INTRAPLATE TECTONICS: DETERMINING PARAMETERS OF TECTONIC ACTIVITY FROM THE PLATE BOUNDARY TO THE CONTINENTAL CRATON

A new paradigm is taking shape in understanding intraplate tectonics from a global perspective. The continental craton of the North American plate offers a unique vantage for this type of study. The Canadian Shield along with its outlying geological provinces offers a stable craton for quantifying a baseline of knowledge of minimal tectonic activity. As part of NASA's Solid Earth and Natural Hazards (SE/NH) program, the Global Earthquake Satellite System (GESS) has been proposed to help monitor dynamic crustal motion. However, much of the impetus has been devoted tectonics at well-defined plate boundaries. Tectonics at the intra-plate level would act as an important baseline for quantifying the crustal dynamic range or signal-noise to correlate significant events. Most intraplate studies have focused on localized, infrequent events. Whereas a regional tectonic dataset in a Geographical Information System (GIS) format would provide a synoptic perspective of crustal activity (Yates, et. al, 1999). The thematic layers of each tectonic dataset would contain: 100-year seismic data, macro-scale faulting, focal mechanisms, lineaments, orogenic belts, rifting, regional stress vectors from the World Stress Map (WSM), and Holocene volcanism. This approach has been applied before with the Digital Tectonic Activity Map (DTAM) in quantifying global tectonic activity for the past one million years (Lowman, et. al., 1999). The two plates that our study will include both the North American and Eurasian plates. The approach is as follows: (1) Amalgamate and co-register the tectonic data, (2) Define the spatial scale of the plate boundary region, (3) Determine the transition zone(s) between the plate boundary and craton, and (4) Delineate the intraplate region for study. Once the intraplate region(s) has been defined, we will need to select Areas Of Interest (AOI) for future calibration and validation sites for GESS. Our NASA-funded study is a works-in-progress and we would welcome input of any technique in quantifying intra-plate tectonics.