Earthquakes: God's Shaking Power

When Sinai shakes, it is not weather. Exodus gives a fixed set of phenomena - thunder, lightning, a thick cloud, a loud trumpet blast, and an earthquake - and those become the standard signature of God arriving.
Later writers reuse them deliberately. Psalm 68 recalls God's presence with his people in Sinai and the theophany that came with it. Revelation reaches for the same imagery when it describes the throne.
So an earthquake in Scripture is usually a citation. The writer is telling you which event this one resembles.
Scripture links:
- Exodus 19:18 - the mountain wrapped in smoke, and the whole mountain trembling.
- Psalm 68:8 - the earth quaked and the heavens poured down at the presence of God.
Sinai set the vocabulary. Almost everything after it is quoting.