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1.
Result of the algorithm of earthquake prediction, published in 1982, is examined in this paper. The algorithm is based on the hypothesis of long-range interaction between strong and moderate earthquakes in a region. It has been applied to the prediction of earthquakes withM6.4 in Southern California for the time interval 1932–1979. The retrospective results were as follows: 9 out of 10 strong earthquakes were predicted with average spatial accuracy of 58 km and average delay time (the time interval between a strong earthquake and its best precursor) 9.4 years varying from 0.8 to 27.9 years. During the time interval following the period studied in that publication, namely in 1980–1988, four earthquakes occurred in the region which had a magnitude ofM6.4 at least in one of the catalogs: Caltech or NOAA. Three earthquakes—Coalinga of May, 1983, Chalfant Valley of July, 1985 and Superstition Hills of November, 1987—were successfully predicted by the published algorithm.The missed event is a couple of two Mammoth Lake earthquakes of May, 1980 which we consider as one event due to their time-space closeness. This event occurred near the northern boundary of the region, and it also would have been predicted if we had moved the northern boundary from 38°N to the 39°N; the precision of the prediction in this case would be 30 km.The average area declared by the algorithm as the area of increased probability of strong earthquake, e.g., the area within 111-km distance of all long-range aftershocks currently present on the map of the region during 1980–1988 is equal to 47% of the total area of the region if the latter is measured in accordance with the density distribution of earthquakes in California, approximated by the catalog of earthquakes withM5. In geometrical terms it is approximately equal to 17% of the total area.Thus the result of the real time test shows a 1.6 times increase of the occurrence ofC-events in the alarmed area relative to the normal rate of seismicity. Due to the small size of the sample, it is of course, beyond the statistically significant value. We adjust the parameters of the algorithm in accordance with the new material and publish them here for further real-time testing. 相似文献
2.
—A succession of precursory changes of seismicity characteristic to earthquakes of magnitude 7.0–7.5 occurred in advance of the Kobe 1995, M = 7.2, earthquake. Using the Japan Meteorological Agency (JMA) regional catalog of earthquakes, the M8 prediction algorithm (Keilies-Borko and Kossobokov, 1987) recognizes the time of increased probability, TIP, for an earthquake with magnitude 7.0–7.5 from July 1991 through June 1996. The prediction is limited to a circle of 280-km radius centered at 33.5°N, 133.75°E. The broad area of intermediate-term precursory rise of activity encompasses a 175 by 175-km square, where the sequence of earthquakes exhibited a specific intermittent behavior. The square is outlined as the second-approximation reduced area of alarm by the "Mendocino Scenario" algorithm, MSc (Kossobokov et al., 1990). Moreover, since the M8 alarm starts, there were no swarms recorded except the one on 9–26 Nov. 1994, located at 34.9°N, 135.4°E. Time, location, and magnitude of the 1995 Kobe earthquake fulfill the M8-MSc predictions. Its aftershock zone ruptured the 54-km segment of the fault zone marked by the swarm, directly in the corner of the reduced alarm area. The Kobe 1995 epicenter is less than 50 km from the swarm and it coincides with the epicenter of the M 3.5 foreshock which took place 11 hours in advance. 相似文献
3.
1991年7月1日、22日在云南省施甸太平乡先后发生了5.0、5.2级两次中强地震。保山行署地震局曾在震前作出了正确的中、短期预报和震后作了无震预报。本文客观地提供了这次地震前后预报的科学依据、中短期自适应加权定量综合判定模式实际计算结果及一系列对策的实况;同时讨论了孕震区内短临阶段前兆变化的异常特征。 相似文献
4.
2017年8月8日四川九寨沟发生MS7.0地震。震前我们实验室主要做出以下预测：（1）根据我国强震的空间分布有序性规律,在2015年曾做出预测：甘肃省东南部、四川交界处将来可能会发生8级地震;（2）根据44年周期和7年周期,2016年预测四川区域在2017年会有7.5级地震发生;（3）依据地磁仪器观测到的数据异常,2017年7月28日认为近期将有6~7级地震发生。九寨沟地震发生后,经综合分析我们的三次预测,以及6—7月在四川茂县出现的多次滑坡事件,认为若将这些因素结合起来,将会是一个很好的短临预测方式。 相似文献
5.
