ON STATISTICAL APPROACHES TO THE STUDY OF CERAMIC ARTEFACTS USING GEOCHEMICAL AND PETROGRAPHIC DATA*

The scientific analysis of ceramics often has the aim of identifying groups of similar artefacts. Much published work focuses on analysis of data derived from geochemical or mineralogical techniques. The former is more likely to be subjected to quantitative statistical analysis. This paper examines some approaches to the statistical analysis of data arising from both kinds of techniques, including ‘mixed‐mode’ methods where both types of data are incorporated into analysis. The approaches are illustrated using data derived from 88 Late Bronze Age transport jars from Kommos, Crete. Results suggest that the mixed‐mode approach can provide additional insight into the data.     

MULTIVARIATE MIXTURE OF NORMALS WITH UNKNOWN NUMBER OF COMPONENTS: AN APPLICATION TO CLUSTER NEOLITHIC CERAMICS FROM AEGEAN AND ASIA MINOR USING PORTABLE XRF*

Multivariate techniques and especially cluster analysis have been commonly used in archaeometry. Exploratory and model‐based techniques of clustering have been applied to geochemical (continuous) data of archaeological artefacts for provenance studies. Model‐based clustering techniques such as classification maximum likelihood and mixture maximum likelihood have been used to a lesser extent in this context and, although they seem to be suitable for such data, they either present practical difficulties—such as high dimensionality of the data—or their performance gives no evidence that they are superior to standard methods. In this paper standard statistical methods (hierarchical clustering, principal components analysis) and the recently developed model‐based multivariate mixture of normals with an unknown number of components, are applied and compared. The data set provides chemical compositions of 188 ceramic samples derived from the Aegean islands and surrounding areas.     

GROUND MOTION ANALYSIS IN THE ANCHORAGE BASIN: 1-D APPROACH

Understanding the dynamic behaviour of soil in the Anchorage basin in southcentral Alaska is essential for seismic hazard assessment of this highly seismically active region. The analysis of site responses for 40 sites from weak-motion and strong-motion data with amplitudes less than 0.1 g showed a strong influence of subsurface geological conditions on the characteristics of ground motion. Particularly, the sites in the central part of the city, including the downtown area, showed prominent resonance peaks around 1 Hz with amplification values up to about 4. The numerical analysis, based on one-dimensional multi-layer soil models shows that site response characteristics, and especially aforementioned peaks, are largely related to the thick, soft layer of Quaternary deposits, particularly cohesive fades of Bootlegger Cove Formation. The computed transfer functions for soil profiles of six representative sites are in accord with the site responses in the frequency range from 1 to 5 Hz. There is no significant change in amplification values below 2 Hz corresponding to large-amplitude (up to 0.38 g) ground motions; however, above 2-3 Hz the amplification values are greatly reduced in this case.     

METROPOLITAN AND NON-METROPOLITAN POPULATION TRENDS IN CANADA, 1966–1982

This paper discusses broad population movements within and between metropolitan and nonmetropolitan regions in Canada during the recent past. It is based on an annual series of aggregate migration at the metropolitan level. Three complementary approaches are used in order to distill information from this vast array of interregional flows. The first is based on net migration. The second, disequilibrium analysis, is based on the difference between the observed population shares of regions and a set of calculated steady-state population shares which would result if the currently observed set of interregional migration rates remained constant. Both approaches indicate short-term effects of migration on the evolving pattern of regional growth and decline. The third approach, based on aggregate interregional flows, allows one to observe some changes in migration behaviour which are not made evident by the first two approaches.