Tegan Hall

PhD Candidate

Madsen Building (F09), Room 358
School of Geosciences


Supervisor: Dr. Dan Penny

Associate Supervisor: Prof. Roland Fletcher


PhD Title: The architecture of collapse: using network theory to understand the decline of complex civilizations.


Low-density, urban complexes play a significant role in industrialisation and as a precursor to the vast sprawls of interconnected settlements, or “megalopoli”, that are proliferating worldwide. The necessity of analysing these societies as complex systems has been overlooked so far, and as a result important insights into the overarching processes involved in state development and decline are being missed. In particular, little is known about the spatial and hierarchical consequences of the removal of any central administrative hub and the subsequent breakdown of communication and infrastructural networks. Such knowledge will increase our understanding of the inherent vulnerability of these urban systems, and is therefore of great importance for ensuring the sustainability of our highly urbanised and interconnected world.

Few ancient states epitomise the low-density, urban complex like the medieval Khmer state that dominated mainland Southeast Asia between the ninth and fifteenth centuries AD. Ruled for the most part from its capital city of Angkor, the remainder of the kingdom consisted of a vast spread of peripheral settlements interconnected via a series of road and fluvial transport networks. Beset by severe environmental and political stresses during the latter centuries of its dominance, by the middle of the fifteenth century the royal court abandoned Angkor and migrated south to port cities in the Phnom Penh region. It is undoubted that this event caused a disruption to the geographical and political dominance of the Khmer in Southeast Asia from which it never recovered, and as such this event has provided fodder for collapse studies during more than a century of scholarship in the region. However, most of these studies have focused on Angkor alone, and on the socio-economic, political and environmental causes of its decline. As a result very little is known about the consequences of Angkor’s abandonment for the remainder of the kingdom or the structural consequences on the kingdom as a networked system. Was there a cascading collapse of regional settlements in the network or were they more resilient than is assumed?

This project aims to employ a systems theory approach in the analysis of the devolution of complex, low-density societies. Using the Khmer Empire as a case study, it will investigate the power of a subset of systems theory – network theory – in explaining the structural and spatial disintegration of the kingdom. This project will use palaeoenvironmental techniques to reconstruct landscape histories (and from which infer settlement occupation histories) of a number of peripheral settlements throughout the kingdom from the beginning of the Angkor period to the Empire’s collapse, and onward through Cambodia’s transition to modernity. Moving beyond the reductionist approach of causal correlation models and toward one that captures the broader, dynamic principles at work in human-environment systems (without ignoring the more complex and multivariant inputs specific to each case) will provide necessary insight into the resiliency or vulnerability of complex societies and contribute to the understanding of the processes governing complex systems in general.

Conference Proceedings

  • Hall, T. and Penny, D. Using local fire history as a proxy for occupation of a Khmer industrial outpost during the decline of the Angkor Empire. AAA/ASHA 2014 Joint Conference: Culture, Climate, Change: Archaeology in the Tropics, Cairns, 1-3 December 2014.