CALIBRATION OF THE SPECIFIC BARRIER MODEL TO EASTERN NORTH AMERICA EARTHQUAKES

摘要

The paucity of high-quality strong motion data for moderate and large earthquakes in Eastern North America (ENA) makes it difficult to reliably estimate strong ground motions for future earthquake events in the region. The stochastic modeling approach, that utilizes a seismological model to describe the spectral amplitudes of the ground motion and their scaling with earthquake size, is arguably the only viable method of ground motion prediction in ENA. For this purpose, the seismological model must be calibrated using the available recorded (preferably strong motion) data from small and moderate earthquakes in ENA. The source model that we use in the present study is the "specific barrier model", proposed and developed by Papageorgiou and Aki (1983a, 1983b, 1985) and Papageorgiou (1988). We present results of the calibration of the "specific barrier model" using the available strong motion data base of ENA earthquakes, as well as inferred source spectra for the 25 November 1988 Saguenay earthquake (M_w 5.8) and 19 October 1990 Mont Laurier earthquake (M_w 4.5) in Quebec, Canada. We present estimates of the "global" and "local" stress drops believed to be representative of earthquake sources in ENA and we propose a "scaling law" of the source spectra of ENA earthquakes.