Tsunami Splitting
The vertical displacement of the plate results in the vertical displacement of the water above it. The resulting wave spits into two waves that travel in opposite directions, as shown in Figure 9.6, creating the effect seen in Animation 9.1. Indonesia, Thailand, and nearby islands bore the brunt of the "local tsunami", which arrived less than an hour after the earthquake. Eric Geist, the USGS geophysicist from the Pacific Coastal and Marine Science Center, has written that "if you see the tsunami, it is too late to outrun it".
Figure 9.6 Schematic diagram of tsunami splitting, soon after
generation.
Source: Eric Geist, USGS Pacific Coastal and Marine Science Center, http://www.usgs.gov/media/images/tsunami-wave-splitting-soon-after-generation
This work is in the Public Domain.