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通过对华北地区 1 6次中强地震的地震活动演化指数YH值异常特征的归类分析 ,认为YH值的变化特征能较好地综合反映中强地震孕震阶段地震活动时空强的演化规律 ,可以应用于中强地震发震时间的中短期预测 相似文献
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主成分分析法在地震预测中的应用研究 总被引：10，自引：0，他引：10
用1979年7月9日江苏溧阳6．0级地震前后震中附近地区的地震资料，选择与地震活动强度有关的3级以上地震的频次N、b值、η值、A（b）值、Mf值和Ac值等6个参量进行主成分分析，实现对上述参量的有效约减。这6个参量之间具有一定的相关性，各参量在不同时段的变化各有所异，预报效果并不理想。但是根据主成分分析可以得到反应地震强度异常特征的综合指标形，发现该指标在2次溧阳地震前出现明显的异常变化，震后异常恢复。表明综合指标形可以较好地反映地震活动异常增强的特征。文章还对与主成分分析所得结论的有关问题进行了讨论。 相似文献
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采用多因子分析的主成分分析法,选择与地震活动强度有关的地震频次N(ML≥3.0)、b值、η值、Mf值、A(b)值和Ac值等6个参量进行分析,实现对上述参量的有效约简,得到反映地震强度特征的综合指标W.发现指标W在辽宁海城7.3级、岫岩5.4级地震前出现明显的异常变化,震后恢复.表明综合指标W可以较好的反映地震活动的异常特征. 相似文献
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利用主成分分析法研究东北地震活动异常 总被引：5，自引：1，他引：4
选择与地震强度有关的地震频次N(ML≥3.0)、b值、η值、Mf值、A(b)值和AC值共6个参量进行主成分分析,实现对上述参量的有效约简。这6个参量之间有一定的相关性,在不同时段各参量的变化各有所异。根据主成分分析可以得到反应地震强度特征的综合指标W。1970年以来东北14次5级以上浅源地震前W都出现明显的异常变化,震后恢复。这表明综合指标W可以较好地反映地震活动的异常特征。 相似文献
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主成分分析法在林甸Ms5．1地震回顾性预测中的应用 总被引：3，自引：1，他引：2
用2005年林甸Ms5．1级地震前后震中附近的地震资料,选择与地震强度有关的3级以上地震频次N、b值、Mf值、C值、和Ac值等6个参量进行主成分分析,实现对上述参量的有效约简。这6个参量之间有一定的相关性,各参量在不同时段的变化各有所异,预报效果并不理想。但是根据主成分分析可以得到反映地震强度的综合指标W,发现该指标在震源区附近出现明显的异常变化,震后异常恢复。表明综合指标W可以较好的反映地震活动的异常特征。 相似文献
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使用因子分析方法研究吉林前郭地震前的地震活动异常 总被引：1，自引：1，他引：0
本文用2006年吉林前郭MS5.0级地震前后震中附近的地震资料,选择反映地震活动时、空、强特征的地震频次N（ML≥3.0）、b值、η值、A（b）值、Mf值、Ac值、C值和D值8个参量进行因子分析。这些参量之间有一定的相关性,各参量在不同时段的变化各有所异,预报效果并不理想。根据因子分析得到反映地震活动时、空、强特征的综合指标Wfa值,该指标在前郭MS5.0级地震前出现明显异常变化,表明综合指标Wfa值可以较好地反映地震活动的异常特征。 相似文献
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选择从不同侧面反映地震活动时、空、强特征的地震频次N(MLge;3.0)、b值、eta;值、A(b)值、Mf值、Ac值、C值和D值8个参量进行主成分分析. 通过主成分分析方法可以得到反映地震活动时、空、强异常特征的综合指标W. 通常这8个参量之间具有一定的相关性,各参量在不同时段的变化各有所异,预报效果并不理想. 但是综合指标W在华北13次5.8级以上地震前出现明显的异常变化. 表明综合指标W可以较好地反映地震活动时、空、强异常特征. 本文还对主成分分析所得结论的有关问题进行了讨论. 相似文献
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主成分分析法在汶川地震预测中的应用 总被引：4，自引：0，他引：4
选择与地震强度有关的3级以上地震频次N（ML≥3．0）、b值、η值、Mf值、C值和A。值等6个参量进行主成分分析,实现对上述参量的有效约简。这6个参量之间有一定的相关性,各参量在不同时段的变化各有所异,但是根据主成分分析可以得到映应地震强度特征的综合指标W,发现该指标W在汶川8．0级大地震前出现明显的异常变化。这表明综合指标可可以较好的反映地震活动的异常特征。 相似文献
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IntroductionMaximumentropyspectralmethod(MEM)(Burg,1972)hadbeenamethodusuallyusedinstudyingtheseismicityanditsmainpurposeistofindthedominantspectrainthelong-termseismicityprocessesinthepastyears(Zhu,1985).Inthispaper,themethodisappliedtostudywhethertherearesomespecialspectraofseismicityinsomespecificstagesinearthquake-generatingprocesses.Sowestudyseparatelythenormalandabnormalstageofearthquakeactivity,whoseactiveprocessisregardedasstablestochasticprocess,inordertofindtheirspectracharactersan… 相似文献
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本文利用晋冀蒙交界地区1500年以来记录较完整的MS5.0及以上历史地震烈度资料和2000年以来的地震活动资料，分别进行地震灾害危险性和地震活动性分析。首先，利用ArcGIS将历史地震烈度资料数字化，没有等震线记录的地震用烈度衰减关系计算烈度圈半径。将研究区划分成0.1°×0.1°的网格，将烈度资料分配到与之相交的每个网格，并用烈度-频度关系计算每个网格的烈度a、b值。基于地震发生遵从泊松分布的假定，估算未来50年内晋冀蒙交界区遭受某一地震烈度的超越概率。同时，计算50年超越概率10%对应的地震烈度，计算结果表明张家口蔚县、阳原和山西广灵县周边地区的地震危险性较高。最后，采用中小地震能量密度值计算方法，对2000年以来的现今地震活动进行定量分析，与历史地震烈度资料分析结果进行对比，发现中小地震活动圈定的危险区与历史地震烈度资料评估计算的概率高值区相对应，因此，这两种方法可为晋冀蒙交界地区的地震活动性和危险性评价提供参考。 相似文献
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1833年云南省昆明市嵩明杨林地区发生了1次强烈地震,震级被定为8级,这也是迄今为止云南省震级最大的地震。本文选取该地震震中一带为研究区（24.7°～25.5°N,102.3°～103.3°E）,采用网格点密集值计算方法对研究区1966年以来仪器记录的地震进行了计算。根据地震密集等值线图确定研究区有2个地震密集区。通过不同的时窗分析了密集区内地震活动的时间分布特征。利用地震密集时空分布特征与历史强震间的关系,给出了1833年嵩明8级地震震中位置校正的建议。此外,还通过地震密集时空动态变化分析发现,21世纪以来研究区地震密集由NE逐渐向SW方向发展。该现象可能在一定程度上反映出区域应力的变化特征。 相似文献
