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On 11 March 2011, the magnitude 9.0 earthquake and tsunami caused immense damage to the residents, social infrastructure, and also to cultural assets in coastal areas of northeast Japan.　Since the so-called ‘3.11 shock’, we have needed to confront various serious problems: sorting out cultural properties from debris, and conserving and preserving rescued finds, among the other things. In these conditions, the collective relocation of former residents of afflicted areas is also under discussion. Although most people who lived in the tsunami-affected area refuse to live in coastal areas, proposed relocation areas tend to overlap with areas known to have important archaeological sites.

These conditions dramatically exposed the weakness of information infrastructures in Japanese archaeology. There are no integrated archaeological databases, which anyone can access and use freely, and this prevents analysis of the current situation. Even an accurate count of archaeological sites around the afflicted areas cannot be determined; archaeological sites registered by each local government and by the Nara National Research Institute for Cultural Properties (NNRICP) are different. Thus, it is difficult to grasp the scale of damage. The reason for this problem is derived from the definition of ‘archaeological sites’. In Japanese archaeology, the three concepts of ‘sites’, ‘architectural remains’ and ‘artifacts’ are used for archaeological activities, and ‘sites’ are defined as places with evidence of human activities including either ‘architectural remains’, ‘artifacts’, or both. However, archaeological sites are actually managed in terms of survey units rather than archaeological units. For this reason, some local governments try to reintegrate or redivide survey units into archaeological units, and others do not. At the NNRICP, archaeological sites are managed based on survey reports, and their geographical locations are assigned coordinate points based on such reports. There is no way to count the true number of archaeological sites.

Even so, we need to use this uncertain information to tackle current problems such as the collective relocation of sufferers. In this study, I attempt to analyse the current condition of afflicted areas using datasets, originally constructed by NNRICP, and now managed by the Consortium for Earthquake-Damaged Cultural Heritage (CEDACH). First, I verify the accuracy of the datasets, then analyse the distribution of archaeological site complexes without considering the three definitions of archaeological materials used in Japanese archaeology, visualising archaeological sites overlapped with the tsunami damage area, and creating a damage prediction map for the collective relocation of sufferer of the ‘3.11 shock’. All of these analyses were conducted with the R statistical package and GRASS GIS, and the processes and the source codes will be shown in this paper.

Although the priority resides in securing a quick and safe relocation of the local population, the need to investigate the current situation of the archaeological heritage remains a critical issue. The 3.11 earthquake exposed the problems of the current digital management of the archaeological heritage and the importance of tackling the intrinsic uncertainty in existing databases. This alternative problem does not fit neatly into the response to the 3.11 shock in Japan.

 

Great East Japan Earthquake; data verification; analysis of present condition