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Vladimir Kossobokov 1,2,3 , Anastasia NekrasovA 1 , Polina Schepalina 4

NH4.3/SM3.04 Statistical analysis of spatio -temporal properties of earthquake occurrence. Seismic dynamics in advance and after the World’s largest earthquakes, 1985-2017. Vladimir Kossobokov 1,2,3 , Anastasia NekrasovA 1 , Polina Schepalina 4

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Vladimir Kossobokov 1,2,3 , Anastasia NekrasovA 1 , Polina Schepalina 4

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  1. NH4.3/SM3.04 Statistical analysis of spatio-temporal properties of earthquake occurrence Seismic dynamics in advance and after the World’s largest earthquakes, 1985-2017 Vladimir Kossobokov 1,2,3, Anastasia NekrasovA 1, Polina Schepalina 4 1 Institute of Earthquake Prediction Theory & Mathematical Geophysics, Russian Academy of Sciences, Moscow, Russia 2Institut de Physique du Globe de Paris, Paris, France 3 International Seismic Safety Organization, Arsita, Italy 4Russian State University of Oil and Gas, Moscow, Russia E-mail: volodya@mitp.ru ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  2. The observed variability of seismic dynamics in advance and after the 71 earthquakes of MW = 7.8 or greater is characterized in terms of several moving averages, including • seismic rate, • the Benioff strain release, • inter-event time, τ, • the Utsu estimate of b-value, and • the USLE control parameter, η where USLE stands for Unified Scaling Law for Earthquakes, i.e. a generalization of the Gutenberg-Richter relationship accounting for naturally fractal distribution of earthquake loci, which states that the distribution of inter-event times τ depends only on the value of variable η. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  3. Data : Earthquake series nearby the location of all Mw7.8 or larger earthquakes worldwide, 1985-2017 The USGS/NEIC ANSS catalog searches of magnitude 4 or greater earthquakes at the angular distance R=(exp(M-5.6)+1)/2 from each of the 71 epicenters of great earthquakes (M ≥ 7.8) within 10 year before through 3 years after their occurrence. + 1985-03-03 22:47:07 M=8.0 -33.135 -71.871 33 ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  4. Parameters : seismic rate, N Origin time: 2011-03-11 05:46:24 M9.1 Latitude 38.297°N, Longitude 142.373°E, Depth 29 km ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  5. Parameters : the Benioff strain release - Σ10β(Mi-α), β = 0.5 Origin time: 2011-03-11 05:46:24 M9.1 Latitude 38.297°N, Longitude 142.373°E, Depth 29 km ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  6. Parameters : inter-event time, τ(dual to seismic rate, N) Origin time: 2011-03-11 05:46:24 M9.1 Latitude 38.297°N, Longitude 142.373°E, Depth 29 km ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  7. Parameters : control parameter, η = τ× 10B×(5-M) × LC From a physical viewpoint, the scaling parameter η controls self-organized non-linear seismic system of a given region, so that the distribution of inter-event times τ depends only on this parameter. Origin time: 2011-03-11 05:46:24 M9.1 Latitude 38.297°N, Longitude 142.373°E, Depth 29 km B=0.9, C=1.38 50 per. Moving average ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  8. Since the pioneering works of Keiiti Aki and M. A. Sadovsky Okubo, P.G., K. Aki, 1987. Fractal geometry in the San Andreas Fault system. J. Geophys. Res.,92 (B1), 345-356; Садовский М.А. и др.б 1982. О свойстве дискретности горных пород. Изв. АН СССР. Физика Земли, № 12, 3-18; the understanding of the fractal nature of earthquakes and seismic processes keeps growing. The Unified Scaling Law for Earthquakesthat generalizes Gutenberg-Richter relation suggests - log10N = A + B·(5 - M) + C·log10L where N = N(M, L) is the expected annual number (i.e., seismic rate) of earthquakes with magnitude M in an earthquake-prone area of linear dimension L. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  9. Parameters :b-value (Utsu, 1965), b = log10e / (Mav – Mmin) Origin time: 2011-03-11 05:46:24 M9.1 Latitude 38.297°N, Longitude 142.373°E, Depth 29 km Mav is 50 per moving average, Mmin= 4.5 ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  10. Results (just a few…)The multi-parametric description of earthquake activity nearby the 71 locations of Mw7.8 or larger earthquakes worldwide provides the quantitative evidence for better understanding seismic process in advance and after catastrophic phase transitions in dynamics of the Earth hierarchical system of lithospheric blocks-and-faults. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  11. Results : different seismic regimeThe 71 locations characterized with widely distributed estimates (A,B,C) of USLE. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  12. Results : different levels of τand η Correlations ofτ and ηbefore and after t*: 0.554, 0.205, 0.160 (0.441) ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  13. Results : switching levels of τand η before and after the main shocks τ(t*-3, t*-1) /τ(t*-1, t*) η(t*-3, t*-1) /τ(t*-1, t*) τ(t*-1, t*) /τ(t*+1, t*+2) η(t*-1, t*) /η (t*+1, t*+2) τ(t*-3, t*-1) /τ(t*+1, t*+2) η(t*-3, t*-1) /η(t*+1, t*+2) ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  14. Results : variability of behaviorsBenioff strain release normalized to its 10-year valuenearby the location of all the 71Mw7.8 or larger earthquakes worldwide, 1985-2017 10 years before 3 years after ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  15. conclusions : A systematic statistical analysis of earthquake series nearby the location of all Mw7.8 or larger earthquakes worldwide, 1985-2017, discloses that seismic activity, in a long-term, resides at rather steady levels, in a mid-term, may switch intermittently from one level to a different one at the times associated with occurrence of catastrophic main shocks, and, in a short-term, may follow different scenarios. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  16. conclusions : Statistically, the results of our analysis of earthquake series nearby the location of the 71 great earthquakes, 1985-2017 • do not support the presence of universality in seismic energy release, • provide fundamental constraints on modeling realistic earthquake sequences by geophysicists, • can be used to improve local time-Dependent Assessment of Seismic Hazard. The study supported by the Russian Science Foundation Grant No.16-17-00093. ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

  17. Thank you! “When sorrows come, they come not single spies, but in battalions”(William Shakespeare, 1564-1616) ♦ European Geosciences Union ♦ General Assembly 2018 ♦ 8 - 13 April - Vienna, AUSTRIA ♦

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