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M7.7 earthquake, Tonga, 1981-09-01

MagnitudeM7.7ms

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Depth25 km

Time (UTC)1981-09-01 09:29

Rank in 19811 / 83among M6+

Rank since 1900266 / 14,458

Energy vs an M6×355approx.

133 km NE of Hihifo, Tonga · -14.96, -173.09

M6.5+ within 300 km (largest first)

2009 M8.1M8.1

1917 M8.0M8.0

1975 M7.8M7.8

1981 M7.7M7.7

1977 M7.6M7.6

2023 M7.6M7.6

1995 M7.4M7.4

1984 M7.2M7.2

2000 M7.2M7.2

1957 M7.1M7.1

1978 M7.0M7.0

1913 M6.9M6.9

Earlier M6+ within 300 km

Event	Time (UTC)	Depth	Place
M6.0 1981-06-01	1981-06-01 14:07	33 km	31 km SE of Hihifo, Tonga
M6.0 1980-10-09	1980-10-09 16:19	33 km	75 km NNE of Hihifo, Tonga
M6.2 1980-08-24	1980-08-24 20:10	39 km	82 km N of Hihifo, Tonga
M6.5 1980-06-18	1980-06-18 10:49	43 km	79 km NNE of Hihifo, Tonga
M6.0 1978-07-17	1978-07-17 13:26	292 km	182 km SSE of Mata-Utu, Wallis and Futuna
M6.4 1978-07-02	1978-07-02 04:01	25 km	194 km WNW of Hihifo, Tonga
M7.0 1978-06-17	1978-06-17 15:11	33 km	206 km SE of Hihifo, Tonga
M6.2 1978-06-11	1978-06-11 14:27	33 km	80 km NNE of Hihifo, Tonga
M6.2 1978-03-03	1978-03-03 10:48	33 km	79 km NNE of Hihifo, Tonga
M6.0 1977-09-13	1977-09-13 00:21	33 km	77 km NE of Hihifo, Tonga

Energy ratio uses the rule that one magnitude unit is about 32 times the energy. Magnitudes and locations are USGS values and can differ from national agencies. Older records are less complete and less precise.