• S C Gupta

      Articles written in Journal of Earth System Science

    • Aftershock activity of Bhuj earthquake of january 26th, 2001

      Ashwani Kumar S C Gupta A K Jindal Sanjay Jain Vandana

      More Details Abstract Fulltext PDF

      Following a large-sized Bhuj earthquake (Ms = 7.6) of January 26th, 2001, a small aperture 4-station temporary local network was deployed, in the epicentral area, for a period of about three weeks and resulted in the recording of more than 1800 aftershocks (-0.07 ≤ML <5.0). Preliminary locations of epicenters of 297 aftershocks (2.0 ≤ML <5.0) have brought out a dense cluster of aftershock activity, the center of which falls 20 km NW of Bhachau. Epicentral locations of after-shocks encompass a surface area of about 50 × 40 km2 that seems to indicate the surface projection of the rupture area associated with the earthquake. The distribution of aftershock activity above magnitude 3, shows that aftershocks are nonuniformly distributed and are aligned in the north, northwest and northeast directions. The epicenter of the mainshock falls on the southern edge of the delineated zone of aftershock activity and the maximum clustering of activity occurs in close proximity of the mainshock. Well-constrained focal depths of 122 aftershocks show that 89% of the aftershocks occurred at depths ranging between 6 and 25 km and only 7% and 4% aftershocks occur at depths less than 5 and more than 25 km respectively. The Gutenberg-Richter (GR) relationship, logN = 4.52 - 0.89ML, is fitted to the aftershock data (1.0<-ML<5.0) and theb-value of 0.89 has been estimated for the aftershock activity.

    • CODA Q estimates for Kumaun Himalaya

      A Paul S C Gupta Charu C Pant

      More Details Abstract Fulltext PDF

      CodaQ (Qc) estimates for the Kumaun Himalaya region have been obtained in high frequency range. Local earthquakes, recorded by a digital seismic network in the region, which fall in the epicentral distances range of 10 to 80 km and with a local magnitude range of 1.4 to 2.8, have been used. The coda waves of 30 sec window length, filtered at seven frequency bands centered at 1.5, 3, 6, 9, 12, 18 and 24Hz, have been analysed using the single backscattering model. The values ofQc estimates vary from 65 to 283 at 1.5 Hz to 2119 to 3279 at 24.0 Hz which showed thatQc is frequency dependent and its value increases as frequency increases.

      A frequency-dependentQc relationship,Qc = (92 ± 4.73)f(1.07±.023), is obtained for the region representing the average attenuation characteristics of seismic waves for Kumaun Himalaya region.

  • Journal of Earth System Science | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.