Reviewed by USGSChina100y ago
M7.7 earthquake 31 km SSW of Wuwei, China
Sunday, May 22, 1927, 22:32:50 UTC · 37.666°N, 102.493°E
A magnitude 7.7 earthquake struck 31 km SSW of Wuwei, China on Sunday, May 22, 1927, 22:32:50 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.7
- Major · mw
- Depth
- 15 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: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
5.4 megatons of TNT
That is about 355 times the Hiroshima bomb. It released about 11,220 times the energy of a magnitude 5.0.
Tectonic setting
780 km
from the nearest mapped plate boundary, between the Amur and Eurasian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
15 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 200 km
USGS lists 4 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.0 on May 23, 1927. 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 6 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.0139 km ENE of Baiyin, ChinaDecember 25, 1920 · 267 km E of this epicenter
- 6.275 km WNW of Xining, ChinaApril 12, 1921 · 165 km SW of this epicenter
- 6.1138 km SSW of Yinchuan, ChinaDecember 28, 1920 · 260 km E of this epicenter
- 6.0116 km SW of Yinchuan, ChinaJanuary 7, 1921 · 263 km E of this epicenter
- 5.9170 km ENE of Jinchang, ChinaMarch 22, 1918 · 204 km NE of this epicenter
- 5.783 km E of Xining, ChinaMay 22, 1927 · 110 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 288,872 recorded deaths. The most severe:
- 1920M8.3
Gansu Province, Shanxi Province
16 Dec 1920 · 277 km away · intensity XII
235,502 deaths$25 million damagetsunami
- 1927M7.7
Gansu Province
22 May 1927 · 0 km away · intensity XI
40,912 deathsExtreme damage ($25M+)
- 1921M6.2
Ningxia
12 Apr 1921 · 165 km away
10,000 deathsExtreme damage ($25M+)
- 1709M7.5
Ningxia
14 Oct 1709 · 249 km away · intensity X
2,032 deathsExtreme damage ($25M+)
- 1852M6.0
Ningxia
26 May 1852 · 239 km away · intensity VIII
300 deathsSevere damage ($5–24M)
- 1819M5.8
Qinghai Province
24 Feb 1819 · 175 km away · intensity VII
126 deathsModerate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.