European Geosciences Union;Katlenburg-Lindau: Copernicus Publications
摘要:
摘要： Despite early optimism, pre-earthquake anomalous phenomena can be determined by using enhanced amplitude at the ultra-low-frequency range from geomagnetic data via the Fourier transform. In reality, accuracy of the enhanced amplitude in relation to earthquakes (deduced from time-varied geomagnetic data) would be damaged by magnetic storms and/or other unwanted influences resulting from solar activity and/or variations in the ionosphere, respectively. We substitute values of the cross correlation between amplitudes, summarized from the earthquake-related (0.1–0.01 Hz) and the comparable (0.01–0.001 Hz) frequency bands, for isolated amplitude enhancements as indexes of determination associated with seismo-magnetic anomalies to mitigate disturbance caused by magnetic storms. A station located about 300 km away from the others is also taken into account to further examine whether changes of the cross correlation values are caused by seismo-magnetic anomalies limited within local regions or not. Analytical results show that the values suddenly decrease near epicenters a few days before and after 67% (= 6/9) of earthquakes ( M > = 5) in Taiwan between September 2010 and March 2011. Seismo-magnetic signals determined by using the values of cross correlation methods partially improve results yielded from the Fourier transform alone and provide advantageous information of earthquake locations. 出版者： Katlenburg-Lindau: Copernicus Publications 出版日期： 2012-05-25 出處： Natural hazards and earth system sciences, 2012-05, Vol.12 (5), p.1747-1754 資源來源： Agricultural & Environmental Science Collection 版權： COPYRIGHT 2012 Copernicus GmbH 版權： Copyright Copernicus GmbH 2012 識別號： ISSN: 1684-9981 識別號： ISSN: 1561-8633 識別號： EISSN: 1684-9981 識別號： DOI: 10.5194/nhess-12-1747-2012
