the Central Volcanic Zone and the Austral Volcanic Zone. Other volcanoes in the region include the Laguna del Maule, almost due west from Payún Matrú. Local Payún Matrú is a shield volcano whose foot coincides with the elevation contour and which extends mainly east–west; rising about above the surrounding terrain it covers about of land with lava and has diverse landforms. Ignimbrites cover and flatten its northern and eastern slopes, while in the west and south lava domes and coulées predominate; these have often rough surfaces and are difficult to traverse. The lower slopes are more gentle and covered by Pleistocene-Holocene lava flows. Wind erosion has created flutes, grooves and yardangs within the ignimbrites, such as in the western sector where yardangs reach heights of and widths of . The total volume of this shield is about . A and caldera lies in the summit region of the shield and covers a surface area of about . It is surrounded by several peaks, which clockwise from north include the Nariz/Punta del Payún, the Punta Media, the Punta Sur and the approximately Cerro Matru or Payen. In the field however Cerro Matru appears smaller than Nariz. The caldera was once wide but erosion of its flanks and later activity have reduced its size and buried the rim below coulées, lava domes, lava flows and pumice cones that were emplaced after the caldera collapse. The exception are the northern and southern walls which are almost vertical; remnants of old andesitic and trachyandesitic volcanism crop out there. The caldera also contains a permanent lake known as "" that is fed by snowmelt and by occasional rainfall. Matrú's highest active point field is the high, conical, eroded Payun stratovolcano. It is also known as Payun Liso, Payún and Payún Liso. This volcano rises from the southern side of Payún Matrú, away from the caldera. It has a summit crater open to the north and it has a volume of about . Payún Matrú volcanic field Aside from the caldera, the field contains about 300 individual volcanic vents with diverse morphologies distributed in a western Los Volcanes group that reaches to the Rio Grande River and the eastern Guadaloso and El Rengo groups. These fields are also known as West Payún Matrú or West Payén and East Payún Matrú or East Payén, respectively. Two further ruptures, known as "Chapua" and "Puente", have been identified east