Synthetic marigrams of 2001 Peru tsunami

Coseismic vertical displacement provides the initial conditions for tsunami propagation. Because the rupture area extended landward of the coastline, only part of the coseismic deformation was transferred to generating a tsunami. Local propagation is calculated using a finite-difference approximation to the linear long-wave equations and the 2-minute Smith and Sandwell (1997) bathymetric data (Copyright). An 8 s time step was used in the propagation model. Reflection boundary conditions were imposed at the 50 m isobath. At this water depth, synthetic marigrams near offshore coastal communities are shown here. The actual wave response at the coast would have been modified by nearshore bathymetric changes and shoaling of the wave.

Please note that the time scale for the Arica, Chile synthetic marigram above is compressed by a factor of 2 (0-160 min.) compared to the other stations (0-80 min.). For comparison to other modeling efforts that include tide gauge stations at greater distances, see the NOAA/PMEL Center for Tsunami Research page. As with other observed tsunamis, there are multiple waves that impact the coastline, arising from complex reflections and trapped modes. In most cases, the first/direct arrival is not the largest wave.