地震预报效能评分讨论 总被引：1，自引：0，他引：1
以前的各种评价地震预报效能的方法只考虑预报意见对应实发地震情况，而未顾及预报意见本身中所预报的区域的大小、时间的区间的长短和震级的范围对评分应起的作用。本文首先评价地震预报本身的确定率，而不管此预报意见未来是否报准了地震。其次是本文给出了实际发生的地震超出预报意见所限定的范围时地震预报报准率的计算方法，进而给出了地震预报成功率的计算方法。 相似文献
6.
IntroductionMaximumentropyspectralmethod(MEM)(Burg,1972)hadbeenamethodusuallyusedinstudyingtheseismicityanditsmainpurposeistofindthedominantspectrainthelong-termseismicityprocessesinthepastyears(Zhu,1985).Inthispaper,themethodisappliedtostudywhethertherearesomespecialspectraofseismicityinsomespecificstagesinearthquake-generatingprocesses.Sowestudyseparatelythenormalandabnormalstageofearthquakeactivity,whoseactiveprocessisregardedasstablestochasticprocess,inordertofindtheirspectracharactersan… 相似文献
7.
Pei-Yan Chen 《地震学报(英文版)》1997,10(2):181-191
In this paper, the relation that the curves of nonlinear parameter H and its difference ΔH bear with strong earthquakes in North China has been studied. First, the RSH algorithm has been applied to the North China
region; the schemes of six quantitative prediction indexes have been studied in detail and then tested by tracing-back predictions.
The result shows that all the six prediction schemes are of certain prediction efficiency and have passed the test. Among
the six schemes, A and E are of the best effect, with correlation coefficients R of 0.47 and 0.48 respectively. We recommend these two schemes for practical use in prediction in the future. Furthermore,
the relation between the curve of ΔH (the difference of H) and strong earthquake has been studied. Based on the above results, the RSΔH algorithm that uses the
ΔH value to predict strong earthquake has been put forward and applied to predict strong earthquakes in North China. The correlation
coefficient R of tracing-back prediction by this method is 0.45; this means that this method is also of better prediction efficiency. A
combined application of these two algorithms has also been proposed. By the combined method, the time length spanned by false
predictions can be shortened and thus the R value can be raised.
Contribution No. 96A0033, Institute of Geophysics, SSB, China.
This project sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
8.
2022年1月8日青海门源县发生6.9级地震,此次地震前青海地区出现了大量地球物理观测异常。2021年10月下旬青海地区出现地磁垂直强度极化高值异常,10月27日异常台站最多,并在门源-祁连至兴海地区形成一个面积约为6.6×104km2的高值异常区;此外,2021年7—11月青海地区8项地下流体观测数据出现准同步异常变化。结合青海及周边地区历史震例的分析结果,认为2021年11月23日至2022年1月23日,青海西北部地磁垂直强度极化高值区内可能发生5.6～6.4级地震。门源6.9级地震发生在地磁垂直强度极化异常出现后的73天,震中位于预测区的边缘,地震的发生时间和地点与预测意见一致,但震级超出预测意见上限值0.5级。此次地震前基于地球物理观测地震预测指标体系开展的短临异常跟踪分析过程,对中国大陆西部地震预报工作具有一定的参考意义。 相似文献
9.
