Time-predictable model applicability for earthquake occurrence in northeast India and vicinity

Abstract. Northeast India and its vicinity is one of the seismically most active regions in the world, where a few large and several moderate earthquakes have occurred in the past. In this study the region of northeast India has been considered for an earthquake generation model using earthquake data as reported by earthquake catalogues National Geophysical Data Centre, National Earthquake Information Centre, United States Geological Survey and from book prepared by Gupta et al. (1986) for the period 1906–2008. The events having a surface wave magnitude of Ms≥5.5 were considered for statistical analysis. In this region, nineteen seismogenic sources were identified by the observation of clustering of earthquakes. It is observed that the time interval between the two consecutive mainshocks depends upon the preceding mainshock magnitude (Mp) and not on the following mainshock (Mf). This result corroborates the validity of time-predictable model in northeast India and its adjoining regions. A linear relation between the logarithm of repeat time (T) of two consecutive events and the magnitude of the preceding mainshock is established in the form LogT = cMp+a, where "c" is a positive slope of line and "a" is function of minimum magnitude of the earthquake considered. The values of the parameters "c" and "a" are estimated to be 0.21 and 0.35 in northeast India and its adjoining regions. The less value of c than the average implies that the earthquake occurrence in this region is different from those of plate boundaries. The result derived can be used for long term seismic hazard estimation in the delineated seismogenic regions.

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Validity of time-predictable seismicity model for Nepal and its adjoining regions

Journal of Nepal Geological Society ◽

10.3126/jngs.v38i0.31476 ◽

2008 ◽

Vol 38 ◽

pp. 15-22 ◽

Cited By ~ 1

Author(s):

Harihar Paudyal ◽

H. N. Singh ◽

D. Shanker ◽

V. P. Singh

Keyword(s):

Main Shock ◽

Time Interval ◽

Generation Model ◽

Nepal Himalaya ◽

Seismogenic Sources ◽

Main Shocks ◽

Earthquake Generation ◽

Event Times ◽

Seismicity Model

Earthquake generation model for the Nepal Himalaya and its adjoining regions was studied using seismicity data from 1963 to 2004 reported in the catalogues of National Geophysical Data Centre, Colorado and U. S. Geological Survey. The earthquakes having a surface wave magnitude Ms≥5.1 were considered to establish the statistical relation. Four seismogenic sources based on clusters of earthquakes have been identified in the region. It is observed that the time interval between two consecutive main shocks depends on the preceding main shock magnitude (Mp) and not on the forthcoming main shock magnitude (Mf). The result supports the applicability of time-predictable model for Nepal and its adjoining regions. A linear relation is established connecting the logarithm of the inter-event times between two successive main shocks (T) and magnitude of preceding main shock in the form log T =cMp + a where parameter a is a function of the minimum magnitude of the earthquake considered and the tectonic loading, and c is a positive constant. The physical meaning of the model is that larger the magnitude of the preceding main shock the longer will be the time interval for the forthcoming earthquake. The values of constants c and a for Nepal Himalaya and its adjoining regions are computed to be 0.25 and -0.65 respectively. This result can be utilised to compute the time of occurrence of the impending strong earthquake within the delineated seismogenic sources and may be used for assessing the long-term seismic hazard in the region.

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Analysis of potential seismic sources of tsunamis in the Black Sea region, using data from various catalogues

10.5194/egusphere-egu21-8278 ◽

2021 ◽

Author(s):

Emil Oynakov ◽

Liliya Dimitrova ◽

Lyubka Pashova ◽

Dragomir Dragomirov

Keyword(s):

Black Sea ◽

Scientific Evidence ◽

Active Faults ◽

Active Regions ◽

The Black Sea ◽

Earthquake Catalogues ◽

Crimean Peninsula ◽

Black Sea Region ◽

Global Science ◽

Using Data

Low-laying territories along the Black Sea coastal line are more vulnerable to the possible high (long) waves due to tsunami events caused by strong earthquakes in the active seismic regions. Historically, such events are rare in the Black Sea region, despite some scientific evidence of tsunamis and their recordings through continuous sea-level observations with tide gauges built in certain places along the coast. This study analyses seismic data derived from different international earthquake catalogues - NEIC, ISC, EMSC, IDC and Bulgarian national catalogue (1981 - 2019). A catalogue of earthquakes within the period covering the historical to the contemporary seismicity with magnitudes M &#8805; 3 is compiled. The data are processed applying the software package ZMAP, developed by Stefan Wiemer (http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/index.html). The catalogues' completeness is calculated to assess the reliability of the historical data needed to assess the risk of rare tsunami events. The prevailing part of the earthquakes' epicentres are in the seismically active regions of Shabla, the Crimean peninsula, the east and southeast coast of the Black Sea forming six main clusters, which confirmed previous studies in the region. In these areas, several active and potentially active faults, which can generate tsunamigenic seismic events, are recognized.Acknowledgements: The authors would like to thank the Bulgarian National Science Fund for co-funding the research under the Contract &#1050;&#1055;-&#1057;&#1045;-&#1050;&#1054;&#1057;&#1058;/8, 25.09.2020, which is carried out within framework of COST Action 18109 &#8220;Accelerating Global science In Tsunami HAzard and Risk analysis&#8221; (AGITHAR; https://www.agithar.uni-hamburg.de/).

