M6.9 earthquake 121 km NNW of Jiangyou, China

Monday, August 16, 1976, 14:06:45 UTC · 32.752°N, 104.157°E

A magnitude 6.9 earthquake struck 121 km NNW of Jiangyou, China on Monday, August 16, 1976, 14:06:45 UTC, at a depth of 16.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on August 25, 1933.

Magnitude: 6.9; Strong · ms
Depth: 16 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VII; Very strong (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

338 kilotons of TNT

That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.

Tectonic setting

433 km

from the nearest mapped plate boundary, between the Eurasian and Yangtze plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

16 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 100 km

USGS lists 9 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M6.7 on August 23, 1976. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 28 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 22 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 107,115 recorded deaths. The most severe:

1718M7.5
Gansu Province
19 Jun 1718 · 268 km away · intensity X
73,000 deathsExtreme damage ($25M+)
1879M8.0
Gansu Province
1 Jul 1879 · 71 km away · intensity XI
22,000 deathsExtreme damage ($25M+)
1933M7.4
Sichuan Province
25 Aug 1933 · 100 km away · intensity X
9,300 deathsExtreme damage ($25M+)
1765M6.5
Gansu Province: Wushan, Gangu
2 Sep 1765 · 241 km away · intensity IX
2,068 deathsExtreme damage ($25M+)
1881M6.5
Gansu Province
20 Jul 1881 · 103 km away · intensity VIII
480 deathsSevere damage ($5–24M)
1936M6.0
Gansu Province
1 Aug 1936 · 215 km away · intensity VIII
115 deathsSevere damage ($5–24M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers