arXiv subjects

N. Zymaris

Publications and source records attributed to N. Zymaris.

16 recordsLinked to original sources

arXiv2012

Does Global seismic energy release increase? An analysis based on the Lithospheric Seismic Energy Flow Model (LSEFM). The case of mega - earthquakes (M > 9)

In this work the data of the earthquake catalog of the NOAA, National Geophysical Data Center (NGDC) are processed in terms of global seismic energy release. The determined Global Cumulative Seismic Energy Release (GCSER) graph as a function of time, is analyzed in the magnitude domain (discrete energy windows). Characteristic components of the analyzed graph are: its accelerated deformation character observed for energy windows lower than the background seismicity (M = 7.0 - 7.5), its lock state that started on 1923 and long seismic quiescence periods that preceded recent mega - earthquakes. The background GCSER value oscillates during the last century with a period of 60 years and with increasing amplitude. The recent (1952 - 2012) 5 mega - earthquakes are closely related to the amplitude increase of the GCSER oscillation. Hence, it is suggested that more mega - earthquakes are probable due to occur in the future. A global mechanism is postulated for the generation of the mega - earthquakes based on the principles of the non-linearity of the earth, the Markovitz wobble and the expanding earth. The determination of the magnitude of the 5 recent mega - earthquakes by the Lithospheric Seismic Energy Flow Model (LSEFM) method indicates that the latter is globally applicable. Key words: Global seismicity, expanding earth, mega - earthquakes, Markowitz wobble, background seismicity, magnitude determination

physics.geo-ph↗

arXiv2012

Preseismic electric signals generated by critical stress loading of the lithosphere. A review of the type of signals obtained from a long lasted (1999 to 2012) experiment conducted in Greece

In this work a review is made of the various preseismic electric signals that have been observed before large EQs in Greece during the period of 1999 to 2012. The observed preseismic electric signals comply quite well with the theoretical ones that are expected to be generated by a large scale piezoelectric mechanism been activatsd at the focal area due to its excess stress-load. Preseismic electric signals of the total piezoelectric field, its first time derivative, its oscillation due to M1 and K1 tidal components have been observed by single monitoring sites during the actual 1999 to 2012 experiment in Greece. Moreover, the "strange attractor like" electric preseismic signal was detected by the simultaneously use of two distant monitoring sites. It is demonstrated that the preseismic electric signals can not only determine quite accurately a very short time window for the EQ occurrence and its epicentral location but the latter can be achieved without any prior knowledge of the geological, tectonic setting or past seismic history of the seismogenic area. The predicted pending EQ is treated as a single isolated destructive nature event which sends clear warning signals well before its occurrence. Real examples are presented from the Greek territory. Key words: piezoelectricity, electric preseismic signals, strange attractor like, earthquake prediction.

physics.geo-ph↗

arXiv2012

Do large EQs occur randomly in time? The Mexico EQ (20th of March, 2012, Mw = 7.4) as viewed in terms of local lithospheric oscillation due to M1 and K1 tidal components. A brief presentation

The time of occurrence of the large EQ that occurred recently in Mexico (March 20th, 2012, Mw = 7.4) is compared to the peak amplitude occurrence time of the local M1 and K1 tidal components. It is shown that the specific EQ occurred one (-1) day before the next following peak of the M1 tidal component, and was delayed for only +20 minutes after the corresponding K1 tidal peak. Therefore, the specific seismic event complies quite well with the earlier proposed physical mechanism (lithospheric oscillation) that causes triggering of large EQs. Key words: Mexico, large earthquakes, M1 tidal wave, K1 tidal wave, lithospheric oscillations, tidal oscillations, short-term earthquake prediction.

physics.geo-ph↗

arXiv2011

The Earth's oscillating electric field (T = 1 day) in relation to the occurrence time of large EQs (Ms>5.0R). A postulated theoretical physical working model and its statistical validation

The mechanically oscillating, due to tidal forces, lithosperic plate activates, because of its high content in quartzite, the generation of a piezoelectric field. Due to the same mechanical oscillation the lithosphere is generally at a state of an oscillating stress load. Therefore, large EQs which occur at the peaks of the stress load must coincide with the peaks of the generated piezoelectric potential. In this work a physical mechanism is postulated that accounts for the latter hypothesis. The postulated model is statistically tested by comparing the time of occurrence of 280 large EQs (Ms>5.0R) which occurred during the period from 2003 to 2011, to the same period of time Earth's electric field registered at ATH (Athens) and PYR (Pyrgos) monitoring sites located in Greece. The comparison has been made for the oscillating component of T = 1 day and for both the E - W and N - S directions. The statistical results indicate that the postulated model does not behave randomly. Instead, it represents a smooth normal distribution which peaks on the zero deviation in time between the time of occurrence of the large EQs and the amplitude peaks of the Earth's oscillating electric field. Therefore, the proposed physical model is an acceptable one and can be used for the finer refinement of the prediction of the occurrence time of a large EQ within a day's time period.

