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1.
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   

2.
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   

3.
Predictions of earthquakes worldwide by the M8-MSc algorithm, which defines locations of Times of Increased Probability (TIPs), have been tested for nearly two decades, and the authors claim a high rate of success. Thus, it might be appropriate to ask what the consequences in terms of human losses may be if the expected earthquakes should occur. The loss estimating tool QUAKELOSS also has been tested in real-time mode during the last five years with success. Therefore, it is reasonable to estimate the order of magnitude of human losses if great earthquakes should occur in TIPs. Here I compare the consequences if M 8.5 earthquakes should happen in the current TIPs of southern Sumatra and central Chile (Kossobokov and Soloviev, 2008, centers at 4.75S/102.625E and 31.25S/71.77 W, respectively). The selection of the attenuation function is calibrated by matching theoretically calculated intensities and fatalities to the observed values in historic earthquakes. In both areas, the standard attenuation function I use is applicable. The results show that in southern Sumatra fatalities are expected to number fewer than 1,000 (possibly as much as a factor of 5 fewer), whereas they are likely to be larger than 1,000 (possibly as much as a factor six) in central Chile. These figures, however, do not account for possible tsunami effects. The difference is due to two factors. The earthquake sources are farther offshore, and there are only small settlements along the coast in southern Sumatra, whereas along the Chilean coast, large harbor cities are located in the northern part of the TIP area. Regardless of TIP predictions, large earthquakes are to be expected along the Chilean coast. Therefore, it seems advisable to implement mitigating measures in La Serena and Coquimbo, where most of the victims are expected.  相似文献   

4.
This paper researches TIP before 23 strong earthquakes occurring in the eastern part and the southern and northern zones of the western part of China and their nearby areas in recent decades.The results show that 18 strong earthquakes occurred within the diagnosed TIP.The TIP precaution occupies about 30% of the total space-time domain which we researched,indicating quite good results of intermediate-term prediction of earthquakes.The algorithm CN can thus be used as an intermediate-term prediction method for strong earthquakes.  相似文献   

5.
杜兴信 《地震研究》1994,17(2):204-209
使用地震频次及其变化，平均震级和地震加权和的变化作为地震流函数研究了发生在１９８０－１９８９年期间中国大陆的６级强震前的地震概率增长时间。结果表明，１０次强震中９次发生在ＴＩＰ之后，而且最长ＴＩＰ为３．５年，ＴＩＰ总时空占有率为３０％。用同样的原则对新区进行识别也获得了好的结果。  相似文献   

6.
The application of the CN algorithm to a new earthquake catalogue, for the period from 1932 to 1993, obtained by merging Romanian and U.S.S.R. data, allows us to monitor, on the intermediate time scale. the preparation of strong, intermediate-depth earthquakes in the Vrancea region. Four of the five strong earthquakes with magnitudes above 6.4 are predicted. The total duration of the Time of Increased Probability (TIP) of the occurrence of an earthquake (TIP) occupies 21.7% of the time interval under consideration, i.e., about 2.5 years for each strong earthquake.  相似文献   

7.
强震前中期地震活动的变化及TIP预测研究   总被引：2，自引：0，他引：2  
黄德瑜  陈Yong 《地震》1995,(4):323-327
用改进的Ｍ８算法研究了１９７９年以来我国华北西南及邻近地区共１６次强震前的ＴＩＰ，即震发生概率增长时间。结果表明，１４次强震发生在补判定为概率增长时间的ＴＩＰ内。ＴＩＰ警戒约占研究部时空域的３７％，获得了较好的强震中期预测内符效果。表明该方法可作为强震中期预测的手段之一。  相似文献   

8.
This paper offers a positive research result of TIP before 16 strong earthquakes in North and Southwest China and their nearby areas since 1979 by using improved algorithm M8.The result showed that 14 of them were determined to occur within the times of increased probability.TIP precaution occupies about 37% of the total space-time domain.That means we have made quite good results of intermediate-term prediction of strong earthquakes.So the method could be used as one of the useful means of the intermediate-term prediction of strong earthquakes.  相似文献   

9.
Using pattern recognition techniques, we formulate a simple prediction rule for a retrospective prediction of the three last largest eruptions of the Popocatépetl, Mexico, volcano that occurred on 23 April–30 June 1997 (Eruption 1; VEI ~ 2–3); 11 December 2000–23 January 2001 (Eruption 2; VEI ~ 3–4) and 7 June–4 September 2002 (Eruption 3; explosive dome extrusion and destruction phase). Times of Increased Probability (TIP) were estimated from the seismicity recorded by the local seismic network from 1 January 1995 to 31 December 2005. A TIP is issued when a cluster of seismic events occurs under our algorithm considerations in a temporal window several days (or weeks) prior to large volcanic activity providing sufficient time to organize an effective alert strategy. The best predictions of the three analyzed eruptions were obtained when averaging seismicity rate over a 5-day window with a threshold value of 12 events and declaring an alarm for 45 days. A TIP was issued about six weeks before Eruption 1. TIPs were detected about one and four weeks before Eruptions 2 and 3, respectively. According to our objectives, in all cases, the observed TIPs would have allowed the development of an effective civil protection strategy. Although, under our model considerations the three eruptive events were successfully predicted, one false alarm was also issued by our algorithm. An analysis of the epicentral and depth distribution of the local seismicity used by our prediction rule reveals that successful TIPs were issued from microearthquakes that took place below and towards SE of the crater. On the contrary, the seismicity that issued the observed false alarm was concentrated below the summit of the volcano. We conclude that recording of precursory seismicity below and SE of the crater together with detection of TIPs as described here, could become an important tool to predict future large eruptions at Popocatépetl. Although our model worked well for events that occurred in the past, it is necessary to verify the real capability of the model for future eruptive events.  相似文献   

