Remote sensing data applied to the reconstruction of volcanic activity in the Valley of the Volcanoes, Central Volcanic Zone, Peru

Abstract

The Valley of the Volcanoes is a representative area of the extension of the Quaternary Andahua Group with which it overlaps. Some of its eruption centres have renewed activity after more than 500 ka. Recreating the history of the Valley of the Volcanoes activity required satellite data and remote sensing-based methods for visualizing the terrain surface. We used SRTM 30 m DEM, channels 4, 3, 2; Landsat 7, 8 and ASTER images. We verified and refined the obtained data during field works using Structure-from-Motion (SfM) to create of 3D models of selected geoforms. Satellite data allowed us to create: Red Relief Image Map, Topographic Position Index and Normalised Difference Vegetation Index (NDVI) maps. In the Valley of the Volcanoes, we analysed 12 lava fields with a total area of 326.3 km2 and a volume of approx. 20 km3. We determined the number of eruptions centres that yielded to 41 small lava domes and 23 scoria cones. This domes are classified as monogenetic volcanoes, however five of them can be considered polygenetic e.g. Puca Mauras. We used NDVI to develop chronology map of lavas. This allowed us to extract same-age eruption centres and associated volcanoes that represent the same eruptive time phase connected by fault lines: first generation (0.5–0.27 Ma) NW-SE and NE-SW, second (Pleistocene/Holocene) NNW-SSE and third (Holocene-Historical) again NW-SE and NE-SW. We carried out the reconstruction of the central part of the Valley of the Volcanoes because only there repeated phases of volcanic activity can be inferred with remote sensing and geological mapping. The results of this study led us to indicate that this area should be observed since it is very likely that future eruptions will occur.