Japanese Tsumani 2011 Effects on the Geomagnetic Field: Preliminary Results

The vertical component of the geomagnetic field observed by ground-based observatories of the INTERMAGNET network has been used to analyze the effects of the Japanese tsumani, 2011. The purpose of this work is to observe the geomagnetic variations induced by a tsunami resulting from the strong earthquake on 11 February 2011. We choose four stations that were influenced or more direct affected by the tsumani. The stations considered in this analysis were: Kanoya (KNY), Memambetsu (MMB), Guam (GUA) and Charters Towers (CTA). To detect these disturbances in the geomagnetic data, the discrete wavelet technique have been used in three levels of decomposition. We were able to detect the localized behavior of the geomagnetic variations induced by the movement of electrically conducting sea-water through the geomagnetic field, i. e., the identification of transients related to the tsunamis. As well, using the minutely magnetogram data, it was able to localize the inicial phase and time of the tsunami maximum height. The first interpretation of the results suggests that discrete wavelet transform can be used to characterize the tsumanis effects on the geomagnetic field, but need further study.