An Inhomogeneous Distribution Model of Strong Earthquakes along Strike-Slip Active Fault Segments on the Chinese Continent and Its Implication in Engineering Seismology

摘要

Through the statistical analysis of earthquake distribution along 51 strike-slip active fault segments on the Chinese continent, we found that strong earthquake distribution along the seismogenic fault segments is inhomogeneous and the distribution probability density p(K) can be stated as p(K) = 1.1206e~(-3.947K~2) in which K = S/(L/2), S refers to the distance from earthquake epicenter to the center of a fault segment, L is the length of the fault segment. The above model can be utilized to modify the probability density of earthquake occurrence of the maximum magnitude interval in a potential earthquake source. Nevertheless, it is only suitable for those potential earthquake sources delineated along a single seismogenic fault. This inhomogeneous model has certain effects on seismic risk assessment, especially for those potential earthquake sources with higher earthquake reoccurrence rates of the maximum magnitude interval. In general, higher reoccurrence rate of the maximum magnitude interval and lower exceeding probability level may bring larger difference of the results in seismic risk analysis by adopting the inhomogeneous model, the PGA values increase inner the potential earthquake source, but reduce near the vicinity and out of the potential earthquake source. Taking the Tangyin potential earthquake source as an example, with exceeding probability of 10% and 2% in 50 years, the difference of the PGA values between inhomogeneous model and homogenous models can reach 12% .