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741.
An evaluation of the magnitude of historical earthquakes is proposed, through an empirical relation based on a felt area of historical earthquakes derived from a vectorial modelling of macroseismic intensity distribution. 相似文献
742.
A comparison of the most used magnitude-intensity relations is carried out, with reference to a spatial window coinciding with Calabria and northeastern Sicily, evaluating their consistency with different data sets taken from several catalogues. M values indicated in the catalogues and the corresponding average value have been used choosing the relation to be adopted on the basis of the level of their adaptability to points, rather than prearranged models. 相似文献
743.
Michel?CaraEmail author Wolfgang?Brüstle Monika?Gisler Philipp?K?stli Christophe?Sira Claire?Weihermüller Jér?me?Lambert 《Journal of Seismology》2005,9(3):317-328
The 2003 Ml = 5.4 Rambervillers earthquake, north-east of France, is the largest seismic event recorded north of the Alps
since the 1992 Ms = 5.3, I0 = VII, Roermond earthquake, Netherlands. With a maximum macroseismic intensity of VI-VII EMS-98, the 2003 event was broadly
felt to a distance of 300 km from the epicentre. It provides a unique opportunity to test and compare the different procedures
used in France, Germany and Switzerland when evaluating macroseismic intensities. The main purpose of this paper is to present
a common transfrontier macroseismic map based on the EMS-98 intensity scale. Maximum horizontal accelerations recorded in
the area are compared to the intensity values, and we propose to use a differential technique to re-estimate the magnitude
of the 1682 Remiremont, I0 = VIII, earthquake, which occurred 40 km south of Rambervillers. 相似文献
744.
A. A. Kiratzi G. F. Karakaisis E. E. Papadimitriou B. C. Papazachos 《Pure and Applied Geophysics》1985,123(1):27-41
A data set of nineteen, mainly shallow, moderate to large earthquakes, which occurred in the Aegean and the surrounding area, has been used to derive empirical relations for kinematic fault parameters. Thus the relations between seismic momentM
0 and magnitudeM
s andm
b and betweenM
0 andM
s and fault dimensionsS andL have been determined. From these relations and theoretical ones it was deduced that earthquakes in the Aegean and the surrounding events, chiefly interplate, are characterized by low average stress drop values. Values of ranging from 1 to 30 bar are consistent with the data. It was also found that, in general terms, most of the data obey the geometrical similarity conditionL=2w, whereL is the fault length measured along the strike andw is its width measured along the dip. For strike-slip faults, however, the conditionL=4w seems to hold. 相似文献
745.
惠州断层长约20 km,宽约5 km,产状135°—150°/NE∠65°—75°,在断层露头处可见复合断层角砾岩,这反映出该断层曾发生过多次运动.为研究该断层最新活动时代及地震危险性,得到的现今惠州断层垂直形变图显示,该区明显受区域活动构造所控制,垂直形变幅度相对较小,无明显的高速度梯度带;地壳水平运动状态测点的运动... 相似文献
746.
747.
通过计算功率谱密度来讨论上海地震台阵所测远震面波震级与美国国家地震信息中心(NEIC)震级的差别,对不同震级、不同方位和不同震中距的地震震级差别进行了比较和讨论,并给出初步结果. 相似文献
748.
Egypt is recognized as a moderate seismicity region where earthquakes are distributed within several active regions. Owing
to sparse distribution of both seismicity and seismic stations, mostly moderate-size Egyptian earthquakes were recorded by
regional stations. One of such cases is the moderate-size earthquakes of moment magnitudes greater than 4.0 which struck the
Western Desert of Egypt in 1998 and 1999. These events are the first instrumentally recorded earthquakes occurring in the
area. In the present study, the source mechanism for these earthquakes was estimated using the waveform data recorded from
one of the very broadband MedNet seismograph stations and polarities from the national short-period seismographs. An iterative
technique was applied to find the best-fit double-couple mechanism by a grid search over strike, dip and rake. Regional synthetic
seismograms were calculated by using f–k integration in the frequency range of 0.03–0.1 Hz. A crustal structure fitted to surface wave dispersion curves was used
to compute Green’s function. Focal depths were determined through the grid search method for a range of source depths. Our
results show a normal faulting mechanism with minor strike-slip component. The NNW trend has been chosen as a preferred rupture
plane in consistence with surface and subsurface faults and microearthquake seismicity in the epicenteral area as well. 相似文献
749.
750.