Strike-Slip Basins Along 1999 Earthquake Rupture, Anatolian Fault, Turkey

In 1999 Turkey experienced two major earthquakes which occurred 86 days apart on the North Anatolian Fault System. The first of these earthquakes occurred on August 17, 1999 along the main western strand of the North Anatolian Fault and was Mw7.4. The second of these earthquakes occurred November 12, 1999 along the Düzce strand of the North Anatolian fault and was Mw 7.2. This rapid succession of earthquakes caused major damage and loss of life in the cities of Düzce and Bolu, Turkey. These cities are located in two poorly understood, strike-slip basins bounded by strands of the North Anatolian Fault.

Shortly after the November 12 event, a team of Purdue University geologists and civil engineers surveyed the cities of Bolu and Düzce and produced a geo-referenced set of structural damage data. Using this data as a starting point the original intention of this research was to determine if there was a correlation between the spatial distribution of structural damage and the stratigraphy, basin fill composition, and geometry of the Düzce and Bolu basins. In order to accomplish this analysis, new stratigraphic cross-sections, basin depth isopach maps and basin composition contour maps have been generated for the Bolu and Düzce basins using borehole data. The combination of these new products with an analysis of older regional and local geologic maps has made it possible to: 1) Better understand the structural configuration of the basins and their bounding faults, 2) Understand the geometry and fill composition of each basin, 3) Better determine how each basin is related to the North Anatolian fault zone and, 4) Determine if a link exists between basin morphology and structural damage in the Bolu basin. The products of this research have gone far beyond the original intent and have brought new insight to the poorly understood Düzce and Bolu strike-slip basins.

Building damaged during the November 12, 1999 Duzce Earthquake: Duzce, Turkey	View of Golyaka pull-apart basin with the Almacik mountains in the background