[wolfcreek]

Try this site and it's links.

http://users.tpg.com.au/users/tps-seti/crater.html

I found it interesting Hawaii volcanoes emit massive amounts of iridium suggesting a mantle piercing impact.

[gleeaikin]

If you look at the direction of the seamounts that go back in time from the Hawaiian Islands, you will see that there is an abrupt turn toward the north in the earliest ones. The change in direction to the present course I think occurred about 43 mya.