EARTHQUAKES IN THE LOS-ANGELES METROPOLITAN REGION - A POSSIBLE FRACTAL DISTRIBUTION OF RUPTURE SIZE

Although there is debate on the maximum size of earthquake that is pos sible on any of several known fault systems in the greater Los Angeles metropolitan region, it is reasonable to assume that the distribution of earthquakes will follow a fractal distribution of rupture areas. F or this assumption and an overall slip-rate for the region of approxim ately 1 centimeter per year, roughly one magnitude 7.4 to 7.5 event is expected to occur every 245 to 325 years. A model in which the earthq uake distribution is fractal predicts that, additionally, there should be approximately six events in the range of magnitude 6.6 in this sam e span of time, a higher rate than has occurred in the historic record .