Any large earthquake is a terrifying experience. Anyone who tells you differently has lost their mind. Buildings aren't supposed to move – when they sway dramatically most people feel uncomfortable.
Small and medium sized earthquakes are different. People can become accustomed to them — in Tokyo people aren't very dramatic about shindo 3 earthquakes.
The Shindo 3 ExperienceYour first earthquake experience is likely to be a shindo 3 or below. How much you feel it depends largely on where you are when it happens.
If you're walking through a field you might not notice a shindo 3 earthquake at all. Earthquakes are made worse by engineering. It takes a very large earthquake to knock down a tree.
If you're driving your tires might rumble a little and you may feel a very slight loss of control. You'll notice an earthquake far more on a bridge.
If you're walking on a sidewalk in central Tokyo you'll immediately notice that buildings are swaying a little. They may emit a creaking sound.
When it comes to earthquakes, there's a big difference between buildings. Old buildings were designed to be flexible — they really move. Large modern buildings may have equipment that reduces shaking. Shaking is also proportional to your floor — the higher up you are the more the building moves.
At first, you may feel that it's you — you might feel like you're suddenly a little off balance. The best way to confirm if there's an earthquake (or you're just dizzy) is to look at hanging objects such as blinds.
The building may make strange noises and visibly move. Many people describe a slightly dizzy feeling.
Adapting to EarthquakesThere are people who laugh in the face of danger — but it's rare.
The average person is never going to adapt to a earthquake over shindo 4. However, smaller earthquakes of shindo 3 are so common that some Japanese people barely acknowledge them.
The first time you experience a shindo 3 earthquake in Japan you may notice that your coworkers just keep working. Some might mumble "jishin da" (it's a earthquake). Many Japanese find that stopping work to worry doesn't solve anything (shoganai) — it's best to just keep going. With time you may join them.