scholarly journals Numerical evidences of almost convergence of wave speeds for the Burridge–Knopoff model

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
C. Mascia ◽  
P. Moschetta
Keyword(s):  
Numerical Approximation ◽  
Seismic Event ◽  
Numerical Estimate ◽  
Propagation Speed ◽  
Seismic Events ◽  
Almost Convergence ◽  
Stick Slip ◽  
Wave Speeds ◽  
Temporal Averaging ◽  
Predictor Corrector

AbstractThis paper deals with the numerical approximation of a stick–slip system, known in the literature as Burridge–Knopoff model, proposed as a simplified description of the mechanisms generating earthquakes. Modelling of friction is crucial and we consider here the so-called velocity-weakening form. The aim of the article is twofold. Firstly, we establish the effectiveness of the classical Predictor–Corrector strategy. To our knowledge, such approach has never been applied to the model under investigation. In the first part, we determine the reliability of the proposed strategy by comparing the results with a collection of significant computational tests, starting from the simplest configuration to the more complicated (and more realistic) ones, with the numerical outputs obtained by different algorithms. Particular emphasis is laid on the Gutenberg–Richter statistical law, a classical empirical benchmark for seismic events. The second part is inspired by the result by Muratov (Phys Rev 59:3847–3857, 1999) providing evidence for the existence of traveling solutions for a corresponding continuum version of the Burridge–Knopoff model. In this direction, we aim to find some appropriate estimate for the crucial object describing the wave, namely its propagation speed. To this aim, motivated by LeVeque and Yee (J Comput Phys 86:187–210, 1990) (a paper dealing with the different topic of conservation laws), we apply a space-averaged quantity (which depends on time) for determining asymptotically an explicit numerical estimate for the velocity, which we decide to name LeVeque–Yee formula after the authors’ name of the original paper. As expected, for the Burridge–Knopoff, due to its inherent discontinuity of the process, it is not possible to attach to a single seismic event any specific propagation speed. More regularity is expected by performing some temporal averaging in the spirit of the Cesàro mean. In this direction, we observe the numerical evidence of the almost convergence of the wave speeds for the Burridge–Knopoff model of earthquakes.

The Koyna earthquake of December 10 1967: A multiple seismic event

1971 ◽  
Vol 61 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Harsh K. Gupta ◽  
B. K. Rastogi ◽  
Hari Narain
Keyword(s):  
Seismic Event ◽  
Strong Motion ◽  
Seismic Events ◽  
Field Observations ◽  
Rupture Velocity ◽  
P Waves ◽  
Seismic Arrays ◽  
Sine Curve ◽  
Curve Method ◽  
Different Origin

abstract The analysis of P waves recorded at seismological observatories and seismic arrays at teleseismic distances and strong motion seismographs located at Koyna Dam suggest the Koyna earthquake of December 10 1967 to be a complex multiple event. Six of the events could be identified, and the second and third events are located with respect to the initiation using the Gutenberg sine-curve method at distances of 6 and 17 km due south, the average rupture velocity being 3.4 km/sec. The findings are consistent with the field observations and the different origin times, epicenters and magnitudes reported for the earthquake. Seismic array records are found to be very useful in examining the multiplicity of seismic events.

What allows seismic events to grow big?: Insights from b-value and fault roughness analysis in laboratory stick-slip experiments

Geology ◽  
2017 ◽  
Vol 45 (9) ◽  
pp. 815-818 ◽  
Author(s):  
Thomas H.W. Goebel ◽  
Grzegorz Kwiatek ◽  
Thorsten W. Becker ◽  
Emily E. Brodsky ◽  
Georg Dresen
Keyword(s):  
B Value ◽  
Seismic Events ◽  
Stick Slip ◽  
Fault Roughness ◽  
Roughness Analysis

Early Cambrian Seismic Events and Their Tectonic Significance in Western Zhejiang

2012 ◽  
Vol 524-527 ◽  
pp. 42-48
Author(s):  
Fu Sheng Guo ◽  
Zhao Bin Yan ◽  
Liu Qin Chen
Keyword(s):  
Seismic Event ◽  
Regional Distribution ◽  
Sedimentary Rocks ◽  
Seismic Events ◽  
Time Interval ◽  
Early Cambrian ◽  
Distribution Characteristics ◽  
Early Paleozoic ◽  
Tectonic Events ◽  
Tectonic Significance

The two early Cambrian seismic events could be found from sedimentary rocks at Peilingjiao section of Kaihua County, Baishi and Fangcun sections of Changshan County in western Zhejiang, except for Jiangshan area. The seismic event at Baishi outcrop can be correlated to the second seismic event at Peilingjiao section. Taking Fangcun as epicenter of the second seismic event, the magnitude of paleoseism in western Zhejiang is about 7~7.6. According to investigation on regional distribution of seismic events, the two seismic activities should be regulated by large Kaihua-Chun’an fault, but unrelated with Jiangshan-Shaoxing fault or Changshan-Xiaoshan fault. However, the formation time of Kaihua-Chun’an fault has not yet been determinate. Based on controlling on Silurian, the possible formation age was inferred to early Paleozoic. The distribution characteristics of seismites indicate that the Kaihua-Chun’an fault was already being active during early Cambrian and seismic activities may be response to Sinian tectonic events in western Zhejiang. By the way of analysis on paleoseismic rhythm, the time interval of the two seismic events in western Zhejiang is less than 5.0 Ma, which may be the result of early frequent activities of Kaihua-Chun’an fault.

Study on PRA Procedure Considering Combination of Multiple Events Using DQFM Methodology

2018 ◽  
Author(s):  
Hirohisa Yamakawa ◽  
Hitoshi Muta
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Seismic Event ◽  
Seismic Events ◽  
Power Station ◽  
Component Failure ◽  
Multiple Events ◽  
Fukushima Daiichi ◽  
Tsunami Event ◽  
Direct Quantification

Fukushima Daiichi Nuclear Power Station accident occurred by the Great East Japan Earthquake on March 11, 2011. After that, continuous enhancement of nuclear safety is being required in Japan. The accident of Fukushima was caused by the seismic induced tsunami event, namely, multiple events. The other examples of multiple events due to the seismic event are such as internal fire and internal flooding in the nuclear power plants. In addition, structures, such as a building, and piping might be damaged by the seismic event, which could impact component failure dependently. In order to consider these kinds of events, the development of PRA procedures for multiple events caused by the seismic events will be highly demanded. So, we developed a basic PRA methodology for seismic induced tsunami events using “Direct Quantification of Fault Tree using Monte Carlo simulation (DQFM) methodology”. And we verified its applicability through the evaluation.

scholarly journals Seismic vulnerability of structures: application to the Civil Protection building in Andorra

2020 ◽  
Vol 21 (5) ◽  
pp. 514
Author(s):  
Matthias Barus ◽  
Olivier Dalverny ◽  
Hélène Welemane ◽  
Jean-Pierre Faye ◽  
Carmen Martin
Keyword(s):  
Seismic Event ◽  
Seismic Vulnerability ◽  
Natural Frequencies ◽  
Computation Method ◽  
Seismic Events ◽  
Civil Protection ◽  
Structural Behaviour ◽  
Linear Dynamic ◽  
Dynamic Computation ◽  
Interesting Approach

This works deals with the seismic vulnerability of buildings in the Pyrenees mountains region where almost a thousand earthquakes are recorded each year in the border area. The challenge is twofold: first to detect the damage due to seismic events and then to localize it inside studied buildings. Operational Modal Analysis (OMA) coupled with numerical modelling by Finite Element (FE) constitutes an interesting approach to address these issues. Here we intend to apply such methodology on a strategic building located in Andorre-la-Vieille whose structure is complex, irregular and heterogeneous. The structural behaviour of the building is studied through frequency computation method in order to identify its undamaged behaviour. A seismic event is next simulated by a non-linear dynamic computation method which creates damage within the structure. Numerical results (natural frequencies, modal shapes and damage location) allow highlighting damaged zones induced by the earthquake and quantify degradation level in these areas. Accordingly, some guidelines may be given in view of the future instrumentation of the building (accelerometers and RAR).

scholarly journals Seasonal variations of glacier dynamics at Kronebreen, Svalbard revealed by calving related seismicity

2011 ◽  
Vol 5 (6) ◽  
pp. 3291-3321 ◽  
Author(s):  
A. Köhler ◽  
A. Chapuis ◽  
C. Nuth ◽  
J. Kohler ◽  
C. Weidle
Keyword(s):  
Seismic Event ◽  
Single Channel ◽  
Temporal Distribution ◽  
Seismic Events ◽  
Self Organizing Maps ◽  
Processing Scheme ◽  
Glacier Dynamics ◽  
Glacier Front ◽  
Glacier Velocity ◽  
Visual Observations

