TY JOUR TI Variations of the total electron content in the ionosphere from GPS data recorded during the Hector Mine earthquake of October 16, 1999, California KW total electron content KW GPS monitoring KW Hector Mine earthquake KW earthquake precursors. JO Russian Journal of Earth Sciences AU Afraimovich, E.L. AU Astafieva, E.I. AU Gokhberg, M.B. AU Lapshin, V.M. AU Permyakova, V.E. AU Steblov, G.M. AU Shalimov, S.L. PY 2004 IS 6 PB Geophysical Center of the Russian Academy of Sciences