Macroseismic analysis of slope movements triggered by the 2011 Lorca Earthquake (Mw 5.1): application of the ESI-07 scale

Abstract

256 procesos de ladera ocurrieron como consecuencia del terremoto de Lorca de 2011 (5,1 Mw). La mayor parte son procesos de caídas y avalanchas de rocas con volúmenes máximos que alcanzaron los 1000 m3 en 11 casos. El análisis “Box-counting” de estos procesos indica que el área total afectada por los mismos es de 135 km2, pero solo 85 km2 contienen al menos un caso. Los procesos de mayores dimensiones se registraron en los principales relieves estructurales, paredes de ramblas y zonas de badlands de la zona, pero se identifica una zona de ca. 9-10 km2 en el área epicentral (Barranco Hondo) en la que ocurrieron el 23% de los casos. El análisis permite delinear zonas de intensidades en zonas escasamente pobladas desprovistas de datos EMS, e identifica una intensidad máxima VIII ESI-07256 slope movements were triggered during the 2011 Lorca earthquake (Mw 5.1). They mainly are rock falls and rock avalanches with maximum volumes of 1000 m3 for 11 cases. Box counting analysis indicate that the total area affected by slope movements is of 135 km2, but only 85 km2 contain recorded events. The larger slope movement occurred along the main structural reliefs, deep rambla-valleys, and badlands of the zone. Box-counting also identifies a zone of ca. 9-10 km2 in the epicentral area (Barranco Hondo) in which about the 23%of the cases occurred.The performed analysis allows to delineate and refine the intensity zones in sparsely populated zones without EMS intensity data, identifying VIII ESI-07 intensity from secondary and primary earthquake environmental effects, no detected in previous macroseismic analyses of the zone