Sun quakes from solar flares

This new discovery refers to the "solar flare" part of the quaking process.
Astronomers have already known that sound waves ripple through the Sun's plasma towards the interior and are able produce a five minute pattern which is called a starquake or five-minute oscillations.

Before this discovery, scientists previously thought that the oscillations of the sound waves were caused by the gas churning near the interior of the Sun. However, this recent discovery has shown them that, though the gas is a part of it, occasional solar flares cause more powerful oscillations.

The theory is similar to the way one might hear constant ringing in their ears after occasionally listening to REALLY loud music The key thing is that it is sudden and the power difference is large.
Astronomers have found that when there are increases in solar flares, there are also increases in the power of the quaking.

Large flares will shake up the sun and make it vibrate.
This process can also be observed on Earth, as, after large Earthquakes, there is a constant ringing of seismic waves for a few weeks.

Exactly how the solar flares are causing the quakes is still unclear. We only know that solar flares do correlate, but we still don't know why it happens. But this will definitely help us figure it out, as we will be able to observe the solar flares and the star quakes now.

More information about this discovery can probably be found in the May 1st issue of Astrophysical Journal Letters, which comes from data collected with the Solar and Heliospheric Observatory (SOHO), a joint venture between NASA and ESA.