Evento principal y réplicas importantes del Terremoto de Limón

Abstract

Combining local, regional and teleseismic seismological information, we find the principal aftershocks (Mc≥  4.4) of the Limon earthquake of April 22, l991 (Mw=7.7). They define a rupture area of 85 x 45 km², it is similar to that found using small magnitude earthquakes (Mc≥ 4.4). Using the arrivals reported by seismological stations located at different epicentral distances, allow us to obtain a focal mechanism solution that corresponds with a thrust oblique faulting event (strike 120°, dip angle 30° , slip 63°). Our interpretation of an acelerogram obtained 70 km southwest of the mainshock epicenter, permit us to identify five subevents during the rupture process, this defines the Limon earthquake as a complex and multiple event. Finally, we find that many aftershocks occurred on thrust and strike slip secondary faults; they are located a different distances and trends from the mainshock epicenter.