Adaptive techniques for extraction of pre-seismic parameters of Total Electron Content (TEC) at anomaly crest station

Abstract

Total electron content (TEC) data, obtained from satellites, are used in the search for imprints for identifying the probability factor of an impending earthquake. Extraction of earthquake induced signature is done mainly from day-to-day variations in TEC peak (TEC peak. ). The use of a single parameter such as TEC peak is not always enough to formulate such a pointer. The paper therefore focuses on the need to introduce other markers such as the shape of TEC profile and to utilize any modification in the profile shape caused by an impending earthquake to identify precursors. An automatic pattern matching approach for processing global positioning system (GPS) generated TEC records is introduced to achieve this aim and TEC profiles are passed through a template framed from the time series of quiet day data. The Dynamic Time Warping (DTW) algorithm is adopted to look for deviations in the entire TEC profile of days prior to the earthquake with respect to the template. Variation, if any, would be used as an index of earthquake induced signature. A few case studies using this algorithm are presented in the paper. Work is based on TEC data collected from the GPS receiver at Guwahati (268 10 0 N, 918 45 0 E), an equatorial anomaly crest station.

Anomalous Variations of Ionosphere Associated with the Strong Earthquake at Pakistan-Iran Border at a Low Latitude Station Agra, India

“…In the results of TEC presented above, we have emphasized the generation of positive anomalies (enhancements in TEC) in the light of large earthquake of 16 April 2013. This result is supported by earlier workers (Liu et al 2004b, Dabas et al 2007, Devi et al 2012. However, recently some workers have shown the significance of negative and positive TEC anomalies also (Liu et al 2009, Pulinets 2012.…”

“…In India, the studies of ionospheric precursors have also been done at Agra (Chauhan et al 2012, Pundhir et al 2014, Guwahati (Devi et al 2012), Kolkata (DasGupta et al 2006), Varanasi (Singh et al 2012), Delhi (Dabas et al 2007, Surat (Karia and Pathak 2011), Allahabad (Maurya et al 2013).…”

A novel approach for ionospheric total electron content earthquake precursor and epicenter detection for low-latitude

“…Again, the profile behavior of electron content as precursor imposed by an equatorial earthquake and low latitude earthquake may not be similar, since anomaly crest shift may lead to both increase and decrease of TEC, which depends on magnitude, closeness of the epicenter to the observing station. Past studies suggests that the TEC peak value analysis for prediction of an impending earthquake which is not reliable most of the time and produces false prediction results since the peak value is also associated with other factors (Devi et al, 2012). The Dynamic time warping method has also been applied to identify TEC anomalies related to earthquakes with low latitude TEC data (Devi et al, 2012), but this method suffers from the limitation in that it cannot resolve fine structure.…”

“…For this a template is formed for by selecting TEC profiles of quiet days for each month to filter out the geomagnetically disturbed factors. Earlier research reports that the anomaly enhancement of TEC peak occurs in not only during noon periods but also at post noon and after sunset hour prior to an impending earthquake (M Devi et al, 2012), which is an important mark along with the shape of profile in the new proposed method. The proposed pattern matching method for earthquake prediction is based on perceptually important point (PIP) identification.…”

Soft Computing Technique for Recognition of Earthquake Precursor from Low Latitude Total Electron Content (TEC) Profiles

“…And it is expected that the certainty factor should be low before this event. Thus from a number of quiet day TEC profiles a template for this particular month is created to measure distance of deviation between template and time series of other days of this month and the certainty factor is calculated [15]. We now take one stronger recent earthquake to test the reliability of this approach.…”