Nonlinear principal component analysis in the detection of ionospheric electron content anomalies related to a deep earthquake (>300 km, M 7.0) on 1 January 2012, Izu Islands, Japan

Abstract

Nonlinear principal component analysis (NLPCA) and image processing are used to detect an ionospheric total electron content (TEC) anomaly above Japan's Izu Islands relating to an earthquake on 1 January 2012 (UT) (Mw = 7.0). This earthquake was 348 km deep. The earthquake occurred at 05:27:54 UT; NLPCA is applied to the time period 06:40 to 12:00 UT. NLPCA shows that the TEC anomaly is highly localized and decreases in intensity with time. PCA was unable to detect the anomaly. This work discusses potential reasons for the TEC anomaly over the Izu Islands after this earthquake and possible reasons including acoustic‐gravity waves, radon gas release, and P‐type semiconductor effects.