Seismic Activity in the Atiquipa Region of Southern Peru

The coastal region near Atiquipa in Peru's Arequipa Department lies within one of the world's most seismically active zones. This area forms part of the Peru-Chile subduction system, where the Nazca Plate converges with and descends beneath the South American Plate at rates of approximately 6–7 cm per year. The resulting megathrust earthquakes occur frequently along the plate interface, often at depths between 20 and 50 km.

Historical records document repeated large-magnitude events in southern Peru, including the destructive 2001 Arequipa earthquake (Mw 8.4) and earlier events in 1868 and 1687 that generated significant tsunamis. These quakes reflect the locked segments of the subduction zone that periodically release accumulated strain.

Instrumental data since 2000 highlight a cluster of strong earthquakes centered near Atiquipa. On 25 September 2013, a magnitude 7.1 event struck 16 km west-southwest of the town at a depth of 40 km. This was followed by a magnitude 7.1 earthquake on 14 January 2018 located 37 km west of Atiquipa. Most recently, a magnitude 7.2 shock occurred on 28 June 2024 approximately 10 km west-southwest of Atiquipa. These three events, all within roughly 40 km of one another, illustrate ongoing seismic release along this segment of the plate boundary.

The shallow to intermediate depths of these earthquakes produce intense ground shaking in coastal communities. Local geology, characterized by steep Andean foothills and narrow coastal plains, amplifies hazards from landslides and liquefaction in river valleys. Post-event studies consistently note aftershock sequences lasting weeks to months, consistent with the region's tectonic setting.

Ongoing monitoring by national and international networks continues to track strain accumulation. The proximity of the recent 2024 event to the 2013 and 2018 shocks suggests possible interaction between adjacent fault patches, though detailed rupture modeling remains an active research topic.

References

USGS Earthquake Catalog (earthquake.usgs.gov)
Global CMT Catalog
Peru Geophysical Institute (IGP) reports on southern Peru seismicity