physics.geo-ph↗

arXiv2011

Can large (M >= 8) EQs be triggered by tidal (M1) waves? An analysis of the global seismicity that occurred during 1901 - 2011

The analysis of two global data sets of large earthquakes (2010 - 2011, 30 samples of M \geq 7R and 1901-2011, 178 samples of M \geq 8R) reveals that there exists a cause and effect relation between the vertical tidal M1 component amplitude peak and the time of occurrence of the latter EQs. A physical model mechanism is postulated that justifies the obtained results. It is shown that the tidal waves can trigger a large EQ, despite their small amplitude, provided that the seismogenic area is under critical stress load conditions. Actually, it is shown that a large EQ can be triggered by the cooperative action of all vertical tidal components but mainly by the M1 and K1 ones. Examples are presented from the most recent global large EQs (Summatra, Mw = 9.1, 2004 and Japan, Mw = 9.0, 2011) and from Greece (Kythira, Greece, Ms = 6.9R, 2006 and Skyros, Greece, Ms = 6.1R, 2001). The postulated physical model provides the means for the implementation of the first step towards a really short-term earthquake prediction.

physics.geo-ph↗

arXiv2011

On the recent large EQ of Karpathos, Greece (April 1st, 2011, Ms = 6.7R) and its similarities to the large EQ of the January 1st, 2006 (Ms = 6.9R) at East of Kythira, Greece

The recent large EQ that occurred in Greece (April 1st, 2011, Ms = 6.7R) is investigated as far as it concerns regional geophysical features of the Greek territory. In particular, the EQ location is compared to the deep lithospheric fracture zones and faults, derived from the analysis of the corresponding earth's gravity field; to the current seismic potential map determined from the study of the past seismicity, while its time of occurrence is compared to the peaks of the M1 and diurnal tidal waves. The detailed investigation of the earth's electric field that was recorded by the ATH monitoring site, located in Athens, revealed the presence of short train like pulses type electric seismic precursory signals which were generated short (1 - 2 days) before the EQ occurrence time. Moreover, the analysis (for T = 1 day) of the earth's oscillating electric field, that was simultaneously recorded at PYR and ATH monitoring sites, revealed that the "strange attractor like" seismic electric precursor preceded for 1 - 2 days the EQ occurrence time. A similar behavior was observed from the large EQ of the East Kythira (Ms = 6.9R, January, 8th, 2006). It is concluded that the same regional tectonic mechanism controlled and generated both the analyzed EQs while the adopted geophysical earth models have been validated.

physics.geo-ph↗

arXiv2011

The Japan earthquake of March 11th, 2011 (Mw = 8.9R) as viewed in terms of local lithospheric oscillation due to M1 and K1 tidal components. A brief presentation

The time of occurrence of the large EQ that occurred recently in Japan (March 11th, 2011, Mw = 8.9) is compared to the time of peak amplitude occurrence of the M1 and K1 tidal components. It is shown that the specific EQ occurred on the peak of the M1 tidal component, and deviates for only 45 minutes from the corresponding K1 tidal peak. Therefore, the specific seismic event complies quite well with the earlier proposed physical mechanism (lithospheric oscillation) that causes triggering of large EQs.

physics.geo-ph↗

arXiv2011

A short note on the two most recent large EQs of New Zealand (Mw=7.0 on September 3rd, 2010 and Mw=6.1 on February 21st, 2011). A typical example of tidally triggered large EQs by the M1 tidal component

The time of occurrence of the two most resent large EQs of New Zealand (Mw = 7.0 on September 3rd, 2010 and Mw = 6.1 on February 21st, 2011) is compared to the time when the lithospheric oscillation at the focal area reaches its peak amplitude in terms of the M1 (Moon declination) tidal component. The observed very good coincidence of the EQs occurrence time with the lithospheric oscillation peak amplitude time for the M1 tidal component clearly suggests that both these EQs were triggered by the M1 component of the lithospheric tidal oscillation. It is speculated that large preseismic electric signals should be observed before the EQs occurrence if the appropriate hardware were installed.

physics.geo-ph↗

arXiv2010

The background seismicity rate of the Greek territory, considered as a unified seismogenic area, for the period 1964 - 2010. Is Greece in course for a large seismic event?

