Analysis of ionospheric VTEC disturbances before and after the Yutian Ms7. 3 earthquake in the Xinjiang Uygur Autonomous Region

An earthquake with a magnitude of Ms7.3 hit Yutian in the Xinjiang Uygur Autonomous Region on February 14,2014.This research investigates the interference phenomena in solar activities and geomagnetics,and adopts the quartile method to analyze the Global Ionosphere Map( GIM) Vertical Total Electron Content( VTEC) data provided by the Center for Orbit Determination in Europe( CODE),as well as the difference between GIM VTEC and International Reference Ionosphere( IRI) VTEC data.The ionospheric VTEC disturbances at the earthquake epicenter are examined before and after the event.At UTC 8 ∶00 on February 2,a strong VTEC disturbance emerged in the sky near the epicenter.A strong VTEC disturbance also emerged in the sky of the southern Hemisphere area,which is symmetric with the areas north of the equator.The methods used in analysis of the difference between GIM VTEC and IRI VTEC information can effectively fill the gaps in analysis that uses only the GIM VTEC data.