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On the validity of the regional time and magnitude predictable model in China

Annals of Geophysics ◽

10.4401/ag-3756 ◽

1999 ◽

Vol 42 (5) ◽

Author(s):

C. Qin ◽

E. E. Papadimitriou ◽

B. C. Papazachos ◽

G. F. Karakaisis

Keyword(s):

Physical Meaning ◽

Main Shock ◽

Active Regions ◽

Time Interval ◽

Tectonic Loading ◽

Simplified Form

A simplified form of the "regional time and magnitude predictable model" gives the time interval, T, between two successive mainshocks in a region and the magnitude, Mf, of the following mainshock by the relations: logT=cMP+a; Mf=CMp+A, where Mp is the magnitude of the preceding mainshock, a, A are constants which depend on the minimum considered mainshock and on the region's tectonic loading (moment rate). The physical meaning of the model is that the larger the magnitude of the preceding main shock, Mp, the longer the time, T, will be till the occurrence of the next one and the smaller its magnitude, Mf. This means that parameters c and C are positive and negative, respectively, when the model has been found valid for a certain area. In order to examine if the above model is appropriate to describe the seismicity behavior in the area of China, a detailed inspection was carried out aiming to show if the estimated values of parameters c and C favor the model. The results show that c tends to the global value 0.33, obtained by Papazachos and Papadimitriou (1997), and that C tends to be within the range [-0.30, -0.23]. The results, which favored the model, greatly outnumber those that do not follow it, the latter being concentrated around the boundaries of the seismically active regions. It is concluded that the results, which favor the model, obviously dominate the whole territory of China.

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Prediction of upcoming grand episodes of solar activity

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318001734 ◽

2018 ◽

Vol 13 (S340) ◽

pp. 325-326

Author(s):

G. L. Jayalekshmi ◽

P. R. Prince

Keyword(s):

Solar Activity ◽

Active Regions ◽

Phase Changes ◽

Activity Level ◽

Time Interval ◽

The Sun ◽

Strong Magnetic Fields ◽

Periodicity Analysis ◽

Long Time ◽

Grand Minima

AbstractSunspots are active regions on the surface of the Sun having strong magnetic fields. Activity level of the Sun shows long-time scale phenomena known as grand episodes-Grand maxima and Grand minima. Present study examines grand episodes shown by sunspot numbers (1090-2017), using methods of wavelet transform and sinusoidal regression. Time interval analysed includes two grand maxima and four grand minima. Interval in between grand episodes are regular oscillations. Phase changes found from periodicity analysis clearly show the presence of upcoming grand episodes. The forthcoming grand episodes are suggested to be two grand minima which are likely to occur between the years 2100-2160 and 2220-2300.

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Correlation between tectonic CO2 Earth degassing and seismicity is revealed by a 10-year record in the Apennines, Italy

Science Advances ◽

10.1126/sciadv.abc2938 ◽

2020 ◽

Vol 6 (35) ◽

pp. eabc2938 ◽

Cited By ~ 3

Author(s):

G. Chiodini ◽

C. Cardellini ◽

F. Di Luccio ◽

J. Selva ◽

F. Frondini ◽

...

Keyword(s):

Large Scale ◽

Continuous Process ◽

Active Regions ◽

Temporal Relations ◽

Earthquake Cycle ◽

Earthquake Occurrence ◽

Gas Emission ◽

Seismic Sequences ◽

Long Time ◽

High Seismicity

Deep CO2 emissions characterize many nonvolcanic, seismically active regions worldwide, and the involvement of deep CO2 in the earthquake cycle is now generally recognized. However, no long-time records of such emissions have been published, and the temporal relations between earthquake occurrence and tectonic CO2 release remain enigmatic. Here, we report a 10-year record (2009–2018) of tectonic CO2 flux in the Apennines (Italy) during intense seismicity. The gas emission correlates with the evolution of the seismic sequences: Peaks in the deep CO2 flux are observed in periods of high seismicity and decays as the energy and number of earthquakes decrease. We propose that the evolution of seismicity is modulated by the ascent of CO2 accumulated in crustal reservoirs and originating from the melting of subducted carbonates. This large-scale, continuous process of CO2 production favors the formation of overpressurized CO2-rich reservoirs potentially able to trigger earthquakes at crustal depth.

