Reviewed by USGSChina50y ago
M4.3 earthquake 80 km NW of Jiangyou, China
Monday, August 23, 1976, 21:02:07 UTC · 32.349°N, 104.203°E
A magnitude 4.3 earthquake struck 80 km NW of Jiangyou, China on Monday, August 23, 1976, 21:02:07 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 4.3
- Light · mb
- Depth
- 33 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
393 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
33 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 50 km
USGS lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.1 on September 1, 1976. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 33 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.4101 km WNW of Jiangyou, ChinaAugust 25, 1933 · 67 km SW of this epicenter
- 6.9121 km NNW of Jiangyou, ChinaAugust 16, 1976 · 45 km N of this epicenter
- 6.794 km NNW of Jiangyou, ChinaAugust 23, 1976 · 16 km N of this epicenter
- 6.5128 km NNW of Kangding, ChinaMay 29, 1919 · 282 km SW of this epicenter
- 6.499 km NNW of Jiangyou, ChinaAugust 21, 1976 · 25 km N of this epicenter
- 6.3146 km NW of Jiangyou, ChinaNovember 9, 1960 · 67 km NW of this epicenter
- 6.261 km S of Tianshui, ChinaAugust 1, 1936 · 235 km NE of this epicenter
- 6.1127 km WNW of Jiangyou, ChinaMarch 14, 1938 · 73 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 23 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 34,320 recorded deaths. The most severe:
- 1879M8.0
Gansu Province
1 Jul 1879 · 105 km away · intensity XI
22,000 deathsExtreme damage ($25M+)
- 1933M7.4
Sichuan Province
25 Aug 1933 · 67 km away · intensity X
9,300 deathsExtreme damage ($25M+)
- 1765M6.5
Gansu Province: Wushan, Gangu
2 Sep 1765 · 282 km away · intensity IX
2,068 deathsExtreme damage ($25M+)
- 1881M6.5
Gansu Province
20 Jul 1881 · 144 km away · intensity VIII
480 deathsSevere damage ($5–24M)
- 1792M6.0
Sichuan Province: N Of Qianning
7 Sep 1792 · 297 km away · intensity VIII
205 deathsModerate damage ($1–5M)
- 1936M6.0
Gansu Province
1 Aug 1936 · 248 km away · intensity VIII
115 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.