  The first observations of seismic responses to solar flares were carried out
using time-distance (TD) and holography techniques applied to SOHO/MDI
Dopplergrams obtained from space and un-affected by terrestrial atmospheric
disturbances. However, the ground-based network GONG is potentially a very
valuable source of sunquake observations, especially in cases where space
observations are unavailable. In this paper we present updated technique for
pre-processing of GONG observations for application of subjacent vantage
holography. Using this method and TD diagrams we investigate several sunquakes
observed in association with M and X-class solar flares and compare the
outcomes with those reported earlier using MDI data. In both GONG and MDI
datasets, for the first time, we also detect the TD ridge associated with the
September 9, 2001 flare. Our results show reassuringly positive identification
of sunquakes from GONG data that can provide further information about the
physics of seismic processes associated with solar flares.