The analysis of the earthquakes catalog of Greece for the period 1964 to 2010 indicates a continuously increasing no. of seismic events. A detailed determination of the cumulative seismic energy release, for specific earthquake magnitudes, revealed that for magnitudes up to Ms = 5.0R the Greek territory, considered as a unified seismogenic area, is at a state of accelerating deformation for almost the last 10 years. The background seismicity rate, considering constant cumulative seismic energy release for the entire study period, corresponds to a magnitude of Ms = 5.5R, while for earthquakes of larger magnitudes the Greek seismogenic area behaves irregularly. The results are compared to the different phases (Mjachkin et al, 1975) a seismogenic area undergoes before a large seismic event. From this comparison it is concluded that the Greek territory is probably in the course for a large seismic event in the years to come.

physics.geo-ph↗

arXiv2010

The Andravida, Greece EQ (8/06/2008, Ms=7.0R). An "a posteriori" analysis for the determination of its location, occurrence time and magnitude parameters in terms of short-term predictability

The Andravida EQ, Greece (8/6/2008, Ms=7.0R) seismic parameters: location, time of occurrence and magnitude were determined "a posteriori" in an attempt to verify the predictability of the large EQs. The Earth's electric field, after its processing by de-noising techniques, was used, in conjunction with appropriate physical models, for the determination of the epicenter by triangulation. The time of occurrence was determined in very short-term mode by the use of the tidal waves (M1, K1) and the "strange attractor like" seismic electric precursor, while its magnitude was calculated by the application of the "lithospheric seismic energy flow model" applied on the past seismicity of the Andravida EQ regional seismogenic area. The quite accurate obtained results corroborate the validity of the methodology and suggest its use as a valuable tool for predicting large earthquakes. Key words: earthquake prediction, epicenter area, time of occurrence, earthquake magnitude, seismic potential, tidal waves.

physics.geo-ph↗

arXiv2009

Medium - long term earthquake prediction by the use of the oscillating electric field (T = 365 days) generated due to Earth's orbit around the Sun and due to its consequent oscillating lithospheric deformation

We study the Earth's electric field monitored at PYR (Greece) monitoring site, for a period of more than six years (May 23rd, 2003 to September 7th, 2009). It is compared, in particular its oscillating component of T = 365 days, with the Perihelion - Aphelion dates of the Earth's orbit around the Sun, with the same component of the Earth's magnetic field, with the corresponding same period tidal oscillation and with the occurred large EQs of the same period of time. The obtained results suggest that the oscillating electric field component is generated by large scale piezoelectricity triggered by the Earth's shape - lithospheric oscillating deformation. The driving mechanism (yearly tidal variation) precedes the Aphelion - Perihelion dates for a month complying with the corresponding tidal friction behavior of the Earth's shape deformation. The Earth's oscillating electric field peaks coincide with the Perihelion - Aphelion dates while the triggered large EQs are clustered very close to the Perihelion - Aphelion dates. Moreover it is shown that the observed Earth's oscillating electric field is not related to or induced by the corresponding Earth's magnetic field. In conclusion, the Earth's oscillating electric field character could be used as medium to long term electric seismic precursor of large EQs. Keywords: tidal waves, Earth deformation, preseismic electric signals, magnetic field, Perihelion, Aphelion, earthquake prediction.

physics.geo-ph↗

arXiv2009

Seismic electric precursors observed prior to the 6.3R EQ of July 1st 2009, Greece and their use in short-term earthquake prediction

The normalized raw data of the Earth's electric field, monitored at PYR, ATH, HIO monitoring sites in Greece, are studied as far as it concerns the presence of electric seismic precursors. Electric preseismic pulses, plateau-like anomalous electric field and Very Long Period (VLP) anomalies were detected prior to the occurrence of the July 1st, 2009 large (Ms = 6.3R) EQ in Greece. Further processing of the same data revealed the true form of the generated preseimic potential thus providing an indirect estimation of the time window of the occurrence of the large EQ. Finally, by correlating, at pairs, the anomalous electric field from all monitoring sites it is possible to calculate the "strange attractor like" seismic electric precursor that provides a time window for the occurrence of the large EQ and utilizes the determination not only of the regional seismogenic area that has been activated but also a more precise epicenter too.

physics.geo-ph↗

arXiv2009

Decomposing the "strange attractor like" seismic electric precursor into simpler components

An attempt is made in this work to decompose the "strange attractor like" seismic electric precursor into more simple and elementary components. The basic data files of the orthogonal (NS, EW) components of the Earth's electric field used for the compilation of the corresponding phase maps are decomposed by a joint non-linear inversion scheme into two basic oscillating electric fields. The first one, called "signal", is attributed to a single current source while the second, called "noise", is attributed to the mix-up of some regional and randomly located current sources. The comparison of the phase maps compiled from the raw data files to the ones compiled by the "signal" and "noise" data shows that the newly compiled "strange attractor like" phase maps preserve their predictive property while their appearance resembles simpler geometrical shapes (pure hyperbolas and ellipses). Moreover, it is postulated that its generating mechanism is the stress waves applied in the regional area by the combined interaction of the Sun, Moon and Earth (tidal waves). The latter mechanism, when the seismogenic area is under critical stress-charge conditions, triggers new current sources at places where the stress has reached locally critical stress levels and hence the "strange attractor like" seismic precursor is generated.