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Constraints on the Timing of Surface Uplift of the Iranian Plateau (Arabia-Eurasian Collision Zone) from Clumped Isotope Thermometry on Pedogenic Carbonates

10.5194/egusphere-egu2020-13280 ◽

2020 ◽

Author(s):

Paolo Ballato ◽

Alexis Licht ◽

Katharine Huntington ◽

Andrew Schauer ◽

Andreas Mulch ◽

...

Keyword(s):

Global Climate ◽

Time Interval ◽

Plate Boundaries ◽

Order Problem ◽

Iranian Plateau ◽

Surface Uplift ◽

Pedogenic Carbonates ◽

Collision Zone ◽

Clumped Isotope ◽

Orogenic Plateaus

Orogenic plateaus are extensive, elevated, arid, generally internally drained, morphotectonic provinces of low internal topographic relief that represent a striking and enigmatic feature of Earth&#8217;s continental landscapes. They are located along convergent plate boundaries and have a profound impact on regional and global climate, erosional processes, local- to far-field deformation mechanisms and the long-term distribution of biomes and biodiversity. Although the paramount role of large orogenic plateaus in shaping our planet is widely appreciated, the question of why, where, and how some orogenic systems develop large plateaus remains a first-order problem in our understanding of lithospheric evolution and orogenic processes.Here, we present a clumped isotope paleoaltimetry study to document the elevation history of the Iranian Plateau, with the goal of understanding the rates and mechanisms of orogenic plateau rise. This plateau is in the Arabia-Eurasia collision zone, has a mean elevation of ~ 1.8 km, steep margins with mountain peaks higher than 4 km, and experienced surface uplift sometime after the middle Miocene as documented by the occurrence of ca. 17-My-old marine deposits in the plateau interior.Preliminary results from Early Miocene to Quaternary pedogenic carbonates on the plateau interior and the adjacent, less elevated, intermontane Tarom basin suggest that surface uplift must have occurred sometime between 12-11 and 8 Ma. The lack of significant crustal shortening and thickening during this time interval and the occurrence of a renewed phase of adakitic volcanism by ca. 11 Ma suggests that surface uplift may have been driven by deep-seated processes associated with asthenospheric flow.

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Seismically active area monitoring by robust TIR satellite techniques: a sensitivity analysis on low magnitude earthquakes in Greece and Turkey

Natural Hazards and Earth System Science ◽

10.5194/nhess-5-101-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 101-108 ◽

Cited By ~ 23

Author(s):

R. Corrado ◽

R. Caputo ◽

C. Filizzola ◽

N. Pergola ◽

C. Pietrapertosa ◽

...

Keyword(s):

Seismic Activity ◽

Active Regions ◽

Space Time ◽

Data Sets ◽

Earthquake Occurrence ◽

Validation Data ◽

Analysis Technique ◽

Definition Of ◽

Area Monitoring ◽

Low Magnitude

Abstract. Space-time TIR anomalies, observed from months to weeks before earthquake occurrence, have been suggested by several authors as pre-seismic signals. Up to now, such a claimed connection of TIR emission with seismic activity has been considered with some caution by scientific community mainly for the insufficiency of the validation data-sets and the scarce importance attached by those authors to other causes (e.g. meteorological) that, rather than seismic activity, could be responsible for the observed TIR signal fluctuations. A robust satellite data analysis technique (RAT) has been recently proposed which, thanks to a well-founded definition of TIR anomaly, seems to be able to identify anomalous space-time TIR signal transients even in very variable observational (satellite view angle, land topography and coverage, etc.) and natural (e.g. meteorological) conditions. Its possible application to satellite TIR surveys in seismically active regions has been already tested in the case of several earthquakes (Irpinia: 23 November 1980, Athens: 7 September 1999, Izmit: 17 August 1999) of magnitude higher than 5.5 by using a validation/confutation approach, devoted to verify the presence/absence of anomalous space-time TIR transients in the presence/absence of seismic activity. In these cases, a magnitude threshold (generally M<5) was arbitrarily chosen in order to identify seismically unperturbed periods for confutation purposes. In this work, 9 medium-low magnitude (4<Mb<5.5) earthquakes which occurred in Greece and Turkey have been analyzed in order to verify if, even in these cases, anomalous TIR transients can be observed. The analysis, which was performed using 8 years of Meteosat TIR observations, demonstrated that anomalous TIR transients can be observed even in the presence of medium-low magnitude earthquakes (4<Mb<5.5). As far as the research (just started) of possible correlation among TIR anomalies and earthquake occurrence is concerned, such a result suggests that: a) in order to identify seismically unperturbed periods for confutation purposes, a magnitude threshold (at least) lower than 4 should be used; b) the proposed validation/confutation approach should be applied in low-seismicity areas in order to find suitably long seismically quiescent periods.

