Evidence of a new geomagnetic resonant structure observed at Teoloyucan station, Mexico (TRS, Teoloyucan Resonant Structure) in the period 1999-2001, is presented in the paper. Two resonant lines were observed at the frequency bands fR2=10.2-11.1 mHz and fR2=13.6-14.5 mHz, sometimes accompanied by low and high level harmonics. The polarization of the resonant structure is purely linear: it appears in the H-component (horizontal component) only, and no resonant line is observed either in Z- or D-components (vertical and declination components). The intensity of the resonance structure displays certain time dependence, both resonant lines almost disappear during the period 10-18 UT (04-12 LT). No similar resonant structure was observed at the nearest to Teoloyucan (TEO) referent stations, such as Los Alamos (LAL, USA), and Jicamarca (JIC, Peru). It was shown that there is a correlation between the resonances and geomagnetic activity, and that there are changes in their structure at the time of major and great earthquakes. Possible source models responsible for the TRS generation are discussed.
