Earthquakes Near Tonga – an update

Earthquakes near Tonga have continued at a steady rate since Thursday’s major earthquake, but their intensity has rapidly abated.

Data supplied by the US Geological Survey show that earthquakes near Tonga were occurring at the rate of 10 per day for Thursday and Friday, New Zealand time. However, their intensity has quickly diminished, with 70% being 4th magnitude events yesterday.

The earthquakes are distributed over depths varying between 15 and 58 kilometres.

A summary of data to hand including the main shock, with dates in NZ time, is as follows:
Thursday May 4 – M7 (1), M6 (1), M5 (6), M4 (2)
Friday May 5 – M7 (0), M6 (0), M5 (3), M4 (7)

For an earthquake that was virtually magnitude 8, the steady rate of events and rapid abatement in the strength of aftershocks seems unusual. However, it is possible that additional events for Thursday and Friday will be posted by USGS as time permits.

An update on the aftershock trend will be posted here in two days’ time, unless further information indicating a change comes to hand.

One Response to “Earthquakes Near Tonga – an update”

  1. Chris says:

    It has been a rather bizarre event all together. When was the last time anyone heard of a 7.8/7.9 (I think there is still some confusion as to the original magnitude) – without out the single loss of life, or a building even collapsing??

    Rather strange to have so few post-event earthquakes – but a good thing for the people of Tonga.

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