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M6.6 earthquake, Alaska, 1978-04-12

MagnitudeM6.6ms

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Depth14 km

Time (UTC)1978-04-12 03:42

Rank in 197829 / 90among M6+

Rank since 19003469 / 14,458

Energy vs an M6×8approx.

94 km SSE of Old Harbor, Alaska · 56.42, -152.69

M6.5+ within 300 km (largest first)

2018 M7.9M7.9

1900 M7.9M7.9

1912 M7.1M7.1

1923 M7.0M7.0

1989 M7.0M7.0

1912 M7.0M7.0

1999 M7.0M7.0

1951 M6.9M6.9

1964 M6.9M6.9

2021 M6.9M6.9

2001 M6.9M6.9

2015 M6.8M6.8

Earlier M6+ within 300 km

Event	Time (UTC)	Depth	Place
M6.0 1974-08-01	1974-08-01 07:59	33 km	89 km SE of Old Harbor, Alaska
M6.3 1974-08-01	1974-08-01 05:55	33 km	94 km SE of Old Harbor, Alaska
M6.1 1974-08-01	1974-08-01 05:07	10 km	97 km SE of Old Harbor, Alaska
M6.4 1972-03-24	1972-03-24 03:38	70 km	77 km ESE of Chignik, Alaska
M6.6 1968-04-23	1968-04-23 20:29	19 km	124 km SSE of Halibut Cove, Alaska
M6.1 1966-04-16	1966-04-16 01:27	35 km	36 km ESE of Akhiok, Alaska
M6.2 1966-01-22	1966-01-22 14:27	27 km	125 km S of Akhiok, Alaska
M6.2 1965-12-22	1965-12-22 19:41	51 km	37 km NNW of Aleneva, Alaska
M6.8 1965-09-04	1965-09-04 14:32	29 km	17 km N of Ouzinkie, Alaska
M6.2 1965-06-23	1965-06-23 11:09	22 km	76 km SSE of Old Harbor, Alaska

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.