According to "A History of Kachemak Bay - the Country, the Communities," by Homer author Janet Klein, one theory holds that the Spit is the offspring of Kachemak Bay and Cook Inlet's complex currents. The second theory says the Spit is a terminal moraine composed of sand, gravel, coal and other debris left by a glacier retreating into the Kenai Mountains.

Giving his vote to the second theory is Ed Berg, geology instructor at the Kachemak Bay and Kenai River campuses of the Kenai Peninsula College-University of Alaska Anchorage. Based on years of study, Berg describes the Spit as the exposed part of an underwater moraine for a tidewater glacier. A well drilled near the end of the Spit helped pinpoint its origin.

"When you look at the well logs, you see about 300 feet of sand and gravel, which is what you would expect from a moraine," said Berg, who, along with his colleague, Dick Reger, a geologist from Soldotna, date the Spit at approximately 16,500 years old.

The last major glaciation to leave its mark on the Kenai Peninsula consisted of four periods: Moosehorn, Killey, Skilak and Elmendorf. It is the third, Skilak, that created the Spit, according to Reger. It also shaped Archimandritof Shoals, a large submarine fan on the seaward side of the moraine. Local mariners know this area by the green buoy that marks the shoals a mile west of the Spit.

During the Good Friday earthquake of 1964, the Homer Spit dropped seven feet.

"Five feet of that was due to compaction, just like at the beach when you fill a big tin can with sand and shake it down. It compacts," Berg said. The additional two-foot drop was due to tectonic subsidence.

Would the Spit disappear without human efforts, such as the riprap, large rocks, placed on its seaward side?

"It could go away," Berg said. "But it would take time."