Five Things You May Not Know About Tsunamis

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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.