Andagua Valle de los Volcanes is located in the South Andean region of Peru, in Arequipa, on the west flank of the Western Cordillera Chila, between the districts of Orcopampa, Andahua and Huambo, provinces of Castilla y Caylloma, 300 km NW of the city of Arequipa.
The geographic coordinates in the Andahua square are 15º 29′ 52.6” South latitude and 72º 21′ 10.2” longitude West of Greenwich, and its UTM coordinates are 783 696 East and 8 284 740 North, with an altitude of 3 586 MASL.
It is a spectacle typical of prehistoric times, when the planet was still in full formation. As if it were a lunar landscape, it is located to the East and perpendicular to the Colca.
The Andagua River runs through the Valley of the Volcanoes, from north to south, east of the Coropuna volcanic massif, for more than 80 km.
This valley is, in turn, a deep open fault that extends to the Huambo sector and that the Colca later cut, almost perpendicularly. The bottom of this open fault, which now appears as a valley, is filled with abundant basaltic lava flows, dispersed in several stages.
Curiously, the river runs underground for 17 km covered by lava, from the Chachas lagoon to the Mamacocha lagoon, and reaches the Colca river as an important tributary (Mamacocha river).
The lava flows originated from multiple eruptions of small volcanoes (80, according to Hoempler) that arose as blisters emerged from the degassing of the lavas themselves or as a product of other direct eruptions from magmatic hearths.
The highest of the Andagua volcanoes is the Pucamauras, 350 m above the valley level. There are others from 50 to 70 m and smaller ones, from 15 to 20 m, like the Chilcayoc.
In the geological history of the volcanic formation of southern Peru, these Andagua volcanoes represent one of its last events of about two hundred thousand years ago, during the Quaternary, until some in historical times.
This valley must be considered as a great geological fault, the continuity of the Valley of the Volcanoes has been abruptly interrupted by the tectonic fault, in which the Colca River has settled in its downward course, so that the floor of the Andagua side is between 500 and 800 m lower than the floor on the Huambo side.
It is evident that this jump is due to the faulting in this sector and, in a later phase, to the faulting of the Valley of the Volcanoes. Geographical data such as these are those that show the existence of large-magnitude breaks in the earth’s crust, even for people who are not enlightened in geological subjects.
The observation can be made from the town of Ayo (1,956 m; riverbed at 1,405 m), located at the end of the Valley of the Volcanoes and almost on the Colca River. Logically, the fault plane has been greatly eroded and now appears somewhat inclined and almost rounded.
The unevenness between the two banks of the river is evident, but it is not easy to establish the direction of the movement that produced the fault.
The flora is strange, as it thrives in the small places free of lava on top of volcanic ash. The dominant vegetation is cacti, especially the giant prismatic ones and some isolated plants from Chachacoma, Puma Rosa, which are medicinal and widely used by the local inhabitants.
There are small agricultural areas between the volcanoes, where potatoes, corn, and wheat are planted exclusively for self-subsistence.
The town of Andagua, at 3,600 m above sea level, was important during the Colony. Currently, the Orcopampa mine, 40 km from Andagua, is still in operation. The fauna is characteristic of the puna at 3,800MASL.