Five Things You May Not Know About Tsunamis

On today's Please Explain, Leonard spoke to geologist Lori Dengler and seismologist Geoff Abers about the tsunami in Japan. In addition to finding out that earthquakes can cause whirlpools, we found out a lot more about how tsunamis are closer to us than we think.

1. It is possible to have an aftershock that could cause another tsunami - although not one as big as this one. Chile has been experiencing very powerful aftershocks for over a year since its February 2010 earthquake, the most powerful of which happened just a month ago. It's believed that Japan will experience powerful aftershocks for at least another month.

2. Tsunamis don't necessarily only occur in oceans - they can also occur in lakes. In fact, the earthquake that happened two weeks ago in Christchurch, New Zealand produced a sort of tsunami-like phenomenon at the foot of the Tasman glacier.

         

3. Although this is the largest earthquake in Japanese history, there is paleotsunami evidence that suggests that earthquakes in the low 9 range on the Richter scale were possible in the region.

4. Anything that displaces the ocean floor can produce a tsunami. In fact, the first numerical codes to try and predict tsunami propagation were developed by the Defense department to look at what would happen if you exploded a nuclear device under the water.

                       Projected wave height of the tsunami as it travels across the globe (via NOAA)

5. There was a major tsunami in 1929 that hit the East Coast at Grand Banks, Newfoundland related to a collapse of the continental shelf. It's a phenomenon that could happen anywhere along the East Coast, including New York. In fact, although it sounds impossible, a tsunami could actually hit New York if seismic activity in the Caribbean heats up.