Seismic Hazards Evaluation of California Based on Frequency and Focus Depth of Past Earthquakes

California is one of the most seismically active regions of the world, small to moderate earthquakes occur throughout the year. Detailed analysis of earthquakes of magnitude greater than 4.0 occurred in California during 1911-2011.  We have considered earthquakes of magnitude greater than 4.0 in an area of one degree by one degree in whole of California to study the spatial probability of earthquakes and likely controlling parameter.  Using Poisson regression technique, it was found that each cell of one degree by one degree is affected by the frequency and depth of past earthquakes.  Similarly, we extended our analysis for whole United States, partitioned into one degree by one degree, an analogous result was obtained.  In addition, we have found that the probability of an earthquake within a cell is influenced by the past earthquakes that have occurred beyond the perimeter of the cell.  The results found for California and whole of United States remains consistent as the size of the cell decreases (e.g. 0.1 degree by 0.1 degree).  Our results show that the probability of a future earthquake is likely to be influenced by the focal depth of earthquakes within the region.  The study of past earthquakes will help to identify earthquake vulnerability that will help us to follow seismic building codes to minimize the damage due to an impending earthquake.