physics.geo-ph↗

arXiv2009

Preseismic oscillating electric field "strange attractor like" precursor, of T = 6 months, triggered by Ssa tidal wave. Application on large (Ms > 6.0R) EQs in Greece (October 1st, 2006 - December 2nd, 2008)

In this work the preseismic "strange attractor like" precursor is studied, in the domain of the Earth's oscillating electric field for T = 6 months. It is assumed that the specific oscillating electric field is generated by the corresponding lithospheric oscillation, triggered by the Ssa tidal wave of the same wave length (6 months) under excess strain load conditions met in the focal area of a future large earthquake. The analysis of the recorded Earth's oscillating electric field by the two distant monitoring sites of PYR and HIO and for a period of time of 26 months (October 1st, 2006 - December 2nd, 2008) suggests that the specific precursor can successfully resolve the predictive time window in terms of months and for a "swarm" of large EQs (Ms > 6.0R), in contrast to the resolution obtained by the use of electric fields of shorter (T = 1, 14 days, single EQ identification) wave length. More over, the fractal character of the "strange attractor like" precursor in the frequency domain is pointed out. Finally, a proposal is made that concerns the continuous monitoring of the specific preseismic attractor in distinct different wave lengths of the oscillating Earth's electric field so that an early warning system can be utilized. As a refinement of the "strange attractor like" methodology, the guide lines of a generalized inversion scheme are presented so that the epicenter of the driving mechanism (seismic epicentral area) can be estimated in a least squares sense.

physics.geo-ph↗

arXiv2009

Preseismic oscillating electric field "strange attractor" like precursor, of T=14 days, triggered by M1 tidal wave. Application on large (Ms > 6.0R) EQs in Greece (March 18th, 2006 - November 17th, 2008)

The "strange attractor like" precursor, calculated from the Earth's oscillating electric field registered at PYR and HIO monitoring sites located in Greece, is studied in the domain of T = 14 days. It is assumed that the generating precursory signals focal mechanism is triggered by the corresponding M1 (moon declination) tidal wave. The obtained results from the analysis of eight (8) cases of large (Ms>6.0R) EQs that occurred from March 18th, 2006 to November 17th, 2008 suggest the validity of the method. Moreover, it is found that the specific methodology applied for T = 14 days behaves very closely to the same one when applied for T = 1 day even though there is a resolution decrease in the calculated predictive time window for the occurrence of the oncoming large EQ. It is speculated that this type of precursor, once it is present in one distinct oscillating component of the seismic precursory generated electric field, then, most probably, it is present in most of its other oscillating components. The latter suggests the investigation of the preseismic precursory electric field at its longer wavelengths i.e. components triggered by the Ssa (6 months, moon declination) oscillating components. The large value of the obtained success rate (predicted EQs / total no. of large EQs) suggests its use as a time prediction tool in the domain of the "short-term prediction".

physics.geo-ph↗

arXiv2008

Preseismic electric field "strange attractor" like precursor analysis applied on large (Ms > 5.5R) EQs, which occurred in Greece during December 1st, 2007 - April 30th, 2008

In order to investigate the capability of the preseismic electric field "strange attractor like" precursor as a time predictor of a large EQ within a short time window (short-term prediction), the specific methodology was applied on the Earth's electric field recorded during a rather long seismically active period (December 1st, 2007 - April 30th, 2008) of Greece. During this period of time a number (8) of large (Ms > 5.5R) earthquakes took place. The particular analysis is presented in detail for the following EQs: the Monemvasia EQ (January 6th 2008, Ms = 6.6R), the Methoni EQs (February 14th 2008 Ms = 6.7R, February 19th 2008 Ms = 5.6R, February 20th 2008 Ms = 6.5R, February 26th 2008 Ms = 5.7R), the Skyros EQ (March 19th 2008 Ms = 5.5R) and the Mid Southern Creta EQ (March 28th 2008 Ms = 5.6R). The obtained results from the analysis of the afore mentioned EQs, in conjunction to the ones obtained from an earlier presentation of the particular methodology (Thanassoulas et al. 2008a), suggest: an average time of initiation of the preseismic precursor of the order of (9) days before the EQ occurrence, a precursor average duration of the order of (7) days, while the elapsed time between the end of the precursor till the EQ occurrence time is, at average, only (2) days. These results suggest an objective and easy to apply method for the short-term EQ prediction, based on the registration of the Earth's electric field on ground surface.

physics.geo-ph↗