AbstractWe analyze the magnetic field data recorded by ELF antennas operated by ISUAL project of NCKU at Lulin Observatory in Taiwan (120.87°E , 23.46°N, 2862m). The data adopted in this analysis is from year of 2009 to 2010 with wave signals below 10Hz primarily investigated. The signals are measured in both H (north-south) and D (east-west) components.
In this study, we focus on developing computing codes to derive parameters associated with polarizations from these two observed components. The ellipticity, orientation, and sense of polarization can then be calculated. We use Fourier and polarization analysis to analyze ELF magnetic field data and then compare these ELF results with geomagnetic and seismic data from 2009 to 2010. The seismic events are categorized in three different regions( Taiwan Island, Okinawa trough, Luzon Arc), based on the fault feature of the epicenters, and the association with the analyzed ELF event parameters are studied. In addition, the geomagnetic index are also compared and the ELF emissions are found to have little possibility to be deduced from geomagnetic activities or storms. The results suggest that the observed ELF disturbances are more sensitive to seismic events before main shock, especially for events occurred on Taiwan Island compared with the other two regions. These results also show us the ELF signals do not relate with geomagnetic activities and storms.
|Date of Award||2011|
|Supervisor||Bing-Chih Chen (Supervisor)|
- ELF disturbances
- polarization analysis
- seismic activities
- geomagnetic activities