Casos históricos de licuación de sedimentos inducidos por sismos en Venezuela desde 1530

the study of liquefaction cases in venezuela has led to the evaluation of 44 seismic events, keeping just 26 of them and discarding 18 events that were not reliable enough. from those events kept, 8 belong to the western region, 4 to the center region, and 14 to the eastern venezuela, spanning a period of 470 years. the employed methodology was based on an italian study by the galli and ferrelli group in the years 1995 and 1999 which will be described in this paper. a first step consisted in the gathering of the original reports and data directly or indirectly pertinent to liquefaction occurrence, from historical and contemporary sources. in a second phase, a catalogue was generated from the critical evaluation of the gathered data. this catalogue contains the description of the causative earthquake and the related liquefaction evidence. besides, the catalogue is visually summarized in a map showing the earthquake epicenter and the areal liquefaction distribution. for practical reasons, the map is regionally subdivided in three zones: west, center and east venezuela. finally, with the magnitude and epicentral distances -calculated by difference of coordinates -an empiric relationship was established, represented by the equation m = 1.07 log (x) +1.57, where m = magnitude and x = epicentral distance. this equation, combined with the liquefaction evidences and site effects, let us conclude that liquefaction in venezuela occurs with event magnitudes greater than 5 and within distances up to 200 km from the epicenter. also, it allows us deduce that some macroseismic epicentral locations and/or some magnitudes were sub-evaluated, such as those of the 1530, 1797, 1853, 1900, and 1944 earthquakes, thus requiring re-evaluation and their epicenters relocated.