Supplementary material to "Changes in ground deformation prior to and following a large urbanlandslide in La Paz, Bolivia revealed by advanced InSAR"

Abstract

The 2011 Pampahasi landslide is one of seven historical landslides exceeding 1 Mm 3 in the La Paz area.Landslides of possibly similar size to the 2011 event happened in 1582 and 1873 in the southwest part of the La Paz valley system, but little is known of these events aside from sparse written accounts.The first event affected an area of 2 km 2 or more and buried the villages of Canoma and Ango Ango, which were likely located in Llojeta Valley (Fig. S1).This landslide claimed about 200 lives (Cabeza de Vaca, 1586; transcribed in Jiménez de la Espada, 1965, p. 342-351 andin Arispe, 2011).The second event involved extensive ground movement over an area of about 8 km 2 (Markham, 1874) and more rapid, localized movement that destroyed an area named Tembladerani (Markham, 1874) located southwest of the city centre, causing 32 deaths (Crespo, 1902).Its location may correspond to the modern area of the city called Tembladerani (Fig. S1), although Dobrovolny (1962) applies this name to a landslide deposit in Llojeta Valley.The loss of life from these two events suggests velocities exceeding several metres per second or, at the very least, a lack of prompt evacuation.Four smaller landslides happened in the twenty-first century in the Llojeta and Allpacoma valleys near the margins of the La Paz and Achocalla basins (Hermanns et al., 2012; Fig. 1B); they destroyed about 51 homes but did not claim any lives (Roberts, 2016) (Table S1).Most of these failures involved weakly lithified, fine-grained sediments of the middle part of the La Paz Formation, including large areas that had been previously mobilized by large paleolandslides.