The prediction for seismicity trends of M≥8 in the world by analysis of seismicity patterns

After completion of a study on predicting risky zones of earthquake of M≥8 for 1-3 years in the mainland of China,which was supported by Chinese Joint Seismological Science Foundation(D07018 and D08009),a further study was extended to that of greater magnitudes in the world.Based on the historical earthquake cases,we finished the research report,forecasting global earthquakes with magnitude more than 8.0 using the image analysis of seismicity.In this research report,we summarize 11 abnormal seismicity images for predicting earthquake of M≥8.0 around the world.In our research report,we predicted earthquakes of M≥8.0 from June 2009 to June 2014,the medium term predicting within 5 years period.Among these 5 predictive areas,three earthquakes occurred,which is Samoa M8.1 Earthquake on 29 September 2009,Talca M8.5 Earthquake on 27 January 2010,Chile,and Eastern Sendai M9.0 Earthquake on 11 March 2011,Japan respectively.Here we introduce the main items of the image analysis of seismicity and we predict three earthquakes and think that the image analysis of seismicity can be of help.     

Correlation between the seismicity parameters

Though the forecast and prediction of earthquakes is a commonly accepted difficult problem in science, thestep towards the exploration and knowledge of the generation and occurrence of earthquakes has never stopped. Ithas strong scientific exploration nature and great social efficacy in disaster reduction. For this reason, it has alwaysbeen the object and motivation pursued assiduously by earthquake researchers. It is beyond doubt that the study ofseismicity is still one of the important infor…     

Role of reservoirs in sustained seismicity of Koyna-Warna region—a statistical analysis

Koyna-Warna region in western India is a globally recognized site of reservoir-triggered seismicity near the Koyna and Warna reservoirs. The region has been reported with several M?>?5 earthquakes in the last five decades including M6.3 Koyna earthquake which is considered as the largest triggered earthquake worldwide. In the present study, a detailed statistical analysis has been done for long period earthquake catalogues during 1968–2004 of MERI and 2005–2012 of CSIR-NGRI to find out the spatio-temporal influence of the Koyna and Warna reservoirs impoundment on the seismicity of the region. Depending upon the earthquake clusters, we divided the region into three different zones and performed power spectrum and singular spectrum analysis (SSA) on them. For the time period 1983–1995, the earthquake zone near the Warna reservoir; for 1996–2004, the earthquake zone near the Koyna reservoir; and for 2005–2012, the earthquake zone near the Warna reservoir found to be influenced by the annual water level variations in the reservoirs that confirm the continuous role of both the reservoirs in the seismicity of the Koyna-Warna region.     

Patterns of seismic sequences in the Levant—interpretation of historical seismicity

There are historical accounts of about a hundred damaging earthquakes that occurred during the last two millennia in the Levant, in and around the Dead Sea fault system, and about half of which were associated with additional felt shocks. Several modes of earthquake sequences can be distinguished in them: (a) In 46 accounts, only one single event is noted. These are not known from tectonic settings similar to that of the Levant, and may just be a result of incomplete reporting. (b) In four cases, quakes preceded the mainshock by minutes, hours, and up to several weeks—possibly foreshocks. (c) Thirty-five mainshock–aftershock sequences were noted, lasting hours, days, weeks, months, and even more than a year; four of these also have foreshocks. No typical delay time was recognized for the largest or most significant aftershocks: they appeared up to several months later. (d) Six of the reported mainshock–aftershock sequences appeared in a “storm.” Another 13 sequences are insufficient to specify further.     

The numerical method of Fourier eigen transform and its application in seismicity analysis

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The behavior of seasonal variations in induced seismicity in the Koyna–Warna region,western India

Based on the earthquake catalog data for the Koyna–Warna region of induced seismicity in western India, the seasonal variations in seismic activity associated with annual fluctuations in the reservoir water level are analyzed over the time span of the entire history of seismological observations in this region. The regularities in the time changes in the structure of seasonal variations are revealed. The seasonal seismic activity is minimal in May–June when the reservoir level is lowest. During the remaining part of the year, the activity has three peaks: the fall peak in September, winter peak in November–December, and spring peak in February–March. The first mentioned peak, which falls in the phase of the water level reaching its maximal seasonal value is considered as the immediate response of the fluid saturated medium to the additional loading under the weight of reservoir water. The two subsequent maxima concur with the decline phase in the reservoir level and are interpreted as the delayed response associated with the changes in the properties of the medium due to water diffusion. It is shown that the intensities of the immediate and delayed responses to the seasonal water level variations both vary with time as does their ratio. The probable factors affecting the variations in the intensity of the seasonal components of the reservoir-induced seismicity are discussed.     

