Passive wavefield imaging using the energy norm

In passive seismic monitoring, full wavefield imaging offers a robust approach for the estimation of source location and mechanism. With multicomponent data and the full anisotropic elastic wave equation, the coexistence of Pand Smodes at the source location in time-reversal modeling allows the development of imaging conditions that identify the source position and radiation pattern. We propose an imaging condition for passive wavefield imaging that is based on energy conservation and is directly related to the source mechanism. Similar to the correlation between decomposed Pand Swavefields, which is the most common imaging condition used in passive elastic imaging, the proposed imaging condition compares the different modes present in the displacement field without costly wave-mode decomposition, and produces a strong and focused correlation at the source location. Numerical experiments demonstrate the advantages of the proposed imaging condition (compared to others that require decomposed wavefields), its sensitivity with respect to velocity inaccuracy and sparse acquisition, and its quality and efficacy in estimating the source location.