Continuous creep measurements on the North Anatolian fault

Wednesday, 17 December 2014: 5:30 PM
David Mencin1, Roger G Bilham2, Haluk Ozener3, Bahadir Aktug3, Asli Dogru4, Semih Ergintav5, Ziyadin Cakir6 and Alkut Aytun7, (1)UNAVCO, Inc. Boulder, Boulder, CO, United States, (2)University of Colorado, Boulder, CO, United States, (3)Bogazici University, Kandilli Observatory and ERI.-Department of Geodesy, Istanbul, Turkey, (4)Kandilli Observatory, Istanbul, Turkey, (5)Bogazici University, Kandilli Observatory and ERI.- Geodesy, Istanbul, Turkey, (6)Istanbul Technical University, Geology, Istanbul, Turkey, (7)Ankara University, Geophysics, Ankara, Turkey
Surface creep was recognized as early as 1969 on the North Anatolian fault near Ismetpasa and continues to the present day at rates of the order of 5 mm/yr. Although subsurface creep is currently monitored using Insar and GPS, continuous creep measurements on the surface fault have been intermittent. In 2014 we installed a carbon-fiber rod creepmeter at Ismetpasa and a second creepmeter across the surface rupture of the 1999 Izmit earthquake, which is also known to be creeping at depth. The creepmeters have a resolution of 5 µm and a range of 2.2 m. Each creepmeter uses two sensors- a subsurface LVDT (resolution 5 µm range 10 mm) and an above-ground rotary Hall effect sensor (resolution 25 µm and range 2.2 m) and their data are transmitted via the Iridium satellite as 30 minute samples every 2 hours. The hybrid sensors on the creepmeters are similar to others currently operating on the Hayward, Calaveras, and San Andreas faults. Their ability to capture slow slip, coseismic rupture or afterslip has been tested in deployments on the rapidly creeping Jackson, Wyoming landslide (1-3 mm/day). Installed creepmeters will be a powerful tool to search the possibilities of the transient or episodic creep and they will be used to validate the results of on-going monthly InSAR and campaign GPS studies, along the north Anatolian fault.