Approximately 1.5 nm from the Ponta do Seretta on the west coast of Terceira are the remains of a submarine volcano which erupted in the 19th century. The depths over this are given as 25 metres, but in a heavy swell from the south west through to north there may be breaking waves there and so it is best avoided. It would not be encountered on passages from Sao Jorge or Graciosa towards Angra do Heroismo on Terceira or to Praia do Vitoria around the south side of Terceira.