Parameters of seismic source as deduced from 1Hz ionospheric GPS data: Case study of the 2011 Tohoku-oki event

Following the first-time ionospheric imaging of a seismic fault, here we perform a case study on retrieval of parameters of the extended seismic source ruptured during the great M9.0 Tohoku-oki earthquake. Using 1Hz ionospheric GPS data from the Japanese network of GPS receivers (GEONET) and several GPS satellites, we analyze spatiotemporal characteristics of coseismic ionospheric perturbations and we obtain information on the dimensions and location of the sea surface uplift (seismic source). We further assess the criterion for the successful determination of seismic parameters from the ionosphere: the detection is possible when the line of sights from satellites to receivers cross the ionosphere above the seismic fault region. Besides, we demonstrate that the multisegment structure of the seismic fault of the Tohoku-oki earthquake can be seen in high-rate ionospheric GPS data. Overall, our results show that, under certain conditions, ionospheric GPS-derived TEC measurements could complement the currently working systems, or independent ionospherically based system might be developed in the future.