Probabilistic and Deterministic Assessment of Seismic Threat in Neiva (Colombia) through the Use of Next Generation Attenuation Equations

Abstract

This article presents a probabilistic and deterministic assessment of a seismic threat in Neiva as of 2013, using the recent and robust attenuation equations corresponding to the Next Generation Attenuation (NGA) developed in the United States. These equations were proposed by Abrahamson and Silva, Boore and Atkinson, Campbell and Bozorgnia, Chiou, Youngs and Idriss. Regarding the deterministic assessments, conservative scenarios are presented, and considering a total rupture of the fault, the PGA would be of 550, 355, 305, 400 and 375 Gal due to the La Dina fault. These values are considered as the maximum credible seism. For the probabilistic analysis, due to the fact that the NGA equations are applicable to earthquakes with magnitudes between 5 and 8, the catalogue was drastically reduced. Therefore, a statistical analysis was performed with data of magnitudes between 4 and 7.2 and the catalogue was completed, assuming a Poisson distribution. The assessed accelerations (average plus a standard deviation) were 280, 230 280, 305 and 320 Gal, respectively