Real time monitoring of moment magnitude by waveform inversion

extremal region detection guided by maxima of gradient magnitude

a problem of computer vision applications is to detect regions of interest under dif- ferent imaging conditions. the state-of-the-art maximally stable extremal regions (mser) detects affine covariant regions by applying all possible thresholds on the input image, and through three main steps including: 1) making a component tree of extremal regions’ evolution (enumeration), 2) obtaining region ...

Full waveform inversion guided by travel time tomography

Full waveform inversion (FWI) is a process in which seismic data in time or frequency domain is fit by changing the velocity of the media under investigation. The problem is non-linear, and therefore optimization techniques have been used to find a geological solution to the problem. The main problem in fitting the data is the lack of low spatial frequencies. This deficiency often leads to a lo...

Discretized Adjoint State Time and Frequency Domain Full Waveform Inversion: A Comparative Study

This study derives the discretized adjoint states full waveform inversion (FWI) in both time and frequency domains based on the Lagrange multiplier method. To achieve this, we applied adjoint state inversion on the discretized wave equation in both time domain and frequency domain. Besides, in this article, we introduce reliability tests to show that the inversion is performing as it should be ...

Downhole microseismic monitoring of hydraulic fracturing: a full- waveform approach for complete moment tensor inversion and stress estimation

Downhole microseismics has gained in popularity in recent years as a way to characterize hydraulic fracturing sources and to estimate in-situ stress state. Conventional approaches only utilize part of the information contained in the microseismic waveforms such as the P/S amplitude ratio and/or P first motion polarity to determine the microearthquake focal mechanisms and infer stress state. Thu...

Application of Time Domain and Single Frequency Waveform Inversion to Real Data