Kenji Ohta

TL;DR: In this article, the authors present a network of ULF monitoring in the Tokyo area by describing their ULF magnetic sensors and finally present a few, latest results on seismogenic electromagnetic emissions for recent large earthquakes with the use of sophisticated signal processing.

TL;DR: In this article, the authors analyzed quantitatively the results from coordinated measurement consisting of ELF transients, VLF subionopheric disturbances and lightning discharges associated with the optical events.

TL;DR: In this article, an anomalous effect in the Schumann resonance has been found, possibly associated with two large land earthquakes (one is the Chi-chi earthquake and another one on 2 November 1999 (Chia-yi earthquake) with a magnitude again greater than 6.0).

TL;DR: In this paper, the phase difference of these ELF emissions (BX, BY) was measured, and it was shown that these emissions are linearly polarized, suggesting that they have propagated in the subionospheric waveguide over long distances.

TL;DR: In this paper, the authors summarized the electromagnetic precursory phenomena for the 2004 Mid Niigata Prefecture earthquake on October 23, 2004, and found that three different kinds of seismogenic perturbations have been observed; (1) lithospheric DC/ULF emissions, (2) atmospheric radio noise in the VHF band and (3) ionospheric disturbances.