天山地区地震韵律的初步探讨     

杨章 《内陆地震》1990,4(2):126-133

根据新疆及苏联天山地区的地震目录和古地震研究成果,将整个天山地区的地震韵律划分为地震世、地震亚世、地震期、地震幕、地震阶五级,探讨了各级韵律的特征。估计了我国天山地区未来地震活动趋势。  相似文献   

Long- and middle-term behaviour of the tilt and strain variations in the decade following the 1976 friuli earthquake in NE Italy     

W. J. Mao  P. Santero  M. Zadro 《Pure and Applied Geophysics》1990,132(4):653-677

Tilt and strainmeter data collected in the Friuli seismic area between 1977 and 1985 have been analyzed to study the stress-strain field and/or the elastic parameter variations in the area after the strong 1976 seismic event.We concentrated on three different frequency bands, respectively linked with the tidal waves, the seasonal effect and the secular one. The results from the first two bands point at an increase of the local rigidity modulus.Relevant stresses induced by the seasonal groundwater level variations have been found, thus supporting the hypothesis that they can act as triggering effects. The secular trend reveals significant tectonic stress modifications. It appears that the post-seismic tectonic stresses faded during 1981–1983, and were followed by a new loading phase.On leave from the Institute of Geodesy and Geophysics of the Chinese Academy of Sciences. Ph. D. student at the Institute of Geodesy and Geophysics, Trieste University.  相似文献   

Intermediate and deep earthquakes in Spain     

E. Buforn  A. Udías  R. Madariaga 《Pure and Applied Geophysics》1991,136(4):375-393

Recent improvements in the seismological networks on the Ibero-Maghrebian region have permitted estimation of hypocentral location and focal mechanisms for earthquakes which occurred at South Spain, Alboran Sea and northern Morocco of deep and intermediate depth, with magnitudes between 3.5 and 4.5. Intermediate depth shocks, range from 60 to 100 km, with greater concentration located between Granada and Málaga. Fault-plane solutions of 5 intermediate shocks have been determined; they present a vertical plane in NE-SW or E-W direction. Seismic moments of about 10¹⁵ Nm and dimensions of about 1 km have been determined from digital records of Spanish stations.P-wave forms are complex. This may be explained by the crustal structure near the station, discontinuities in the upper mantle and inhomogeneities near the source. Deep activity at about 650 km has only 3 shocks since 1954 (1954, 1973, 1990). Shocks are located at a very small region. Fault-plane solutions show a consistent direction of the pressure axis dipping 45° in E direction. For the 1990 shock seismic moment is 10¹⁶ Nm and dimensions 2.6 km. TheP-waves are of simpler form with a single pulse. The intermediate and deep activities are not connected and no activity has been detected between 100 and 650 km. The intermediate shocks may be explained in terms of a recent subduction from Africa under Iberia in SE direction. The very deep activity must be related to a sunk detached block of lithospheric material still sufficiently cold and rigid to generate earthquakes.  相似文献   

山西地震带中与强震活动有关的两种滑坡     

陈国顺 《华南地震》1991,11(2):40-46

本文以滑波理论为依据，总结了山西地震带的两种不同特点的滑坡。即：振荡式滑坡及触发式滑坡。虽然两种滑坡都可分为变形、解体、滑动、毁灭等四个阶段，但其动力不同。振荡式滑波的滑动面倾角小，因而滑力来源于强震振动，而触发式滑坡的滑动面倾角大，因而滑力来自滑体本身静荷载。对两种滑坡的研究对预防及减轻强震带来的次生灾害有重要的意义。  相似文献   

Site response using coda-wave techniques: Applications to short period data from central and southern Italy     

Edoardo Del Pezzo  Marcello Martini  Giuliano Milana 《Pure and Applied Geophysics》1991,136(1):127-141

The method of coda waves was applied to two different sets of data for the evaluation of the relative site response.The first set of data consists of low magnitude earthquakes with closely spaced locations, recorded at a small aperture array of velocimeters located in the Abruzzo region, central Italy. The second set of data is composed of events with epicentral distance ranging from 20 to 300 km, recorded at a seismological network with an aperture of about 100 km located in the Puglia region, southern Italy.Results show that the coda wave method furnishes stable estimates of the site effect. An amplification, relative to an arbitrary site, of a factor of about 2 occurs in the 1.7–6 Hz frequency band for two stations of the Abruzzo network, while an amplification factor of about 0.5 occurs in the whole frequency band (1–24 Hz) for one of the stations of the Puglia network. This station is located in an area which is correlated with a low macroseismic intensity anomaly.  相似文献   

