Qualla: 2005 Northern Peru Earthquake

2005 Northern Peru Earthquake: Introduction

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. It was 8:55 in the evening on Sunday, September 25, 2005, when the ground beneath northern Peru began to move. The shock that arrived was magnitude 7.5, but its hypocenter was 115 kilometers down inside the subducted slab of the Nazca plate, deep enough that the energy spread out across most of the continent. People in Bogotá felt their buildings sway. So did people in much of Ecuador and western Brazil. The town that took the worst of it was Lamas, an old Inca-era hill town in the Department of Loreto, where 102 houses were destroyed and 3,000 people were left without homes.

Image: Mikenorton | CC BY-SA 3.0

2005 Northern Peru Earthquake: Deep, Not Shallow

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. Most damaging earthquakes are shallow. They rupture in the upper crust where buildings sit, and the energy stays concentrated. The September 25, 2005 event was different. Its hypocenter sat roughly 115 kilometers below the surface, inside the lithosphere of the Nazca plate that h...

Image: Mikenorton | CC BY-SA 3.0

2005 Northern Peru Earthquake: What Happened in Lamas

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. Lamas is a hill town founded in the 17th century, perched on a ridge above the surrounding jungle, with a population that includes a substantial Quechua Lamista community whose ancestors were resettled here generations ago. The town's older neighborhoods are built almost entirely...

Image: Mikenorton | CC BY-SA 3.0

2005 Northern Peru Earthquake: A Wide Footprint

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. Beyond Lamas, the toll spread thinly across a vast area. One woman was killed by a collapsing house in La Libertad, far to the southwest. Another death occurred in San Martín Province. In Moyobamba, walls of some buildings collapsed, in a town that had still not fully recovered f...

Image: Mikenorton | CC BY-SA 3.0

2005 Northern Peru Earthquake: The Red Cross at the Door

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. Reaching Lamas in the days after a disaster is not easy. The town sits in the foothills of the Andes where they spill into the upper Amazon, and the road network is limited. Ten Red Cross volunteers from Moyobamba were the first organized responders to arrive. Despite difficult w...

Image: Mikenorton | CC BY-SA 3.0

2005 Northern Peru Earthquake: A Region That Keeps Shaking

Thu, 16 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. Earthquakes of similar magnitude and mechanism occurred close to the 2005 event in 1990, 1991, 2019, and 2021. The pattern reflects the geometry of the subducting Nazca plate beneath northern Peru, where flat-slab subduction creates ongoing deformation of both the descending slab...

Image: Mikenorton | CC BY-SA 3.0