Author(s)

Minakshi Devi, Alaka Medhi, Arup Jyoti Dev Sarma Sarma, Ananda Kumar Barbara

Department of Physics, Gauhati University, Guwahati, India..

The processes leading to the growth and inhibition of equatorial anomaly before major earthquake (EQ) were viewed in this paper by examining global Total Electron Content (TEC) that contoured over longitude sectors covering Africa to Pacific, in association with EQ events of Japan (M = 9) that occurred at 135°E to 145°E and 35°N to 40°N, on March 9 and 11, 2011 and of Indonesia (M = 8.6) that took place at 2.311°N, 93°E, in April 11, 2012. The paper focuses on the development of abnormal increase in density in the night sector around—10° latitude zone prior to the two major EQ events, though their epicenters are separated widely from the anomaly region. The F-layer density variations from relevant locations and TEC features obtained from GPS at Appleton anomaly crest station are utilized as supporting inputs. The possible sources leading to the anomalous development in density are discussed in the frame of EQ time consequences of lithospheric-atmospheric processes between the equator and beyond. The role of electric field generated by pre EQ preparatory activities and dynamical coupling modes through seismic fault line are brought in to the ambit of discussion.

TEC Global; Earthquake; Equatorial Anomaly; F-Layer Density

M. Devi, A. Medhi, A. Sarma and A. Barbara, "Growth and Inhibition of Equatorial Anomaly Prior to an Earthquake (EQ): Case Studies with Total Electron Content (TEC) Data for Major EQs of Japan 2011 and Indonesia 2012," Positioning, Vol. 4 No. 3, 2013, pp. 240-252. doi: 10.4236/pos.2013.43024.