Strong-motion data from large (M ≥ 7.2) shallow crustal earthquakes invariably make up a small proportion of the records used to develop empirical ground motion prediction equations (GMPEs). Consequently GMPEs are more poorly constrained for large earthquakes than for small events. In this article peak ground accelerations (PGAs) observed in 38 earthquakes worldwide with M ≥ 7.2 are compared with those predicted by eight recent GMPEs. Well over half of the 38 earthquakes were not considered when deriving these GMPEs but the data were identified by a thorough literature review of strong-motion reports from the past 60 years. These data are provided in an electronic supplement for future investigations on ground motions from large earthquakes. The addition of these data provides better constraint of the between-event ground-motion variability in large earthquakes. It is found that the eight models generally provide good predictions for PGAs from these earthquakes, although there is evidence for slight under- or over-prediction of motions by some models (particularly for M > 7.6). The between-event variabilities predicted by most models match the observed variability, if data from two events (2001 Bhuj and 2005 Crescent City) that are likely atypical of earthquakes in active regions are excluded. For some GMPEs there is evidence that they are over-predicting PGAs in the near-source region of large earthquakes as well as over-predicting motions on hard rock. Overall, however, all the considered models, despite having been derived using limited data, provide reliable predictions of PGAs in the largest crustal earthquakes. 相似文献
10.
ＲｅｄｉｓｃｕｓｓｉｏｎｏｎｔｈｅｓｅｉｓｍｉｃｒｅｇｉｍｅｎｅｔｗｏｒｋＺｅ－ＧａｏＷＡＮＧ（王泽皋）；Ｐｅｉ－ＱｉｎｇＳＵＮ（孙佩卿）；Ｊｉｎｇ－ＣｈｕｎＧＡＯ（高景春）；Ｓｈｕ－ＬｉａｎＬＩ（李淑莲）；ＸｕｅＺＨＡＮＧ（张雪）ａｎｄＹａｎＧＵＯ... 相似文献
11.
In the seismic flow it is often observed that a Strong Earthquake (SE), is followed by Related Strong Earthquakes (RSEs), which occur near the epicenter of the SE with origin time rather close to the origin time of the SE. The algorithm for the prediction of the occurrence of a RSE has been developed and applied for the first time to the seismicity data of the California-Nevada region and has been successfully tested in several regions of the world, the statistical significance of the result being 97%. To date it has been possible to make five successful forward predictions, with no false alarms or failures to predict.The algorithm is applied here to the Italian territory, where the occurrence of RSEs is a particularly rare phenomenon. Our results show that the standard algorithm is successfully directly applicable without adjustment of the parameters. Eleven SEs are considered. Of them, three are followed by a RSE, as predicted by the algorithm, eight SEs are not followed by a RSE, and the algorithm predicts this behaviour for seven of them, giving rise to only one false alarm. Since, in Italy, often the series of strong earthquakes is relatively short, the algorithm has been extended to handle such a situation. The result of this experiment indicates that it is possible to attempt to test a SE, for the occurrence of a RSE, soon after the occurrence of the SE itself, performing timely preliminary recognition on reduced data sets. This fact, the high confidence level of the retrospective analysis, and the first successful forward predictions, made in different parts of the World, indicates that, even if additional tests are desirable, the algorithm can already be considered for routine application to Civil Defence. 相似文献
12.
L. L. Romachkova V. G. Kossobokov G. F. Panza G. Costa 《Pure and Applied Geophysics》1998,152(1):37-55
—Large earthquakes in Italy are preceded by a specific seismic activation which could be diagnosed by a reproducible intermediate-term earthquake prediction method—a modification for lower seismic rate areas of the algorithm, known as M8 (Keilis-Borok and Kossobokov, 1990). Use has been made of the PFG-ING catalog of earthquakes, compiled on a regular basis, to determine areas and times of increased probability for occurrences of M≥ 6 earthquakes. In retroactive simulation of forward prediction, for the period 1972–1995, both the 1976 Friuli, M = 6.1 and the 1980 Irpinia, M = 6.5 earthquakes are predicted. In the experiment where priority magnitude scale is used, the times of increased probability for a strong earthquake to occur (TIPs) occupy less than a quarter of the total magnitude-space-time domain, and are rather stable with respect to positioning of circles of investiga tion. Successful stability tests have been made considering a recently compiled catalog (CCI97) (Peresan et al., 1997). In combination with the CN algorithm results (Costa et al., 1996) the spatio-temporal uncertainty of the prediction could be reduced to 5%. The use of M8 for the forward prediction requires the computations to be repeated each half-year, using the updated catalog. 相似文献
13.
