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Triaxial acelerografic data related to replies of Armenia earthquake in Colombia (25-01-99, Mw=6.2) have been used to determine the transfer function of Soft Formation / Hard Rock in two sites of Armenia city by using a neuronal network. This network was trained with spectral data of HARD ROCK as input parameter and spectral data of Soft Formation as output parameter for N-S and Z components. The error of the neuronal network respect to the training data was of 0,01%. It allowed to simulate spectral data for the E-W component of registries with a quadratic mean error minor to 8%. It was possible to observe that with these few records used, the neuronal networks facilitate the process of deduction of transference functions linear and not-linear oriented to the dynamic ground evaluation. [ABSTRACT FROM AUTHOR]

Abstract: The Abanico del Quindío (AQ) fan, a volcaniclastic deposit from the Ruiz–Tolima volcanic complex (RTVC), Colombia, provides insight into recent deformation in the Central Andes. The use of geological observations, geophysical measurements, and estimates of fault-scarp ages constrain timing of recent tectonic activity. Gravity and magnetic analyses, along with geomorphologic cartography, allow the detection of lateral variations in basement distribution and at least three structural trends that cut the AQ: the Armenia fault (NNE), El Danubio fault (NNW), and Hojas Anchas fault (E–W). Recent deformation in the zone results from slip on the Armenia and El Danubio faults and suggests a maximum interval magnitude of 5.1< M w <6.3, with ages ranging between 2560±480yr B.P. and 4120±780yr B.P. Although no surface ruptures are associated with historical events on the fault segments in this zone, blind structures may have influenced the hypocentral distribution of events recorded after the Armenia Earthquake (M w 6.2, 25-01-1999). Further geophysical studies are needed to understand the Romeral Fault System and assess the earthquake hazard for the city of Armenia. [Copyright &y& Elsevier]