On 9 May 2017 a strong earthquake occurred at Vanuatu at a depth of 186 km. The seismic event occurred at 13:52:12 UTC and had an estimated moment magnitude (Mw) 6.8.
Three planetary alignments from 6 to 9 May preceded the earthquake, most notably Mars-Mercury-Saturn and also Sun-Mercury-Saturn. Seismic activity could have been considerably larger with this planetary geometry, but from 23 January to 16 July Earth simply did not produce magnitude 7 earthquakes. It was one of the magnitude 7 droughts that characterized 2017, 2018 and 2019. The first lunar peak after the Mars-Mercury-Saturn alignment occurred on 7-8 May peaking 10, after which a Mw 6.4 earthquake occurred at the Andreanof Islands, Aleutian Islands. This lunar peak was almost immediately followed by a second peak reaching index 13 on the 9th converging with the critical planetary geometry on 8-9 May. Increased seismic activity continued with a Mw 6.0 early on the 9th at the Ryukyu Islands, Japan, followed by the strong earthquake at Vanuatu. Seismic activity continued in the low 6 magnitude range until the 15th. The next seismic increase began on 29 May with a Mw 6.6 earthquake when Earth aligned with Mars and Saturn.
Mars-Mercury-Saturn 2017-05-06, 6:51:28 263°22'12" Moon-Earth-Venus 2017-05-07, 2:58:19 4°25'30" Earth-Moon-Jupiter 2017-05-07, 22:37:44 194°31'51" Sun-Mercury-Saturn 2017-05-08, 16:24:45 263°07'34" Moon-Earth-Mercury 2017-05-08, 19:17:04 25°02'56" Moon-Earth-Uranus 2017-05-08, 20:23:28 25°36'35" Mars-Venus-Saturn 2017-05-09, 7:29:36 263°39'06"