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Stochastic analysis of earthquake activity in two seismogenic fault systems in Greece.

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.10965 ◽

2016 ◽

Vol 47 (3) ◽

pp. 1099

Author(s):

Ch. Gkarlaouni ◽

E. Papadimitriou ◽

S. Lasocki ◽

G. Lizurek ◽

V. Karakostas ◽

...

Keyword(s):

Normal Fault ◽

Active Regions ◽

Earthquake Activity ◽

Earthquake Occurrence ◽

Seismogenic Fault ◽

Aegean Area ◽

Corinth Gulf ◽

Seismicity Rate ◽

Event Time ◽

Smoothed Bootstrap

Possible systematic variations in earthquake occurrence and fluctuations in seismicity behaviourof two seismically active regions in Greece which share common seismotectonic properties, is the aim of this study. Mygdonia graben in northern Greeceis characterized by arather moderate background seismicity, with small earthquakes between 2008-2012 whereas Corinth Gulf in southern Greeceexhibits a constantly high seismicity rate with several seismic activations during the recent instrumental period or before. The statistical approach of seismicity was accomplished, regardingthe magnitude, the inter-event time and distance for recent seismicity as a tool to quantify complex earthquake occurrence ordense spatial andtemporal clustering. For this reason, complete catalogues were compiled for the time period of the study. Probabilistic tests such as the smoothed bootstrap test for modality and bump–hunt were employed in order to unveil the complexity of the probability density function distribution of the above parameters. On the other handspatial earthquake distribution wasalso investigated under the frameof their fractal properties since the fractal coefficientcan largely express the clustering degree of seismicity. The goal of this stochasticanalysisis the quantification of the differentiationin seismicity propertiesinthese two important seismogenic normal fault populations in the back arc Aegean area.

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Some possible correlations between electro-magnetic emission and seismic activity during West Bohemia 2008 earthquake swarm

Solid Earth ◽

10.5194/se-1-93-2010 ◽

2010 ◽

Vol 1 (1) ◽

pp. 93-98 ◽

Cited By ~ 2

Author(s):

P. Kolář

Keyword(s):

Seismic Activity ◽

Earthquake Swarm ◽

Electromagnetic Emission ◽

Active Regions ◽

Observation Time ◽

Time Interval ◽

Seismic Region ◽

West Bohemia ◽

Long Time ◽

Electro Magnetic

Abstract. A potential link between electromagnetic emission (EME) and seismic activity (SA) has been the subject of scientific speculations for a long time. EME versus SA relations obtained during the 2008 earthquake swarm which occurred in West Bohemia are presented. First, a brief characterisation of the seismic region and then the EME recording method and data analysis will be described. No simple direct link between EME and SA intensity was observed, nevertheless a deeper statistical analysis indicates: (i) slight increase of EME activity in the time interval 60 to 30 min before a seismic event with prevalent periods about 10 min, (ii) some gap in EME activity approximately 2 h after the event, and (iii) again a flat maximum about 4 h after the seismic events. These results qualitatively correspond with the observations from other seismically active regions (Fraser-Smith et al., 1990). The global decrease of EME activity correlating with the swarm activity decay was also observed. Due to the incomplete EME data and short observation time, these results are limited in reliability and are indicative only.

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The Spot Activity of FK Comae Berenices

International Astronomical Union Colloquium ◽

10.1017/s0252921100079963 ◽

1991 ◽

Vol 130 ◽

pp. 381-383

Author(s):

Lauri Jetsu ◽

Jaan Pelt ◽

Ilkka Tuominen ◽

Harold Nations

Keyword(s):

Active Regions ◽

Phase Coherence ◽

The Other ◽

Stellar Surface ◽

Time Interval ◽

Flip Flop ◽

Non Linear ◽

Spot Activity

AbstractThe active regions of FK Comae Berenices show a flip-flop behaviour, i.e. the concentrated part of spot-activity shifts exactly to the other side of stellar surface, and then remains on the same longitude for a time interval from a few years to a decade. The activity shows excellent phase coherence with respect to these two active longitudes separated 180 degrees from each other. FK Comae may provide a physical example of a non-linear dynamo, which shows surprisingly simple observational changes in the pattern of the magnetically induced spot configurations.

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