ESI-07 ShakeMaps for Instrumental and historical events in the Betic Cordillera (SE Spain): a preliminary approach applied to seismic hazard based on geological data

Abstract

This work presents shake scenarios for two earthquakes occurred in the Betic Cordillera (SE Spain) such as the AD 2011 Lorca event (VIII ESI07; 5.2 Mw) and AD 1863 Huércal-Overa event (VIII ESI07; 4.9 Mw). The Lorca event presents instrumental measures, allowing comparison of the distribution and magnitude of the modelled PGA values, as well as a detailed field based characterization and mapping of the related geological effects. To explain the wide variety of slope movements and other geological effects recorded along the studied earthquakes, obtained PGA models must include a topographic amplification factor, normally not considered instandard Shake models. Additionally, Vs 30models derived from topography resulted in overestimations of the PGA values in flat terrains, such as, pediments or flat erosion surfaces, carved in resistant materials. This was corrected applying a factor related to the thickness of the Quaternary deposits. The incorporation of those basic amplification actors upgraded the resulting macroseismic scenarios, clearly identifying zones prone to record nvironmental damage