The United States Geological Survey assigned the quake a preliminary magnitude estimate of 7.8 on the Moment magnitude scale, which was later increased to 8.0, and at the end settled on 7.9. The earthquake had its epicenter 165 km south of Neiafu, Tonga, or 2145 km northnortheast of Auckland, New Zealand. Since the earthquake occurred underwater, tsunami warnings were issued, but then lifted. Small, barely noticed aftershocks occurred at 06:56 and 08:28. In addition, the next night, around local midnight, an aftershock of magnitude 6. Such a relatively strong shock after such a long time is a quite exceptional occurrence. On the other hand, earthquakes happen so regularly in this area that the distinction between aftershock and next shock may blur.