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

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

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

1-2 MAGDAS stations in Africa 4

Abbrev. Station Name NationGG Lat.GG Lon.GM Lat.GM Lon.Install FYMFayumEgypt /1/200 8 ASWAswanEgypt /12/20 08 KRTKhartoumSudan /9/200 8 AABAdis AbabaEthiopia /8/200 6 ILRIlorinNigeria /8/200 6 LAGLagosNigeria /9/2008 ABJAbidjan Ivory Coast /9/2006 NABNairobiKenya /9/200 8 DES Dar Es Salaam Tanzania /9/200 8 LSKLusakaZambia /9/200 8 MPTMaputo Mozambiq ue /9/200 8 DRBDurban South Africa /9/2008 HERHermanus South Africa /9/ Locations of African stations

Magnetic Field Main Field Generated internally From the outer core External Field Electric currents in the ionosphere, particles ionized by solar radiation CrustalField Crustal Field Variations caused by local magnetic anomalies in the earth’s crust 2- Introduction 2-1 Components of Geomagnetic Field 6 ≈ 97 % Main Field ≈ 2 % External Field ≈ 1% Crustal Field

Pulsations observed on the ground Solar Wind Magnetosphere Ionosphere Lithosphere 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. A ： amplitude of ULF pulsation B ： source wave f(LT) ： local time dependence σ:amplification factor [Chi et al.,1996] Space origin Lithosphere origin

Wave FormClassesPeriod [s]Frequency [mHz] ContinuousPc Pc10.2 – 5200 – 5000 Pc25 –10100 – 200 Pc310 – 4522 – 100 Pc445 – – 22 Pc5150 – – 6.6 IrregularPi Pi11 – 4025 – 100 Pi240 – – Classifications of ULF waves The ultra-low-frequency (ULF) waves cover roughly the frequency range from 1 mHz to 1 Hz 8

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. 9

3- Results and Discussion Power spectrum for H component 10

Pc3 H-Component Pc3 D-Component 11

Pc3 H-Component

Pc4 H-Component Pc4 D-Component 13

Pc4 H-Component Pc4 D-Component 14

Pc4 H-Component

Latitudinal dependence of Pc3 amplitude 16

Latitudinal dependence of Pc4 amplitude

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

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. 19

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

Thank You ありがとうございまし た 21