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Introduction In recent years the study of the digital seismology has made great progress due to the wide use of the broadband digital records. And many fine results of the focal theory have obtained. The focal theory mainly studies the physical process of the seismic fracture and production of the seismic wave, as well as its traveling process. One of the great progresses is to simulate the fracture process in the active fault. Especially a new concept of the fracture mechanics has been intro… 相似文献
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Time variations in the parameters of seismic activity in two regions in Greece, which are known to have different geodynamical
conditions, are analyzed using the FastBEE algorithm suggested in (Papadopoulos and Baskoutas, 2009). The study is based on the data on weak earthquakes that occurred
in two local regions. One region pertains to the zone dominated by intensive compression stress field, while another is located
in the region of a relatively lower intensity extension stress field. It is shown that in the zone of compression the seismic
parameters exhibit anomalous temporal behavior before strong earthquakes with Ms ≥ 5.7, whereas in the zones of extension, similar anomalies precede earthquakes with lower magnitudes of up to Ms ≥ 4.9. The most informative parameters for the purposes of predicting strong seismic events are the released seismic energy
in the form logE
2/3 and the slope of the frequency-magnitude dependence, b-value. The seismic activity in the region, expressed in terms of the logarithmic number of earthquakes, per unit time in some cases
does not exhibit any particular pattern of behavior before strong earthquakes. In the time series of the studied parameters,
four stages in the seismic process are clearly distinguished before strong earthquakes. Typically, a strong earthquake has
a low probability to occur within the first two stages. Instead, this probability arises at stage III and attains its maximum
at the end of this stage coinciding with the occurrence of the strong earthquake. We suggest these features of the time series
to be used for the assessment of seismic hazard and for the real-time prediction of strong earthquakes. The time variations
in the b-value are found to be correlated with the time variations inlogE
2/3. This correlation is closely approximated by the power-law function. The parameters of this function depend on the geodynamical
features of the region and characterize the intensity and the type of the regional tectonic stresses. The results of our study
show that the FastBEE algorithm can be successfully applied for monitoring seismic hazard and predicting strong earthquakes. 相似文献
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In this paper, we calculated the seismic pattern of instrumental recorded small and moderate earthquakes near the epicenter of the 1303 Hongtong M=8 earthquake, Shanxi Province. According to the spatial distribution of small and moderate earthquakes, 6 seismic dense zones are delineated. Temporal distribution of ML≥2 earthquakes since 1970 in each seismic dense zone has been analyzed. Based on temporal distribution characteristics and historical earthquake activity, three types of seismicities are proposed. The relationship between seismic types and crustal medium is analyzed. The mechanism of three types is discussed. Finity of strong earthquake recurrence is proposed. Seismic hazard in mid-long term and diversity of earthquake disaster in Shanxi seismic belt are discussed. 相似文献
