scholarly journals Source parameters of seismic events potentially associated with damage in block 33/34 of the Kiirunavaara mine (Sweden)

2017 ◽  
Vol 65 (6) ◽  
pp. 1229-1242 ◽  
Author(s):  
Emilia Nordström ◽  
Savka Dineva ◽  
Erling Nordlund
Keyword(s):  
Source Parameters ◽  
Seismic Events

scholarly journals SOURCE PARAMETERS of STRONG EARTHQUAKES OCCURRED in the BAIKAL REGION and TRANSBAIKALIA in 2015

2021 ◽  
pp. 217-225
Author(s):  
A. Filippova ◽  
N. Gileva
Keyword(s):  
Baikal Region ◽  
Source Parameters ◽  
Seismic Hazard Assessment ◽  
Normal Fault ◽  
Baikal Rift Zone ◽  
Body Waves ◽  
Small Scale ◽  
Seismic Events ◽  
Study Region ◽  
Moment Tensors

We calculated seismic moment tensors in a double-couple approximation (focal mechanisms, scalar seismic moments, and moment magnitudes) and hypocentral depths for twenty earthquakes with Mw≥4.2 that occurred in the Baikal region and Transbaikalia in 2015. The initial data were amplitude spectra of Rayleigh and Love waves obtained from their records at the broadband seismic stations of the IRIS and the DK networks and first-motion polarities of body waves recorded at regional distances. A combination of the normal fault and strike-slip movements dominate in the sources of the major part of the study earthquakes. For the strongest of the considered seismic events (Mw≥4.6), the subvertical compression and subhorizontal tension in the SE-NW direction prevail, i.e. the tension is perpendicular to the main structures of the Baikal rift zone. The seismic events with Mw<4.6 are characterized by a more scattered orientation of compression and tension axis that could be caused, for instance, by stress redistribution in small-scale crustal blocks after stronger earthquakes. The obtained results are of great value for issues concerned with seismic hazard assessment and the development of geodynamical models of the lithosphere evolution of the study region.

Pseudo-probabilistic identification of fracture network in seismic clouds driven by source parameters

2020 ◽  
Vol 223 (3) ◽  
pp. 2066-2084
Author(s):  
Rike Koepke ◽  
Emmanuel Gaucher ◽  
Thomas Kohl
Keyword(s):  
Source Parameters ◽  
Synthetic Data ◽  
Fracture Network ◽  
Gas Production ◽  
Minimum Size ◽  
Seismic Events ◽  
Data Sets ◽  
Weighting Functions ◽  
Hydraulic Stimulation ◽  
Rupture Plane

SUMMARY Fracture networks in underground reservoirs are important pathways for fluid flow and can therefore be a deciding factor in the development of such reservoirs for geothermal energy, oil and gas production or underground storage. Yet, they are difficult to characterize since they usually cannot be directly accessed. We propose a new method to compute the likelihood of having a fracture at a given location from induced seismic events and their source parameters. The result takes the form of a so-called pseudo-probabilistic fracture network (PPFN). In addition to the hypocentres of the seismic events used to image the fracture network, their magnitudes and focal mechanisms are also taken into account, thus keeping a closer link with the geophysical properties of the rupture and therefore the geology of the reservoir. The basic principle of the PPFN is to estimate the connectivity between any spatial position in the cloud and the seismic events. This is done by applying weighting functions depending on the distance between a seismic event and any location, the minimum size of the rupture plane derived from the event magnitude, and the orientation of the rupture plane provided by the focal mechanism. The PPFN is first tested on a set of synthetic data sets to validate the approach. Then, it is applied to the seismic cloud induced by the deep hydraulic stimulation of the well GPK2 of the enhanced geothermal site of Soultz-sous-Forêts (France). The application on the synthetic data sets shows that the PPFN is able to reproduce fault planes placed in a cloud of randomly distributed events but is sensitive to the free parameters that define the shape of the weighting functions. When these parameters are chosen in accordance with the scale of investigation, that is, the typical size of the structures of interest, the PPFN is able to determine the position, size and orientation of the structure quite precisely. The application of the PPFN to the GPK2 seismic cloud reveals a large prominent fault in the deep-northern part of the seismic cloud, supporting conclusions from previous work, and a minor structure in the southern upper part, which could also be a branch of the main fault.

