what branch of earth science is an earthquake?

[jgringolts]

My project is to write a little about the Earthquake that occured in Illinois and i need some required information. what branch of science earth quakes are are one of my required things.

[mark p]

id say its geophysics rather than geology but definetley seismology as a sub-branch

[wallaroo w]

I was going to answer seimicology, but I see the answers above mine are spelled differently.