Liquefaction phenomena associated with historic earthquakes: Their analysis in the evaluation of the seismic hazard in Argentina

Abstract

Liquefaction phenomena have caused the most destructive effects during the main earthquakes happened in Argentina. However, to exception of San Juan's province, studies referred to these phenomena are scarce, fundamentally due to the poor preservation of the structures. Although liquefaction has been described in many seismic regions of the world, in Argentina their effects have been underestimated. After the Spanish colonization, they have registered at least thirteen destructive earthquakes and associated liquefaction effects (1817, 1861, 1844, 1894, 1899, 1920, 1927, 1929, 1944, 1948, 1949 y 1952) that negatively impacted in the economy of the region along the last 200 years. However, it doesn't exist a clear relationship between the epicenters and the main Quaternary structures and in most of the cases, neither associated historical ruptures have been recognized, with the exception of those observed in La Laja (1944), Lago Fagnano (1949) and Niquizanga (1977) faults. It is also probable that many of these destructive earthquakes have been characterized by deformations distributed in folds and secondary faults, without surficial ruptures. During these earthquakes, the effects of liquefaction were the most spectacular results in the seismic shakes, causing most of the recorded damages. Becouse of that the study of the soils with physical conditions susceptible to suffer liquefaction during the occurrence of an earthquake in populated areas of Argentina, is a high-priority investigation field to carry out for an appropriate urban planning in the north-western portion of the country.