Seasonal modulation of interseismic strain buildup in northeastern Japan driven by snow leads

Distinct periodic variations with annual frequencies are often found in the time series of continuous Global Positioning System (GPS) site coordinates in northeastern Japan, They show maximum are-normal contraction of a few m illimeters as well as maximum subsidence of 1 to 2 centimeters, both in Mar ch, In northeastern Japan, it snows heavily on the western flank of the bac kbone range, attaining a maximum depth of several meters in March, When obs erved snow depths were compared with the Load distribution estimated from t he CPS data, the surface loads caused by the snow were found to be largely responsible for the annual displacement of GPS sites, The snow load modulat es secular strain buildup in northeastern Japan due to the Pacific Plate su bduction, but its relevance to the seasonal change of earthquake occurrence s remains uncertain.