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1.
Correlation Fractal and Multifractal Characteristics of Seismic Activity in the Taiwan Area, China 总被引：2，自引：0，他引：2
XU Jiandong HUANG Jianf WEI Fuquan YAN Yunpeng LI Yaping LIN Chien-te Institute of Geology China Earthquake Administration Beijing Chin Earthquake Administration of Fujian Province Fuzhou Fujian China China Aero Geophysical Survey Remote Sensing for Land Resources Beijing China Leader University Tainan Taiwan China 《《地质学报》英文版》2005,79(2):225-232
Based on the analysis of newly collected data of plate tectonics, distribution of active faults and crustal deformation, the Taiwan area is divided into two seismic regions and six seismic belts. Then, correlation fractal dimensions of all the regions and belts are calculated, and the fractal characteristics of hypocenteral distribution can be quantitatively analyzed. Finally, multifractal dimensions Dq and f(α) are calculated by using the earthquake catalog of the past 11 years in the Taiwan area. This study indicates that (1) there exists a favorable corresponding relationship between spatial images of seismic activity described with correlation fractal dimension analysis and tectonic settings; (2) the temporal structure of earthquakes is not single but multifractal fractal, and the pattern of Dq variation with time is a good indicator for predicting strong earthquake events. 相似文献
2.
Mustafa Toker 《Central European Journal of Geosciences》2013,5(3):423-434
The Van earthquake (M W 7.1, 23 October 2011) in E-Anatolia is typical representative of intraplate earthquakes. Its thrust focal character and aftershock seismicity pattern indicate the most prominent type of compound earthquakes due to its multifractal dynamic complexity and uneven compressional nature, ever seen all over Turkey. Seismicity pattern of aftershocks appears to be invariably complex in its overall characteristics of aligned clustering events. The population and distribution of the aftershock events clearly exhibit spatial variability, clustering-declustering and intermittency, consistent with multifractal scaling. The sequential growth of events during time scale shows multifractal behavior of seismicity in the focal zone. The results indicate that the extensive heterogeneity and time-dependent strength are considered to generate distinct aftershock events. These factors have structural impacts on intraplate seismicity, suggesting multifractal and unstable nature of the Van event. Multifractal seismicity is controlled by complex evolution of crustal-scale faulting, mechanical heterogeneity and seismic deformation anisotropy. Overall seismicity pattern of aftershocks provides the mechanism for strain softening process to explain the principal thrusting event in the Van earthquake. Strain localization with fault weakening controls the seismic characterization of Van earthquake and contributes to explain the anomalous occurrence of aftershocks and intraplate nature of the Van earthquake. 相似文献
3.
Multifractal behaviour of interevent time sequences is investigated for the earthquake events in the NW Himalaya, which is one of the most seismically active zones of India and experienced moderate to large damaging earthquakes in the past. In the present study, the multifractal detrended fluctuation analysis (MF-DFA) is used to understand the multifractal behaviour of the earthquake data. For this purpose, a complete and homogeneous earthquake catalogue of the period 1965–2013 with a magnitude of completeness M w 4.3 is used. The analysis revealed the presence of multifractal behaviour and sharp changes near the occurrence of three earthquakes of magnitude (M w ) greater than 6.6 including the October 2005, Muzaffarabad–Kashmir earthquake. The multifractal spectrum and related parameters are explored to understand the time dynamics and clustering of the events.
相似文献4.
Multifractal behaviour of interevent time sequences is investigated for the earthquake events in the NW Himalaya, which is one of the most seismically active zones of India and experienced moderate to large damaging earthquakes in the past. In the present study, the multifractal detrended fluctuation analysis (MF-DFA) is used to understand the multifractal behaviour of the earthquake data. For this purpose, a complete and homogeneous earthquake catalogue of the period 1965–2013 with a magnitude of completeness M w 4.3 is used. The analysis revealed the presence of multifractal behaviour and sharp changes near the occurrence of three earthquakes of magnitude (M w ) greater than 6.6 including the October 2005, Muzaffarabad–Kashmir earthquake. The multifractal spectrum and related parameters are explored to understand the time dynamics and clustering of the events. 相似文献
5.
