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Three‐dimensional distribution of ionospheric anomalies prior to three large earthquakes in Chile
Author(s) -
He Liming,
Heki Kosuke
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069863
Subject(s) - epicenter , tec , geology , ionosphere , earth's magnetic field , seismology , total electron content , anomaly (physics) , spatial distribution , geophysics , geodesy , magnetic field , physics , condensed matter physics , quantum mechanics , remote sensing
Using regional Global Positioning System (GPS) networks, we studied three‐dimensional spatial structure of ionospheric total electron content (TEC) anomalies preceding three recent large earthquakes in Chile, South America, i.e., the 2010 Maule ( M w 8.8), the 2014 Iquique ( M w 8.2), and the 2015 Illapel ( M w 8.3) earthquakes. Both positive and negative TEC anomalies, with areal extent dependent on the earthquake magnitudes, appeared simultaneously 20–40 min before the earthquakes. For the two midlatitude earthquakes (2010 Maule and 2015 Illapel), positive anomalies occurred to the north of the epicenters at altitudes 150–250 km. The negative anomalies occurred farther to the north at higher altitudes 200–500 km. This lets the epicenter, the positive and negative anomalies align parallel with the local geomagnetic field, which is a typical structure of ionospheric anomalies occurring in response to positive surface electric charges.