The Mystery of Easter Island

Easter Island: Multiple Lessons Environmental Suicide (Diamond) or something else? Very Isolated Easter Island was annexed by Chile in 1888. It lies 3510 km west of the Chilean mainland. Easter Day in 1722 Imagine what the first Dutch explorers thought when they first accidentally sailed to Rapa Nui (Easter Island) and saw the statues.

Statistics Rapa Nui (Easter Island)is 5 hours (3600 km) by jet airplane from Chile (2000km from the closest inhabited island). The island is triangular and about 20

kilometers long. (27S) Some statues weigh over 100 tons (the largest were close to 10 meters high). Hundreds (887) of statues all around the island. How did it fall apart? There is clear evidence that Easter Island once was a heavily populated (perhaps 20,000 people) and rich society.

In 1772 the population was estimated at 2500 There is clear evidence that this big population collapsed and most of the population died. Collapse triggers? Natural or Culturally induced? Collapse Generic Story

Natives came originally from Polynesia -probably accidentally found Rapa Nui (Easter Island) while they were lost. Statues were built by natives cut from soft volcanic stone on the island. Society collapsed before the Europeans arrived caused by overpopulation and poor use of resources

Roughly triangular in shape with complex topography (locally isolated valleys) and has 3 major volcanoes. Geography Settlement of the Pacific

Islands 1000 B.C. 600 A.D. 500 B.C. 1200 A.D. 600 A.D. 800 A.D. The Pacific Islands were settled from the northwest, probably from Asia and Melanesia, in a series of

waves in westerly, then northerly (Hawaii) and southerly (New Zealand) directions 900 A.D. But maybe 400 AD and this is crucial to collapse Moai Easter Island has hundreds of large

stone statues (moai). 13-32 feet tall 10-87 tons in weight Thriving Population Evidence suggests that Easter Island had a large and rich thriving society.

Many house foundations (enough for 20-30K people) Agricultural Intensification (large composting pits, water dams, stone chicken houses, stone windbreaks) suggests a lot of food was needed and grown. Society was broken into 11-12 territories or clans (requires a critical mass population

For such fragmentation. ~800 people per square mile. No Collapse Rapa Nui (Easter Island) must have seemed like paradise to the first natives of perhaps 100 people. Forests Seafood Plenty of space Clues to Deterioration

Pollen in soil samples can show how plant life changes over time. Bones of animals show that less and less fish was eaten as time advanced. Bones of humans show evidence of cannibalism. A statue based economy

Constructed in 3 waves 1100 A.D. Statues grew larger and more elaborate as time went by some kind of clan one ups-manship fairly weird Economy centered around statue building Many roads Clan based niches in statue production Food production concentrated to free up

labor for statue construction Why so zealous? The stone on Easter Island is the best carving stone in the Pacific Society was isolated, so the energy expended in other Pacific societies (trading, raiding,

exploration, and colonization) was directed inward Chiefs got stature not by inter-island interaction but by competing for status by a game of statue one-upman-ship Later ones had a pukao, or large stone hat Clan based society, let each clan specialize so while each group had a monopoly on some item, trade between groups was the norm.

Statue Physics All these methods require the use of Logs How were they raised? 1. Transport, Raising, and Food Production issues suggest that many trees were cut down to provide for statue production and to clear land for food production. 2. When discovered in the early 1800s there were no trees on Easter Island 3. Did Deforestation lead to the collapse? An Abrupt end

Statue building, and the complex Easter Island society ended abruptly about 1600 A.D. Incomplete statues still embedded in quarry

Total number of moai on Easter Island: 887 Total number of maoi that were successfully transported to their final ahu locations: 288 (32% of 887) Total number of moai still in the Rano Raraku quarry: 397 (45%) Total number of moai lying 'in transit' outside of the Rano Raraku quarry: 92 (10%) Stone carving tools left to lie

Chicken houses abandonded Roads left in disrepair What happened? Collapse Standard Scenario Forests Gone No trees on island when discovered by Europeans Pollen analysis shows that indigenous palm trees were grown in the time of early settlers large areas given over to food production (upland farms) Food supply limited

upland farms abandoned analysis shows large game birds disappeared Large fish and seal bones also disappeared (no trees, no canoes, no deep water fishing) Fuel supply limited carbon tested early fires were trees, later fires were grasses Erosion soil eroded from base of statues,

Unrest In the last days statues of rival clans were torn down Reasons for collapse Cults formed and statues were built to worship the cults. Many trees were cut down in order to move the statues (log rolling compare to Stonehenge) Rats ate the seeds leaving the island without trees Boats slowly disappeared so people could no longer fish. The soil washed into the sea (tropical thunderstorms) because there were no trees no means to farm.

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