Abstract. We detect and cluster waveforms of seismic signals recorded close to the calving front of Kronebreen, Svalbard, to identify glacier-induced seismic events and to investigate their relation to calving processes. Single-channel geophone data recorded over several months in 2009 and 2010 are combined with eleven days of direct visual observations of the glacier front. We apply a processing scheme which combines conventional seismic event detection using a sensitive trigger algorithm and unsupervised clustering of all detected signals based on their waveform characteristics by means of Self-Organizing Maps (SOMs). We are able to distinguish between false detections, instrumental artifacts, and three classes of signals which are, with different degrees of uncertainty, emitted by calving activity. About 10 % of the directly observed calving events close to the geophone (<1 km) can be correlated with seismic detections. By extrapolating the interpretation of seismic event classes beyond the time period of visual observations, the temporal distribution of glacier-related events shows an increase in event rate in autumn, particularly for the class which is clearly related to iceberg calving. Using the seismic event distribution in this class as a proxy for the calving rate and measurements of glacier velocity and glacier front position, we discuss the relationship between glacier dynamics and calving processes. On the seasonal time-scale, the well-marked glacier acceleration in spring is not accompanied by an increase in calving related seismicity. With a slowdown in glacier velocity in autumn, however, a remarkable increase in calving related seismicity is observed. The rate of seismic events due to calving seems thus to behave rather independently from the actual glacier speed, suggesting a complex and indirect dynamical link between the two quantities.

scholarly journals BELARUS

2020 ◽  
pp. 208-215
Author(s):  
T. Aronova ◽  
G. Aronov ◽  
T. Protasovitskaya ◽  
V. Aronov
Keyword(s):  
Seismic Event ◽  
Seismic Energy ◽  
Mining Area ◽  
Activity Level ◽  
Seismic Events ◽  
Average Value ◽  
Long Time ◽  
Event Distribution ◽  
Time Average ◽  
Seismicity Analysis

. The review of annual seismicity in the territory of Belarus based on the data of two analog and seventeen digital stations is presented. 57 events with Кd=4.6–8.8 are recorded, all of them are located in the southern part of the territory, including the Soligorsk mining area. The maximum seismic energy released in March, August, October and November. The maximum number of earthquakes was observed from July to August and from October to November. The N(K) andΣE functions in 2014 were compared with those within 1983–2013. The number of events in 2014 is 1.34 times more than its average value for previous 31 years. The level of the seismic energy released in 2014 is 2.43 times more than in 2013 and 2.05 times lower than its long-time average value. The distributionof earthquakes by depth intervals showed that the earthquake foci are mostly located in the upper 20 km part of the Earth’s crust. However, the foci of 47 earthquakes are located at depths below 10 km. A slope of the graph showing the recurrence of the events with representative energy classes Кd=6–8 in 2014 was calculated. Its modulus γ=|0.48| is lower than the value γ=|0.5| in 2013. The distribution of all the events in 2014 is represented in real time. Quiet seismic periods and seismic activation periods were determined. The distribution of the seismic events by the hourly intervals showed the periods of the daytime and nighttime increase of the seismic event number. The maximum and minimum values N in the seismic event distribution by the days of the week were determined. The seismicity analysis has shown that the seismic activity level in 2014 was higher than that in 2013, but lower than its long-time average value.

scholarly journals Sismicidad en regiones del norte de Chile

2017 ◽  
pp. 141
Author(s):  
Nelson Osvaldo Infante Fabres
Keyword(s):  
Natural Disasters ◽  
Seismic Activity ◽  
Seismic Event ◽  
Seismic Events ◽  
The North ◽  
The World ◽  
Northern Regions ◽  
Potential Case ◽  
Basic Concepts

