Mantle electrical conductivity profile of Niger delta region

Journal of Earth system science

Francisca N Okeke1³  K Yumoto2²  Stan O Agha3¹  Daniel N Obiora1³ 

[1] Department of Industrial Physics, Ebonyi State University, PMB 053, Abakaliki, Nigeria.$$;Space Environment Research Centre, Kyushu University, Fukuoka 812-8581, Japan.$$;Department of Physics and Astronomy, University of Nigeria, Nsukka 410, Nigeria.$$

关键词: Conductivity profile;    Niger delta;    solar quiet day current;    spherical harmonic analysis (SHA);    mantle;    magnetic data.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

The mantle electrical conductivity-depth profile of the Niger delta region in Nigeria has been determined using solar quiet day ionospheric current (Sq).The magnetometer data obtained in 2010 from geomagnetic stations installed in Lagos by magnetic dataset (MAGDAS) in 2008 and data from magnetometers installed in some parts of Niger delta by Center for Basic Space Science, University of Nigeria, Nsukka, were employed in this study. Gauss spherical harmonic analysis (SHA) method was used to separate the internal and external field contributions to Sq current system. The result depicted that the conductivity profile rose steadily from about 0.032 S/m at a depth of 89 km to 0.041 S/m at 100 km and 0.09 S/m at 221 km. This high conductivity region agreed with the global seismic low velocity region, the asthenosphere. The conductivity profile continued increasing downward until it got to 0.157 S/m at a depth of about 373 km (close to the base of upper mantle), 0.201 S/m at 784 km and reached 0.243 S/m at a depth of 1179 km at the lower mantle.

【 授权许可】

Unknown