An earthquake is the result of a sudden release of energy in the Earth's
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...

 that creates seismic wave
Seismic wave
Seismic waves are waves of energy that travel through the earth, and are a result of an earthquake, explosion, or a volcano that imparts low-frequency acoustic energy. Many other natural and anthropogenic sources create low amplitude waves commonly referred to as ambient vibrations. Seismic waves...

s. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured using observations from seismometer
Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...

s. The moment magnitude
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...

 is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe.

563    The Byzantine church Hagia Sophia in Constantinople is dedicated for the second time after being destroyed by earthquakes.

1293    An earthquake strikes Kamakura, Kanagawa, Japan, killing about 30,000.

1531    Lisbon, Portugal is hit by an earthquake--thousands die.

1556    The deadliest earthquake in history, the Shaanxi earthquake, hits Shaanxi province, China. The death toll may have been as high as 830,000.

1667    An earthquake devastates Dubrovnik, then an independent city-state.

1667    A deadly earthquake rocks Shemakha in the Caucasus, killing 80,000 people.

1755    Lisbon earthquake: In Portugal, Lisbon is destroyed by a massive earthquake and tsunami, killing between sixty thousand and ninety thousand people.

1759    An earthquake hits the Mediterranean destroying Beirut and Damascus and killing 30,000-40,000.

1763    A massive earthquake occurs on the same day in Komárom in Hungary, in Komárno in Slovakia and in Zsámbék in Hungary.

1812    The strongest in a series of earthquakes strikes New Madrid, Missouri.