Liquefaction phenomena associated with historical earthquakes in San Juan and Mendoza Provinces, Argentina

Mendoza and San Juan provinces which represent the most seismically active regions of Argentina have been affected by at least nine destructive earthquakes with magnitudes >= 6.3 in the period 1861-1997. During these events, earthquake-induced liquefaction processes have caused the most severe damages in properties and fields impacting adversely on regional development and economy. Analysing historical liquefaction data we corroborated the relation between liquefaction phenomenon with sediment grain size and depth of phreatic level. We also noted that even the distance from liquefaction features to epicentres increases with earthquake magnitude, previous empirical relations for distance/magnitude are not enough accurate to predict liquefaction feature distance. Moreover, we suggest that when physical conditions of terrain are suitable, liquefaction phenomenon can occur even at greater distances than those established by empirical manner. In addition, regarding potential risk for this seismically region, the most liquefaction vulnerability areas were established taken into account the historical data and the presence of Holocene-Pleistocene deposits with present higher phreatic level. Our findings are essential for future proper territorial planning and they should be useful for minimize economical losses caused by secondary effects in these seismic regions of Argentina. (c) 2006 Elsevier Ltd and INQUA. All rights reserved.