Narasimhan Harikrishna Ferlisi Settimio Cascini Leonardo De Chiara Giovanna Faber Michael Havbro 《Natural Hazards》2015,77(1):117-125
We analyzed the fractal and multifractal properties of the earthquake time series occurred around the Enguri dam in West Georgia by applying the methods of detrended fluctuation analysis and multifractal detrended fluctuation analysis. We examined the interevent time series in two periods: (1) 1960–1980, in which the investigated area was characterized by the natural seismicity; and (2) 1981–2012, in which the quasi-periodic change of the reservoir water level affected the earthquake generation. Our findings show that the water level variation may influence the fractal properties of earthquake temporal distribution in the local area around the Enguri dam. In particular, it is observed that the time distribution features of seismicity occurred in the second period are more persistent than the natural seismicity occurred in the first period. Furthermore, the seismic process of the second period shows a lower multifractal degree than that of the first period, indicating that the influence of quasi-periodic fluctuation of water level features the seismicity as more regular compared to the natural seismicity. 相似文献
6.
Sequential cumulative moment release data of macroearthquakes (Mw≥4.3) of seventeen seismic zones (A to Q) belonging to NE-Himalaya, Burmese-Andaman arc and West- Sunda arc are analysed by Hurst analysis, a non-parametric statistical procedure to identify clustering of low and high values in a time series. The moment release in a zone occurs in alternate positive, negative and positive sloping segments forming a wave like pattern with intervening small horizontal segment. The negative sloping segments indicate decelerated moment release pattern or temporal slackening of elastic strain release with high b–value (>0.95). The horizontal segment indicates temporal clustering of moderate magnitude events/seismic moments with moderate b-values (0.8–0.95). The positive segment is characterised by accelerated moment release within a short span of time indicating temporal clustering of larger magnitude earthquakes/seismic moments and exhibit lowest b–value (<0.7). All zones attest moderate to high Hurst K values, range 0.7-0.86. The pattern in Hurst plots, specially a reversal of trend after prolong negative slope is used for earthquake prognostication in the seismic zones. Our analysis shows that most of the zones register a notable reversal of Hurst clustering trend after a prolonged negative slope which is accompanied by a major earthquake near its end. However, South Burma region (Zone-I) and Tripura fold belt and Bangladesh Plain (Zone-K) do not show any moderate or large shock around the end of the negative sloping trend in Hurst plot. Hence, these two zones can be considered more prone to produce moderate to larger earthquakes in future. 相似文献
7.
Multifractal Analysis of the Arnea,Greece Seismicity with Potential Implications for Earthquake Prediction 总被引：2，自引：0，他引：2
Two-dimensional multifractal analysis is performed in a seismic area of Northern Greece responsible for recent strong earthquakes, including the Arnea sequence of May 1995, culminating in a Mw 5.3 event on 4/5/1995. It is found that multifractality gradually increases prior to the major seismic activity and that declusterization replaces clusterization not long before its initialization. The fractal dimensions D(q) (q > 0) abruptly drop for aftershocks, reflecting their very strong spatial clustering. The observed seismicity patterns seem to be compatible with a percolation process. Before the main sequence, the fractal dimension is consistently in the range 1.67–1.96 (standard deviation included). Percolation theory predicts 1.9 for 2D percolation clusters and 1.8 for the backbone of 3D percolation clusters. If the observed gradual increase in multifractality is due to multifractality reaching a maximum prior to the major slip (percolation), this may enable us to roughly estimate its time of occurrence. 相似文献
8.
Measuring multifractality in seismic sequences 总被引：6，自引：0，他引：6
We investigated the multifractal structure of the interevent times between successive earthquakes that occurred in Umbria-Marche, which is one of the most seismically active areas of central Italy. We used the Multifractal Detrended Fluctuation Analysis (MF-DFA), which permits detection of multifractality in nonstationary series. Analyzing the time evolution of the multifractal behaviour of the seismic sequence, a loss of multifractality during the aftershocks is revealed. 相似文献
9.
