It would probably take too much time to fabricate; ring manufacturing is fast but not instantaneous. With foreknowledge of the exact problem he could have probably done better.So obviously the SI can't butt his head against the problem until he can make a barrier to block the tsunami, but that's not an orange way of thinking. How about using shiny toys to solve the problem?
We know that there have to be plenty of artificial gravity generators in his tech database, and he has plenty of ways of generating electricity. How about making a gravity generator with as large an area of effect as possible with the gravity pointing towards the tsunami, then feed it power from bleed torsion generators?
Another possibility that occurred to me was producing large numbers of cold generators and creating a temporary ice wall. Which again requires manufacturing time.