The solar active region NOAA 11719 produced a large two-ribbon flare on 11 April 2013 .
We have investigated the sudden variations in the photospheric magnetic fields in this active region during the flare employing the magnetograms obtained in the spectral line Fe I 6173 Å by the Helioseismic and Magnetic Imager ( HMI ) onboard Solar Dynamics Observatory ( SDO ) .
The analysis of the line-of-sight magnetograms from HMI show sudden and persistent magnetic field changes at different locations of the active region before the onset of the flare and during the flare .
The vector magnetic field observations available from HMI also show coincident variations in the total magnetic field strength and its inclination angle at these locations .
Using the simultaneous Dopplergrams obtained from HMI , we observe perturbations in the photospheric Doppler signals following the sudden changes in the magnetic fields in the aforementioned locations .
The power spectrum analysis of these velocity signals show enhanced acoustic power in these affected locations during the flare as compared to the pre-flare condition .
Accompanying these observations , we have also used the near-simultaneous chromospheric observations obtained in the spectral line H \alpha 6562.8 Å by the Global Oscillation Network Group ( GONG ) to study the evolution of flare ribbons and intensity oscillations in the active region .
The H \alpha intensity oscillations also show enhanced oscillatory power during the flare in the aforementioned locations .
These results indicate that the transient Lorentz force associated with the sudden changes in the magnetic fields could drive the localized photospheric and chromospheric oscillations , like the flare-induced oscillations in the solar atmosphere .