Structure Collapse: Patterns in the Archaeological Record

by Amy Socha

Mentor: Lauren Sullivan, Anthropology and Archaeology; funding source: Discovery Fund


My research this summer was concerned with identifying and studying patterns of physical collapse in the archaeological record.  These patterns exist in what is left behind; the types and quantities of artifacts and their relative positions are indicative of what happened in, near, or to a structure before, while, and after it was abandoned.  These patterns also exist in how a structure collapses and the shape of the mound formed around it.  In terms of cause and effect, abandonment and physical processes like erosion and soil formation are the causes of collapse, and the effect is the formation of an archaeological site. 

Abandonment, which I define as ceasing to utilize an object or space, occurs worldwide and is the origin of much of the archaeological record, another major source being intentional burial. I am primarily concerned with the abandonment of structures, which comes in three forms: seasonal or temporary, long-term, and permanent.  Permanent abandonments are those that are counted as part of the archaeological record, so those are the ones I focus on.  Permanent abandonments are either intentional or unintentional.  Unintentional abandonments tend to be sudden, sometimes violent, and often destructive, as they result from events like natural disasters or warfare that force a group from a particular location.  Intentional abandonments can result as a cultural response to certain sudden forces, particularly after illness or death when a space may be seen as “tainted” or “cursed” depending on the beliefs of the population.  Intentional abandonments are more often the result of a decision to no longer maintain a structure – perhaps replacing materials had become too expensive or labor intensive and building a new structure would be more efficient, or because that structure had served its intended purpose and was no longer useful to a person, group, or culture. 

The first half of my research studied abandonment and defined the factors of and stages for natural deterioration.  These factors include climate, building material, and human interference.  I define the stages of natural abandonment as structural weakening, collapse and mound formation, and final burial.  While these stages are generally sequential, they are not mutually exclusive, meaning that elements of collapse and mound formation may occur during processes of structural weakening and then continue into final burial, though largely slowed.  In the stage of burial, a structure is at relative equilibrium with its environment, meaning that it is being eroded at very slow rates if at all, and the mound is relatively stable, large blocks are no longer falling and the soil is settled.  The second half of my research is currently underway.  I am describing methods of identifying the previously discussed patterns in the field through a volumetric analysis of mounds.  The volume of a mound can be analyzed synchronically (concerning one specific time – in this case when it is being studied by archaeologists) and diachronically (concerning change through time).  Both approaches will mathematically divide mounds into their components and compare those components to the total volume of the mound.  The purpose of this analysis is to gather more information during survey, that can both inform a future excavation of the structure by indicating how much sediment may have accumulated on top of the structure and answer certain research questions without excavation.  One example of a question volumetric analysis could be used to help answer is population size.  Mathematical analysis of the volume of a mound may be able to indicate the approximate size of the structure within it, and structure sizes throughout an area can indicate how many people may have been living there.

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