Himalayan seismicity is related to continuing northward convergence of Indian plate against Eurasian plate. Earthquakes in this region are mainly caused due to release of elastic strain energy. The Himalayan region can be attributed to highly complex geodynamic process and therefore is best suited for multifractal seismicity analysis. Fractal analysis of earthquakes (mb ?? 3.5) occurred during 1973?C2008 led to the detection of a clustering pattern in the narrow time span. This clustering was identified in three windows of 50 events each having low spatial correlation fractal dimension (D C ) value 0.836, 0.946 and 0.285 which were mainly during the span of 1998 to 2005. This clustering may be considered as an indication of a highly stressed region. The Guttenberg Richter b-value was determined for the same subsets considered for the D C estimation. Based on the fractal clustering pattern of events, we conclude that the clustered events are indicative of a highly stressed region of weak zone from where the rupture propagation eventually may nucleate as a strong earthquake. Multifractal analysis gave some understanding of the heterogeneity of fractal structure of the seismicity and existence of complex interconnected structure of the Himalayan thrust systems. The present analysis indicates an impending strong earthquake, which might help in better hazard mitigation for the Kumaun Himalaya and its surrounding region. 相似文献
10.
Earthquake activity related to seismic cycles in a model for a heterogeneous strike-slip fault 总被引：1，自引：0，他引：1
We investigate the evolution of seismicity within large earthquake cycles in a model of a discrete strike-slip fault in elastic solid. The model dynamics is governed by realistic boundary conditions consisting of constant velocity motion of regions around the fault, static/kinetic friction and dislocation creep along the fault, and 3D elastic stress transfer. The fault consists of brittle parts which fail during earthquakes and undergo small creep deformation between events, and aseismic creep cells which are characterized by high ongoing creep motion. This mixture of brittle and creep cells is found to generate realistic aftershock sequences which follow the modified Omori law and scale with the mainshock size. Furthermore, we find that the distribution of interevent times of the simulated earthquakes is in good agreement with observations. The temporal occurrence, however, is magnitude-dependent; in particular, the small events are clustered in time, whereas the largest earthquakes occur quasiperiodically. Averaging the seismicity before several large earthquakes, we observe an increase of activity and a broadening scaling range of magnitudes when the time of the next mainshock is approached. These results are characteristics of a critical point behavior. The presence of critical point dynamics is further supported by the evolution of the stress field in the model, which is compatible with the observation of accelerating moment release in natural fault systems. 相似文献
11.
受环太平洋地震带影响,华北平原地区地震频发,尤其是处于中国首都经济圈的京津冀地区的地震事件备受关注。通过对历史文献资料及地震台网记录中的地震事件统计、分析,重建该地区地震事件历史并获取其潜在的空间分布特征及时间规律,对未来地震事件的早期预警具有重要参考意义。分析结果表明,公元前231年至公元2018年期间京津冀地区发生的1044起地震事件中,以有感地震和中强地震为主,小地震、强烈地震以及大地震发生频次较低。地震记录完整性分析结果表明,除小地震外,其他等级地震记录自公元1400年以来基本完整。在空间分布上,京津冀地区历史地震呈“T”字形分布,沿1条北西—南东走向地震带和1条北东—南西走向地震带分布。在时间上,京津冀地区地震事件呈现出阶段性的变化,在公元1480—1680年间以及1950年以来2个时间段内较为活跃,发生频率较高,频谱分析结果进一步表明地震记录存在45年的复发周期。在月际尺度上,地震事件同样存在季节性差异且多发于夏秋季节,同时地震密集区域在年内呈现出自西向东迁移的现象。最后,根据历史地震事件发生的时间规律,在未来一段时间内京津冀地区仍将处于地震活跃期,存在发生强震的风险。 相似文献
12.
