Microseismic Source Research Articles

An investigation of two‐second microseisms associated with cold fronts and a new method for tracking the cold front center

Two tripartite stations have been set up six miles apart. Each consists of three two‐second horizontal seismographs recording at a drum speed of 600 mm/min.In addition, three stations equipped with two‐second vertical and horizontal instruments have been set up on a triangle with sides of 8.3, 6.75 and 6.0 miles.Results to date are somewhat confusing. There is evidence of a microseismic source southwest of New York. There is also evidence of wave trains identifiable between two stations six miles apart indicating a velocity of microseismic waves of less than one mile per second. A new method is presented of recording microseisms on an oscilloscope and reading the time differences of each pair of stations along the axis of the observed Lissajous ellipse.