Lake Superior has an average depth of about 483 feet (147 meters). Its maximum depth is approximately 1,332 feet (406 meters), which is near the eastern end of Grand Island in the northern part of the lake. This area is known as the “Southwest Point of the lake” and is located offshore from the town of Munising, The minimum depth of Lake Superior can vary widely across different areas of the lake, but it generally ranges from a few feet to around 30 feet (9 meters).
And then Wikipedia:
The Superior Shoal is a geologic shoal of approximately 20 square miles (52 km2) located 50 miles (80 km) north of Copper Harbor, Michigan in the middle of Lake Superior, the highest point of which lies only 21 feet (6.4 m) below the lake's surface.[
Out of the east channel at Munising going towards the reef out in the lake there is a set of pillars that come up to around 100 to 150 feet down.
Only about 100 yards long and very narrow.
The guy i used to fish with caught the biggest laker he ever caught off those pillars.
Now days i suppose those are positioned with technology now. Back then we didnt have that and if you followed the compass reading coming out of the channel, you were lucky to catch them.
We fished the big reef lots. Also got caught in the biggest storm we ever experienced out there. Had to run up to another place east to get docked.
The big lake is the head end of the Great Midcontinental Rift.
One of the known largest buildups of lava on earth
That rift runs all the way to OK and, most likely, beyond on the west and most likely all they way down to AL on the east...they just dont know yet. But the west is confirmed.
The earthquakes that happen around OK and MO etc, is likely caused by fault lines caused by the ice depressing that area in the last ice age and now is rebounding.
If you go to Eagle Harbor in the UP of Michigan, you can stand on the southern edge of that rift...the earths crust is exposed. Meaning if you try and dig to get below the rock you wont be able to do it. The rock is tilted at about a 25 degree angle. The northern edge is at about Isle Royal. The rock tilts the other way there. The ancient rift is in the lake there.