Probabilistic seismic reliability assessment of telecommunication networks under mainshock–aftershock sequences: a Chilean case study

Telecommunication networks are essential during emergencies, yet their seismic performance is often assessed under mainshock-only assumptions. This paper proposes a PSHA-based Monte Carlo framework to quantify the additional degradation induced by aftershocks on the connectivity of the Chilean National Research and Education Network (REUNA). Earthquake scenarios are generated from an empirical seismic catalog (Chile, 1940--2025, M ≥ 5.0) using parametric sampling for magnitude and depth and a cluster-informed spatial model that preserves the dominant north--center--south organization of seismicity. Ground motion is computed with a Chile-calibrated GMPE and translated into component damage via HAZUS fragility formulations for nodes and segment-level modeling for buried fiber links, including permanent ground deformation effects. Aftershock impact is incorporated through a scenario-based secondary event and a sequential damage update on surviving components, yielding a final post-sequence state. Reliability is evaluated through source--terminal (s--t) connectivity and summarized by cluster. Results show systematic damage accumulation and measurable reliability losses under mainshock--aftershock conditions, with region-dependent patterns and identifiable vulnerable nodes.