scholarly journals Pattern of Stress-Strain Accumulation due to a Long Dipslip Fault Movement in a Viscoelastic Layered Model of The Lithosphere–Asthenosphere System

2013 ◽  
Vol 18 (3) ◽  
pp. 653-670 ◽  
Author(s):  
S.K. Debnath ◽  
S. Sen
Keyword(s):  
Mantle Convection ◽  
Integral Transformation ◽  
Active Regions ◽  
Viscoelastic Layer ◽  
Seismic Events ◽  
Strain Accumulation ◽  
Fault Movement ◽  
System A ◽  
Earthquake Faults ◽  
Stress Accumulation

Abstract The process of stress accumulation near earthquake faults during the aseismic period in between two major seismic events in seismically active regions has become a subject of research during the last few decades. In the present paper a long dip -slip fault is taken to be situated in a viscoelastic layer over a viscoelastic half space representing the lithosphere-asthenosphere system. A movement of the dip-slip nature across the fault occurs when the accumulated stress due to various tectonic reasons, e.g., mantle convection etc., exceeds the local friction and cohesive forces across the fault. The movement is assumed to be slipping in nature, expressions for displacements, stresses and strains are obtained by solving the associated boundary value problem with the help of integral transformation and Green's function method. A detailed study of these expressions may give some ideas about the nature of stress accumulation in the system, which in turn will be helpful in formulating an earthquake prediction programme

scholarly journals Interaction among neighbouring rectangular finite strike slip faults in a linear viscoelastic half space representing lithosphere-asthenosphere system

MAUSAM ◽  
2021 ◽  
Vol 71 (4) ◽  
pp. 699-708
Author(s):  
DEBNATH PAPIYA ◽  
SEN SANJAY
Keyword(s):  
Half Space ◽  
Correspondence Principle ◽  
Integral Transform ◽  
Active Regions ◽  
Fault System ◽  
Model Parameters ◽  
Seismic Events ◽  
Linear Viscoelastic ◽  
Earthquake Faults ◽  
Stress Accumulation

There are seismically active regions consisting of fault system with a number of neighbouring earthquake faults. A movement across any one of them may affect the nature of stress accumulation near the others. Mathematical models may be developed to study these interactions and the pattern of interseismic stresses during the aseismic period in between two consecutive seismic events. In this paper, the lithosphere-asthenosphere system is being represented by a linear viscoelastic half space. The material of the half space is expected to possess the properties of both Maxwell and Kelvin type materials. It is assumed that the system is under a steady shear stress generated by some tectonic phenomena. For obtaining the solution for displacement, strain and stresses from the resulting boundary value problem, Integral transform, Green’s function techenique and correspondence principle have been used. Appropriate estimates of the model parameters were used in carrying out the numerical computations for investigating the nature of interactions among the faults.

Analysis of seismic instability of the Vancouver Island lithoprobe transect

1986 ◽  
Vol 23 (12) ◽  
pp. 2057-2067
Author(s):  
E. Nyland ◽  
Qing Li
Keyword(s):  
Subduction Zone ◽  
Mantle Convection ◽  
Seismic Refraction ◽  
Element Model ◽  
Failure Criteria ◽  
Vancouver Island ◽  
Seismic Events ◽  
Rock Failure Criteria ◽  
Gravity Measurements ◽  
Plate Subduction

Seismic refraction and reflection surveys and gravity measurements over Vancouver Island, British Columbia, Canada, can constrain a finite-element model of the geodynamics of the subduction zone. Stress estimates obtained from this model have been combined with rock failure criteria to yield a probability measure of seismic risk that assumes seismic events start from a dilute distribution of Griffith cracks. The results are in agreement with the observed seismicity and lead to the suggestion that the dominant mechanism of this oceanic plate subduction zone is gravitational ridge push and mantle convection.

scholarly journals LOCAL EARTHQUAKE TOMOGRAPHY IN THE BROADER AREA OF WESTERN CORINTH GULF

