International audience ; Multidisciplinary investigations have been carried out on sections and sediment cores from a lake and peat bogs in the Western Cordillera in the Central Andes of Southern Peru, around Nevados Ampato, Sabancaya and Hualca Hualca volcanic massif. More than 850,000 inhabitants of the city of Arequipa and the Colca valley are concerned by further activities of those volcanoes. The aim of the current study is to complete the Holocene tephrostratigraphical model for southern Peru in which about 40 tephras are distributed within the past 50,000 years. The tephras described in this paper have been discovered in two sites: the large peat-bog of Sallalli at the southern piedmont of the Sabancaya volcano, and the Laguna Mucurca, a salar (brine lake) 15 km W of Nevado Ampato. The Sallalli peat-bog is located in a glacially shaped piedmont, which has been dammed by recent moraines and lava flows 10 km SE of the summit of Nevado Sabancaya. The peat section, which spans a large part of the Holocene period (since ca. 9650 yr), encompasses at least five tephras. The most recent ones consist in plinian ash-falls caracterized by rhyolitic glass shards that can be linked either with the AD 1600 eruption of the Huaynaputina volcano (120 km to the ESE) or with an eruption of the Misti volcano (60 km to the SE) that occurred between 800 cal BC and 200 cal AD. The other tephras consist in phreotomagmatic products of local origin likely erupted by the Sabancaya volcano, or by the Ampato volcano, within the periods bracketed as follows: (i) 150 cal AD and 100 cal BC; (ii) 150 and 420 cal BC; (iii) 2100 and 2500 cal BC; and (iv) 7420 et 7750 cal BC. The recent lacustrine deposits of the Laguna Mucurca host traces of a plinian ash-fall from Huaynaputina volcano and a scoriaceous tephra of phreatomagmatic origin. The latter was emplaced between 920 and 760 cal BC. This tephra has probably been produced by one of the neighbouring cones located in the field of monogenic volcanoes close to Huambo on the southern edge ...