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The Gujarat region, situated in the westernmost part of India, experienced a deadly intraplate 2001 Mw 7.6 Bhuj earthquake. In the aftermath of the disaster, the Institute of Seismological Research established the Gujarat (India) seismic network in 2006. The network is being operated in online and offline modes, whereas, seismicity monitoring is being done in near-real-time, using data received from the online seismic stations. The Coronavirus disease-19 lockdown provided an opportunity to assess the network reliability in a difficult and challenging scenario. The positive aspect of the lockdown is reflected in signal-to-noise ratio, which improved significantly at all the sites during the lockdown, with more prominent being at sites located on top of the Quaternary sediments due to the absence of high-frequency anthropogenic noise. A sharp fall in the seismic background noise is noticed at most of the stations during the lockdown period, with respect to the prelockdown period. We used the lockdown data to identify other natural sources of noise, besides anthropogenic. The lockdown helped in solving the enigma of seismicity in certain pockets, which turned out to be related to quarry blasts.

Background:The nature of asymmetric fission of preactinides is not yet understood in detail, despite intense experimental and theoretical studies carried out at present. Purpose: The study of asymmetric and symmetric fission of 180,182,183 Hg and 178 Pt nuclei as a function of their excitation energy and isospin. Methods: Mass-energy distributions of fission fragments of 180 Hg, 178 Pt (two protons less than 180 Hg), and 182 Hg (two neutrons more than 180 Hg) formed in the 36 Ar + 144 Sm, 142 Nd, and 40 Ca + 142 Nd reactions were measured at energies near and above the Coulomb barrier. Fission of 183 Hg obtained in the reaction of 40 Ca with 143 Nd was also investigated to see if one extra neutron could lead to dramatic changes in the fission process due to the shape-staggering effect in radii, known in 183 Hg. The measurements were performed with the double-arm time-of-flight spectrometer CORSET. Results: The observed peculiarities in the fission fragment mass-energy distributions for all studied nuclei may be explained by the presence of a symmetric fission mode and three asymmetric fission modes, manifested by the different total kinetic energies and fragment mass splits. The yield of symmetric mode grows with increasing excitation energy of compound nucleus. Conclusions: The investigated properties of asymmetric fission of 180,182,183 Hg and 178 Pt nuclei point out the existence of well-deformed proton shell at Z ≈ 36 and a less deformed proton shell at Z ≈ 46.