Learning by Research

Thesis Title: Archaeoseismological approach in the Heartland of the Incas (Cusco, Peru). Potentialities and limitations for the current seismic hazard assessment and the past earthquake risk perception.

The region of Cusco (Peru), crossed by numerous active faults, is characterized by a diffuse and largely under-documented crustal seismicity. In a region subject to such a seismic hazard, and where the written sources appear only 500 years ago, the instrumental and historical data are not sufficient to provide an accurate assessment.

In this regard, the archaeoseismology is a complementary approach that consists in identifying the evidence of the seismic activity in the archaeological record. The region of Cusco, cradle of the Inca Empire, is famous worldwide for its monumental stone sites, such as Machu Picchu and Saqsaywaman. Well-preserved, these sites represent a unique opportunity to improve both the current assessment of the seismic hazard as well as our understanding of its past management.
Through a cross-disciplinary approach, including a survey of the seismic damage on 17 Inca sites, an analysis of geomorphological data and a reinterpretation of ethnohistorical sources, we demonstrate the potential of Inca architecture to record earthquakes and suggest the occurrence of at least one major earthquake between the 15th and 16th centuries. Furthermore, the ambient vibration analysis of a historical structure located in France emphasizes the relevance of civil engineering techniques in the understanding of past construction strategies while it opens perspectives in terms of modeling and preservation of the Inca heritage.

As the first large-scale archaeoseismological project in South America, this exploratory work aims to be a baseline for renewing the approach about the seismic hazard and the societies (past and present) in the Andean Highlands.

Key Words: Inca, archaeoseismology, Peru, Cusco, seismic hazard, palaeoearthquakes

Doctoral School: ED STEP - Sciences de la Terre, de l’Environnement et des Planètes & ED SHPT - Sciences de l'Homme, du Politique et du Territoire
Research Laboratory: Institut des Sciences de la Terre (ISTerre - UGA/CNRS/USMB/IRD/UGE)
Thesis Supervision: Laurence AUDIN and David GANDREAU

> To find out about all the 2023 thesis prizes