b-Values of two tectonic parts in the circum-pacific belt

Tsapanos, Theodoros M.

doi:10.1007/bf00876999

Cited by 70 publications

(48 citation statements)

References 21 publications

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“…Statistically, the b-value is the slope on the log N * M regression line and is a constant parameter that determines the rate of fall in the frequency of occurrence of events with increasing magnitude. High b-values indicate a large number of small earthquakes expected in regions of low strength and large heterogeneity, and low b-values indicate high resistance (asperity) and homogeneity of the constituent rock-mass (TSAPANOS, 1990;UDIAS, 1999;WASON et al, 2002). In natural situations, b-values are found to lie between 0.5 and 1.5, depending on the tectonics of a region.…”

Section: Introductionmentioning

confidence: 99%

Seismic b-Value and the Assessment of Ambient Stress in Northeast India

Khan

Ghosh

Chakraborty

et al. 2010

Pure Appl. Geophys.

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Abstract-Seismicity data of northeast India, recorded between 1986 and 1999 by a local network, are analysed for estimation of bvalues. Based on the obtained values, viz. low (b B 0.5), moderate (0.5 \ b B 0.7) and high (b [ 0.7), the study area is classified into different seismic-domains. An assessment of stress level is also carried out in identifying seismic-domains. Seismic activities, though mostly confined in some sectors, are presumably triggered by mutual interaction of the Shillong Plateau, Mikir Hills, IndoBurman Ranges and the easternmost part of the Himalayas, and the contributions from deep-seated fractures cannot be ignored. The results resemble the seismic character of a foreland setting adjacent to a convergent margin. The b-values estimated for 240 square grids of dimension 0.6°9 0.6°over five seismic domains indicate wide variation. An analysis of cumulative seismic moment release (M O ) in different layers also indicates an anomaly in reference to the total seismic-energy budget of the five zones. The lower b-value and higher M O recorded at relatively lower depth (*30 km) towards the southwest of the study area might be associated with upward bulging of a strong lithosphere. The bulging is perhaps regionally compensated by the downward flexing of the descending Indian lithosphere beneath the Upper Assam area; features unequivocally observed in any foreland setup. Towards the north and east of the study area, random variations of in both b-value and M O along the converging zone suggest a varied tectonic environment with active interaction between the tectonic elements in these areas.

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Section: Introductionmentioning

confidence: 99%

Seismic b-Value and the Assessment of Ambient Stress in Northeast India

Khan

Ghosh

Chakraborty

et al. 2010

Pure Appl. Geophys.

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“…These values were distributed into four groups, smaller than 6.50, 6.50-7.00, 7.00-7.50 and greater than 7.50. These three groups of The b parameter is considered to be closely related to tectonic characteristics of a region (Hatzidimitriou et al, 1985;Wang, 1988;Tsapanos, 1990). It seems to be in close connection with the geological age of an area (Allen et al, 1965).…”

Section: Discussion and Resultsmentioning

confidence: 99%

“…For the historical and instrumental periods, results of completeness analysis are made in this study are shown in Table 2. The method used to assess the completeness of the data of this catalogue has been described in the literature (e.g., Tsapanos, 1990;Tsapanos & Papazachos, 1998). The completeness was assessed on the basis of the cumulative frequency distribution of the magnitudes, and of the cumulative frequency distribution of the number of earthquakes with magnitudes larger than a certain value.…”

Section: Fig 2 Earthquake Epicenter Distribution and Different 9 Sementioning

confidence: 99%

The North Anatolian Fault Zone: an Evaluation of Earthquake Hazard Parameters

Bayrak¹,

Çınar²,

Bayrak³

2011

New Frontiers in Tectonic Research - At the Midst of Plate Convergence

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“…first 67 days) and then stabilizes around an average value 0.88 thereafter. It is known the value ''b'' acts as a ''stressmeter'' in earth crust and depends inversely on the applied differential stress and tectonic character of the region (Hatzidimitriou et al 1985, Tsapanos 1990). Initial high shear stress within the system during the generation of main-shock is reflected by a very low b-value (*0.4).…”

Section: Variations In Spatio-temporal B-valuesmentioning

confidence: 99%

Incipient status of dyke intrusion in top crust – evidences from the Al-Ays 2009 earthquake swarm, Harrat Lunayyir, SW Saudi Arabia

Mukhopadhyay

Mogren

Mukhopadhyay

et al. 2013

Geomatics, Natural Hazards and Risk

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The 2009 earthquake-swarm in the Al-Ays volcanic zone in Harrat-Lunayyir in NW Saudi-Arabia is unique because of its intense character and focal-depth distribution at two depth bands (5-10 and 15-20 km) in upper crust without volcanic eruption. We investigate an anatomy of the dyke-intrusion model that supports the mechanism for the swarm itself with seismotectonics, pore pressure diffusion process and inference model. Inferred dyke-intrusion initially started at depth had a five-day peak period (15-20 May 2009) since inception of eventrecordings, following which the activity diminished. The process of pore pressure perturbation and resultant ''r-t plot'' with modelled diffusivity (D ¼ 0.01) relates the diffusion of pore pressure to seismic sequence in a fractured poro-elastic fluidsaturated medium. The spatio-temporal b-values show high b-values (41.3) along the zone of dyke intrusion (length 10 km and height 5 km) at *20km depth. The main-shock and other prominent earthquakes originated on a moderate b-value zone (*1.0). Temporal b-value analysis indicates an exceptionally low b-value (*0.4) during the main-shock occurrence. The AlAys lava-field is inferred to underlie a seismic volume trending NW-SE bounded on both sides by two NW-SE trending fault systems, dipping 40-508 opposite to each other within a proposed nascent rift setting.

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b-Values of two tectonic parts in the circum-pacific belt

Cited by 70 publications

References 21 publications

Seismic b-Value and the Assessment of Ambient Stress in Northeast India

Seismic b-Value and the Assessment of Ambient Stress in Northeast India

The North Anatolian Fault Zone: an Evaluation of Earthquake Hazard Parameters

Incipient status of dyke intrusion in top crust – evidences from the Al-Ays 2009 earthquake swarm, Harrat Lunayyir, SW Saudi Arabia

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