Locating a microseismic event using deconvolution

Abstract

We demonstrate a technique to enhance the ability of imaging the location of a microseismic event by improving both spatial and temporal focusing. The technique improves locating a microseismic event in a velocity model for which the interface boundaries are approximate but where it has the correct mean slowness. Our method designs a signal to be rebroadcasted from the receivers, using only the waves recorded at each receiver, such that the wave field has an optimal temporal focus at the source location. Additionally, this procedure leads to an improved spatial focus of the wave field. The numerical test shown include additive noise. This proposed technique only involves a simple preprocessing step to the recorded data and its cost is hence negligible compared to the total cost of microseismic imaging.

An inverse source problem for a variable speed wave equation with discrete-in-time sources

“…Clusters of microseismic events delineate faults and can indicate new or reactivating regions of failure. We mention the work of Foulger and Julian [12] and Douma et al [6].…”

Uniqueness for a seismic inverse source problem modeling a subsonic rupture

“…In addition, we will draw upon ideas from the theory of inverse initial source problems, in particular, from [9] where a time-reversal approach for an inverse initial source problem with a non-constant wave speed was introduced. The motivation for [9] was the medical imaging modality known as thermoacoustic tomography but similar ideas have been used in many other applications, including geophysical ones; for timereversal methods used in rupture detection, see [10], [11], [12], [13], [14], [15], [16], and in microseismicity see [17], [18], [19].…”