Mw 7.8 Portugal

On 27 December 1722 a major earthquake occurred in Portugal. The seismic event occurred between 17:00 and 18:00 LT and had an estimated magnitude (M) 7.8.

A series of planetary alignments occurred from 22 to 28 December, most notably Earth-Mercury-Mars on 22 December and Mercury-Venus-Neptune on 24 December converging with a Sun-Mercury-Uranus alignment. These alignments are well-known to precede major earthquakes. In addition, Venus aligned with the Sun and Jupiter in the morning of the 27th. A high lunar peak occurred on 22 December coinciding with Earth's alignment. However, no lunar peak of significance occurred in the 2-3 days before the earthquake.

Earth-Mercury-Mars        1722-12-22, 14:25:12  254°43'30"
Mercury-Venus-Neptune     1722-12-24,  6:41:19   59°29'19"
Sun-Mercury-Uranus        1722-12-24, 16:58:13  209°40'28"
Venus-Sun-Jupiter         1722-12-27, 10:41:47  262°32'09"
Venus-Sun-Saturn          1722-12-28, 22:03:38  264°54'53"

Moon-Earth-Jupiter        1722-12-22,  2:54:53  263°57'15"
Moon-Earth-Saturn         1722-12-22,  5:55:03  265°32'31"
Moon-Earth-Sun            1722-12-22, 23:33:33  274°48'02"
Moon-Earth-Venus          1722-12-26,  5:09:46  314°18'24"
					

SSGI COMMON graph of critical planetary (PG) and lunar (LG) geometry