Possibility for identifying the new subduction zon

Authors: JyhWoei Lin

Publish Date: 2014/07/24

Volume: 8, Issue: 7, Pages: 5141-5151

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Abstract

A twodimensional principal component analysis 2DPCA has been performed to examine ionospheric total electron content TEC data in order to detect TEC precursor for a deep earthquake that occurred at 025942 on 14 August 2012 UTC M w  = 77 with its depth at 6259 km near Poronaysk Russia The examined TEC data were during the time period from 0000 on 09 August to 0250 on 14 August 2012 UTC which were 5 days before the earthquake because the ionospheric precursors usually revealed in such time period Liu et al 2006 An ionospheric TEC precursor with the larger principal eigenvalues of 2DPCA has been localized around the epicenter during the time period from 0225 to 0230 on 14 August 2012 UTC and the duration time was at least 5 min Ionizing radiation radon gas release should be a possibility to cause the anomalous TEC fluctuation eg electron density variation If an amount of radiation radon which caused the TEC anomalies was trapped in the asthenosphere then the asthenosphere should be very thick with deep bottom in this zone which belongs to the subduction zone between the Pacific plate and North America A zone that was previously unknown to be the subduction zone could now be identified as through an earthquakerelated TEC anomaly Therefore in this study not only TEC anomaly could be detected but also a new plate boundary with subduction zone is possible to be found However if this very deep earthquake does indeed record interplate seismicity then the asthenosphere in this region must have large thickness

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