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Yusuf Bayrak Serkan Öztürk Hakan Çınar G. Ch. Koravos T. M. Tsapanos 《Pure and Applied Geophysics》2008,165(7):1367-1390
Complete data set of earthquakes in Turkey and the adjacent areas has been used in order to compute the ω values in 24 seismic
regions of Turkey. The parameter is obtained through Gumbel’s third asymptotic distribution of extreme values and is well
known as upper bound magnitude. This is an interpretation that no earthquake magnitude greater than ω can occur in a region. The results also estimate the
most probable magnitude for a time period of 100 years. The estimates of ω exceed the value of 7.00 in 20 of the 24 seismic
regions. An effort is also made to find a relation between the magnitude and the length of a fault in the complicated tectonics
of Turkey and the surrounding area. Earthquake hazard revealed as tables and maps are also considered for Turkey and the surrounding
area. 相似文献
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Source parameters of the earthquakes of the Baikal rift system 总被引：1，自引：0，他引：1
A. A. Dobrynina 《Izvestiya Physics of the Solid Earth》2009,45(12):1093-1109
The dynamic parameters of the earthquake source—the seismic moment, the moment magnitude, the source radius, the stress drop,
and the amplitude of displacement—are determined by the amplitude Fourier spectra of the body shear waves (S-waves) for 62 earthquakes of the Baikal rift system with the energy class of K
P
= 9.1–15.7. In the calculations I used the classical Brune model. The seismic moment of the earthquakes being investigated
changes from 3.65 × 1011 N m to 1.35 × 1018 N m, and the radii of earthquake sources vary from 390 m to 1.84 km. The values of the drop in stress Δσ grow with an increase
in the seismic moment up to 1.7 × 108 Pa. For the group of weak earthquakes (M
w
= 1.7–3.3), extremely low values of the drop in stress 103–104 Pa are observed. The maximum amplitude of displacement in the source amounts to 5.95 m. The empirical equations between the
seismic moment and the other dynamic parameters of the source are determined. The regional dependence of the seismic moment
and energy class is obtained: log M
0 ± 0.60 = 1.03K
P
+ 3.17. The character of the relationship between the seismic moment and the corner frequency indicates that the classical
scaling law of the seismic spectrum for the earthquakes in question is not fulfilled. The obtained estimates of the dynamic
parameters are in satisfactory agreement with the published data concerning the analogous parameters of the other rift zones,
which reflects the general regular patterns of the destruction of the lithosphere and the seismicity in the extension zones
of the lithosphere. 相似文献
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地震序列发震构造研究是区域地震活动性和地震危险性分析的重要基础。2017年3月渤海海域发生地震序列活动,该序列发生在郯城-庐江断裂带与张家口-渤海地震带的交汇部位,区域构造较为复杂。然而在渤海海域,连续运行的固定地震监测仪器难以布设,导致地震监测能力相对较弱。本文首先采用模板匹配方法对序列遗漏地震进行检测,再使用波形互相关震相检测进行震相校正,基于校正后的震相到时数据对序列进行精定位,并计算序列中2次最大地震的震源机制解。通过计算共检测到目录遗漏地震32个,约为台网目录中地震数量的1.8倍。根据波形互相关聚类分析发现渤海地震序列可分为2组,一组为M_L4.4地震及其余震序列,一组为最大震级M_L3.5的震群,另有一个M_L1.6地震与其他地震波形相似度较低,可能为一个孤立的地震事件。精定位和震源机制结果显示,2组地震均为NE走向,M_L4.4地震发生在低倾角正断层,M_L3.5地震发生在高倾角走滑断层。最后结合区域地质构造相关研究成果,认为M_L4.4地震及其余震序列发震构造为渤中凹陷内NE向低倾角的伸展性正断层,M_L3.5震群发震构造为NE向倾角较陡的次级走滑断层。 相似文献