Urban Cannibalism: Expanding Agglomeration Shadow to Function Extraction in Arrested Transition

Indonesia’s metropolitan connectivity infrastructure, which is premised on equitable development, operates in reverse. In Gerbangkertosusila, the regency closest to Surabaya grew the slowest, as seen in Bangkalan after the opening of the Suramadu Bridge. The agglomeration shadow literature (Meijers and Burger 2010) explains why metropolitan peripheries grow slowly but does not distinguish transitional shadows from structural, extractive ones. Friedmann’s (1966) spatial evolution model assumes a phase transition that, in this case, has stalled. This paper introduces the concept of cannibalism to name the active-extractive mode of agglomeration shadow that emerges when a metropolitan system is trapped in arrested transition, and operationalizes it through the Cannibalism Index, the ratio of external pull to local strength, computed across 149 H3 hexagons with a Newton–Reilly gravity model built on OpenStreetMap Point of Interest data and O’Sullivan’s urbanization economies framework, then supplemented by Location Quotient and Shift-Share analyses of sectoral GRDP. Results show seven Agglomeration Core hexagons, all concentrated in Surabaya City; no Independent Hub emerges outside the core, and sixteen Shadow Zone hexagons mark areas vulnerable to cannibalization. A three-way distance-decay test on Bangkalan, Mojokerto, and Lamongan finds that distance protects peripheries from core pull but does not build internal functional strength. The Mojokerto case study reveals a function-extractive split: industry settles in the regency through Ngoro Industrial Park, while the professional services that should accompany it remain in Surabaya. Gerbangkertosusila is more accurately classified as a polynuclear monocentric region in arrested transition than a mature polycentric system. This diagnosis carries direct planning implications: connectivity without functional deconcentration is not a strategy for empowering peripheries but a state-facilitated extraction mechanism. Keywords: agglomeration shadow, urban cannibalism, arrested transition, functional polycentricity, cannibalism index, Gerbangkertosusila.