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41.
Saurabh Baruah Devajit Hazarika Naba K. Gogoi P. Solomon Raju 《Journal of Earth System Science》2007,116(1):37-47
Microearthquake spectra from Jubilee Hills, Hyderabad are analyzed to observe the effect of attenuation and site on these
spectra. The ratios of spectral amplitudes at lower and higher frequency are measured for three different stations at varying
epicentral distances to estimate Q value for both P-and S-wave in near and sub-surface layer. Average estimates of Qp and
Qs are 235 and 278 respectively. Value of Qs/Qp larger than 1.0 suggests dry crust for most of the Jubilee Hills region. The
near-surface low Qp and Qs for 0 km to 0.9 km depth coincide with the soil layer, top and semi-weathered and highly fractured
zone. In contrast, at a shallower depth beneath the Jubilee Hills area, Hyderabad, we obtain high Qp and Qs zone, which corresponds
to the dense and high velocity rocks of the region. The varying corner frequencies for these spectra are inferred to be characteristics
of site. Comparisons of disparity in spectral content with reference to hard rock site conclude that lithology of the northwest
part of Jubilee Hills area amplify about twice the incoming seismic signal, as compared to the southern part best outlined
at 8 to 10 Hz only. 相似文献
42.
Anbazhagan P. Mog Kunjari Rao K. S. Nanjunda Prabhu N. Siddharth Agarwal Ayush Reddy G. R. Ghosh Sima Deb Malay Kr. Baruah Saurabh Das Sarat Kr. 《Natural Hazards》2019,98(2):425-450
Natural Hazards - An earthquake of moment magnitude Mw 5.7 shook the northeastern region of India on 3 January 2017 at 14 h:39 min:0.5 s local time. The duration of the... 相似文献
43.
Saurabh Baruah Santanu Baruah Naba Kumar Gogoi Olga Erteleva Felix Aptikaev J. R. Kayal 《地震学报(英文版)》2009,(3):283-291
Strong ground motion parameters for Shillong plateau of northeastern India are examined. Empirical relations are obtained for main parameters of ground motions as a function of earthquake magnitude, fault type, source depth, velocity characterization of medium and distance. Correlation between ground motion parameters and characteristics of seismogenic zones are established. A new attenuation relation for peak ground acceleration is developed, which predicts higher expected PGA in the region. Parameters of ... 相似文献
44.
Attenuation of coda waves in the Northeastern Region of India 总被引：1，自引：0，他引：1
Coda wave attenuation quality factor Qc is estimated in the northeastern region of India using 45 local earthquakes recorded
by regional seismic network. The quality factor Qc was estimated using the single backscattering model modified by Sato (J
Phys Earth 25:27–41, 1977), in the frequency range 1–18 Hz. The attenuation and frequency dependence for different paths and the correlation of the
results with geotectonics of the region are described in this paper. A total of 3,890 Qc measurements covering 187 varying
paths are made for different lapse time window of 20, 30, 40, 50, 60, 70, 80, and 90 s in coda wave. The magnitudes of the
analyzed events range from 1.2 to 3.9 and focal depths range between 7 and 38 km. The source–receiver distances of the selected
events range between 16 and 270 km. For 30-s duration, the mean values of the estimated Qc vary from 50 ± 12 (at 1 Hz) to
2,078 ± 211(at 18 Hz) for the Arunachal Himalaya, 49 ± 14 (at 1 Hz) to 2,466 ± 197 (at 18 Hz) for the Indo-Burman, and 45
± 13 (at 1 Hz) to 2,069 ± 198 (at 18 Hz) for Shillong group of earthquakes. It is observed that Qc increases with frequency
portraying an average attenuation relation for the region. Moreover, the pattern of Qc − 1 with frequency is analogous to the estimates obtained in other tectonic areas in the world, except with the observation that
the Qc − 1 is much higher at 1 Hz for the northeastern region. The Qc − 1 is about 10 − 1.8 at 1 Hz and decreases to about 10 − 3.6 at 18 Hz indicating clear frequency dependence. Pertaining to the spatial distribution of Qc values, Mikir Hills and western
part of Shillong Plateau are characterized by lower attenuation. 相似文献
45.
Arpita Sharma Ananya Saikia Puja Khare B P Baruah 《Journal of Earth System Science》2014,123(7):1705-1715
In the present investigation, 37 numbers of high sulphur tertiary coal samples from Meghalaya, India have been studied on the basis of proximate and ash analysis. Various statistical tools like Bivariant Analysis, Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA), and also the geochemical indicators were applied to determine the dominant detrital or authigenic affinity of the ash forming elements in these coals. The genetic interpretation of coal as well as the coal ash has been carried out based on chemical compositions of high temperature ash (HTA) by using Detrital/Authigenic Index. X-Ray Diffraction (XRD) analysis was also carried out to study the mineralogy of the studied coal ashes. Both statistical tools and geochemical indicators have confirmed the detrital nature of these coals as well as the ash forming elements. 相似文献
46.
Olga Erteleva Felix Aptikaev Saurabh Baruah Santanu Baruah Sajal K. Deb J. R. Kayal 《Natural Hazards》2014,70(1):733-753
Strong ground motion parameters for the Guwahati city area, the capital city of the state of Assam in northeast India, are examined with the help of data accrued from local as well as worldwide network. Empirical relations are proposed for the ground motion parameters as a function of earthquake magnitude, distance, fault type, source depth and velocity characteristics of medium. Seismotectonics of the study region is examined, and a maximum credible earthquake M S ~ 8.0 is presumed from the Brahmaputra fault, the nearest source zone in the city area. Such great/major event may cause intensity of the of 9.3 with a probability of 0,95 in the Guwahati city during time interval of 500 years. Further, the design spectrum with 67 % confidence level and the synthetic three-component accelerograms are constructed. These results are much relevant and useful for structural engineering to mitigate seismic hazards in the region. 相似文献