The earthquakes were with magnitudes greater than or equal to four in which some were felt and some were not.
Tonga Geological Services said 22 were shallow-focus earthquakes with an average magnitude of 4.9.
13 were intermediate focus earthquakes with 4.7 average magnitude and 22 were deep-focus earthquakes with 4.4 average magnitudes.
The highest magnitude for earthquakes detected by the monitoring system in May was 6.5 and the lowest was 4.0.
There were two felt events reported for May.
Both of the earthquakes caused light ground shaking.
The first earthquake on 26 May was felt in Vava’u.
The second earthquake on 31 May was felt in Tongatapu.
No damages were reported from these events.