Statistical analysis on energy field of seismicity in Ningxia and its neighborhood region

IntroductionOneofnotablefeaturesofseismicityistherandomoccurrenceofearthquakesinspaceandtime.Oneessentialelementofseismicityisthatearthquakereleasedenergycanbetakenastherandomfunctionsofspatialandtemporalcoordinates.Therandomfunctioncanbecalledseismicityenergystochasticfieldorearthquakeenergyfield.Sincetheseismicityisrelatedinspaceandtime,usingtheconceptofstochasticfield,thetotalfeatureofregionalseismicactivitycanbeconsidered,ratherthanthestatisticsofasingleearthquakeinthepast.Therefore,thefe…     

Temporal and spatial variations of seismicity scaling behavior in Southern México

R/S analysis is used in this work to investigate the fractal correlations in terms of the Hurst exponent for the 1998–2011 seismicity data in Southern Mexico. This region is the most seismically active area in Mexico, where epicenters for severe earthquakes (e.g., September 19, 1985, M_w = 8.1) causing extensive damage in highly populated areas have been located. By only considering the seismic events that meet the Gutenberg–Ritcher law completeness requirement (b = 0.97, M_GR = 3.6), we found time clustering for scales of about 100 and 135 events. In both cases, a cyclic behavior with dominant spectral components at about one cycle per year is revealed. It is argued that such a one-year cycle could be related to tidal effects in the Pacific coast. Interestingly, it is also found that high-magnitude events (M_w ≥ 6.0) are more likely to occur under increased interevent correlations with Hurst exponent values H > 0.65. This suggests that major earthquakes can occur when the tectonic stress accumulates in preferential directions. In contrast, the high-magnitude seismic risk is reduced when stresses are uniformly distributed in the tectonic shell. Such cointegration between correlations (i.e., Hurst exponent) and macroseismicity is confirmed for spatial variations of the Hurst exponent. In this way, we found that, using the Hurst exponent standpoint, the former presumed Michoacan and the Guerrero seismic gaps are the riskiest seismic zones. To test this empirical finding, two Southern Mexico local regions with large earthquakes were considered. These are the Atoyac de Alvarez, Guerrero (M_w = 6.3), and Union Hidalgo, Oaxaca (M_w = 6.6), events. In addition, we used the Loma Prieta, California, earthquake (October 17, 1989, M_w = 6.9) to show that the high-magnitude earthquakes in the San Andreas Fault region can also be linked to the increments of determinism (quantified in terms of the Hurst exponent) displayed by the stochastic dynamics of the interevent period time series. The results revealed that the analysis of seismic activity by means of R/S analysis could provide further insights in the advent of major earthquakes.     

The application of seismic data with different precision in the determination of seismicity parameters

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Statistical assessment of seismicity patterns in Italy: Are they precursors of subsequent events?

The variations of seismicity rate in Central Apenninesprior to the sequence started in September, 1997 (at00:33 UTC, M _L5.6) has been analysedby statistical methods, with the purpose of pointingup eventual periods of quiescence. The analysis wascarried out on the instrumental catalogue of theIstituto Nazionale di Geofisica (ING), covering theperiod from January 1975 to March 1998. In apreliminary phase, the catalogue was declustered usingthe Reasenberg algorithm. After that, eventualmagnitude shifts due to variations in the modalitiesof observation have been individuated and corrected.The subsequent analysis, carried out making use of theZmap software package, has put in evidence thatthe sequence of September 1997 was preceded bya 2.5 year period characterised by absence of eventsof magnitude larger than 3.2, in an area approximately20 × 40 km wide, including the epicentre of themain shock. The statistical methodology shows thatonly 1/10³ of the space-time volumes analysed inthis study, exhibited quiescence of the same level.The study of seismicity rate change correlated toprevious main shocks in a larger area of CentralApennines shows that none of them were preceded by aseismic quiescence, specially close to the epicentreof the main shock, and lasting until the time ofoccurrence of the main shock as in the 1997 case.Actually, we found other patterns of precursoryquiescence with different time or space distribution.We conclude that precursory quiescence is a realfeature of Central Apennines seismicity, but it isdifficult to define a simple hypothesis, which appliesto the generality of cases and can be tested beforeimplementation in a system of earthquake riskmitigation.     

