Newshub Earthquake hits Tongan coast 26/06/2017 The quake measured 6.3 on the seismic scale. A 6.3 magnitude earthquake has hit an area about 200 kilometres northwest of Tonga. The quake hit at 5.42am this morning, at a depth of 40 kilometres. There have been no immediate reports of tsunami threat, damage or casualties. Newshub.