Regional variation of coda Q in Kopili fault zone of northeast India and its implications

Bora, Nilutpal; Biswas, Rajib; Добрынина, А. А.

doi:10.1016/j.tecto.2017.11.008

Cited by 20 publications

(14 citation statements)

References 77 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several researchers opined that Kopili Zone has been witness to high seismic activities in the recent past. Attenuation studies as well as microearthquake studies also evinces this assertion [2][3][4][5][6]. Additionally, major part of Assam is characterized by alluvium soils which make cities as well as locations more vulnerable to seismic waves.…”

Section: Discussionmentioning

confidence: 88%

“…Recent studies indicate that Tezpur and its neighbouring region are characterized by low velocity zones at certain points. This poses as a major threat for seismic amplification [3][4][5][6][7][8]. Apart from this, resonance frequency estimates come in the range of 0.5 to 2.8 Hz which is further accompanied by larger amplification values in certain pockets [10].…”

Section: Discussionmentioning

confidence: 99%

“…Above all, Assam remained witness to great earthquake of magnitude 8.6 in the year 1950 which resulted in huge casualties. It is pertinent to mention here that Indian tectonic plate is continuously wedging into the Eurasian plates at a speed of 44 mm/year which is a large contributor of strain build-up [2][3][4][5][6][7][8][9][10].…”

Section: Current Seismicitymentioning

confidence: 99%

See 2 more Smart Citations

A brief review of the recent Assam Earthquake

Biswas¹

2021

Preprint

Self Cite

View full text Add to dashboard Cite

The recent Assam Earthquake has been previewed in the context of the recent seismicity pertaining to Kopili Fault of northeast India. Kopili fault of northeast India is known for its active seismicity. The ground motion parameters in the context of peak ground acceleration, peak ground velocity and peak spectral acceleration stand out for their implications. Considering the strong magnitude of the event, there is imminent need for earthquake resilient buildings as well as hazard mitigation strategies in order to tackle post-earthquake scenarios.

show abstract

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A brief review of the recent Assam Earthquake

Biswas¹

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…These values suggest the region is dominated by local faults and fractures due to the connectivity between the north and middle branches of the NAFZ. For instance, in the Kopili Fault Zone (India), the coda Q study performed by Bora et al [2018] demonstrates that the seismic activity is in correlation with the low values of coda wave decay. Additionally, in NW Himalayan Region, Kumar et al [2005] evaluated low Q o values through the whole main boundary thrusts and other fault segments.…”

Section: Resultsmentioning

confidence: 99%

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

Yavuz

Barış²

2019

Annals of Geophysics

View full text Add to dashboard Cite

The Armutlu Peninsula, is located in a geologically complex system on the North Anatolian Fault Zone and inside the high populated Marmara Region. Due to its location and importance, the Marmara Region has been subject to various studies in the past; now, this study is aimed to determine the local attenuation characteristic of the Armutlu Peninsula. In this study, 75 earthquake data that were recorded between 2013-2014, were analyzed by 9 seismic stations. The magnitudes (Ml) and the focal depths of the earthquakes vary from 1.5 to 3.3 and 0.9 to 16.9 km, respectively. A single back-scattering model was used for calculation of the coda wave quality factor. The lapse times were determined between 20 and 40 s at intervals of 5 s and they were filtered at central frequencies of 1.5, 3, 6, 9 and 12 Hz band-pass designed filter. Minimum 5 signal/noise ratio and 0.7 correlation coefficient data used to obtain reliable results. The CODAQ subroutine integrated in the SEISAN software was used for data processing. For each station, low values of the quality factor at 1 Hz (Q o ) and high values of the frequency dependent parameter (n) were determined. In the Armutlu Peninsula and its surroundings, Q c =51f 0.91 for 20 s and Q c =112f 0.72 for 40 s window lengths were calculated by using 9 stations. There is a tendency between increasing Q o and decreasing n parameters. Otherwise, for station TRML, located near the geothermal hotspot, these parameters are in direct proportion with each other, as Q c =46f 0.97 for 20 s and Q c =74f 1.06 for 40 s window lengths. These parameter changes are directly connected with the geothermal activity. the rate of coda wave attenuation [Aki, 1969]. Local/regional recorded coda waves (up to 100 km epicentral distance) and their power spectra as well as coda duration are relatively independent from the focal distance [Aki and Chouet, 1975]. Q c determination studies are generally performed in tectonically active fields, active volcanic regions, earthquake swarm areas, magmatic flows and geothermal areas [

show abstract

“…Besides, towards north, the main constituents comprise of thick sediments of Bengal. Among those earthquakes, KF had witnessed major event having magnitudes greater than seven [Biswas et al, 2018 a,b].…”

Section: Seismotectonics Of Kopili Regionmentioning

confidence: 99%

P- and S-wave attenuation in the Kopili region of northeastern India

Bora

Biswas

2019

Annals of Geophysics

Self Cite

View full text Add to dashboard Cite

We comprehensively analyze attenuation factor in Kopili region and its neighboring area. Corresponding to influence of frequency on attenuation, Q P and Q S are estimated from direct P and S waves. The results establishes higher values of Q for S waves (Q S =(101±4)f(1.4±0.05)) than for P waves (Q P =(45±3)f(1.3±0.07))in the 1.5-12 Hz frequency band. It is seen that our findings agree with other published results on tectonically active regions that is characterized by high degree of heterogeneity. Hence, it can be useful for further studies in ground motion prediction in Kopili region. The low value of quality factors corresponding to P and S waves refers to seismically actives areas with complex heterogeneity. The estimated value of Q S /Q P and their subsequent association with frequency affirm the dominance of scattering as a major contribution to diminution of seismic amplitudes. This is further corroborated by local geological settings.

show abstract

Regional variation of coda Q in Kopili fault zone of northeast India and its implications

Cited by 20 publications

References 77 publications

A brief review of the recent Assam Earthquake

A brief review of the recent Assam Earthquake

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

P- and S-wave attenuation in the Kopili region of northeastern India

Contact Info

Product

Resources

About