The role of near-field interaction between seismic waves and slope on the triggering of a rockslide at Lorca (SE Spain)
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AutorAlfaro, P.; Delgado, J.; García-Tortosa, F. J.; Giner, J. J.; Lenti, L.; López-Casado, Carlos; Martino, S.; Scarascia Mugnozza, G.
Copernicus Publications; European Geosciences Union (EGU)
Ground motionTopographic amplificationInduced landslidesPacoima canyonLate mioceneEarthquake
Alfaro, P.; et al. The role of near-field interaction between seismic waves and slope on the triggering of a rockslide at Lorca (SE Spain). Natural Hazards and Earth System Sciences, 12: 3631-3643 (2012). [http://hdl.handle.net/10481/32277]
PatrocinadorThis work was partially funded by research groups VIGROB-53 and VIGROB-184 (Universidad de Alicante) and by the projects tec2008–06764–c02–02 and CGL2011–30153–c02–02.
A ~1000 m3 rockslide occurred close to Lorca (SE Spain) during the main shock (Mw = 5.1) of the May 2011 seismic sequence. The location of the rockslide, within 10 km of the earthquake epicenter and along the southern slope of a valley in which similar geological conditions occur on both slopes of the valley, suggests a significant near-field effect due to local seismic response. This could be related to the specific interaction between the topography and the obliquely propagating seismic waves. A dynamic stress strain numerical model was constructed using the FLAC 7.0 finite difference code to back analyze the Lorca rockslide event and relate its occurrence to both the local seismic amplification and the interaction between seismic waves and local topography. The results indicate that only for seismic waves with incidence angles in the range 0°–50° are the occurred slope instabilities expected. These results do not significantly change when varying the values for either stiffness or strength parameters within the range of the experimental data.