What Might Happen If We Had a Magnitude 15 Earthquake

As part of their ongoing “What If?” series, Randall Munroe of xkcd and Henry Reich of MinutePhysics explained what might happen if a Magnitude 15 earthquake took place. The force would be so great that all of the Earth’s water simply evaporate. On the plus side, however, there wouldn’t be any floods, hurricanes, or tsunamis to worry about.

In order to get to magnitude 10, you’d need a ruptured fault line three and a half thousand kilometers long… and a magnitude 11 quake would require a fault that went half way around the world! A magnitude 15 earthquake would be a million times more powerful than that, and involve the release of enough energy to evaporate all the water on earth

They also talk about the bottom end of the Richter/Moment Magnitude scale.

Since we usually hear about earthquakes with ratings somewhere between 3 and 9, a lot of people probably think of 10 as the top of the scale and 0 as the bottom. In fact, there is no top or bottom to the scale!

In fact, the negative aspect of the scale encompasses daily events.

A cat falling off a dresser would have a magnitude of negative two. A cat knocking your cell phone off your nightstand would have magnitude negative three. Magnitude negative four is like a penny falling off of a dog. Magnitude negative five is a key press on an IBM model M mechanical keyboard. Negative six is a key press on a lightweight keyboard. Negative seven is a single feather fluttering to the ground. A fine grain of sand falling onto the pile at the bottom of a tiny hourglass would be a magnitude negative eight quake.