Um terramoto em 1767

Numa carta de 23 de Novembro de 1767 alguém descreveu o que terá sido um terramoto que se fez sentir em Macau...

"Last night, at 50 minutes after nine o'clock, we were all surprised with a heavy shock of an earthquake, which continued above a minute. This shock was so great that the house rocked, and I was afraid we were all going down into the bowels of the earth. Another sock we felt five minutes after eleven o'clock, but not so great: and at three this morning another pretty great. In all we have had five shocks, but the first was the greatest. It came with a rolling, and a dreadful night in the air; so that at first some people thought it to be the firing of guns, or thunder at some distance. At the firth shock I could hardly hold my feet; but, thank God, no bad accident has happened; and I hope the Almighty will deliver us from any more of the frightful shocks. I was up almost the whole night. The wind was northerly, but faint, and it was fury hot; the sky close and cloudy, and not a far to be seen. The oldest people here say, they never remember to have felt so violent shock, and of so long continuance. The ships in the harbour hooked and whirled about, and those on board imagined at first that it had been a whirlwind. "
Terá havido mesmo um terramoto em Macau? 
Dos livros que consultei sobre dados cronológicos do século 18 não encontrei qualquer referência. Pode ainda admitir-se que, não sendo época de tufões, estamos perante um fenómeno meteorológico de tal forma gravoso - em pleno Inverno - que a pessoa que o testemunhou admitiu tratar-se de um sismo quando talvez não tivesse sido mais do que uma grande tempestade... Será?...