scholarly journals MTfit: A Bayesian Approach to Seismic Moment Tensor Inversion

2018 ◽  
Vol 89 (4) ◽  
pp. 1507-1513 ◽  
Author(s):  
D. J. Pugh ◽  
R. S. White
Keyword(s):  
Bayesian Approach ◽  
Seismic Moment ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Seismic Moment Tensor

scholarly journals HybridMT: A MATLAB/Shell Environment Package for Seismic Moment Tensor Inversion and Refinement

2016 ◽  
Vol 87 (4) ◽  
pp. 964-976 ◽  
Author(s):  
Grzegorz Kwiatek ◽  
Patricia Martínez‐Garzón ◽  
Marco Bohnhoff
Keyword(s):  
Seismic Moment ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Seismic Moment Tensor

Seismic Moment Tensor Inversion of an Induced Microseismic Event, Offshore Norway: An Insight into the Possible Cause of Wellbore Liner Failure during a Drilling Operation

2021 ◽  
Vol 92 (6) ◽  
pp. 3460-3470
Author(s):  
Zoya Zarifi ◽  
Fredrik Hansteen ◽  
Florian Schopper
Keyword(s):  
Seismic Moment ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Seismic Moment Tensor ◽  
Isotropic Component ◽  
High Pump ◽  
Dc Component ◽  
Pump Pressure ◽  
Microseismic Event ◽  
Possible Cause

Abstract A microseismic event with Mw∼0.8 was recorded at the Grane oilfield, offshore Norway, in June 2015. This event is believed to be associated with a failure of the wellbore liner in well 25/11-G-8 A. The failure mechanism has been difficult to explain from drilling parameters and operational logs alone. In this study, we analyzed the detected microseismic event to shed light on the possible cause of this event. We inverted for the seismic moment tensor, analyzed the S/P amplitude ratio and radiation pattern of seismic waves, and then correlated the microseismic data with the drilling reports. The inverted seismic moment indicates a shear-tensile (dislocation) event with a strong positive isotropic component (67% of total energy) accompanied by a positive compensated linear vector dipole (CLVD) and a reverse double-couple (DC) component. Drilling logs show a strong correlation between high pump pressure and the occurrence of several microseismic events during the drilling of the well. The strongest microseismic event (Mw∼0.8) occurred during peak pump pressure of 277 bar. The application of high pump pressure was associated with an attempt to release the liner hanger running tool (RT) in the well, which had been obstructed. Improper setting of the liner hanger could have caused the forces from the RT release to be transferred to the liner and might have resulted in ripping and parting of the pipe. The possible direct impact of the ripped liner with the formation or the likely sudden hydraulic pressure exposure to the formation caused by the liner ripping may explain the estimated isotropic component in the moment tensor inversion in the well. This impact can promote slip along the pre-existing fractures (the DC component). The presence of gas in the formation or the funneled fluid to the formation caused by the liner ripping may explain the CLVD component.

A fast, automated seismic moment tensor inversion approach for mine-induced microseismic data

First Break ◽  
2020 ◽  
Vol 38 (4) ◽  
pp. 75-82
Author(s):  
Lindsay Smith-Boughner ◽  
Irina Nizkous ◽  
Ian Leslie ◽  
Sebastian Braganza ◽  
Ian Pinnock ◽  
...  
Keyword(s):  
Seismic Moment ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Seismic Moment Tensor ◽  
Microseismic Data

scholarly journals Seismic Moment Tensor Solutions from GeoNet Data to Provide a Moment Magnitude Scale for New Zealand

2021 ◽  
Author(s):  
◽  
Elizabeth de Joux Robertson
Keyword(s):  
New Zealand ◽  
Seismic Moment ◽  
Moment Tensor ◽  
Velocity Model ◽  
Moment Tensor Inversion ◽  
Moment Magnitude ◽  
Seismic Moment Tensor ◽  
Waveform Data ◽  
Moment Tensors ◽  
The Moment

<p>The aim of this project is to enable accurate earthquake magnitudes (moment magnitude, MW) to be calculated routinely and in near real-time for New Zealand earthquakes. This would be done by inversion of waveform data to obtain seismic moment tensors. Seismic moment tensors also provide information on fault-type. I use a well-established seismic moment tensor inversion method, the Time-Domain [seismic] Moment Tensor Inversion algorithm (TDMT_INVC) and apply it to GeoNet broadband waveform data to generate moment tensor solutions for New Zealand earthquakes. Some modifications to this software were made. A velocity model can now be automatically used to calculate Green's functions without having a pseudolayer boundary at the source depth. Green's functions can be calculated for multiple depths in a single step, and data are detrended and a suitable data window is selected. The seismic moment tensor solution that has either the maximum variance reduction or the maximum double-couple component is automatically selected for each depth. Seismic moment tensors were calculated for 24 New Zealand earthquakes from 2000 to 2005. The Global CMT project has calculated CMT solutions for 22 of these, and the Global CMT project solutions are compared to the solutions obtained in this project to test the accuracy of the solutions obtained using the TDMT_INVC code. The moment magnitude values are close to the Global CMT values for all earthquakes. The focal mechanisms could only be determined for a few of the earthquakes studied. The value of the moment magnitude appears to be less sensitive to the velocity model and earthquake location (epicentre and depth) than the focal mechanism. Distinguishing legitimate seismic signal from background seismic noise is likely to be the biggest problem in routine inversions.</p>

scholarly journals Edges of overlying seams as a factor responsible for strong mining tremors occurrence during underground hard coal extraction in the light of seismic moment tensor inversion method

2019 ◽  
Vol 133 ◽  
pp. 01005
Author(s):  
Łukasz Wojtecki ◽  
Adam Mirek ◽  
Grażyna Dzik
Keyword(s):  
Seismic Moment ◽  
Longwall Mining ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Coal Extraction ◽  
Hard Coal ◽  
Inversion Method ◽  
Seismic Moment Tensor ◽  
The Difference ◽  
Mining Tremors

Physical processes occurring in the focus of tremor can be identified by solving a focal mechanism via the seismic moment tensor inversion method. In this article the estimation of focal mechanisms of strong mining tremors (according to Polish law tremors of energy higher or equal 1·105 J), which occurred during longwall mining of coal seam no. 507 in one of the hard coal mines in the Polish part of Upper Silesian Coal Basin was performed. Totally 7 strong mining tremors with the local magnitude from 1.84 to 2.52 were analysed. The most probable geomechanical processes in the foci of these tremors have been reconstructed. An attempt to determine the correlation between the edges of overlying seams no. 502, 504 or 506 and strong mining tremors occurrence has been made. The strike of determined nodal planes is in accordance with the azimuth of mentioned edges. The difference between them (absolute value) varies from 0.3° to 34.1° (on average approximately 19°).

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