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Preliminary Results of Latitudinal Dependence of Pc3-4 Amplitudes at 96º MM Stations in Africa

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Preliminary Results of Latitudinal Dependence of Pc3-4 Amplitudes at 96º MM Stations in Africa

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  1. Takla E. M.[1];K. Yumoto[1,2]; M. G. Cardinal[1]; A. Mahrous[3]; G. Mengistu[4]; T. Afullo[5]; A. Macamo[6]; L. Joao[6]; N. Mwiinga[7]; C. Uiso[8]; P. Baki[9]; G. Kianji[9]; K. Badi[10]; S. Malinga[11]; A. Meloni[12]; S. Abe[2]; T. Uozumi[2]; A. Fujimoto[1]; A. Ikeda[1]; T. Tokunaga[1] and Y. Yamazaki[1]. [1] Dept. of Earth and Planetary Sci., Kyushu Univ.;[2] Space Environ. Res. Center, Kyushu Univ.; [3] SWMC, Helwan Univ., Egypt; [4]Dept. of Phys. Addis Ababa Univ., Ethiopia; [5] Dept. of Elec. Engineering Univ. of Kwazulu-Natal, South Africa; [6] Dept. of Phys., Eduardo Mondlane Univ., Mozambique; [7] Dept. of Physics, Univ. of Zambia; [8] Dept. of Phys., Univ. of Dar es Salaam, Tanzania; [9] Dept. of Phys., Nairobi Univ., Kenya; [10] Dept. of Eng., Sudan Univ. of Sci. and Tec.; [11] Hermanus Mag. Observatory, South Africa; [12] INGV, Italy. Preliminary Results of Latitudinal Dependence of Pc3-4 Amplitudes at 96º MM Stations in Africa By

  2. 2 Outline 1-Motivation 2-Introduction and aim of research 3-Results & Discussion 4-Conclusion 5-Future Work

  3. 3 1-Motivation1-1Seismic hazard in Africa Gulf of Aqaba–dead sea shear zone Great Rift Valley

  4. 4 1-2MAGDAS stations in Africa

  5. 5 1-3 Locations of African stations

  6. 6 2- Introduction2-1 Components of Geomagnetic Field ≈ 97 % Main Field ≈2 % External Field ≈1% Crustal Field

  7. A：amplitude of ULF pulsation B：source wave Solar Wind f(LT)： local time dependence Magnetosphere Ionosphere σ:amplification factor Lithosphere Pulsations observed on the ground 2-3 The Ultra low Frequency (ULF) Signals • The magnetic pulsations (ULF waves) that observed at the Earth's surface are a combination from: • 1- ULF Waves produced by processes in the magnetosphere and solar wind • 2- ULF pulsations associated with seismic and volcanic activity. [Chi et al.,1996] Space origin Lithosphere origin

  8. 8 2-4 Classifications of ULF waves The ultra-low-frequency (ULF) waves cover roughly the frequency range from 1 mHz to 1 Hz

  9. 9 2-5 Aim of Research In order to examine or identify the ULF anomalies associated with seismic activities, we need to understand the characteristics of these pulsations. So the purpose of this study is to clarify the characteristic properties of Pc3-4 in Africa through MAGDAS data as a preceding step for studying the geomagnetic anomalies associated with seismic activity in Africa.

  10. 10 3- Results and DiscussionPower spectrum for H component

  11. 11 Pc3 D-Component Pc3 H-Component

  12. Pc3 H-Component

  13. Pc4 D-Component 13 Pc4 H-Component

  14. Pc4 D-Component 14 Pc4 H-Component

  15. Pc4 H-Component

  16. 16 Latitudinal dependence of Pc3 amplitude

  17. Latitudinal dependence of Pc4 amplitude

  18. 18 The Source of Pc3-4 pulsations Shielding Effect C- Observed Pc3 Yoshikawa et al., 2002 1)Upstream waves 2)Surface waves

  19. 19 4- Conclusion • There is no enhancement in the Equatorial Pc3. • The D-component Pc3 is much smaller than the H-component Pc3. • There is an enhancement in the Equatorial Pc4 pulsation • The D-component Pc4 is much smaller than the H-component Pc4. Therefore, we conclude that equatorial Pc3 maybe originated from the upstream region. On the other hand, equatorial Pc4 maybe originated from Pc4 excited at mid or high latitudes.

  20. 20 5-Future Work • Study the annual variations of equatorial Pc3-4 pulsations. • Study the ULF anomalies associated with seismic activities in Africa

  21. 21 Thank Youありがとうございました

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