AS I write, there is news of a massive earthquake in eastern Russia and a resultant tsunami.

A tsunami, a Japanese word meaning “harbour wave”, can be caused by an earthquake, a major rockfall or a meteorite.

Probably one of the best known was the Boxing Day tsunami in Indonesia in 2004, caused by a huge earthquake that occurred over 1,000 miles, slipping 15m vertically. It created a series of waves up to 30m high, which created such devastation that was well documented. Sadly, it was one of the most devastating from a human loss perspective, with about a quarter of a million people being killed.

However, in history we know about occasional mega tsunamis, which are generally defined as waves over 100m in height.

The biggest recorded mega tsunami occurred in 1958 in Lituya Bay, Alaska, when 30 million cubic metres of rock fell vertically into the Gilbert inlet. It created a wave that wiped out all vegetation up to a height of 520m above sea level. Luckily, only two people died in what was a potentially huge natural disaster.

However, we know that the asteroid that hit Earth about 66-million years ago in the Gulf of Mexico, at Chicxulub in the Yucatan Peninsula, was one of the biggest strikes in the world’s history.

The asteroid, which was about 10km in diameter, created a 200km diameter impact crater and a series of tsunamis that were initially over 1,000m high.

Besides wiping out the dinosaurs, mainly from dust blocking out the sun, it caused numerous landslides and secondary tsunamis on a global basis.

Unfortunately, earthquakes are common, we average about 25,000 a year, with about 10 to 15 being classified as major. Luckily, the modern early warning technology is improving all the time, hopefully, reducing the impact.