Imaging Moment Tensors from Surface Arrays

We employ a new method for imaging microseismic sources referred to as Moment Tensor Microseismic Imaging (MTMI). Unlike standard diffraction stack methods our method allows for polarity and amplitude changes produced by the anisotropic radiation pattern from the microseismic source, without a-priori knowledge of the source properties. This is achieved by projecting the data on to moment tensor components before stacking at each image point. In addition to the cancellation of radiation pattern effects the methods advantages include, the production of images for each moment tensor component (allowing determination of the source mechanism given a suitable geometry), as well as the option to include data from multiple component systems and multiple wave types in a single image.