VIEWING AN INTRA-PLATE REGION BY INTEGRATING LANDSAT 5-TM IMAGES WITH DIGITAL DATA INTO AN OBJECT ORIENTED GEOGRAPHICAL INFORMATION SYSTEM

A mosaic of four digital images derived from Landsat 5-TM satellite data (source: NASA-Earth Science Applications Directorate) of western Maine and adjacent Canada was produced to serve as a base for considering regional geology and tectonics in an intra-plate locale. The image was combined with the: a) Digital Elevation Model, b) Canadian and Maine digital geologic maps, c) heat flow data, d) seismicity data, e) World Stress Map (WSM) stress vectors and f) Global Positioning System data into an Object-Oriented Geographical Information System (GIS). The result produced a new and integrated view, including the geomorphology, of the region straddling the St. Lawrence River valley from Mt. Katahdin in Maine to Quebec and Ottawa in Canada.

Earthquake epicenters are highly correlated with areas of high heat flow and the trend of the St. Lawrence River valley. The seismic activity of the area offers a distinctive vantage for understanding crustal dynamics in an intra-plate region because of its spatial distribution along the zones of weakness in the crust. The rift zone is under apparent brittle failure which is manifested by the increasing earthquakes in terms of magnitude and quantity. There are two regional aggregations of seismic epicenters along the St. Lawrence River. Regional Aggregate-1 is from 47-48oN along the river, while Regional Aggregate-2 from 49-50oN.

By quantifying tectonic activity in terms of seismic activity, satellite imagery, heat flow, and structural elements a more comprehensive evaluation of the regional tectonics may be ascertained.