Department of Geography and Environmental Studies

Sarah Bowman, 2006

An Analysis of the Dynamic Fingerprint of Seismicity in the North Atlantic Ocean in Space and Time: Implications for Tsunamigenic Processes

ABSTRACT

The aim of this study is to determine the dynamic fingerprint of seismic activity in the North Atlantic Ocean in space and in time.  The main feature of the North Atlantic Ocean is the Mid-Atlantic Ridge system which is tectonically active.  The seismicity of this region has been recorded and compiled into the ANSS catalogue from which data was extracted.  Based on the quantity of data available, as well as assumed differences in tectonic activity, three distinct zones were established: Zone A 40-55°N 20-45°W, Zone B 26-40°N 30-50°W, and Zone C 10-26°N 35-55°W.  The data were analyzed spatially using a multiscale approach which allows one to view the data at different scales to determine self-similarity and possibly characterize patterns.  A useful tool in a multiscale approach is that of an events thread analysis which was used in this study to determine the persistence of seismicity within each zone.  After noting some interesting results, the direction dependence of spatial correlations was also studied.  The data were also analyzed to determine magnitude relationships for all zones.  The analysis determined that Zone A was persistent, Zone B was both persistent and antipersistent, and Zone C was antipersistent.  There was also a determination of b -values which displayed anomalously high values for all zones which were decreasing from the north to the south.  The magnitude analysis determined that seismicity is persistent.  The results characterized the seismicity patterns of each zone which may be useful for seismic hazard mapping as seismicity may induce landslides and tsunamis.