Structure, hydration and anisotropy of the Nazca Plate and its relation to forearc deformation and seismicity at the northern Chilean margin

Subduction zones are convergent plate boundaries where oceanic lithosphere subducts beneath an overriding tectonic plate into the Earth’s mantle. The differential plate motion of the converging plates generates stress along the plate interface, which is episodically released in the form of seismic energy. Subduction zones are known to host the largest and most destructive earthquakes on Earth, posing a major seismic hazard to nearby populations. In addition, subduction-related earthquakes usually occur offshore, potentially leading to cascading effects further increasing the impact on affected communities. This thesis investigates the structure and geometry of the incoming Nazca Plate in the central Atacama region offshore northern Chile and examines its relationship to seismicity patterns observed along the adjacent continental margin. To achieve these objectives, an integrated geophysical approach that combines 2D amphibious seismic refraction data, high-resolution multibeam bathymetry data, and local seismicity data is employed. The results demonstrate that regional-scale heterogeneities within the incoming plate have a substantial impact and shape the seismicity distribution in the adjacent forearc regions. While fundamental characteristics of the Nazca Plate, such as crustal thickness, velocity structure or slab geometry, agree with other oceanic plates, the distribution of seismicity differs significantly along the margin. These variations are primarily associated with local features of the incoming plate rather than with large-scale differences in the lithospheric architecture. This thesis highlights the impact of regional- scale structures, heterogeneities, and tectonic and hydrogeological processes on the overarching subduction dynamic in the central Atacama region. It emphasizes the importance of detailed structural knowledge of the incoming plate to analyze and understand seismicity in subduction zones, which is an essential prerequisite for an effective hazard assessment and mitigation strategy. Further, this thesis highlights the fundamental value of multidisciplinary and shoreline-crossing approaches for investigating subduction processes and unraveling the complex interactions between plate structure, deformation, and seismicity.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Christian-Albrechts-Universität zu Kiel

Year

2026

Author dc:creator

• Warwel, Arne

Contributors dc:contributor

• Kopp, Heidrun
• Grevemeyer, Ingo

• Chilean margin
• Subduction zone
• Active seismic

Repository record source_url

https://macau.uni-kiel.de/receive/macau_mods_00008918

OAI record oai:identifier

https://macau.uni-kiel.de/servlets/OAIDataProvider?verb=GetRecord&metadataPrefix=xMetaDissPlus&identifier=oai%3Amacau.uni-kiel.de%3Amacau_mods_00008918