Intermediate term earthquake prediction in the area of Greece: Application of the algorithm M8 总被引：1，自引：0，他引：1
The 3 strongest earthquakes,M7.0, which have occurred since 1973 in the area of Greece were preceded by a specific increase of the earthquake activity in the lower magnitude range. This activation is depicted by algorithm M8. This algorithm of intermediate term earthquake prediction was originally designed for diagnosis by Times of Increased Probability (TIPs) of the strongest earthquake,M8.0 worldwide (Keilis-Borok andKossobokov, 1984). At present the algorithm is retrospectively tested for smaller magnitudes in different seismic regions (Keilis-Borok andKossobokov, 1986, 1988). A TIP refers to a time period of 5 years and an area whose linear size is proportional and several times larger than that of the incipient earthquake source. Altogether the TIPs diagnosed by the algorithm M8 in the area of Greece occupy less than 20% and the Times of Expectation (TEs) about 10% of the total space-time domain considered. Also there is a current TIP for the southeastern Aegean sea and 1988–1992. It may specify the long-term prediction given inWyss andBaer (1981a,b).The results of this study are further evidence favoring applicability of algorithm M8 in diverse seismotectonic environment and magnitude ranges and support indirectly the hypothesis of self-similarity of the earthquake activity. It also implies the possibility of intermediate term prediction of the strongest earthquakes in the area of Greece. 相似文献
14.
I. Rotwain G. De Natale I. Kuznetsov A. Peresan G. F. Panza 《Pure and Applied Geophysics》2006,163(1):19-39
The possibility of intermediate-term earthquake prediction at Mt. Vesuvius by means of the CN algorithm is explored. CN was
originally designed to identify the Times of Increased Probability (TIPs) for the occurrence of strong tectonic earthquakes,
with magnitude M ≥ M0, within a region a priori delimited. Here the CN algorithm is applied, for the first time, to the analysis of volcanic seismicity. The earthquakes
recorded at Mt. Vesuvius during the period from February 1972 to June 2004 are considered, and the magnitude threshold M0 selecting the events to be predicted is varied within the range: 3.0–3.3. Satisfactory prediction results are obtained, by
retrospective analysis, when a time scaling is introduced. In particular, when the length of the time windows is reduced by
a factor 2.5–3, with respect to the standard version of CN algorithm, more than 90% of the events with M ≥ M0 occur within the TIP intervals, with TIPs occupying about 30% of the total time considered. The control experiment ``Seismic
History' demonstrates the stability of the obtained results and indicates that the CN algorithm can be applied to monitor
the preparation of impending earthquakes with M ≥ 3.0 at Mt. Vesuvius. 相似文献
15.
Majid Nemati 《地震科学（英文版）》2019,32(2):80-97
Persian territory, which is dividable into major seismotectonic provinces, always suffers from damages of moderate and large earthquakes from ancient era to modern time. Therefore, temporal prediction of earthquake occurrence in this kind of area is an important topic. For this purpose, 628 moderate-large (5.5 ≤MS≤ 8.2) earthquakes occurred in Persia during the period from 400 B.C. to 2015 C.E. were used. Considering the magnitudes of events preceding main shocks and the annual seismic moment release in seismic source areas in the provinces, we calibrated equations predicting inter-event time of occurrence of moderate and large earthquakes (MW>5.5) in Iran. In each source area, inter-event times between moderate and large shocks with magnitudes equal to or larger than a certain cut-off magnitude (MW5.5) were calculated. The inter-event times between the earthquakes were used to compute the relationships using multiple regression technique. Calculated relationships express the basic idea of the time predictable model predicting the occurrence time of the future main shock in a certain seismogen area. However, despite of unavoidable scatter in observations and uncertainties in the results, occurrence times of main shocks during the next years and decades in some source areas in Iran were determined. 相似文献
16.
