A Statistical Study of Seismically Active Solar Flares During 24th Solar Cycle

The report presents the results of the search for M-X class solar flares of the 24th solar cycle, which produced helioseismic waves (sunquakes). We used Dopplergrams from Helioseismic Magnetic Imager (HMI) to detect sunquakes. It was shown that approximately 82 events from the total number (~500) of M – X flares were seismically active. This result is quite unexpected, since it was previously thought that sunquakes are very rare and are observed mainly in strong flares. However, analysis has shown that there are many solar flares of moderate power with strong sunquakes, while in some powerful X flares helioseismic waves were not observed or were weak. Analysis also revealed that during the 24th cycle, there were active regions characterized by the most efficient generation of helioseismic waves during flares. We found that sunquake power correlates with maximal value of GOES lightcurve time derivative better than with GOES class. The new catalog of helioseismic solar flares allows us to make step from the study of individual events to statistical analysis, which will allow us to understand physics of sunquakes better.