Tsunami scattering provinces in the Pacific Ocean

We use a scattering index to identify the regions in the Pacific Ocean wher e topographic features scatter significant tsunami energy. Based on linear wave theory, the index is computed from the Smith/Sandwell topography. Cons istent with numerical simulations, it shows that there is a narrow band of strong scatterers running across the ocean from the northwest (Emperor Seam ount Chain) to the southeast (Easter Island Fracture Zone). The eastern Pac ific is nearly devoid of scatterers, except for this band and isolated feat ures along the eastern margin. To the west of the band lies a region with m oderate scattering; the strongest scattering occurs in the southwestern Pac ific. The Pacific is rimmed by island arcs and shallow continental shelves that also trap and scatter tsunamis. These results show that numerical mode ls of trans-Pacific tsunamis must resolve the effects of the small-scale to pography in order to accurately simulate their wave patterns and amplitudes .