Between September 16 and 27, 1957, 200 earthquakes of intensity V ("Moderate") on the Mercalli scale were registered. On September 23, the ocean waters off the coast of Ponte dos Capelinhos began to boil, and the first vapours were witnessed around 6:30 a.m. one kilometre northwest of the lighthouse. A constant tremor could be sensed, at times reaching a Level IV on the Mercalli scale (MM-31). Three days later, the activity increased; black ash (to about 1400 m) and water vapour (to about 4000 m) rose west of the two "ilhéus" () off the coast. On September 27, beginning at about 6:45 in the morning, a submarine eruption, 300 m from Ponta dos Capelinhos (100 m from the "Ilhéus dos Capelinhos") began. Whale spotters at Costado da Nau, a few meters above the Capelinhos lighthouse, saw the ocean churning to the west and alerted the lighthouse keepers. On October 5: "...the clouds of clay likely rose about one kilometre in height and solid fragments...reaching an area of 1200 metres around..." The buildings in the area began to experience the first damages: windows were broken, tiles fell from the roofs. By the next day, the first ash-fall began on land; "in a few hours a black mat covered the extreme West of island...", reaching 2.5 kilometres from the crater, necessitating the evacuation of the settlements of Norte Pequeno and Canto. Initially, gases and pyroclastic explosions persisted until October 13, while gradually diminishing, but were rapidly replaced by violent explosions, lava bombs, ash and lava streaming into the sea. This intense eruption occurred until the end of October with constant ash raining on Faial, destroying cultural lands, inhibiting normal farming and forcing the residents from local villages to evacuate.