TITLE:
Anomalous Variation in GPS Based TEC Prior to the 5 Earthquakes in 2009 and 2010
AUTHORS:
Kunvar S. Yadav, Sheetal P. Karia, Kamlesh N. Pathak
KEYWORDS:
Total Electron Content, Refractivity, Earthquake
JOURNAL NAME:
Positioning,
Vol.6 No.4,
November
17,
2015
ABSTRACT: The present paper reports the analysis of GPS based TEC measurement corresponding to 5 earthquakes (M > 6.0) that have occurred in 2009 and 2010 during low solar activity period and quiet geomagnetic conditions. The No. of satellites registering high TEC at low elevation angles is observed prior to these earthquakes. The earthquakes are 1) Loyalty Island (22o36'S, 170o54'E) M-6.6 on 19 January 2009, 2) Izu Island (32o48'N, 140o36'E) M-6.6 on 12 August 2009, 3) Ryukyu Islands (23o30'N, 123o30'E) M-6.7 on 17 August 2009, 4) Haiti (18o24'N, 72o30'W) M-7.0 on 12 Jan 2010, 5) Chile (34o12'S, 71o48'W) M-6.9 on 11 March 2010. To identify anomalous behavior of TEC, we compute interquartile range associated with median TEC so as to get upper and lower bound of TEC variation. The results show occurrence of anomalies in VTEC 1 - 13 days prior to the earthquake. The VTEC shows enhancement for all the earthquakes. Enhancement in No. of satellites registering high TEC at low elevation has been observed prior to earthquakes.