An earthquake is a sudden release of energy within the Earth's crust due to fracturing and faulting of lithospheric rocks. Geologist use seismic data, or traveling-propagating waves through the Earth, to quantify Earthquakes that have occurred. Once they can pin-point the location of the Earthquake, they can determine the size and magnitude. This is very important for humans, because if another earthquake were to occur in the same region or location of high magnitude, structures could collapse and many people could be killed. That is why building codes are put in place in certain regions based on seismic activity in the crust. Geologic surveys of the soil and sediment of the surface will also determine these building codes.