Field experiment in Soultz-sous-Forêts, 1993: Changes of the pattern of induced seismicity

The data of the known field experiment on water injection in the borehole were analyzed. Parameters of self-similarity of seismicity were estimated in comparison with the changes of water pressure. Changes of seismicity parameters that indicate the redistribution of the failure from lower scales to upper are revealed. The total number of earthquakes per series of the water initiation found to be depended exponentially on the water pressure and seismic activity maximum is delayed gradually relative to beginning of initiation. The growth of induced seismicity zone in time differs from diffusion model for water flow in the porous medium. Analysis carried out from laboratory data indicates that diffusion growth of the failure area may be realized in the dry specimen, without fluid. It could be assumed that both kinetic processes — water and the failure diffusion — can be significant for the development of seismicity induced by the water injection.     

Relationship between global seismicity and solar activities

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Mathematical modelling of nonlinear behaviour of seismicity

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The seismicity research in the sub-regions of Chinese mainland using strain accumula-ting and releasing model

Introduction Lots of researches suggest that the seismicity is irregular in the space and unsteady on the time. The former behaves as that the earthquakes usually are distributed in bands or zones, the latter behaves as that the seismicity has the active and placid alternant stages (high and low). Analyzing the seismicity of Chinese mainland shows that the distribution of strong earthquakes indicates different distributing pictures in space in different periods. According to strain releasing …     

Deep electrical anomaly in the M7.5 Qiongzhou earthquake region and its relation with future seismicity

From the magnetotelluric detection in the epicentral region and the adjacent areas of the 1605 M7.5 Qiongzhou earthquake, we have discovered there is a low resistive body in the deep crust of the epicentral region. The low resistive body extends straightly from the depth of about 13 km to the upper mantle, which is supposed as an up-rising mantle pole. We therefore consider it is just the existing mantle pole and its upwelling thermal material that result in the faulting and stick-slipping activities of the upper crust, which is an important factor for the M7.5 Qiongzhou great earthquake occurrence. The postseismic faulting activity is characterized by creep, which shows that the risk is greatly decreased for the occurrence of a great earthquake with similar intensity in the future.     

Induced seismicity and the possibilities of controlled relaxation of tectonic stresses in the Earth’s crust

Natural and anthropogenic impacts on seismicity are considered. Taking into account the importance of the discussed problem, the authors propose to open the discussion on the questions considered. In this connection a wide circle of known experimental data is considered, which are indicative of the possibility in principle of active impact on the seismogenic medium for the smooth relieving of accumulated tectonic stresses in the Earth’ s crust. The reasoning is presented of one of the promising ways of the smooth controlled relaxation of the accumulated tectonic stresses in the Earth’s crust at the places of the probable onset of strong earthquakes due to a considerable increase in the plastic slips, which facilitate the decrease of the number and energy of earthquakes. The approach proposed is based on the results of the works on the excited seismicity, obtained in different regions of the Earth. Special attention is given to the most detailed long-term investigations of the excited seismicity in the region of the reservoir of the Nurek hydroelectric station in Tadzhikistan and in the neighborhood of the actively mined Romashkinskoe oil deposit in the Republic of Tatarstan. The results of the laboratory investigations of the behavior of samples made of materials of crystalline and amorphous structures under the action of pressure and vibration are invoked for the substantiation of the physical nature of the observed effects. For the reduction of seismic hazard, it is proposed to use vibration actions and water injection in the bore holes at the places of the expected seismic catastrophes in a time mode matched with the tidal motions of the Earth.     

Influence of statistical time range on estimating seismicity parameters

Introduction At present, the current probabilistic method of seismic hazard analysis in the world is gener-ally adopted in seismic safety evaluation (Cornell, 1968). It supposed that earthquake occurrence conforms to the segmented Poisson distribution model in time and space and the proportional rela-tion among earthquakes of various magnitudes obeys the cut-exponential distribution law in a sta-tistical area in compiling Seismic Intensity Zoning Map in China (1990) owing to the temporal- sp…     

Primary component analysis method and reduction of seismicity parameters

Introduction Data mining (SHAO and YU, 2003) is a new kind of technique developed with database and artificial intelligence in recent years, which processes the data in the database to abstract the im- plied and pre-unknown, but potentially useful information and knowledge from large amounts of incomplete, noisy, blurring and stochastic data. For data mining, data purging is an important link beforehand that includes eliminating noise, making up lost domain, and deleting ineffective data, as…