2017 ◽  
Vol 50 (3) ◽  
pp. 1143 ◽  
Author(s):  
A. Karakonstantis ◽  
P. Papadimitriou
Keyword(s):  
Active Regions ◽  
Seismic Events ◽  
Salt Tectonics ◽  
Fluid Circulation ◽  
Corinth Gulf ◽  
Local Earthquake Tomography ◽  
Time Period ◽  
The World ◽  
Fluid Concentration ◽  
Local Earthquake

In this study, we applied Local Earthquake Tomography in order to investigate the detailed 3-D structure within and around the broader region of Western Corinth Gulf which is one of the most seismically active regions in the world. We use data from the 2012-2014 time-period, selecting about 2,000 seismic events recorded by the local seismic stations of Hellenic Unified Seismological Network (HUSN) and the Corinth Rift Laboratory Network (CRLN). Applying Tomographic Inversion, we produce and interpret 3-D models of Vp, Vs and Vp/Vs ratio in the study area. The obtained results shows several distinct structures, namely areas of high and low Vp/Vs ratio correlating the hypocenter distribution with changes in lithology or fluid concentration. In the area of Patraikos Gulf, an ascending velocity volume was traced that could possibly be connected to salt tectonics in the alpine basement, effecting the fluid circulation as well as the behavior of local faults.

scholarly journals SEISMICITY of the AMUR and PRIMORYE, SAKHALIN, and the KURIL-OKHOTSK REGION in 2015

2021 ◽  
pp. 139-152 ◽  
Author(s):  
T. Fokina ◽  
D. Safonov ◽  
D. Kostylev ◽  
V. Mikhaylov
Keyword(s):  
Seismic Energy ◽  
Active Regions ◽  
Focal Mechanisms ◽  
Local Network ◽  
Seismic Events ◽  
Regional Network ◽  
Okhotsk Region ◽  
South Sakhalin ◽  
Deep Focus

A review of the Amur and Primorye, Sakhalin, and the Kuril-Okhotsk region seismicity for 2015 is presented on the basis of data from the regional network of stationary seismic stations of the Sakhalin branch of the Geophysical Survey RAS with the involvement of data from adjacent seismological Russian and foreign agencies, as well as ten stations of the local network operating in the south Sakhalin. Parameters of 1643 seismic events have been determined, 126 of them are explosions. Focal mechanisms were calculated for 62 earthquakes. 48 earthquakes have shown a macroseismic effect. A map of the epicenters is presented, the distribution of the number N of crustal and deep-focus earthquakes by a magnitude, a total seismic energy ∑E for seismically active regions of three regions are given, in comparison with the average parameters N and ∑E for 20012014. For each region, an analysis of the parameters of the seismic regime in 2015 is given in comparison with long-term averages, the maximum and significant seismic events are described. The seismicity of the Priamurye and Primorye, Sakhalin, and the Kuril-Okhotsk region in 2015 can be characterized as a moderate one.

scholarly journals Interacting inclined strike-slip faults in a layered medium

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 487-498
Author(s):  
KRISHANU MANNA ◽  
SANJAY SEN
Keyword(s):  
Shear Stress ◽  
Layered Medium ◽  
Integral Transforms ◽  
Earthquake Precursor ◽  
Strike Slip ◽  
Time Span ◽  
The Other ◽  
Viscoelastic Layer ◽  
Seismic Events ◽  
Seismic Fault

Two inclined, interacting, strike-slip faults, both buried, situated in a viscoelastic layer, resting on and in welded contact with a viscoelastic half space, representing the lithosphere-asthenosphere system, is considered. Solutions are obtained for the displacements, stresses and strains, using a technique involving the use of Green’s functions and integral transforms, for three possible cases - the case when no fault is slipping, the case when one fault is slipping and the other is locked and the case when both the faults are slipping. The effect of sudden movement across one fault on the shear stress near the fault itself and near the other faults has been investigated. Some situations are identified where a sudden movement across one fault results in the release of shear stress near the other fault, reducing the possibility of seismic movements across it. Other situations are also identified where a sudden movement across one fault increases the possibility of seismic fault movements. A detail study may lead to an estimation of the time span between two consecutive seismic events near the mid points of the faults. It is expected that such studies may be useful in understanding the mechanism of earthquake processes and may be identified as an earthquake precursor.  

scholarly journals Analysis of post-blasting source mechanisms of mining-induced seismic events in Rudna copper mine, Poland

