"How in the world did that just happen?"
Earthquakes aren't all that rare. According to the US Geological Survey website, there are an estimated 1,000,000+ earthquakes per year. Most of these are less than magnitude 2.9, meaning they really cannot be felt.
To understand the reason behind earthquakes, you have to have a few facts first. Way under the surface of the earth, there are things called tectonic plates. They basically float on the magma very slowly, and don't move very much per year, about 2 centimeters. But many times, these plates suddenly slip against each other because of built up friction, causing earthquakes. The place under the ground where this happens is the hypocenter, and above the ground it is the epicenter. The place where the rock slips is called the fault plane.
So earthquakes are basically tectonic plates rubbing against each other.
After the initial earthquake, something called the aftershock happens. Aftershock is less than the actual earthquake, but if the initial quake was big enough the aftershock can cause almost as much damage, sometimes more.
What do tsunamis have to do with earthquakes?
Many times, tsunamis happen because there was an earthquake way down on the sea floor. This slip acts like a paddle, and the energy transfers to the water. The water ends up going on until it eventually loses its energy, or until it hits land, whichever comes first.
Tsunamis can also be caused by underwater volcanoes, underwater explosions, and occasionally even landslides.
This is the base of learning things about tsunamis and earthquakes. As we dive further in, you will understand the science behind earthquakes and tsunamis better, as well as how they are measured. There are a lot of discoveries in store, so sit tight and hold on.
It's gonna be a quakey ride.
