Scientists discovered in 1996 that sunquakes are linked to solar flares. Now, using helioseismic holography, scientists have analyzed a 2011 flare and shown that the impulsive source that generated the sunquake, and the refracted acoustic waves that later rippled the solar surface, was submerged 1,000 kilometers below the photosphere and flare. Further sunquake study could reveal if submerged sources are common and whether they can predict the appearance of flares and potential impact on Earth.

But as scientists discovered in 1996, flares can also create seismic activity — sunquakes — releasing impulsive acoustic waves that penetrate deep into the sun’s interior.

While the relationship between solar flares and sunquakes is still a mystery, new findings suggest that these «acoustic transients» — and the surface ripples they generate — can tell us a lot about flares and may someday help us forecast their size and severity.

A team of physicists from the United States, Colombia and Australia has found that part of the acoustic energy released from a flare in 2011 emanated from about 1,000 kilometers beneath the solar surface — the photosphere — and, thus, far beneath the solar flare that triggered the quake.

The results, published Sept. 21 in The Astrophysical Journal Letters, come from a diagnostic technique called helioseismic holography, introduced in the late 1900s by French scientist Francoise Roddier and extensively developed by U.S. scientists Charles Lindsey and Douglas Braun, now at NorthWest Research Associates in Boulder, Colorado, and co-authors of the paper.

Helioseismic holography allows scientists to analyze acoustic waves triggered by flares to probe their sources, much as seismic waves from megaquakes on Earth allow seismologists to locate their epicenters. The technique was first applied to acoustic transients released from flares by a graduate student in Romania, Alina-Catalina Donea, under the supervision of Lindsey and Braun. Donea is now at Monash University in Melbourne, Australia.

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Materials provided by University of California — Berkeley. Original written by Robert Sanders. Note: Content may be edited for style and length.