Abstract
On May 11th 2011, a rather small earthquake caused nine fatalities in the city of Lorca, SE-Spain. We analyze seismograms from a dense network to characterize the source of this earthquake. We estimate an oblique reverse faulting mechanism, moment magnitude of 5.2 and a shallow hypocenter (4.6 km), at only 5.5 km epicentral distance from the city center. Double difference relocations yield a similar to 5 km long, NE-SW trending distribution of aftershocks SW of the mainshock, suggesting a SW propagating rupture along the Alhama de Murcia fault. We use the Mw 4.6 foreshock and an Mw 3.9 aftershock as empirical Greens functions to estimate apparent source time functions, observing a clear directivity effect. We model apparent durations with a unilateral and asymmetric bilateral rupture, in both cases obtaining rupture directivity of similar to N220 degrees E, towards Lorca. In addition to the near epicenter and shallow depth, directivity may have contributed to the significant impact. Citation: Lopez-Comino, J.-A., F. Mancilla, J. Morales, and D. Stich (2012), Rupture directivity of the 2011, Mw 5.2 Lorca earthquake (Spain), Geophys. Res. Lett., 39, L03301, doi:10.1029/2011GL050498.