The first level on the Richter Scale is 1-2.99. An earthquake with a magnitude of 1-1.99 can only be detected by a seismograph. An earthquake with a 2-2.99 magnitude has a very small probability of being felt. Most occur with little to no damage, but an earthquake with a 2.99 magnitude may occur with swinging of hanging objects. There are about 90,000 that occur each year. One earthquake that happened today at approximately 8:54 a.m 3km west from La Playa, Puerto Rico. It was a 2.9. There was little damage.
A 3-4.99 earthquake is considered a minor quake. There is little damage and the vibrations feel like that of a passing truck. There is some data but not much. They can be detected on a seismograph. Approximately 30,000 occur each year. An earthquake with this magnitude happened two years ago in near Hazard, Kentucky. Some houses had minor cracks and some fallen objects. Only the houses near Hazard got damage, but it was felt by many.
An earthquake with a 5-6.9 is not a major earthquake. It is felt by many, frightens a lot, and can move heavy furniture. There are only about 20 that occur in a year. One that occurred off the coast of Fiji on July 21, approximately at 6:24 a.m. There was no threat of a tsunami. There wasn't any damage because it occurred in the ocean.
An earthquake with a magnitude of 7-8.9 is a major earthquake. The damage that occurs is, buildings being displaced from their foundations, cracks in the Earth, underground pipes broken, and bridges can collapse. There is quite a lot of data and can be felt by all. In 2012 an earthquake with a magnitude of 7.6 struck off the Philippines. It destroyed bridges and roads and left people fleeing for higher grounds in fear of a tsunami. No casualties were reported but a lot of damage took hold.
An earthquake with a magnitude of 9 or more on the Richter Scale is a very major earthquake. They don't occur often but when they do you will know it. Near-total destruction of just about everything and the waves can be seen with the naked eye. There is data on these earthquakes. One major one that happened was the 1960 Chile earthquake. This was said to be the biggest earthquake in history. 10 to 15 minutes after the earthquake Chile was swept with 75 feet high waves from a tsunami and killed dozens. Everything was destroyed and lots of people lost their lives.