par- 24 janvier 2013 ( dernière mise à jour : 1er mai 2018 )
The large (60 Mm3) Maca slow-moving landslide affects thick fine-grained lacustrine sediments in the Colca valley (southern Peru). It affects a village of 850 inhabitants, a tourist roadway (160 000 visitors in 2009), and pre-Inca terraces.
Both rainfall and earthquakes are implied in its kinematics over the last 25 years. In July 1991, a local shallow earthquake of magnitude Mw 5.4 destroyed the western part of the village, killing 14 people, and caused the road to collapse. In June 2001, the subduction earthquake of Arequipa (Mw 8.4), located at about 120km from the site, caused another part of the road to collapse. During the rainy seasons in 2011–2012 and 2012–2013, major reactivations occurred and the road had to be elevated . Irrigation was made impossible by all the new cracks affecting the overall area, and many inhabitants were forced to change their activities or leave the village. Between February and July 2013, several shallow regional earthquakes (magnitudes between 5.2 and 6) destroyed a large part of the village and caused an acceleration of the landslide motion. Following these different events, the decision to move the village was reached in 2013 by the regional authorities, but two years later only a few inhabitants had left.
The landslide has been geodetically monitored since 2001 based on geodetic campaigns, and is permanently monitored since 2012 based on permanent GPS and seismometers, thanks to an active collaboration between ISTerre/IRD (France) and INGEMMET (Peru).
Lacroix P., H. Perfettini, E. Taipe, B. Guillier (2014), Co- and postseismic motion of a landslide ; observations, modeling and analogy with tectonic faults, Geoph Res. Lett., doi : 10.1002/2014GL061170.
Lacroix P., E. Berthier, E. Taipe (2015), Earthquake driven acceleration of slow-moving landslides in the Colca valley, Peru, detected from Pléiades images, Rem. Sens. Env, 165 (148-158).
Zerathe, S., Lacroix, P., Jongmans, D., Marino, J., Taipe, E., Wathelet, M., et al. (2016), Morphology, structure and kinematics of a rainfall controlled slow‐moving Andean landslide, Peru. Earth Surface Processes and Landforms.
Bontemps, N., P. Lacroix, M.-P. Doin (2018), Inversion of deformation fields time-series from optical images, and application to the long term kinematics of slow-moving landslides in Peru, Remote Sensing of Environment, 210, 144-158
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