the april 22, 1991 limón (costa rica) earthquake
DESCRIPTION
The 1991 Limon Ms7.6 earthquake, recorded strong-motion duration 26.6 s and maximum MM intensity XI. Epicenter near the Caribbean coast, the shapes of its isoseismals differ markedly from the code-specified isoacceleration curves for various return periods, as the latter curves assume that all seismic sources are close to the Pacific coast. On the other hand, code design spectra are overconservative for long periods, especially on soft ground. These matters demand a code revision.TRANSCRIPT
