scholarly journals MUYAKAN-II EARTHQUAKE on MAY 23, 2014 with КР=14.3, Mw=5.5, I0=7–8 (Northern Baikal region)

2020 ◽  
pp. 323-333
Author(s):  
N. Gileva ◽  
V. Melnikova ◽  
A. Seredkina ◽  
Ya. Radziminovich
Keyword(s):  
Seismic Moment ◽  
Main Shock ◽  
Moment Tensor ◽  
Seismic Hazard Assessment ◽  
Baikal Rift Zone ◽  
Temporal Analysis ◽  
Seismic Moment Tensor ◽  
Depth Range ◽  
North East ◽  
The North

We consider the May 23, 2014 Muyakan earthquake (Mw=5.5) occurred in the Muyakan Range at the north-east of the Baikal rift zone near the eastern tunnel portal of the Baikal-Amur Mainline. This event was followed by numerous aftershocks (КР=5.6–9.9) which number exceeded 2000 by the end of the year. Spatio-temporal analysis of the Muyakan seismic sequence shows that its epicentral field consists of two isolated clusters: eastern and western ones. All the main events including the foreshocks, main shock and the strongest aftershocks (Mw=4.4; 4.5) occurred in the eastern cluster while only small seismic events (КР<10.0) were recorded in the western one. Seismic moment tensor was calculated for the Muyakan earthquake from surface wave amplitude spectra. As a result, we obtained information about the rift type focal mechanism, scalar seismic moment (M0=1.9•1017 Nm), moment magnitude (Mw=5.5) and hypocentral depth (h=24 km). From regional data, hypocentral depths of the main shock and the major number of the following earthquakes (80 %) were distributed in the depth range h=3–11 km. Maximum intensity of the main shock (4–5 according to MSK-64) was felt in Severomuysk urban village (=29 km). The obtained results could be used for seismic hazard assessment of the crucial part of the Baikal-Amur Mainline.

scholarly journals STRONG EARTHQUAKES in the NORTH of the LAKE BAIKAL REGION (Mw=4.6–4.7) in 2015

2021 ◽  
pp. 276-290
Author(s):  
Ya. Radziminovich ◽  
V. Melnikova ◽  
N. Gileva ◽  
A. Filippova
Keyword(s):  
Lake Baikal ◽  
Baikal Region ◽  
Moment Tensor ◽  
Seismic Hazard Assessment ◽  
Normal Fault ◽  
Seismic Moment Tensor ◽  
Macroseismic Data ◽  
Strong Earthquakes ◽  
The North ◽  
Lake Baikal Region

The paper considers three relatively strong earthquakes that occurred in 2015 in the northern Lake Baikal region: July 7 Upper Akuli earthquake (Mw=4.6) with the epicenter at the headwaters of the Akuli River, and September 25 Gulonga-I (Mw=4.7) and December 13 Gulonga-II earthquakes (Mw=4.6) with the epicenters near the mountain lakes Gulonga. Instrumental and macroseismic data on these seismic events are reported. A seismic moment tensor, calculated from surface wave records, shows normal fault focal mechanisms for Upper Akuli and Gulonga-II earthquakes and strike-slip movements in the source of the Gulonga-I seismic event. The results obtained could be used in further studies of seismic zoning and seismic hazard assessment in the northern Lake Baikal region.

scholarly journals BAIKAL and TRANSBAIKALIA

2020 ◽  
pp. 130-139
Author(s):  
V. Melnikova ◽  
N. Gileva ◽  
A. Seredkina ◽  
O. Masalskii
Keyword(s):  
Seismic Moment ◽  
Rift Zone ◽  
Moment Tensor ◽  
Normal Fault ◽  
Large Earthquake ◽  
Baikal Rift Zone ◽  
Focal Mechanisms ◽  
P Wave ◽  
Seismic Moment Tensor ◽  
High Level

We considered the character of the seismic process in the Baikal and Transbaikalia region in 2014. 8782 earthquakes with КР≥5.6 were recorded within the study territory during that year, 94 % of them were located in the Baikal rift zone. 26 seismic events were felt in the cities, towns and local settlements with the intensity not exceeding 5. The strongest of them (Mw=5.5) occurred in the Baikal-Muya region of the Baikal rift zone and was followed by a large earthquake sequence. Focal mechanisms were determines for 46 shocks from the data on P-wave first motion polarities, seismic moment tensor (focal mechanism, scalar seismic moment (M0), moment magnitude (Mw) and hypocentral depth (h)) was calculated for 11 events from the data on amplitude surface wave spectra. It has been found that normal fault movements are realized in the sources of 59 % of the earthquakes with the obtained focal mechanisms. In general, high level of seismic activity is a characteristic feature of the considered territory in 2014.

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 tensors from synthetic rotational and translational ground motion: Green’s functions in 1-D versus 3-D

2020 ◽  
Vol 223 (1) ◽  
pp. 161-179
Author(s):  
S Donner ◽  
M Mustać ◽  
B Hejrani ◽  
H Tkalčić ◽  
H Igel
Keyword(s):  
Ground Motion ◽  
Seismic Moment ◽  
Structural Model ◽  
Moment Tensor ◽  
Waveform Inversion ◽  
Seismic Moment Tensor ◽  
Tectonic Event ◽  
Moment Tensors ◽  
Rotational Ground Motion ◽  
D Model

SUMMARY Seismic moment tensors are an important tool and input variable for many studies in the geosciences. The theory behind the determination of moment tensors is well established. They are routinely and (semi-) automatically calculated on a global scale. However, on regional and local scales, there are still several difficulties hampering the reliable retrieval of the full seismic moment tensor. In an earlier study, we showed that the waveform inversion for seismic moment tensors can benefit significantly when incorporating rotational ground motion in addition to the commonly used translational ground motion. In this study, we test, what is the best processing strategy with respect to the resolvability of the seismic moment tensor components: inverting three-component data with Green’s functions (GFs) based on a 3-D structural model, six-component data with GFs based on a 1-D model, or unleashing the full force of six-component data and GFs based on a 3-D model? As a reference case, we use the inversion based on three-component data and 1-D structure, which has been the most common practice in waveform inversion for moment tensors so far. Building on the same Bayesian approach as in our previous study, we invert synthetic waveforms for two test cases from the Korean Peninsula: one is the 2013 nuclear test of the Democratic People’s Republic of Korea and the other is an Mw  5.4 tectonic event of 2016 in the Republic of Korea using waveform data recorded on stations in Korea, China and Japan. For the Korean Peninsula, a very detailed 3-D velocity model is available. We show that for the tectonic event both, the 3-D structural model and the rotational ground motion, contribute strongly to the improved resolution of the seismic moment tensor. The higher the frequencies used for inversion, the higher is the influence of rotational ground motions. This is an important effect to consider when inverting waveforms from smaller magnitude events. The explosive source benefits more from the 3-D structural model than from the rotational ground motion. Nevertheless, the rotational ground motion can help to better constraint the isotropic part of the source in the higher frequency range.

Resolution of Seismic-Moment Tensor Inversions from a Single Array of Receivers

2011 ◽  
Vol 101 (6) ◽  
pp. 2634-2642 ◽  
Author(s):  
I. Vera Rodriguez ◽  
Y. J. Gu ◽  
M. D. Sacchi
Keyword(s):  
Seismic Moment ◽  
Moment Tensor ◽  
Seismic Moment Tensor
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