The EI statues date from about 1250 AD to about 1500 AD
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The flaw in that theory is that many of the statues are buried 20 feet from the bottom to the surface. It takes more that a few centuries to have soil accumulate to that depth - more like thousands of years.
Erosion — with volcanic soil, rainy seasons twice a year, after all the trees were cut down. Most statues were not buried much if at all, and the earlier style statues are few.