Searle, AntonyScott, Susan MMcClelland, David2015-12-130264-9381http://hdl.handle.net/1885/87741High power in narrow frequency bands, spectral lines, are a feature of an interferometric gravitational wave detector's output. Some lines are coherent between interferometers, in particular, the 2 km and 4 km LIGO Hanford instruments. This is of concern200310.1088/0264-9381/20/17/3152015-12-12