Seismic Activity Near Azángaro, Peru: Geological Context and Recent Events

Azángaro, located in the Puno region of southern Peru, lies within a highly active seismic zone shaped by ongoing plate tectonics. The area sits on the Andean plateau at elevations exceeding 3,800 meters, where the subduction of the Nazca Plate beneath the South American Plate generates frequent earthquakes across a wide range of depths. On 1 March 2019 at 08:50 local time, a magnitude 7.0 earthquake struck 22 km north-northeast of Azángaro at a focal depth of 267 km. This intermediate-depth event reflects rupture within the subducting Nazca slab as it descends into the mantle. A subsequent magnitude 7.2 earthquake occurred on 26 May 2022 approximately 10 km west of Azángaro, at a distance of 26 km from the 2019 epicenter, underscoring the persistent seismic productivity of the region since 2000. The broader geological setting of southern Peru features the Central Andean orogen, built through millions of years of convergence, crustal shortening, and volcanic activity. The subducting slab beneath this segment of the Andes dips at angles that permit earthquakes to depths greater than 200 km, distinguishing it from shallower crustal events common along the plate boundary. Historical records document multiple large events in the Peruvian Altiplano, consistent with the long-term strain accumulation and release driven by plate motion rates of approximately 6–7 cm per year. These recent events highlight the importance of monitoring intermediate-depth seismicity for understanding slab dynamics and potential links to surface deformation. Although both earthquakes were felt across parts of southern Peru and neighboring Bolivia, their depths limited surface damage compared with shallower crustal shocks. Continued study of the Nazca slab geometry in this sector remains essential for refining seismic hazard assessments in the Altiplano.

References

USGS Earthquake Catalog (events of 1 March 2019 and 26 May 2022) Global CMT Project (focal mechanisms for Andean subduction zone)