We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Magnetic storm free ULF analysis in relation with earthquakes in Taiwan.
- Authors
Wen, S.; Chen, C. H.; Yen, H. Y.; Yeh, T. K.; Liu, J. Y.; Hattori, K.; Peng, H.; Wang, C. H.; Shin, T. C.
- Abstract
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.
- Subjects
TAIWAN; MAGNETIC storms; EARTHQUAKES; GEOMAGNETISM; FOURIER transforms; SOLAR activity; IONOSPHERE
- Publication
Natural Hazards & Earth System Sciences, 2012, Vol 12, Issue 5, p1747
- ISSN
1561-8633
- Publication type
Article
- DOI
10.5194/nhess-12-1747-2012