Large scale landslides triggered by Quaternary tectonics in the Acambay graben, Mexico

• Published in: Earth surface processes and landforms Vol. 35; no. 12; pp. 1445 - 1455
• Main Authors: Norini, G., Capra, L., Borselli, L., Zuniga, F. R., Solari, L., Sarocchi, D.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 30.09.2010; Wiley
• Subjects: Acambay graben; active tectonics; America; Basins; Bgi / Prodig; Failure; Faults; landslide; Landslides; Mexico and Central America; Movements; Physical geography; Rock; Seismic phenomena; Tectonics; Mexico; Quaternary; Neotectonics; Graben; Earth surface processes; Fault; Landslide; Volcanic rock; Tectonics
• ISSN: 0197-9337; 1096-9837; 1096-9837
• DOI: 10.1002/esp.1987

Detailed analysis was conducted on large‐scale gravitational‐tectonic deformations and landslides in the Acambay graben, an intra‐arc basin in the trans‐Mexican volcanic belt (TMVB). Field mapping and remote sensing revealed the slope instability of the northern graben boundary induced by the Acambay‐Tixmadejé fault. Two major landslides of 0·1 km3 and 0·05 km3 in volume were identified and their characteristics were analyzed according to the role of tectonics, mechanism of slope failure, and possible triggering factors. Quaternary faulting played a major role in increasing the local relief, and the activity of the Acambay‐Tixmadejé fault represents the main geomorphic factor conditioning the gravitational movements. Moreover, displacements along this fault generated sliding surfaces and reduced the strength of the rock mass. The two landslides are classified as large‐scale rotational slides involving volcanic rocks of late Miocene‐Pleistocene age. Since the Acambay graben is a seismogenic area with a known maximum horizontal ground acceleration of 0·5 g, a strong earthquake could be ascribed as the possible triggering mechanism of the landslides. Our work represents the first analysis of large gravitational slope movements in tectonically active regions in Mexico, a process that can be common in the intra‐arc basins of the TMVB, where active tectonic, seismicity, weak altered volcanic rocks, and heavy rains affect the slope stability. Copyright © 2010 John Wiley & Sons, Ltd.