10.
用改进的Ｍ８算法研究了１９７９年以来大华北地区存在的ＴＩＰ，即强震发生概率增长时间，结果表明８次中强震有７次发生在被判定为概率增长时间内，ＴＩＰ警戒占研究总时空域的４０．７％，Ｒ评分为０．４６８。获得了较好的中强震中期预测内符效果，表明该方法可作为大华北地区中强震中期预报的手段之一。  相似文献   

11.
ＲｅｓｅａｒｃｈｏｎＴＳＩＰｍｅｔｈｏｄｆｏｒｍｅｄｉｕｍ－ｔｅｒｍｅａｒｔｈｑｕａｋｅｐｒｅｄｉｃｔｉｏｎＤｅ－ＹｕＨＵＡＮＧ（黄德瑜）；Ｙｕａｎ－ＱｉｎｇＺＨＵ（朱元清）；ＹｏｎｇＣＨＥＮ（陈颙）ａｎｄＹｉｎｇＪＩ（季颖）（ＣｅｎｔｒｅｆｏｒＡｎ...  相似文献   

12.
The application of the CN algorithm to a new earthquake catalogue, for the period from 1932 to 1993, obtained by merging Romanian and U.S.S.R. data, allows us to monitor, on the intermediate time scale, the preparation of strong, intermediate-depth earthquakes in the Vrancea region. Four of the five strong earthquakes with a magnitude above 6.4 are predicted, the total duration of the Time of Increased Probability of the occurrence of an earthquake (TIP) occupies 21.7% of the time interval under consideration, i.e., about 2.5 years for each strong earthquake.  相似文献   

13.
—The paper presents the results of application of the CN algorithm to the area of the Southern External Dinarides. Two cases are considered—one for the knowledge gained throughout the considered period of time (1936–1996), and the other when learning ceased in 1986. In the first case 8 out of 9 strong earthquakes could have been predicted, three false alarms are declared (covering 7% of the total time considered) and TIPs occupy 32% of the total time. There is no clear relation between the TIPs duration and the size of the related earthquake. The second case (when the CN functions are defined on the basis of a shorter learning period) produces even slightly better results: only two false alarms are declared. In both cases current alarm exists in the region. All attempts to reduce the area of the regional polygon resulted in poorer prediction results.  相似文献   

14.
—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   

15.
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   

16.
The algorithm CN makes use of normalized functions. Therefore the original algorithm, developed for the California-Nevada region, can be directly applied, without adjustment of the parameters, to the determination of the Time of Increased Probability (TIP) of strong earthquakes for Central Italy. The prediction is applied to the events with magnitudeMM 0=5.6, which in Central Italy have a return period of about six years. The routinely available digital earthquake bulletins of the Istituto Nazionale di Geofisica (ING), Rome, permits continuous monitoring. Here we extend to November 1994 the first study made by Keilis-Boroket al. (1990b). On the basis of the combined analysis of seismicity and seismotectonic, we formulate a new regionalization, which reduces the total alarm time and the failures to predict, and narrows the spatial uncertainty of the prediction with respect to the results ofKeilis-Borok et al. (1990b).The premonitory pattern is stable when the key parameters of the CN algorithm and the duration of the learning period are changed, and when different earthquake catalogues are used.The anlysis of the period 1904–1940, for whichM 0=6, allows us to identify self-similar properties between the two periods, in spite of the considerably higher seismicity level of the earlier time interval compared with the recent one.  相似文献   

17.
本文用ＣＮ算法研究了辽宁省两个地震重点监视防御区的中强震前的强震发生概率增长时间,结果表明预测效果较好,有震报准率为９０％,ＴＩＰ预测警戒占时空率为３０％左右,Ｒ值评分为０．６左右。在ＴＩＰ预测的基础上,进一步用ＳＩＰ方法分析这两个区域的空间背景发震概率的不均匀分布。综合应用ＴＩＰ方法和ＳＩＰ方法,对辽宁省及邻近地区进行了试验性地震预报。  相似文献   

18.
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   

19.
Testing an earthquake prediction algorithm   总被引：1，自引：0，他引：1  
A test to evaluate earthquake prediction algorithms is being applied to a Russian algorithm known asM8 TheM8 algorithm makes intermediate term predictions for earthquakes to occur in a large circle, based on integral counts of transient seismicity in the circle. In a retroactive prediction for the period January 1, 1985 to July 1, 1991 the algorithm as configured for the forward test would have predicted eight of ten strong earthquakes in the test area. A null hypothesis, based on random assignment of predictions, predicts eight earthquakes in 2.87% of the trials. The forward test began July 1, 1991 and will run through December 31, 1997. As of July 1, 1995, the algorithm had forward predicted five out of nine earthquakes in the test area, which success ratio would have been achieved in 53% of random trials with the null hypothesis.  相似文献   

20.
应用ＴＩＰ中期地震预报方法中的ＣＮ算法，对河南省及其邻区发生的中等地震进行了性检验。结果表明内符效果较好，被检验的中等地震中有８０％地震前出现了ＴＩＰ，ＴＩＰ警戒时段占研究时间的２３．３％，综合计算报准率Ｒ值为０．５９。说明该算法对中等地震原中期预报具有实用意义。  相似文献   

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