Just as seismicwaves moving through Earth provide information about our planet's insides, so sound waves travelling through a star carry information about its inner workings.
They found that when earthquakes struck in nearly the same place years or decades apart, seismicwaves generated by the later quakes arrived in Alaska a little sooner than they had the time before.
Preliminary reports ruled out that seismic sound waves created by oil exploration in that stretch of sea could have killed the birds, the environment ministry said.