El presente artículo trata acerca de la sismicidad y de los eventos sísmicos que afectaron durante el mes de marzo y abril del año 2014 a la zona norte de Chile, específicamente, a las regiones de Arica y Parinacota e Iquique y sus principales centros poblados, con un evento sísmico magnitud 8,2Mw. Se utilizó información del Servicio Nacional de Sismología, del Servicio Hidrográfico y Oceanográfico de la Armada de Chile, para analizar tanto la actividad sísmica como sus efectos sobre algunas ciudades localizadas en el borde costero de las regiones norte, ante un potencial evento sísmico de magnitud superior a ocho grados Richter. Asimismo, en el texto se abordan algunos conceptos básicos de sismología que es necesario que la población conozca para comprender e internalizar que Chile es uno de los países que presenta una gran variedad de desastres naturales, especialmente sísmicos,a nivel mundial.Palabras clave: Bordes de placas; cartas de inundación tsunámica; plano de Benioff; escala de magnitud del momentoSeismicity in Northern regions of ChileAbstractThis article addresses seismicity and seismic events affecting the North of Chile during March and April, 2014, specifically at Arica and Parinacota and Iquique regions and the main inhabited areas, with a seismic event of 8.2 Mw in magnitude. It uses information from the National Seismology Service and the Hydrographic and Oceanographic Service of the Chilean Navy to analyze both the seismic activity and the effects on some cities located on the coastal border of the Northern regions, in the potential case of a seismic event stronger than 8 Richter grades in magnitude. The paper also addresses some basic concepts of seismology necessary for the population to understand and internalize that Chile is one of the countries in the world presenting the major variety of natural disasters, especially of seismic nature.Keywords: Plate edges; Tsunamis flood charts; Benioff plane; scale of magnitude at the momentA atividade sísmica em regiões do norte do ChileResumoO presente artigo é sobre a sismicidade e dos eventos sísmicos que afetaram durante o mês de março e abril do ano 2014 para o norte de Chile, especificamente, para as regiões de Arica e Parinacota e Iquique e seus principais centros populacionais, com um evento sísmico de magnitude 8.2 Mw. Utilizou-se informação do Serviço Nacional de Sismologia, do Serviço Hidrográfico e Oceanográfico da Marinha do Chile para analisar tanto a atividade sísmica como também seus efeitos sobre algumas cidades localizadas no borde costeiro das áreas do Norte, ante um potencial evento sísmico de magnitude superior a oito graus Richter. Também no texto abordam-se alguns conceitos básicos de sismologia que é necessário que a população conheça para compreender e interiorizar que o Chile é um dos países que apresentam uma grande variedade de desastres naturais, especialmente sísmicos, a nível mundial.Palavras-chave: Bordes de placas; cartas de inundação de Tsunami; plano de Benioff; escala de magnitude do momento

scholarly journals Ionosperic anomaly due to seismic activities – Part 1: Calibration of the VLF signal of VTX 18.2 KHz station from Kolkata and deviation during seismic events

2009 ◽  
Vol 9 (4) ◽  
pp. 1403-1408 ◽  
Author(s):  
S. Sasmal ◽  
S. K. Chakrabarti
Keyword(s):  
Solar Activity ◽  
Calibration Curve ◽  
Solar Minimum ◽  
Seismic Event ◽  
Space Physics ◽  
Seismic Events ◽  
The Sun ◽  
Reference Signals ◽  
The Mean ◽  
Indian Centre

Abstract. VLF signals are long thought to give away important information about the lithosphere-ionosphere coupling. In order to establish co-relations, if any, between the ionospheric activities and the earthquakes, we need to understand what the reference signals are, throughout the year. The best opportunity to do this is during the period of solar minimum where the number of flares and sunspots are negligible and the data would be primarily affected by the sun and variation would be due to normal sunset and sunrise effects. In this paper, we present the result of the sunrise and sunset terminators as a function of the day of the year for a period of four years, viz, 2005–2008 when the solar activity was very low. The terminators are for the 18.2 KHz VTX signal of the Indian Navy as observed from Indian Centre for Space Physics receiving station located in Kolkata. A total of 624 days of data have been used to obtain the mean plot. Any deviation of observations from this so-called the standardized calibration curve would point to influences by terrestrial (such as earthquakes) and extra-terrestrial events (such as solar activities). We present examples of deviations which occur in a period of 16 months and show that the correlation with seismic events is significant and typically the highest deviation takes place up to a couple of days prior to the seismic event. Simultaneous observations of such deviations from more than one station could improve the predictability of earthquakes.

scholarly journals Proposal for a System Model for Offline Seismic Event Detection in Colombia

2020 ◽  
Vol 12 (12) ◽  
pp. 231
Author(s):  
Julián Miranda ◽  
Angélica Flórez ◽  
Gustavo Ospina ◽  
Ciro Gamboa ◽  
Carlos Flórez ◽  
...  
Keyword(s):  
Machine Learning ◽  
Event Detection ◽  
Seismic Event ◽  
Detection System ◽  
Sample Selection ◽  
P Wave ◽  
Machine Learning Techniques ◽  
Seismic Events ◽  
Seismic Event Detection ◽  
Events Detection

This paper presents an integrated model for seismic events detection in Colombia using machine learning techniques. Machine learning is used to identify P-wave windows in historic records and hence detect seismic events. The proposed model has five modules that group the basic detection system procedures: the seeking, gathering, and storage seismic data module, the reading of seismic records module, the analysis of seismological stations module, the sample selection module, and the classification process module. An explanation of each module is given in conjunction with practical recommendations for its implementation. The resulting model allows understanding the integration of the phases required for the design and development of an offline seismic event detection system.

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