Empirical mode decomposition analysis of Seismo-ionospheric coupling phenomena for finding the short term earthquakes precursor
Abstract
Large numbers of papers have reported on anomalous variation of foF2 signal in the vicinity of an earthquake's epicenter few days before the incoming earthquake. We have analyzed foF2 signal observed by ionosonde located at Kokubunji form 2010-2015 using Cross Correlation analysis method in conjunction with the Empirical Mode Decomposition. The EMD method is used to remove the geophysical noise from the foF2 signals. In cross correlation analysis method the stations located inside the earthquake preparation area, as evaluated using Dobrovolsky equation capture the ionospheric disturbances generated by the seismic event. On the other hand the stations outside of this area are expected to remain unaffected. The results of our study are in agreements with the previous work, evidencing anomalous variation in foF2 signal prior to earthquake in a certain area around the epicenter. Our experimental results also show that precursors may appear as early as 22 days prior to the event. These precursors occurred on different days in the interval of 2-10 days prior to the earthquakes. The main cause of the possible earthquake precursors is E×B drift with the electric field generated over earthquake preparation area and penetrated the ionosphere Keywords: Empirical mode decomposition, E×B drift, foF2 signal, Seismo-ionospheric coupling
- Publication:
-
41st COSPAR Scientific Assembly
- Pub Date:
- July 2016
- Bibcode:
- 2016cosp...41E1838S