Reassessing the earthquake hazard in Kerala based on the historical and current seismicity 总被引：2，自引：0，他引：2
C.P. Rajendran Biju John K. Sreekumari Kusala Rajendran 《Journal of the Geological Society of India》2009,73(6):785-802
Given the lack of proper constraints in understanding earthquake mechanisms in the cratonic interiors and the general absence
of good quality database, here we reassess the seismic hazard in the province of Kerala, a part of the •stable continental
interior•, based on an improved historical and instrumental database. The temporal pattern of the current seismicity suggests
that >60% of the microtremors in Kerala occurs with a time lag after the peak rainfall, indicating that hydroseismicity may
be a plausible model to explain the low-level seismicity in this region. Further, an increment in overall seismicity rate
in the region in the recent years is explained as due to increased anthropogenic activities, which includes changes in hydrological
pathways as a consequence of rapid landscape changes. Our analyses of the historical database eliminate a few events that
are ascribed to this region; this exercise has also led to identification of a few events, not previously noted. The improved
historical database essentially suggests that the central midland region is more prone to seismic activity compared to other
parts of Kerala. This region appears to have generated larger number of significant earthquakes; the most prominent being
the multiple events (doublets) of 1856 and 1953, whose magnitudes are comparable to that of the 2000/2001 (central Kerala)
events. Occurrences of these historical events and the recent earthquakes, and the local geology indicative of pervasive faulting
as shown by widely distributed pseudotachylite veins suggest that the NNW-SSE trending faults in central midland Kerala may
host discrete potentially active sources that may be capable of generating light to moderate size earthquakes. The frequency
of earthquakes in central Kerala evident from the historical database requires that the seismic codes stipulated for this
region are made mandatory. 相似文献
13.
14.
红层软岩内部孔隙具有随机、多样化的分布特点,孔隙结构的变化是影响其宏观力学性能的关键所在。由SEM扫描电镜获取岩样不同饱水时间下的细观结构图像,根据盒维数法计算出孔隙的分形维数,发现随着饱水时间的加长,孔隙的分形维数呈现增大趋势。同时对孔隙的数量、大小进行统计分析,得出不同饱水时间下岩样内部孔隙的分布特征。基于多重分形理论,采用统计矩的方法对孔隙结构进行定量表征。结果表明,孔隙结构的分配函数与q阶次趋于线性关系,验证了该结构的自相似性与无标度性,由广义分形维数D(0)>D(1)>D(2)说明了孔隙具有多重分形特征,由多重分形谱参数分析了孔隙结构的不规则性与复杂程度,更好地表征孔隙大小各异的分布情况。结合孔隙结构的多重分形特征与岩样抗压强度,建立起孔隙结构变化与其力学性能的关联性,对研究红层软岩的损伤过程具有一定的指导意义。 相似文献
15.
滑坡位移多重分形特征与滑坡演化预测 总被引：3，自引：1，他引：2
在系统分析滑坡位移监测资料和位移演化特征的基础上,根据多重分形理论基本原理,对滑坡位移演化所具有的复杂性、突变性和非线性特征进行了分析和研究。单一分形维数对滑坡位移的演化趋势预测存在不足,文中分别以新滩滑坡、丹巴滑坡和黄蜡石滑坡为例,计算了滑坡位移时序演化的多重分维数演化特征。分析和评价位移演化规律与多重分维数演化特征的关系发现,多重分维数D1 > D2 > … > D∞时,滑坡趋于稳定;D1 < D2 < … < D∞时,滑坡向失稳破坏演化。当滑坡位移时序多重分维数演化特征出现拐点时,即分维数由D1 > D2 > … > D∞,经D1 > … > Dn < Dn+1 < … < D∞到 D1 < D2 < … < D∞的演化过程时,滑坡向不稳定的状态演化;当分维数由D1 < D2 < … < D∞,经D1 > … > Dn D2 > … > D∞的演化过程时,滑坡向趋于稳定的状态演化。研究表明,可以运用多重分维数演化特征对滑坡位移演化趋势与规律进行评价与预测。 相似文献
16.
