Helioseismic holography is a technique used to image the sources of seismic disturbances observed at the solar surface. It has been used to detect acoustic emission, known as sun quakes, radiated from X-class solar flares. Since the seismic power emitted by the X-class flares has proved to be independent of the strength of the flare, we have undertaking a systematic search for seismic signatures from M-class solar flares, observed by SOHO-MDI.
We have detected significant acoustic emission from a few M-class solar flares. Preliminary results of the survey of M-type solar flares studied so far is available at: aira.astro.ro/~deanna/M.html.