Application of time- and magnitude-predictable model in the Central Himalaya and vicinity for estimation of seismic hazard

Time dependent seismicity investigation in six seismogenic sources of Nepal and its adjoining areas in the Central Himalaya reveal that there is intermediate time clustering of the moderate size shallow earthquake in each seismogenic source. The inter-event times, between the successive shallow mainshocks, of the magnitude equal to or larger than certain cut-off magnitudes for each of these sources are used for long-term earthquake hazard prediction corresponding to individual sources of the region. For the hazard estimation, the following relations have been established here as: log Tt = 0.46 Mmin +0.07 Mp +0.02 log m0 −2.38, and Mf = 0.78 Mmin −0.25 Mp −0.04 log m0 + 4.32, where Tt is the inter-event time measured in years; Mmin is the moment magnitude of the smallest mainshock considered; Mp is the magnitude of preceding main shock, Mf is the magnitude of the following mainshock and m0 is the moment rate in each source per year. The value of σ = 0.22 and multi-correlation coefficient, R = 0.62 for the first equation and σ = 0.30 and R = 0.59 for the second equation are estimated.Based on these relations and using the magnitude and time of occurrence of the last main shocks in each seismogenic source, time dependent conditional probabilities of the next shallow main shocks during the next 10, 20 and 30 years as well as the magnitude of the expected main shocks are forecast.