Development of an interactive Cloud-based seismic network modelling application on a common Geophysical Processing Toolkit platform

2021 ◽  
Author(s):  
Pavel Golodoniuc ◽  
Januka Attanayake ◽  
Abraham Jones ◽  
Samuel Bradley
Keyword(s):  
Seismic Velocity ◽  
Source Parameters ◽  
Seismic Array ◽  
Seismic Events ◽  
Network Modelling ◽  
Small Magnitude ◽  
Network Sensitivity ◽  
Earthquake Source Parameters ◽  
Minimum Number ◽  
Seismic Networks

&lt;p&gt;Detecting and locating earthquakes relies on seismic events being recorded by a number of deployed seismometers. To detect earthquakes effectively and accurately, seismologists must design and install a network of seismometers that can capture small seismic events in the sub-surface.&lt;/p&gt;&lt;p&gt;A major challenge when deploying an array of seismometers (seismic array) is predicting the smallest earthquake that could be detected and located by that network. Varying the spacing and number of seismometers dramatically affects network sensitivity and location precision and is very important when researchers are investigating small-magnitude local earthquakes. For cost reasons, it is important to optimise network design before deploying seismometers in the field. In doing so, seismologists must accurately account for parameters such as station locations, site-specific noise levels, earthquake source parameters, seismic velocity and attenuation in the wave propagation medium, signal-to-noise ratios, and the minimum number of stations required to compute high-quality locations.&lt;/p&gt;&lt;p&gt;AuScope AVRE Engage Program team has worked with researchers from the seismology team at the University of Melbourne to better understand their solution for optimising seismic array design to date: an analytical method called SENSI that has been developed by Tramelli et al. (2013) to design seismic networks, including the GipNet array deployed to monitor seismicity in the Gippsland region in Victoria, Australia. The underlying physics and mechanics of the method are straightforward, and when applied sensibly, can be used as a basis for the design of seismic networks anywhere in the world. Our engineers have built an application leveraging a previously developed Geophysical Processing Toolkit (GPT) as an application platform and harnessed the scalability of a Cloud environment provided by the EASI Hub, which minimised the overall development time. The GPT application platform provided the groundwork for a web-based application interface and enabled interactive visualisations to facilitate human-computer interaction and experimentation.&lt;/p&gt;

Source parameters of seismic events at Mount Etna volcano, Italy, during the outburst of the 1991–1993 eruption

1995 ◽  
Vol 89 (3-4) ◽  
pp. 149-162 ◽  
Author(s):  
G. Patanè ◽  
G. Coco ◽  
M. Corrao ◽  
S. Imposa ◽  
A. Montalto
Keyword(s):  
Source Parameters ◽  
Mount Etna ◽  
Seismic Events ◽  
Etna Volcano

Toward implementing a grid search moment tensor (GRiD MT) tool for the rapid detection and characterization of seismic events in Metropolitan France

2021 ◽  
Author(s):  
Marine Menager ◽  
Aurélie Trilla ◽  
Bertrand Delouis
Keyword(s):  
Rapid Detection ◽  
Goodness Of Fit ◽  
Moment Tensor ◽  
Source Parameters ◽  
Velocity Model ◽  
Seismic Events ◽  
Grid Search ◽  
More Care ◽  
Recent Earthquakes

&lt;p&gt;The aim of this study is to implement at the CEA a grid search moment tensor inversion scheme (GRiD MT) for the rapid detection and characterization of seismic events, to monitor low to moderate magnitude earthquakes in France. Given the heterogeneity of the seismic network and of the crustal geology over the country, we propose to use a combination of source grids focusing on specific regions. The GRiD MT approach requires an extensive preliminary analysis to define the different inversion parameters (velocity model, frequency band, and stations) and grid spacing (in latitude, longitude and depth). Here, we present the advances made towards the GRiD MT implementation for France. Using recent earthquakes, such as the 2019 ML 5.4 Le Teil earthquake, near Montelimar in Southern France, we discuss the validity of this detection and characterization tool for earthquake routine. The GRiD MT results applied in the South-East region for moderate earthquakes are close to those published by other agencies (USGS, IPGP, OCA, INGV) in terms of location, magnitude and focal mechanism. Nonetheless, more care is needed for the smallest events. We also discuss the precision and the uncertainties in constraining the source parameters using this method, especially when considering the goodness of fit as the unique criterion to identify a potential source, and different Earth&amp;#8217;s structures. In the end, we show that the GRiD MT approach may be an interesting tool to analyze seismic events in France within only a few minutes after their occurrence. However, their low magnitude range raises some challenging questions to be answered.&lt;/p&gt;

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