2015 ◽  
Vol 4 (1) ◽  
pp. 26-38 ◽  
Author(s):  
Alicja Caputa ◽  
Adam Talaga ◽  
Łukasz Rudziński
Keyword(s):  
Underground Mining ◽  
Moment Tensor ◽  
Seismic Events ◽  
Rockburst Hazard ◽  
Mining Areas ◽  
Double Couple ◽  
Source Mechanisms ◽  
Dc Component ◽  
Full Moment Tensor ◽  
Stress Accumulation

Abstract The exploitation of georesources by underground mining can be responsible for seismic activity in areas considered aseismic. Since strong seismic events are connected with rockburst hazard, it is a continuous requirement to reduce seismic risk. One of the most effective methods to do so is blasting in potentially hazardous mining panels. In this way, small to moderate tremors are provoked and stress accumulation is substantially reduced. In this paper we present an analysis of post-blasting events using Full Moment Tensor (MT) inversion at the Rudna mine, Poland, underground seismic network. In addition, we describe the problems we faced when analyzing seismic signals. Our studies show that focal mechanisms for events that occurred after blasts exhibit common features in the MT solution. The strong isotropic and small Double Couple (DC) component of the MT, indicate that these events were provoked by detonations. On the other hand, post-blasting MT is considerably different than the MT obtained for strong mining events. We believe that seismological analysis of provoked and unprovoked events can be a very useful tool in confirming the effectiveness of blasting in seismic hazard reduction in mining areas.

Rethinking the Seismic History of the Gulf of Patti (Northeast Sicily, Italy): New Insights from the Local Historical Archives

2021 ◽  
Author(s):  
Maria D’Amico ◽  
Viviana Castelli ◽  
Monica Maugeri
Keyword(s):  
Seismic Hazard ◽  
Recurrence Relations ◽  
Active Regions ◽  
Seismic Events ◽  
Probabilistic Seismic Hazard ◽  
Historical Archives ◽  
History Of ◽  
Definition Of ◽  
The Right ◽  
Human Losses

Abstract Improving the knowledge of the seismic history of a region plays a key role in the evaluation of recurrence relations for probabilistic seismic hazard analyses. In this study, we present the results of an investigation carried out in two local historical archives in northeast Sicily, Italy. Several letters, petitions, and reports describing the effects of some earthquakes that occurred between the seventeenth and the eighteenth centuries in the Gulf of Patti area were found and analyzed. This contributed in filling the knowledge gap about a series of moderate-to-large seismic events that were overshadowed by catastrophic earthquakes with major impacts both on human losses and cultural heritage. We describe this experience in the hope that other historians will take up the work, looking for other northeast Sicily local archives to investigate because we believe this is the right way toward a better definition of the seismic history of one of the most seismically active regions of Italy.

Polymeric Bearings – A New Base Isolation System to Reduce Structural Damage during Earthquakes

2013 ◽  
Vol 569-570 ◽  
pp. 143-150 ◽  
Author(s):  
Tomasz Falborski ◽  
Robert Jankowski
Keyword(s):  
Structural Damage ◽  
Base Isolation ◽  
Dynamic Properties ◽  
Steel Structure ◽  
Active Regions ◽  
Seismic Events ◽  
Structural Vibrations ◽  
Isolation System ◽  
Base Isolation System ◽  
Rubber Bearings

Base isolators, like lead rubber bearings, high damping rubber bearings or friction pendulum systems are extensively used in practice in many seismically active regions to protect structures against earthquake forces. The present paper reports the results obtained from the experimental study aimed to determine the effectiveness of the Polymeric Bearings in suppressing structural vibrations during dynamic excitations and therefore to minimize structural damage. The response of the analyzed two-storey structure model both fixed and supported by the Polymeric Bearings under different earthquake excitations was studied. The reduction in lateral response due to seismic events was measured by comparing the peak accelerations of the two-storey steel structure models – with and without base isolation system. The results of the study have shown that the use of the Polymeric Bearings leads to significant improvement in dynamic properties by suppressing structural vibrations. The results have indicated that the Polymeric Bearings can be successfully used to reduce damage of structures during seismic events.

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