回顾了2013年郭增建提出的基于地震活动性的"静中动"和后期与作者共同发展的"准静中动"方法,以1987年1月8日在甘肃南部迭部县发生的5.9级地震作为标志性的"准静中动"地震,结合国家地震局在1989年综合划定的1990—2000年南北地震带10年地震危险区,用中长期预测的时间尺度,指出了南北地震带北段三个未来可能发生6~7级地震的地区,其中一个就是四川省九寨沟地区。回顾分析中对"静中动"方法预测效能、存在的问题及一些中长期预测的问题进行讨论,得到两点认识:一是通过这次地震的再次验证,证明"静中动"方法是一种可行的预测地震的独立指标方法,在验证的基础上对该方法进行了优化认识;二是基于"静中动"方法与南北地震带北段10年地震危险区对应地震较为准确的启发,初步认为前兆可以划分为平静期的前兆与活跃期的前兆,而前者可能对于地震的预测意义更大,未来可以沿这一思路开展进一步的论证和研究。 相似文献
17.
“诱发前震”预测效能评价 总被引：1，自引：0，他引：1
“诱发前震”现象在区域地震活动中较普遍,据此提出A-F-B图象预报方法,以区域大震后短时间内发生的小震为预报因子,判断以后大震的位置并推测其震级与时间。为了检验该方法的实用性,统计了我国西南地区1970—1983年和华北地区1966—1984年的地震资料,对其预测效能做了统计评价。评分采用W值与R值。其中:W=1-(漏报率+虚报率);R=报对地震占有面积/应预报地震占有面积-预报区占有面积/研究区总面积。结果为W与R值都大于0.5,波动在0.5～0.8之间;并计算出各种不同预报参量的频数概率分布,给出了单次预报在取不同空间与时间范围的信度。 相似文献
18.
A brief account of the development of the research on mining earthquakes and the general situation of the Mentougou Coal Mine
medium-scale experiment field for earthquake prediction and the project of monitor and prediction is given. The differences
of waveforms between mining earthquakes and natural earthquakes is discussed. The magnitude-frequency distribution of the
79 000 mining earthquakes of overM
l
1. 0 from 1984 to 1995 is summarized. Finally, taking PH and PV, the principal compressive stress components of the focal
mechanism of the mining earthquakes, as the criteria, analyses the stress background of the 12 large mining earthquakes.
Contribution No. 95C0002, Institute of Geophysics, SSB, China.
This study is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
19.
J. Qian 《Pure and Applied Geophysics》1984,122(6):901-920
Electrical resistivity measurements have been conducted as a possible means for obtaining precursory earthquake information. Before five great earthquakes (M>7,h<25 km) in China, the apparent resistivity
a
showed systematic variations within a region 200 km from the epicenters. In particular, 9 stations in the Tangshan-Tianjin-Beijing region prior to the Tangshan earthquake (M=7.8,h=11 km, 27 July 1976) showed a consistent decrease of apparent resistivity around the epicenter, with a maximum resistivity change of 6% and a period of variation of 2–3 years. Simultaneous water table observations in this region showed a declining water table, and ground surface observations indicated a slight (5 mm) uplift in the epicenter region relative to its surroundings.In order to develop an explanation for the observed change of apparent resistivity associated with these great earthquakes, we have used Archie's Law to explore the effects of changes in rock porosity, water content and electrolyte resistivity on measured resistivity.Tentative conclusions of this study are as follows: (1) the apparent resistivity change is opposite to the effect expected from the simultaneous water table trend; (2) the dilatancy needed to give such resistivity variations (assuming Archie's Law holds) is much larger than that needed to explain the observed uplift (by 2–3 orders of magnitude); (3) salinity change in the pore electrolyte is a possible explanation for the variation in resistivity: an increase in the salinity would cause a proportional decrease in resistivity; the data needed to test this hypothesis, however, are lacking; and (4) the effect of changing geometry of rock pores or cracks due to pressure solution may provide an explanation for the decrease in apparent resistivity; it is different in nature from the effect of a volume change in response to stress although the geometry change is also closely related to the stress change. 相似文献