ESI-07 ShakeMaps for instrumental and historical earthquakes based on geological data (Betic Cordillera, SE Spain)

Abstract

This work offers ShakeMaps scenarios for two earthquakes occurred in the Betic Cordillera (SE Spain), the AD 2011 Lorca event (VIII ESI07; 5.2 Mw) and AD 1829 Torrevieja event (X ESI07; 6.9 Mw). The Lorca event presents instrumental measures, allowing the comparison with the modelled PGA values. For both events there are a detailed field characterization and mapping of the coseismic geological and environmental effects catalogued according to the Environmental Seismic Intensity Scale ESI-07. General workflow follows that of the USGS program but in order to explain the important amount of recorded slope movements a) the use of high resolution DTMs and b) the application of a topographic amplification factor is required. To correct deviations of the empirically obtained values of Vs 30 a factor related to the thickness of Quaternary unconsolidated deposits was developed. The incorporation of those corrector factors upgraded the resulting macroseismic scenarios and learned lesson with the Lorca event were applied to the historical Torrevieja event. The results clearly identify zones prone to record environmental damage and are quite suggestive at the time to define the location and/or size of a historical seismic source.