Clustering of Earthquake Events in the Himalaya - Its Relevance to Regional Tectonic Set-up 总被引：1，自引：0，他引：1
The earthquake events of Himalaya of magnitude ≥5.0 from the time window 1905–2000 are statistically analysed. The inter-event time between earthquakes shows Hurst phenomena of temporal clustering which are spatially located in five distinct domains along the Himalayan fold-thrust belt. Out of these, two domains, one around Uttaranchal-Nepal border and the other around Nepal-Sikkim border reveal maximum number of temporal clusters and thus considered as seismically most potential zones of the Himalaya. Both these zones are located at the interface of the orthogonally disposed major tectonic discontinuities of the Peninsular Shield and Himalayan fold-thrust belt. Such zones are geologically most favourable locales for strain accumulation during later-tectonic movement. Statistical analysis points towards a probability of recurrence of seismic events in near future in these two zones. However, validity of such statistical results can be ascertained by detailed geological and geophysical modelling of the terrain. 相似文献
17.
The spatial-temporal distributions of earthquakes in the Kuril-Okhotsk region were analyzed. The events with Ms ≥ 4 from 1980 until 2009 and Ms ≥ 7 from 1910 until 2009 (20576 and 76 earthquakes, respectively) were studied. The specially developed program complex allowed us to obtain the 4-D distribution of the seismic events (along the sections, depths, temporal intervals, and energetic levels). It was shown that the seismic events obviously tend to cluster both along the surface and depth directions. The spatial-temporal analysis of the events (with Ms ≥ 4) in six five-year intervals from 1980 until 2009 has revealed a cyclic increase and decrease in the seismic activity in different time intervals and its cyclic migration from the South through the Central to the North Kuriles and back. The analysis of the strong events with Ms ≥ 7 in twenty 5-year intervals during 1910–2009 has shown that their amount significantly decreased for the last 30 years and the location of the hypocenter depths also changed (only shallow-focus earthquakes have been observed since 1975). The peaks of the seismic activity (1915–1919, 1955–1969, and 2005–2009) are separated by 35-year periods of its decrease. 相似文献
18.
A technique based on the ν-value, which is defined by % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSGbaeaaca% GGOaGafqiXdqNbaebacaGGPaWaaWbaaSqabeaacaaIYaaaaaGcbaWa% a0aaaeaacqaHepaDdaahaaWcbeqaaiaaikdaaaaaaaaaaaa!3CEB!\[{{(\bar \tau )^2 } \mathord{\left/ {\vphantom {{(\bar \tau )^2 } {\overline {\tau ^2 } }}} \right. \kern-\nulldelimiterspace} {\overline {\tau ^2 } }}\], where τ is the time interval between two adjacent earthquakes and indicates the pattern of time sequences of earthquakes, has been applied to the 25 March 1986 Aegean Sea (Greece) earthquake (M L = 5.2) in an attempt to discover temporal changes in seismicity. The analysis of several earthquake sequences revealed that low ν-values preceded the occurrence of relatively large earthquakes. The ν-value technique may be used for monitoring the seismicity changes. 相似文献
19.
The Nurek Reservoir is located in an area of high seismicity. An average of 5–6 earthquakes of (Russian energy class)K = 10 and 1–2 earthquakes ofK = 11 per year occurred in the vicinity of the reservoir. The largest local earthquake recorded fell in the energy classK = 14 (1956).
At the end of 1972, after the water level had risen to 100 m, earthquake activity increased sharply. Three events ofK = 12 were recorded during one month and the total number of earthquakes (K 7) exceeded three times the former mean level of seismicity.
Spatial and temporal properties in the epicentral distribution showed a migration from the southwest toward the reservoir.
Earthquake mechanisms of 215 events ofK 9 since 1960 were analysed. Fault plane solutions for some of the earthquakes which occurred after the impoundment were found to be different from the ordinary ones. 相似文献
20.
《Journal of African Earth Sciences》2011,59(5):829-832
The temporal variation in the seismicity in the Nyamuragira area was investigated for the period 1 July 2004–27 November 2006, prior to the 27 November 2006 eruptions of Nyamuragira. It is found that this eruption was preceded by 11 months by progressive increase in number of long-period earthquakes. This pattern of seismicity, integrated with other geophysical, geological and geochemistry data, is useful for volcano monitoring and risk mitigation. 相似文献