Seismic hazard analysis

This paper presents the seismic hazard analysis performed for SGSITS Indore by the probabilistic approach where in the peak ground acceleration has been calculated for different frequencies considering the attenuation equation given by Raghukanth and Iyenagar. The intra-plate activity, zone-specific parameters for seismicity and fault map has been used to calculate the seismic hazard. The site lies in the central India which has seen a few major earthquakes over time and hence it is of huge importance to acknowledge the probability in coming years.

The Albertine region of Uganda is characterized by high levels of seismic activity and by many active normal faults. The aim of this work is to assess the potential hazard accruing from earthquakes in the Albertine region, using the probabilistic approach to assess the seismic hazard for, specifically, the Hoima and Buliisa districts. The input parameters for the seismic hazard computation were obtained using the earthquake catalogue compiled for the period 1900 to 2012, including earthquakes within an area bounded by latitudes 1.50S to 40N and longitudes 290E to 330E. All magnitudes were homogenized to moment magnitude scale. The study area was divided into two seismic source zones based on seismotectonic analysis. The updated ground motion prediction equation by Pankow and Pechmann was used in the computations. Seismic hazard maps in terms of the Peak Ground Acceleration (PGA) for 10%, 5% and 2% probabilities of exceedance in 50 years were derived.  The results show that the PGA values for both districts fall in the range of 0.152 - 0.162 g, 0.187 - 0.195 g and 0.248 - 0.256 g (where g is the acceleration due to gravity), for return periods of 475, 975 and 2,475 years, respectively. The highest levels of seismic hazard were found in the southwestern part of the Hoima district, where PGA values were in excess of 0.162 g, 0.195 g and 0.256 g for 10%, 5% and 2% chances of exceedance in 50 years, respectively. We conclude that in the Albertine region, the return period for an earthquake capable of causing damage to engineering structures is, on average, 30 years. It is thus recommended that all important engineering structures in the region should be designed for earthquake resistance.