Decentralization has an important geographic dimension that is often overlooked in protocol design. Concentration among validators and information sources can undermine security by increasing exposure to correlated failures, government bans, and natural disasters. Yet in permissionless systems, validator locations cannot be set by protocol rules and instead emerge from economic incentives.

In this paper, we propose a formal model of validators’ geographic location incentives under Ethereum’s protocol design. The model captures the interaction between local and external block building, as well as the distribution of validators and information sources. We characterize the model analytically and complement it with an agent-based simulation calibrated to real-world latency data to quantify how these incentives shape geographic concentration.