Fault－weakening　effect　of　reservoir　temperature　of　hot　spring　and　its　influence　on　seismic　activities     

林元武 《地震学报(英文版)》1994,(2)

Ｆａｕｌｔ－ｗｅａｋｅｎｉｎｇ　ｅｆｆｅｃｔ　ｏｆ　ｒｅｓｅｒｖｏｉｒ　ｔｅｍｐｅｒａｔｕｒｅ　ｏｆ　ｈｏｔ　ｓｐｒｉｎｇ　ａｎｄ　ｉｔｓ　ｉｎｆｌｕｅｎｃｅ　ｏｎ　ｓｅｉｓｍｉｃ　ａｃｔｉｖｉｔｉｅｓ（林元武）Ｆａｕｌｔ－ｗｅａｋｅｎｉｎｇｅｆｆｅ...  相似文献   

The　abnormal　mantle　and　deep　tectonic　process　in　the　southern　region　of　North　China　Plain     

高世玉  胡鸿翔  丁山 《地震学报(英文版)》1994,(Z1)

ＴｈｅａｂｎｏｒｍａｌｍａｎｔｌｅａｎｄｄｅｅｐｔｅｃｔｏｎｉｃｐｒｏｃｅｓｓｉｎｔｈｅｓｏｕｔｈｅｒｎｒｅｇｉｏｎｏｆＮｏｒｔｈＣｈｉｎａＰｌａｉｎＳｈｉ－ＹｕＧＡＯ（高世玉），Ｈｏｎｇ－ＸｉａｎｇＨＵ（胡鸿翔）ａｎｄＳｈａｎＤＩＮＧ（丁山）（Ｉｎ...  相似文献   

菏泽5.9级地震前后三项地震活动性参数的空间动态演化     

王红卫  刁守中 《华北地震科学》1994,12(1):54-61

用地震活动性参数（地震频度Ｎ，地震能量Ｅ和地震ｂ值）的二维空间等值线计算机扫描技术，系统地追踪了１９８３年菏泽５．９级地震前后三项地震活动性参数的空间动态演化情况。结果表明，菏泽５．９级地震前１－４年，河北平原断陷南部地区特别是其东界聊考断裂带地震活动异常增强，地震频度增高，地震能量释放加速而地震ｂ值降低；地震活动增强区的长度约２００余公里，未来主震发生于地震活动增强区的边缘；震后约一年左右震中周  相似文献   

金沙江地震带强震动及其与现今弱震活动关系   总被引：2，自引：0，他引：2  

廖志和 《四川地震》1994,(4):13-24

包括川滇菱块及马边－大关，宣威－弥勒地区在内的金沙江地震带记载（录）了川滇两省发生的绝大部分中、强以上地震，为我国西南一主要地震区。本文重点研究了该范围内强震的重复性及现今弱震密集区的强震危险性问题。金沙江地震带强震具有很高的原地重复性，７级以上强震原地重复率达６５．４％，平均复发时间１５７年；６级地震原地重复率达４１．８％，平均复发时间为２７．２年。川滇地区现今弱震活动密集区在活动期内本身发生６级以上强震的可能性很小。四川地区大多数情况下强震发生在距密集区４０－５０千米处，云南情况较复杂。但在作今后较长时间危险性分析预测时，现今弱震密集区本身仍有发生６级地震的危险，虽然发生７级以上地震可能性不大。  相似文献   

川滇交界中段历史强震及其活动特征     

黄圣睦 《四川地震》1994,(4):25-33

本文在详细补充调查和充分整理前人资料基础上，对川滇交界中段的其中６次强震进行了等烈度图编制，并对川滇菱块东界大地震的等烈度线分布特征进行了研究，按照构造孕育与发震扩展的思路，探讨了川滇交界中段的中长期地震危险性。  相似文献