ABSTRACTThe acoustic time history of the sun's surface is a stochastic (t,x,y)-cube of information. Helioseismologists cross-correlate these noise traces to produce impulse response seismograms, providing the proof of concept for a long-standing geophysical conjecture. We pack the (x,y)-mesh of time series into a single super-long one-dimensional time series. We apply Kolmogoroff spectral factorization to the super-trace, unpack, and find the multidimensional acoustic impulse response of the sun. State-of-the-art seismic exploration recording equipment offers tens of thousands of channels, and permanent recording installations are becoming economically realistic. Helioseismology, therefore, provides a conceptual prototype for using natural noises for continuous reservoir monitoring. |