

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动 (2007年4-5月)

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件."月报"由中国地震台网中心按月做出.     

全球大震和中国及邻区中强震地震活动(2006年10-11月)

本目录中的地震参数来自"中国地震台站观测报告"(简称"月报").其中,国内及邻区给出M≥4.7的事件,全球给出M≥6的事件,"月报"由中国地震台网中心按月做出.     

Volcanic activity and large earthquakes

Several investigators have noted an increase in volcanic activity prior to several large interplate earthquakes in the circum-Pacific area. From these data, I have examined the temporal relationship between the beginning of this increased volcanic activity and the occurrence of large earthquakes. I find that the time (year) of the beginning of enhanced volcanic activity depends on the magnitude of the subsequent large earthquake, for earthquakes with magnitude > 7.5. The volcanoes which exhibit this enhanced activity are situated on the landward side of the rupture zone of the large earthquake, and this study therefore suggests a casual physical relationship between the two phenomena. I also find that this increase in volcanic activity occurs a few years before an increase in the occurrence of smaller earthquakes, noted by several invesigators, in the rupture zones of large earthquakes.     

The ionosphere and solar activity

Summary The correlation between monthly median critical frequencies and solar activity was determined for Washington, D.C. Results were compared with those from a similar study made for six Arctic stations. For noon data (E, F1 andF2 layers), a greater value off _c (at zero sunspot number) and a slightly greater slope were obtained for Washington than for the Arctic locations. The influence of increased solar activity on the behavior of the midnight ionosphere is discussed.     

Solar dynamo and geomagnetic activity

The correlation between geomagnetic activity and the sunspot number in the 11-year solar cycle exhibits long-term variations due to the varying time lag between the sunspot-related and non-sunspot related geomagnetic activity, and the varying relative amplitude of the respective geomagnetic activity peaks. As the sunspot-related and non-sunspot related geomagnetic activity peaks are caused by different solar agents, related to the solar toroidal and poloidal fields, respectively, we use their variations to derive the parameters of the solar dynamo transforming the poloidal field into toroidal field and back. We find that in the last 12 cycles the solar surface meridional circulation varied between 5 and 20 m/s (averaged over latitude and over the sunspot cycle), the deep circulation varied between 2.5 and 5.5 m/s, and the diffusivity in the whole of the convection zone was ～10⁸ m²/s. In the last 12 cycles solar dynamo has been operating in moderately diffusion dominated regime in the bulk of the convection zone. This means that a part of the poloidal field generated at the surface is advected by the meridional circulation all the way to the poles, down to the tachocline and equatorward to sunspot latitudes, while another part is diffused directly to the tachocline at midlatitudes, “short-circuiting” the meridional circulation. The sunspot maximum is the superposition of the two surges of toroidal field generated by these two parts of the poloidal field, which is the explanation of the double peaks and the Gnevyshev gap in sunspot maximum. Near the tachocline, dynamo has been operating in diffusion dominated regime in which diffusion is more important than advection, so with increasing speed of the deep circulation the time for diffusive decay of the poloidal field decreases, and more toroidal field is generated leading to a higher sunspot maximum. During the Maunder minimum the dynamo was operating in advection dominated regime near the tachocline, with the transition from diffusion dominated to advection dominated regime caused by a sharp drop in the surface meridional circulation which is in general the most important factor modulating the amplitude of the sunspot cycle.     

Solar activity and geomagnetic disturbances

An analysis of IZNIRAN magnetic observatory data indicated that geomagnetic storms with sudden and gradual commencements form two independent populations with respect to the disturbance occurrence time and character because the solar sources of these disturbances are different. Storms with sudden and gradual commencements are caused by coronal mass ejections and high-speed solar wind streams from coronal holes, respectively.     

高要断裂的特征及其活动性

高要断裂是一条呈北东向延伸的由多条断裂组成的大断裂,具有多期活动特征,根据不同的活动特征又可将该断裂分为３段。经野外地震地质调查,并在断层面和钻孔的角砾岩岩芯中共取了５个样品作热释光测年,测定断层活动年龄距今均大于１４万ａ,证明断层最后一期活动为中更新世断层年代,可视为非活动断层。     

Seismotectonics and earthquake activity of Kuwait

On March 1997, earthquake monitoring was started inKuwait through the operation of the Kuwait NationalSeismograph Network (KNSN). On Sept. 18, 1997, anearthquake of magnitude 3.9 occurred in the Minagisharea (southwest of Kuwait); it was felt in Kuwait City50 km away from the epicenter which was accuratelylocated using the data of KNSN. Also, some eventswere located in Minagish area and along the westernborders of the State of Kuwait. The same area ofMinagish was shocked on June 2, 1993 with a 4.7magnitude earthquake; it was also felt in Kuwait City. The spatial distribution of the Minagish areaearthquake may show a trend of NE-SW direction. Theisoseismals of the Sept. 18, 1997 earthquake aregenerally elliptical in shape with the major axisoriented NE-SW. The geologic sections and tectonichistory of Kuwait show seismotectonic deformationsince late Eocene time. This activity is related tothe interaction of the Arabian platform and the Zagrosfolded belt. A major break in the sedimentarysuccession which occurred in Kuwait during Eocene andOligocene times indicates that nascent folding anduplift have persisted since that time. The formationof the major topographical feature in Kuwait(Jal-Az-Zor escarpment, Wadi Al-Batin and AhmadiRidge) can be attributed to tectonic activity since Eocene time.The spatial distribution of the recent earthquakeactivity in Kuwait is associated with the surface andsubsurface tectonic structures. The moderate sizeearthquake activity of the State of Kuwait can beconsidered as evidence of recent rejuvenation of thetectonic structures which have been active since Eocene time.     

Connections between whistlers and pulsation activity

Simultaneous whistler records of one station and geomagnetic pulsation (Pc3) records at three stations were compared. In a previous study correlation was found between occurrence and L value of propagation/excitation for the two phenomena. The recently investigated simultaneous records have shown that the correlation is better on longer time scales (days) than on shorter ones (minutes), but the L values of the propagation of whistlers/excitation of pulsations are correlated, i.e. if whistlers propagate in higher latitude ducts, pulsations have periods longer than in the case when whistlers propagate in lower latitude ducts.     

Stress,strain and earthquake activity

There are 13 papers in this special issue on stress field,crustal deformation and seismicity.The great Wenchuan earthquake is a grievous disaster,but Chinese scientists are trying to learn more from the event in order to understand better the physics of earthquakes for