We should pray for the people of Japan in the aftermath of the earthquake. A prayer for Japan. Earthquakes and tsunamis are events that should bring us to repentance (Luke 13:2-5), for each of us deserves to be swept into the ocean by a tsunami, and it is only by God’s mercy that we are not. This event will either harden hearts more toward God, or by God’s grace will break them with contriteness—there is no neutral response. When we view pictures and video of the devastation they remind us of how fragile creatures we really are. It should humble Humanity, especially how we so easily love to elevate our “greatness.”
In the future, just before the Day of the Lord there will be a cluster of celestial and earthly disturbances that will act as a prelude warning to the Day of the Lord.
The sixth seal informs us that there will be this “huge earthquake” accompanied by a cluster of celestial signs:

“Then I looked when the Lamb opened the sixth seal, and a huge earthquake took place; the sun became as black as sackcloth made of hair, and the full moon became blood red;” – Rev 6:11-12

And I don’t believe this will be some regional earthquake; instead, it will be global, since “every mountain” will be moved from its place.
Given the magnitude of this earthquake, it makes perfect sense why the Bible employs tsunami language in two passages on the sign of the Day of the Lord:

“And there will be signs in the sun and moon and stars, and on the earth nations will be in distress, anxious over the roaring of the sea and the surging waves” – Luke 21:25.

Nations do not “distress” over mere ten foot waves. This will be global tsunamis on a massive scale. Interestingly, the Greek term for “surging waves” (salos) can mean “earthquake.” Also, the text indicates that the nations on the earth are not so much distressed and anxious over the celestial signs as they are with the roaring of the sea and surging waves.
The other text is Rev 6:14b:

“and [every] island was moved from its place.”

Again, mere ten foot waves do not accomplish this. No wonder Scripture prophecies that “people will be fainting from fear and from the expectation of what is coming on the world.”
This is a sober truth. Do not fall into the Amos syndrome, in which his audience was deceptively self-assured that they were right with God and that the Day of the Lord was for those “other people.”

“Woe to those who wish for the day of the LORD! Why do you want the LORD’s day of judgment to come? – Amos 5:18

Today is the day for self-examination.