On 20th February, 1835, Charles Darwin was lying down in a wood having a rest in Valvidia, Southern Chile, when he experienced a major earthquake. A few weeks later, he described what happened in a letter home to his sister Caroline:
My dear Caroline,
[…] We are now on our road from Concepciòn.— The papers will have told you about the great Earthquake of the 20th of February.— I suppose it certainly is the worst ever experienced in Chili.— It is no use attempting to describe the ruins—it is the most awful spectacle I ever beheld.— The town of Concepcion is now nothing more than piles & lines of bricks, tiles & timbers—it is absolutely true there is not one house left habitable; some little hovels built of sticks & reeds in the outskirts of the town have not been shaken down & these now are hired by the richest people. The force of the shock must have been immense, the ground is traversed by rents, the solid rocks are shivered, solid buttresses 6–10 feet thick are broken into fragments like so much biscuit.— How fortunate it happened at the time of day when many are out of their houses & all active: if the town had been over thrown in the night, very few would have escaped to tell the tale. We were at Valdivia at the time the shock there was considered very violent, but did no damage owing to the houses being built of wood.— I am very glad we happened to call at Concepcion so shortly afterwards: it is one of the three most interesting spectacles I have beheld since leaving England—A Fuegian savage.—Tropical Vegetation—& the ruins of Concepcion— It is indeed most wonderful to witness such desolation produced in three minutes of time.
February 20th. - This day has been memorable in the annals of Valdivia, for the most severe earthquake experienced by the oldest inhabitant. I happened to be on shore, and was lying down in the wood to rest myself. It came on suddenly, and lasted two minutes, but the time appeared much longer. The rocking of the ground was very sensible. The undulations appeared to my companion and myself to come from due east, whilst others thought they proceeded from south-west: this shows how difficult it sometimes is to perceive the directions of the vibrations. There was no difficulty in standing upright, but the motion made me almost giddy: it was something like the movement of a vessel in a little cross-ripple, or still more like that felt by a person skating over thin ice, which bends under the weight of his body. A bad earthquake at once destroys our oldest associations: the earth, the very emblem of solidity, has moved beneath our feet like a thin crust over a fluid; - one second of time has created in the mind a strange idea of insecurity, which hours of reflection would not have produced. In the forest, as a breeze moved the trees, I felt only the earth tremble, but saw no other effect. Captain Fitz Roy and some officers were at the town during the shock, and there the scene was more striking; for although the houses, from being built of wood, did not fall, they were violently shaken, and the boards creaked and rattled together. The people rushed out of doors in the greatest alarm. It is these accompaniments that create that perfect horror of earthquakes, experienced by all who have thus seen, as well as felt, their effects. Within the forest it was a deeply interesting, but by no means an awe- exciting phenomenon. The tides were very curiously affected. The great shock took place at the time of low water; and an old woman who was on the beach told me that the water flowed very quickly, but not in great waves, to high- water mark, and then as quickly returned to its proper level; this was also evident by the line of wet sand. The same kind of quick but quiet movement in the tide happened a few years since at Chiloe, during a slight earthquake, and created much causeless alarm. In the course of the evening there were many weaker shocks, which seemed to produce in the harbour the most complicated currents, and some of great strength.
Witnessing such a powerful earthquake and its aftermath at first-hand, along with numerous subsequent observations, convinced Darwin that the whole western coast of South America was gradually rising. In this, he went further than Charles Lyell, who, in volume 1 of Principles of Geology—a book which Darwin devoured during the Beagle voyage—had claimed that a section of Chile's coast had undergone recent elevation. On his return to England, Darwin published his findings in The Proceedings of the Geological Society of London, in an 1837 paper entitled Observations of proofs of recent elevation on the coast of Chili, made during the survey of His Majesty's Ship Beagle commanded by Capt. FitzRoy R.N. This paper provided Lyell with considerable ammunition in an ongoing geological dispute he was having with George Bellas Greenough concerning evidence of elevation of the Chilean coast.
Lyell and Darwin were to become fast and close friends. The two men are buried next to each other in Westminster Abbey.