“…Recently, a new class of staggered DG (SDG) methods based on staggered meshes was proposed and analyzed. In particular, the SDG method has been successfully developed for many wave propagation problems Engquist, 2006, 2009;Chung and Lee, 2012;Chan et al, 2013;Chung and Ciarlet, 2013;Chung et al, 2013a) and other applications (Chung et al, 2013b(Chung et al, , 2014a(Chung et al, , 2014bKim et al, 2013Kim et al, , 2014Chung and Kim, 2014). The SDG method is typically applied to the first-order formulation of wave equations, and it starts with two sets of irregular, staggered grids for each of the two unknown functions involved; furthermore, it designs two finite-element spaces on those two sets of staggered grids and carries out integration-by-parts to derive corresponding weak formulations; and finally, it applies the standard leap-frog scheme for explicit time stepping.…”