It is supposed that prior to a large earthquake its focus may send through the Earth lithosphere a long-range effect of strain-related to transient electric signals, which in turn give rise to geomagnetic variations propagated over a wide range of frequencies. Consequently, to confirm long-range electromagnetic anomalous effect related to the M9 Great Tohoku earthquake occurred on 11 March 2011, we retrospectively analyzed the geomagnetic data collected at three observatories placed in Japan (Memambetsu, Kakioka) and Romania (Provita de Sus). The daily mean distributions of the normalized function Bzn and its standard deviation (STDEV) for all the three observatories are performed in the ultra-low frequency range (0.001-0.016Hz) by using the FFT band-pass filter analysis. Additionally, a comparative statistical analysis, based on a standardized random variable equation, was applied to the Bzn time series to emphasize a possible pre-seismic anomalous interval and, consequently, a peak greater than 2.5·STDEV, related to the M9 Tohoku earthquake, was identified on 5-6 February 2011. The lead time was 32 days before the earthquake occurrence. The final conclusion is that the detection area of the pre-seismic electromagnetic effect could be extended to the considerable distances from the epicenter of a giant earthquake.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.